BARRELS
XXXIII
Wednesday, October 21
st
Thursday, October 22
nd
Friday, October 23
rd
, 2020
Table of Contents
BARRELS XXXIII2020
Contents…………………………………………………………………………1
A Special Thanks……………………………………………………………….2
Barrels Program, Overview………..…………………………………………..3
Barrels Program/Invited Speakers & Platform Talks………………………..8
Poster Session Schedule………………………………………………………22
Poster Abstracts…………………………………….…………………………..23
Participant List…………………………………………………………………..32
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A SPECIAL THANK YOU to:
The Organizing Committee:
Solange Brown, MD, Ph.D., Johns Hopkins University
Joshua C. Brumberg, Ph.D., The Graduate Center and Queens College, CUNY
Randy Bruno, Ph.D., Columbia University
Mitra Hartmann, Ph.D., Northwestern University
S. Andrew Hires, Ph.D., University of Southern California
David Kleinfeld, Ph.D., University of California, San Diego
Dan O’Connor, Ph.D., Johns Hopkins University
Robert Sachdev, Ph.D., Humboldt University, Germany
Gordon Shepherd, MD, Ph.D., Northwestern University
Jochen Staiger, M.D., Georg-August-Universirtaet
Conference Support Assistance:
Drew Baughman
Esther Greeman
Gordon Petty
WELCOME TO Barrels XXXIII2020!
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BARRELS XXXIII Program
October 21
st
- October 23
rd
2020
The 33
rd
Annual Barrels Society Meeting
Wednesday, October 21 (All times EDT)
11:30 12:00 Check-in (Please login closer to 11:30 as you must be admitted to the meeting)
12:00 12:10 Welcome: Randy Bruno
Zuckerman Institute, Columbia University
12:10 1:00 Keynote 1: Silvia Arber, Introduced by Daniel Huber
FMI and University of Basel
Disentangling brainstem motor circuits
1:00 1:20 Coffee Break (randomized break-out rooms)
Session 1: Mouse forelimb as a model system
1:201:30 Moderator introduction: Gordon Shepherd
Northwestern University
1:302:00 Daniel Huber
University of Geneva
Do mice ‘hear’ with their limbs?
2:00 – 2:30 Alice Mosberger
Zuckerman Institute, Columbia University
Discovery and refinement of forelimb actions in mice
2:303:00 Abigail Person
University of Colorado
Beyond learning: the cerebellum and predictive control
3:00 3:20 Discussion
3:203:40 Coffee Break (randomized break-out rooms)
Short Platform Talks 1 (10 min including questions)
Moderated by Mitra Hartmann, Northwestern University
3:40 3:50 Nicholas E. Bush
Seattle Children's Research Institute
Continuous, multidimensional coding of 3D complex tactile stimuli by
primary sensory neurons of the vibrissal system
3:50 4:00 Krithiga Aruljothi
UC Riverside
Functional Localization of an Attenuating Filter within Cortex for a Selective
Detection Task in Mice
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4:00 4:10 Christian Waiblinger
Georgia Institute of Technology
The comeback of S1 A journey from sensory representation to behavioral
flexibility
Moderated by Christopher Moore, Brown University
4:10 4:20 Yaroslav Sych
Brain Research Institute, University of Zurich
Mesoscale brain dynamics reorganizes and stabilizes during learning
4:20 4:30 Valerie Ego-Stengel
NeuroPSI, CNRS
Cortical closed-loop brain-machine interface requires biomimetic sensory
feedback
4:30 4:40 Scott Pluta
Purdue University
Sensorimotor integration in the superior colliculus during whisker-guided
orienting behavior
4:40 6:00 Virtual Poster Session
Thursday, October 22 (All times EDT)
11:30 12:00 Check-in (Please login closer to 11:30 as you must be admitted to the meeting)
Session 2: Active sensation
12:0012:10 Moderator introduction: Solange Brown
Johns Hopkins University
12:10 12:40 David Kleinfeld
University of California, San Diego
The coordinates of active vibrissa touch and their representation in L4 of vS1
cortex
12:401:10 Soohyun Lee
National Institute of Mental Health
Brain-wide neural networks of movement-encoding neurons in the primary
somatosensory cortex
1:10 – 1:40 Daniel O’Connor
Johns Hopkins University
Active tongue sensing
1:40 – 2:10 Carl Petersen
EPFL, Switzerland
Cholinergic modulation of wS1 during whisking
2:10 – 2:30 Discussion
2:30 – 2:50 Coffee Break (randomized break-out rooms)
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Short Platform Talks 2 (10 min including questions)
Moderated by Joshua Brumberg (CUNY)
2:50 – 3:00 Jung M Park
Zuckerman Institute, Columbia University
Deep and superficial layers of the primary somatosensory cortex are
indispensable for whisker-based texture discrimination in mice
3:00 3:10 Lara Rogerson-Wood
The University of Sydney
Enhanced targeted microglial-mediated-phagocytosis underlies environmental
enrichments capacity to facilitate the corrective remodeling of a murine
subcortical axonal-guidance defect
3:10 3:20 Ben Efron
Weizmann Institute of Science
Auditory response to sounds originating from whisking against objects
Moderated by Cornelius Schwarz (Univ Tuebingen)
3:20 3:30 Silvana Valtcheva
New York University School of Medicine
Hypothalamic oxytocin neurons respond to infant vocalizations via
noncanonical auditory pathway
3:30 3:40 Tamura Keita
Brain Mind Institute, EPFL
Cortical signal flow during sensorimotor transformation in a whisker
detection and delayed lick task
3:40 3:50 Ewoud Schmidt
Zuckerman Institute, Columbia University
A human-specific modifier of cortical circuit connectivity and function improves
sensory discrimination in mice
Moderated by Garrett Stanley (Georgia Tech)
3:50 4:00 Yasir Gallero-Salas
Brain Research Institute, University of Zurich
Sensory and behavioral components of neocortical signal flow in tactile
and auditory discrimination tasks with short-term memory
4:00 4:10 Cameron Condylis
Boston University
Multiplexed functional and transcriptional readout of mouse primary
somatosensory cortex during behavior
4:10 4:20 Christian L. Ebbesen
New York University
Automatic tracking of mouse social posture dynamics by 3D videography, deep
learning and GPU-accelerated robust optimization
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4:20 4:30 Jim McBurney-Lin
University of California, Riverside
Bidirectional pharmacological perturbations of the noradrenergic system
differentially affect tactile detection
4:30 6:00 Virtual Poster Session
Friday, October 23 (All times EDT)
11:30 12:00 Check-in (Please login closer to 11:30 as you must be admitted to the meeting
12:00 12:50 Keynote 2: Nadine Gogolla, Introduced by Robert Sachdev
Max Planck Institute, Martinsried
Facial expressions and their neuronal correlates in mice
12:50 1:00 Coffee Break (randomized break-out rooms)
Session 3: Reorganization of neuronal representations
1:001:10 Moderator introduction: Dan Feldman
University of California, Berkeley
1:10 1:40 Andrew Hires
University of Southern California
Behavioral and neuronal bases of tactile shape discrimination learning in
head-fixed mice
1:40 2:10 Simon Peron
New York University
Barrel cortex dynamics during optical microstimulation task training
2:10 2:40 Carsen Stringer
Janelia Research Campus
A neural atlas of multi-dimensional behavioral representations
2:40 – 3:00 Discussion
3:00 3:20 Coffee Break
Short Platform Talks 3 (10 min including questions)
Moderated by Robert Sachdev (Humboldt University)
3:203:30 Nathaniel C. Wright
Georgia Institute of Technology
Rapid sensory adaptation in the mouse thalamocortical circuit during
wakefulness, and the relative contribution of thalamic state
3:30 3:40 Jan Jabłonka
University of Warsaw
Interhemispheric interactions participate in the cortical plasticity
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3:40 3:50 Marcel Oberlaender
Max Planck Society
Thalamus gates top-down modulation of cortical output
Moderated by Kate Hong (Carnegie Mellon University)
3:50 4:00 Mikkel Vestergaard
Max-Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC)
The cellular coding of temperature in the mammalian cortex
4:004:10 Alan Urban
Neuro-Electronics Research Flanders
A platform for brain-wide functional ultrasound imaging and analysis of
circuit dynamics in behaving
4:10 4:20 Yuri Vlasov
University of Illinois at Urbana-Champaign
High-frequency whisker vibrations above 1KHz - are they relevant to perception?
4:20 4:30 Wrap-up discussion & Poll
4:30 6:00 Virtual Poster Session
ADJOURN
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BARRELS XXXIII Program
October 21
st
- October 23
rd
2020
The 33
rd
Annual Barrels Society Meeting
Wednesday, October 21 (All times EDT)
11:30 12:00 Check-in (Please login closer to 11:30 as you must be admitted to the meeting)
12:00 12:10 Welcome: Randy Bruno
Zuckerman Institute, Columbia University
12:10 1:00 Keynote 1: Silvia Arber, Introduced by Daniel Huber
FMI and University of Basel
Disentangling brainstem motor circuits
1:00 1:20 Coffee Break (randomized break-out rooms)
Session 1: Mouse forelimb as a model system
1:20 1:30 Moderator introduction: Gordon Shepherd
Northwestern University
1:302:00 Daniel Huber
University of Geneva
Do mice ‘hear’ with their limbs?
I will present our most recent studies suggesting that pallesthesia (the sense of vibrations) and hearing have
much more in common than previously thought. Our data shows that substrate vibrations are not perceived
simply as frequencies, but also as "pitch", similar to hearing. More importantly, we were able to reveal the
common computational principle of how physical stimulus attributes influence the perception of vibro-tactile
pitch: Using matched psychophysical experiments in mice and humans forelimbs we demonstrate that pitch
perception is shifted with increases in amplitude toward the frequency of highest vibrotactile sensitivity in both
species. Vernon Mountcastle's V-shaped somatosensory sensitivity curves are thus put into a very new
perspective.
2:00 2:30 Alice Mosberger
Zuckerman Institute, Columbia University
Discovery and refinement of forelimb actions in mice
Many actions are learned from reinforcement by assigning credit to successful movements. For
complex, continuous movements, this process allows the gradual refinement of an action into a
skill. The neural mechanism of such refinement is only poorly understood as it has not been
studied in an animal model that allows functional circuit dissection.
Classical rodent studies on reinforcement have used discrete action choice tasks that
measure changes in the rate of the correct action, but cannot resolve changes in the shape of the
movement itself a hallmark of refinement.
To overcome this, I have developed a novel task, in which head-fixed mice move a low-friction
planar joystick. Here mice generate complex trajectories with their forelimb while searching for a
hidden reinforced target location. Using pure outcome reinforcement, mice learn to efficiently
move the joystick into different targets by refining trajectory shape.
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Using this task, I am dissecting the neural mechanism of refinement through reinforcement.
Classically, learning from reinforcement is thought to be implemented in the corticostriatal
circuitry. Sensorimotor cortex is proposed to convey a motor command to striatum, that is
assigned with credit by dopamine-dependent plasticity. But projections from cortex to striatum are
heterogeneous, spanning multiple cortical areas and distinct cell types (pyramidal tract (PT) and
intratelencephalic (IT) neurons). It is currently unknown which of these are reinforced to allow
refinement of the shape of a continuous action.
I have anatomically characterized this forelimb corticostriatal network in the mouse and am
currently decoding the cortical motor commands that are sent to striatum during continuous
forelimb movements using my joystick task. Together with optogenetic probing of the necessity
of the corticostriatal motor command for action refinement, these experiments bring us closer to
understanding the mechanisms and circuitry for reinforcement learning.
2:30 3:00 Abigail Person
University of Colorado
Beyond learning: the cerebellum and predictive control
The cerebellum is well appreciated to impart speed, smoothness, and precision to skilled movements such as
reaching. How these functions are executed by the final output stage of the cerebellum, the cerebellar nuclei,
remains unknown. In this talk, I will discuss our data identifying a causal relationship between cerebellar output
and mouse reach kinematics and show how that relationship is leveraged endogenously to enhance reach
precision. I will discuss how our results provide a framework for understanding the physiology and
pathophysiology of the intermediate cerebellum during precise skilled movements.
3:003:20 Discussion
3:20 3:40 Coffee Break (randomized break-out rooms)
Short Platform Talks 1 (10 min including questions)
Moderated by Mitra Hartmann, Northwestern University
3:40 3:50 Nicholas E. Bush, Mitra J.Z. Hartmann, Sara A. Solla
Seattle Children's Research Institute, Northwestern University
Continuous, multidimensional coding of 3D complex tactile stimuli by
primary sensory neurons of the vibrissal system
In the rodent vibrissal system, responses of primary sensory neurons in the trigeminal ganglion (Vg) have long
been thought to segregate into functional classes. However, this view is based on studies that have used only
2D analyses and restricted stimulus sets. Here we begin to reveal the full representational capabilities of Vg
neurons by recording their responses to complex 3D stimulation while quantifying the complete 3D whisker
shape and mechanics. Results show that individual Vg neurons simultaneously represent multiple mechanical
features of the stimulus, do not preferentially encode principal components of the stimuli, and represent
continuous and tiled variations of all available mechanical information. These results directly contrast with
proposed codes in which subpopulations of Vg neurons encode select stimulus features. Instead, individual Vg
neurons likely encode large regions of the complex sensory space. This proposed tiled and multidimensional
representation at the Vg directly constrains the computations performed by more central neurons of the
vibrissotrigeminal pathway. Funding: R01-NS093585 to M.J.Z.H. and S.A.S., F31-NS092335 to N.E.B.
3:50 4:00 Krithiga Aruljothi, Krista Marrero, Zhaoran Zhang, Behzad Zareian, Edward Zagha
UC Riverside
Functional Localization of an Attenuating Filter within Cortex for a Selective
Detection Task in Mice
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An essential feature of goal-directed behavior is the ability to selectively respond to the diverse stimuli in one's
environment. However, the neural mechanisms that enable us to respond to target stimuli while ignoring
distractor stimuli are poorly understood. To study this sensory selection process, we trained male and female
mice in a selective detection task in which mice learn to respond to rapid stimuli in the target whisker field and
ignore identical stimuli in the opposite, distractor whisker field. In expert mice, we used widefield Ca2+ imaging
to analyze target-related and distractor-related neural responses throughout dorsal cortex. For target stimuli,
we observed strong signal activation in primary somatosensory cortex (S1) and frontal cortices, including both
the whisker region of primary motor cortex (wMC) and anterior lateral motor cortex (ALM). For distractor
stimuli, we observed strong signal activation in S1, with minimal propagation to frontal cortex. Our data support
only modest subcortical filtering, with robust, step-like attenuation in distractor processing between mono-
synaptically coupled regions of S1 and wMC. This study establishes a highly robust model system for studying
the neural mechanisms of sensory selection and places important constraints on its implementation. Funding:
Whitehall Foundation (Research 18 Grant 2017-05-71 to E.Z.) and the National Institutes of Health
(R01NS107599 to E.Z.)
4:00 4:10 Christian Waiblinger, Michael F Bolus, Peter Y Borden, Garrett B Stanley.
Georgia Institute of Technology, Emory University
The comeback of S1 A journey from sensory representation to behavioral
flexibility
Behavioral flexibility is crucial for survival in a constantly changing environment. What are the neuronal
processes that recalibrate perception and transform a stimulus into an action? The mouse model has
become indispensable for answering this question, yet it is still unclear whether components associated with
learning and behavior emerge in the early sensory system or elsewhere. Here, we investigate perceptual
changes in the S1 of the mouse during learning and behavioral adaptation. We performed chronic wide-field
imaging with a genetically encoded voltage indicator (GEVI) in mice undergoing a sequence of
psychophysical tests including a learning phase and a detection task for controlled whisker deflections with
changing sensory contingencies. Our results reveal that S1 correlates with behavioral changes in a way that
is experience dependent. During learning, S1 sensitivity is mostly stimulus driven and resistant to changes in
performance, reflective of a relatively static sensory representation of whisker inputs. However, once an
animal reaches expert level and is challenged with a change in stimulus statistics, S1 activity exhibits clear
changes in the representation of the same vibrissa input in different contexts. The change is more
pronounced at a later training stage with more experience. This suggests that the role of S1 in detection
behavior is dynamic and dependent upon the nature of the task and its context. Funding: NIH R01NS085447,
R01NS104928, U01NS094302
Moderated by Christopher Moore, Brown University
4:10 4:20 Yaroslav Sych, Aleksejs Fomins, Leonardo Novelli, and Fritjof Helmchen*
Brain Research Institute, Neuroscience Center, University of Zurich.
Mesoscale brain dynamics reorganizes and stabilizes during learning
Adaptive behavior is coordinated by neuronal networks that are distributed across multiple brain regions.
How cross-regional interactions reorganize during learning remains elusive. We applied multi-fiber
photometry to chronically record simultaneous activity of 12-48 mouse brain regions while mice learned a
tactile discrimination task. We found that with learning most regions shifted their peak activity from reward-
related action to the reward-predicting stimulus. We corroborated this finding by functional connectivity
estimation using transfer entropy, which revealed growth and stabilization of mesoscale networks
encompassing basal ganglia, thalamus, cortex, and hippocampus, especially during stimulus presentation.
The internal globus pallidus, ventromedial thalamus, and several regions in frontal cortex emerged as hub
regions. Our results highlight the cooperative action of distributed brain regions to establish goal-oriented
mesoscale network dynamics during learning.
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4:20 4:30 Aamir Abbasi, Luc Estebanez, Dorian Goueytes, Henri Lassagne, Daniel E. Shulz,
Valerie Ego-Stengel
NeuroPSI, CNRS and University Paris-Saclay, France
Cortical closed-loop brain-machine interface requires biomimetic sensory
feedback
New and improved neuroprosthetics offer great hope for motor-impaired human patients to regain autonomy.
One obstacle facing current technologies is that fine motor control requires near-instantaneous somatosensory
feedback. The way forward is to artificially recreate the rich, distributed feedback generated by natural
movements. Here, we hypothesize that incoming sensory feedback needs to follow biomimetic rules in order to
be efficiently integrated by motor circuits. We have developed a rodent closed-loop brain-machine interface
where head-fixed mice were trained to control a virtual cursor by modulating the activity of motor cortex
neurons. Artificial feedback consisting of precise optogenetic stimulation patterns in the primary
somatosensory cortex coupled to the motor cortical activity was provided online to the animal. We found that
learning occurred only when the feedback had a topographically biomimetic structure. Shuffling the
spatiotemporal organization of the feedback prevented learning the task. These results suggest that the
patterns of inputs that are structured by the body map present in the primary somatosensory cortex of all
mammals are essential for sensorimotor processing and constitute a backbone that needs to be considered
when optimizing artificial sensory feedback for fine neuroprosthetic control. Funded by FRM (Equipe FRM
DEQ20170336761), CNRS (80|Prime), ANR Neurowhisk, Lidex NeuroSaclay, Idex Brainscopes and iCODE,
and FRC (AAP 2018).
4:30 4:40 Scott Pluta
Purdue University
Sensorimotor integration in the superior colliculus during whisker-guided
orienting behavior
Spatial attention involves the parallel integration of multiple, disparately organized neural circuits. These
disparate circuits ultimately converge onto the midbrain superior colliculus (SC), where individual neurons
encode the location of stimuli, sustain working memory and initiate overt movements. However, the role of the
SC in active, somatosensory-guided movements is largely unknown. Since mice do not track objects by
moving their eyes, somatosensory-guided whisker movements provide a unique opportunity for greatly
advancing our mechanistic understanding of overt spatial attention. To probe this topic, we recorded spiking
from the SC while mice used their whiskers to explore the surface of a dynamically moving object. Mice
dynamically optimized their whisking set-point and amplitude to track object movement. Many neurons in the
SC responded to surface movement with an increase in spiking, while others decreased their activity, in a
location-dependent manner. Overall, we observed a clear preference for a particular trajectory of surface
movement. Trajectory tuning was consistent with neuron-specific preferences for whisker curvature and phase
during touch. Spiking in a subset of neurons located in the deepest, motor layer of the SC predicted whisk
amplitude. Overall, these data help establish the rodent whisker system as a valuable model for dissecting the
neural circuits underlying overt spatial attention.
4:40 6:00 Virtual Poster Session
Thursday, October 22 (All times EDT)
11:30 12:00 Check-in (Please login closer to 11:30 as you must be admitted to the meeting)
Session 2: Active sensation
12:00 12:10 Moderator introduction: Solange Brown
Johns Hopkins University
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12:10 12:40 David Kleinfeld
University of California, San Diego
The coordinates of active vibrissa touch and their representation in L4 of vS1
cortex
I will present preliminary behavioral data showing that the angle of vibrissa contact with an object, known to be
proportional to contact force, is also proportional to phase in the whisk cycle. This proportionality among three
quantities resolves many of the discrepancies reported across different laboratories for the decoding of active
touch by the vibrissae. I will further present preliminary data from glutamate imaging studies showing that
individual thalamocortical boutons, known to form an ordered arranged for each vibrissa within L4, represent
touch by phase in the whisk cycle. Similar results are seen in preliminary data from voltage imaging of L4
excitatory cells. We suggest that the phase preference of L4 neurons can function as a labeled line to identify
contact angle; the role of L4 cells in directing read-out and feedback control is under investigation. Work by Rui
Liu in collaboration with Amalia Callado Perez, Martin Deschênes, and Pantong Yao. Supported by NINDS
grants NS097265 and NS107466.
12:40 1:10 Soohyun Lee
National Institute of Mental Health
Brain-wide neural networks of movement-encoding neurons in the primary
somatosensory cortex
Principal neurons in the primary sensory cortices exhibit heterogeneous patterns of activity, not only in
response to sensory stimuli but also, during spontaneous movements. Yet, how these heterogeneous,
behavioral state-dependent patterns of activity arise is largely unknown. Longitudinal two-photon calcium
imaging uncovered a remarkably stable correlation between the activity of principal neurons in layers II/III of
primary somatosensory cortex and spontaneous movements. This population activity could reliably predict
spontaneous movements, but with a subset of neurons accounting for most of the prediction accuracy. The
activity of movement-encoding neurons cannot be explained by sensory feedback, as paralysis of the
contralateral whisker pad did not disrupt correlation with ipsilateral whisker movements and locomotion. During
pharmacological blockade of neuromodulators, the activity levels were altered, but the correlation of neuronal
activity with spontaneous movements was largely maintained. By contrast, glutamatergic transmission blockers
nearly abolished this correlation. Single cell-initiated monosynaptic retrograde tracing and whole-brain
presynaptic network analysis revealed that movement-encoding neurons receive characteristic subcortical
inputs. Our study provides a connectivity rule that supports the representation of spontaneous movements in
the primary somatosensory cortex. Funding: NIH Intramural Research Program.
1:10 1:40 Daniel O’Connor
Johns Hopkins University
Active tongue sensing
The brain generates complex sequences of movements that can be flexibly reconfigured in real-time based on
sensory feedback, but how this occurs is not fully understood. We developed a novel ‘sequence licking’ task in
which mice directed their tongue to a target that moved through a series of locations. Mice could rapidly
reconfigure the sequence online based on tactile feedback. Closed-loop optogenetics and electrophysiology
revealed that tongue/jaw regions of somatosensory (S1TJ) and motor (M1TJ) cortex encoded and controlled
tongue kinematics at the level of individual licks. Tongue premotor (anterolateral motor, ALM) cortex encoded
intended tongue angle in a smooth manner that spanned individual licks and even whole sequences, and
progress toward the reward that marked successful sequence execution. ALM activity regulated sequence
initiation, but multiple cortical areas collectively controlled termination of licking. Our results define a functional
cortical network for hierarchical control of sensory- and reward-guided orofacial sequence generation.
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1:40 2:10 Carl Petersen
EPFL, Switzerland
Cholinergic modulation of wS1 during whisking
Rodents actively acquire tactile information about object location, shape and texture by moving their mystacial
whiskers back and forth to scan their immediate facial environment. There are obvious differences in neuronal
activity comparing periods of active whisker sensing (whisking) and periods of quiet wakefulness (when the
whiskers are not moving). Previous work reported that increased thalamic (Poulet et al., 2012) and cholinergic
(Eggermann et al., 2015) input to wS1 might be key drivers of the changes in cortical state induced by whisking
(Crochet & Petersen, 2006; Poulet & Petersen, 2008). In this talk, I will focus on the impact of acetylcholine
released during whisking upon distinct cell-types in layer 2/3 of mouse barrel cortex. We made two-photon
targeted whole-cell membrane potential recordings from excitatory neurons and various types of genetically-
defined subtypes of GABAergic neurons. We found that VIP neurons (but not 5HT3AR-non-VIP neurons, PV
neurons, SST neurons or excitatory neurons) received a prominent nicotinic excitation during active whisking
and in response to whisker deflection. VIP neurons are typically considered to play a disinhibitory role in
cortical function through their inhibition of SST and PV neurons. To test this hypothesis, we carried out
pharmacological and optogenetic manipulations revealing likely important contributions of cholinergic-driven
VIP-mediated disinhibition to whisker sensory processing. Increased acetylcholine concentrations during active
sensorimotor processing may help integration of top-down and motor-related signals in wS1, as well as
promoting synaptic plasticity, for example enhancing fire-together-wire-together synaptic plasticity between
neurons in interacting cortical regions during goal-directed sensorimotor learning.
2:10 2:30 Discussion
2:30 2:50 Coffee Break (randomized break-out rooms)
Short Platform Talks 2 (10 min including questions)
Moderated by Joshua Brumberg (CUNY)
2:50 3:00 Jung M Park, Y. Kate Hong*, Chris C, Rodgers*, Jacob B. Dahan, Ewoud RE Schimdt,
Randy Bruno
Zuckerman Institute, Columbia University. *Contributed equally as co-second authors
Deep and superficial layers of the primary somatosensory cortex are
indispensable for whisker-based texture discrimination in mice
The neocortex, comprised of multiple distinct layers, processes sensory input from the periphery, makes
decisions, and executes actions. Despite extensive investigation of cortical anatomy and physiology, the
contributions of different cortical layers to sensory guided behaviors remain unknown. Here, we developed a
two-alternative forced choice (2AFC) paradigm in which head-fixed mice use a single whisker to either
discriminate textures of parametrically varied roughness or detect the same textured surfaces. Lesioning the
barrel cortex revealed that 2AFC texture discrimination, but not detection, was cortex-dependent. Paralyzing
the whisker pad had little effect on performance, demonstrating that passive can rival active perception and
cortical dependence is not movement-related. Transgenic Cre lines were used to target inhibitory opsins to
excitatory cortical neurons of specific layers for selective perturbations. Both deep and superficial layers were
indispensable for texture discrimination. We conclude that even basic cortical computations require
coordinated transformation of sensory information across layers. Funding was provided by NIH R01 NS094659
(RMB); NSF GRFP and T32NS064928 (JMP); NIH F32 NS084768 and T32 MH015174 (YKH); and NIH F32
NS096819, Kavli Institute Postdoctoral Fellowship, and Brain & Behavior Research Foundation Young
Investigator Award (CCR).
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3:00 3:10 Lara Rogerson-Wood, Atomu Sawatari, Catherine A. Leamey
The University of Sydney
Enhanced targeted microglial-mediated-phagocytosis underlies environmental
enrichments capacity to facilitate the corrective remodeling of a murine
subcortical axonal-guidance defect
Our lab has shown murine environmental enrichment (EE) from birth partially corrects a subcortical miswiring
caused by removal of an axonal-guidance cue (Ten-m3) with, an associated rescue of visually mediated
behavior. This effect appeared mediated by ectopic projection removal after target (rostral dLGN) innervation.
Further, comparison of effect magnitude at 6 weeks-postnatal (wp) with 3.5 wp indicated this mechanism was
active at 3.5 wp, although the cellular mechanisms were unclear. We hypothesized that microglia an
immune cell with key roles in structural plasticity mediated this through targeted phagocytosis of ectopic
projections. Observation of microglia was undertaken at 3.5 wp in the rostral dLGN of standard-housed Ten-
m3 knock-out mice (SH-KOs; n=5) and those enriched from birth (EE-KOs; n=5). Microglia localized around
the characterized site of projection removal displayed a distinct-phenotype in EE-KOs; Quantitative
comparison with SH-KOs revealed these microglia had an enhanced phagocytic-like profile increased
density (p=.038) and CD68 expression (p=.011) and, a more ameboid morphology (p=.009) and, elevated
levels of phagocytosis - increased density (p=.001) and proportion (p=.003) of projection-containing microglia
and, an increased phagocytosed volume per microglial volume (p=0.016). These results support a model
whereby EE elicits the corrective re-modelling of this subcortical miswiring through enhancing targeted
microglial phagocytosis.
3:10 3:20 Ben Efron, Yonatan Katz and IIan Lampl
Weizmann Institute of Science
Auditory response to sounds originating from whisking against objects
Integration of information from different sensory modalities is essential for faithful representation of the world.
We studied the implications of active whisking sensation in the auditory system of mice and showed that it can
sense sounds resulting from whiskers touching an object, thus the vibrissa system can be used as an audio-
tactile system. We hypothesized that when mice whisk against objects they produce-audible noise. To test this,
we recorded sounds produced when whiskers actively contact objects. We found that when mice whisk against
certain objects, whisking-contact events produce audible broadband sounds. We then asked if these whisking-
touch induced sounds could elicit response in the auditory system. Towards this goal, we recorded activity in
the primary auditory cortex and in the inferior colliculus. To determine that any response is purely auditory we
severed the infra orbital nerve which conveys information from the whiskers to the CNS. Despite the loss of
tactile sensation, we found cells that responded precisely to whisking-touch events. We also muted the noise
produced from an object and presented the mouse with both the muted and unmuted objects. Although tactilely
identical, contacts made with the unmuted objects elicited a much stronger neuronal response in auditory
neurons. These novel findings are potentially relevant to the ethology of rodents that actively explore their
environment by whisking and for understanding of multi-modal integration.
Moderated by Cornelius Schwarz (Univ Tuebingen)
3:20 3:30 Silvana Valtcheva, Habon Issa and Robert C. Froemke
Skirball Institute, New York University School of Medicine
Hypothalamic oxytocin neurons respond to infant vocalizations via
noncanonical auditory pathway
Babies are “sensory traps” for mothers which are highly sensitive to infant needs. We recently showed that
core aspect of maternal behavior, pup retrieval in response to infant vocalizations, is shaped by the interplay
between innate preferences and active learning of auditory cues from pups, facilitated by the neurohormone
oxytocin (OT) (Schiavo, Valtcheva et al., Nature, accepted). Release of OT from hypothalamus might help
the recognition of pup calls but it is unclear how auditory infant stimuli are integrated in OT neurons. Here we
performed in vivo patch-clamp from optically-identified OT neurons in awake maternal mice. OT neurons, but
not other hypothalamic cells, increased their firing rate after pup calls. Using anatomical tracing and slice
physiology, we identified the brain areas (including posterior intralaminar thalamus) relaying acoustic
information to OT neurons. In hypothalamic slices, we mimicked high-frequency thalamic discharge, via
15
optogenetic stimulation, which led to long-term depression of synaptic inhibition and decreased inhibition to
excitation ratio in OT neurons. Increased firing of OT neurons after pup calls in vivo is likely mediated by
disinhibition. When thalamic projections to hypothalamus were inhibited, maternal mice exhibited longer
latencies to retrieve pups, suggesting that the thalamus-hypothalamus noncanonical auditory pathway may
be a specific circuit for disinhibiting OT neurons, gating OT release, and speeding up maternal behavior.
3:30 3:40 Tamura Keita, Esmaeili Vahid, Crochet Sylvain, Petersen Carl.
Brain Mind Institute, Ecole Polytechnique Federale de Lausanne (EPFL)
Cortical signal flow during sensorimotor transformation in a whisker
detection and delayed lick task
We use sensory cues to make appropriate behavior, but the circuit mechanisms converting a sensory input to
a motor output remain to be elucidated. Here, we performed wide-field Ca2+ imaging in mice performing a
task where mice detected a brief whisker deflection, and reported it by licking a spout after a 1-s delay period
that ended with an auditory stimulus. We trained transgenic mice expressing RCaMP in cortical pyramidal
neurons, and longitudinally observed their activity across learning. In correct hit trials, the whisker cue evoked
activation in whisker S1 cortex within 30 ms, followed by whisker S2 within 40 ms, whisker M1/M2, parietal
and retrosplenial cortices within 60 ms, with several areas showing enhancement in expert compared to
novice mice. In striking contrast, S1 and M1 cortices for tongue/jaw (tjS1/M1) in experts sharply decreased
the activity within 80 ms, which might reflect suppression of premature licks. Along the delay period,
sustained activity became prominent in M2 cortices for whisker as well as tongue/jaw in experts. After
auditory-evoked response in A1 cortex, tjS1/M1 developed a prominent activity reflecting the licking. These
results suggest that whisker sensory information was initially rapidly distributed across cortex and then
converged on the M2 cortices for preparing a motor command. Combining optogenetic manipulations
together with wide-field imaging will further reveal how cortico-cortical connections change to produce a
specific behavior.
3:40 3:50 Ewoud Schmidt, Hanzhi Teresa Zhao, Jung Park, Jacob Dahan, Chris Rodgers,
Elizabeth Hillman, Randy Bruno, Franck Polleux
Zuckerman Institute, Kavli Institute for Brain Science, Columbia University
A human-specific modifier of cortical circuit connectivity and function improves
sensory discrimination in mice
Human cortical pyramidal neurons (PNs) are characterized by increased synaptic density and prolonged
synaptic maturation. These features are thought to be critical for human cognition by increasing neuronal
connectivity, including increased feedforward and feedback connectivity. However, we lack insight into how this
connectivity emerged and how it contributes to human cognition. We identified a human gene, SRGAP2C, that
in mouse cortical PNs induces traits in synaptic development similar to those found in humans. Using a novel
implementation of monosynaptic tracing to map inputs from the whole brain onto layer 2/3 PNs in the barrel
cortex, we discovered that SRGAP2C selectively increases cortical feedforward and feedback connectivity. In
vivo 2-photon Ca2+ imaging in the barrel cortex revealed that SRGAP2C improves sensory coding of layer 2/3
PNs by increasing stimulus response probability, while reducing overall spontaneous activity. We examined
whether these structural and functional connectivity changes affect behavior by using a novel two-alternative
forced choice texture discrimination task. We tested the ability of humanized SRGAP2C mice to discriminate
between two different rough textures using their whiskers and found that SRGAP2C mice display an increased
ability to learn this cortex-dependent task. We propose that the emergence of SRGAP2C critically changed
cortical circuit connectivity and function, and provided a key evolutionary step towards improved cognition.
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Moderated by Garrett Stanley (Georgia Tech)
3:50 4:00 Yasir Gallero-Salas, Shuting Han, Yaroslav Sych, Fabian F. Voigt, Balazs Laurenczy,
Ariel Gilad*, Fritjof Helmchen*
Brain Research Institute, University of Zurich, Neuroscience Center Zurich, Hebrew
University Medical School. *Co-senior authorship
Sensory and behavioral components of neocortical signal flow in tactile
and auditory discrimination tasks with short-term memory
In neocortex, each sensory modality engages distinct primary and secondary areas that route information
further to association areas. Where signal flow may converge for maintaining information in short-term memory
and how behavior may influence signal routing remain open questions. Using wide-field calcium imaging, we
compared cortex-wide neuronal activity in layer 2/3 for mice trained in auditory and whisker-based tactile
discrimination tasks with delayed response. In both tasks, mice were either active or passive during stimulus
presentation, engaging in body movements or sitting quietly. Irrespective of behavioral strategy, auditory and
tactile stimulation activated spatially segregated subdivisions of posterior parietal cortex (areas A and RL,
respectively) necessary for task completion and representing stimulus-related information. In the subsequent
delay period, in contrast, behavioral strategy rather than sensory modality determined where short-term
memory was located: frontomedially in active trials and posterolaterally in passive trials. Our results suggest
behavior-dependent routing of sensory-driven cortical information flow from modality-specific PPC subdivisions
to higher association areas.
4:00 4:10 Cameron Condylis, Abed Ghanbari, Karina Bistrong, Zizhen Yao, Thuc Nghi Nguyen,
Hongkui Zeng, Bosiljka Tasic, Jerry L. Chen
Boston University, Allen Institute for Brain Science
Multiplexed functional and transcriptional readout of mouse primary
somatosensory cortex during behavior
Information processing in the neocortex is carried out by neuronal circuits composed of different cell types.
Recent census of the neocortex using single cell transcriptomic profiling has uncovered more than 100 putative
cell types which subdivide major classes of excitatory and inhibitory neurons into distinct subclasses. The
extent to which this molecular classification predicts distinct functional roles during behavior is unclear. Here,
we combined population recordings using two-photon calcium imaging with spatial transcriptomics using
multiplexed fluorescent in situ hybridization to achieve dense functional and molecular readout of cortical
circuits during behavior. We characterized task-related responses across major transcriptomic neuronal
subclasses and types in layer 2/3 of primary somatosensory cortex as mice performed a tactile working
memory task. Distinct task responses were observed in novel excitatory cell types and inhibitory subclasses.
Simultaneous recordings across the population reveal functional connectivity motifs between specific
subclasses and types that either vary or persist across different task-defined networks. Our results reveal that
as neurons are segregated into increasingly discrete molecular types, their task-related properties continue to
differentiate. This broadens our understanding of how neocortical neurons are defined by their transcriptomic
profile, are composed into circuits, and participate in computations during behavior.
4:10 4:20 Christian L. Ebbesen, Robert Froemke
New York University
Automatic tracking of mouse social posture dynamics by 3D videography, deep
learning and GPU-accelerated robust optimization
Social interactions powerfully impact both the brain and the body, but high-resolution descriptions of these
important physical interactions are lacking. Currently, most studies of social behavior rely on labor-intensive
methods such as manual annotation of individual video frames. These methods are susceptible to
experimenter bias and have limited throughput. To understand the neural circuits underlying social behavior,
scalable and objective tracking methods are needed. We present a hardware/software system that combines
3D videography, deep learning, physical modeling and GPU-accelerated robust optimization. Our system is
capable of fully automatic multi-animal tracking during naturalistic social interactions and allows for
simultaneous electro-physiological recordings. We capture the posture dynamics of multiple unmarked mice
17
with high spatial (2 mm) and temporal precision (60 frames/s). This method is based on inexpensive
consumer cameras and is implemented in python, making our method cheap and straightforward to adopt and
customize for studies of neurobiology and animal behavior. FUNDING: This work was supported by The Novo
Nordisk Foundation (C.L.E.), the BRAIN Initiative (NS107616 to R.C.F.) and a Howard Hughes Medical
Institute Faculty Scholarship (R.C.F.).
4:20 4:30 Jim McBurney-Lin, Yina Sun, Lucas S. Tortorelli, Quynh Anh Nguyen, Sachiko Haga-
Yamanaka, Hongdian Yan
University of California, Riverside
Bidirectional pharmacological perturbations of the noradrenergic system
differentially affect tactile detection
The brain neuromodulatory systems heavily influence behavioral and cognitive processes. Previous work has
shown that norepinephrine (NE), a classic neuromodulator mainly derived from the locus coeruleus (LC),
enhances neuronal responses to sensory stimuli. However, the role of the LC-NE system in modulating
perceptual task performance is not well understood. In addition, systemic perturbation of NE signaling has
often been proposed to specifically target the LC in functional studies, yet the assumption that localized
(specific) and systemic (nonspecific) perturbations of LC-NE have the same behavioral impact remains largely
untested. In this study, we trained mice to perform a head-fixed, quantitative tactile detection task, and
administered an α2 adrenergic receptor agonist or antagonist to pharmacologically down- or up-regulate LC-
NE activity, respectively. We addressed the outstanding question of how bidirectional perturbations of LC-NE
activity affect tactile detection, and tested whether localized and systemic drug treatments exert the same
behavioral effects. This work was supported by UCR startup, UC Regents’ Faculty Fellowship, Klingenstein-
Simons Fellowship Awards in Neuroscience, and National Institute of Neurological Disorders and Stroke
1R01NS107355 and 1R01NS112200.
4:306:00 Virtual Poster Session
Friday, October 23 (All times EDT)
11:30 12:00 Check-in (Please login closer to 11:30 as you must be admitted to the meeting
12:00 12:50 Keynote 2: Nadine Gogolla, Introduced by Robert Sachdev
Max Planck Institute, Martinsried
Facial expressions and their neuronal correlates in mice
Unravelling the neuronal underpinnings of sensory perception, valence attribution and emotion state requires
sensitive readouts of subjective experiences. In my talk, I will present recent evidence from my lab showing
that mice exhibit a diverse repertoire of stereotyped and highly experience-specific facial expressions. Using
machine-learning algorithms, we were able to describe mouse facial expressions objectively and quantitatively
at millisecond time scales. We were thus able to decode intensity, value and persistence of the subjective
experience in individual mice and classify facial expressions into emotion-like categories, which share
fundamental properties of basic emotions in humans. Combining facial expression analysis with two-photon
calcium imaging, we identified single neurons whose activity closely correlated with specific facial expressions
in the insular cortex, a brain region implicated in subjective affective experiences in humans.
12:50 1:00 Coffee Break (randomized break-out rooms)
Session 3: Reorganization of neuronal representations
1:00 1:10 Moderator introduction: Dan Feldman
University of California, Berkeley
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1:10 1:40 Andrew Hires
University of Southern California
Behavioral and neuronal bases of tactile shape discrimination learning in
head-fixed mice
Neural representations of the external world are built from patterns of sensory input. In the cortex, these
representations can be surprisingly dynamic, shifting over time and across learning. We investigated this
reorganization using volumetric two-photon imaging of primary somatosensory cortex in mice learning to
discriminate simple shapes with their whiskers. I will present how the representations of shape are distributed
across cortical layers, how they are assembled from sensory input features, and how training increases the
importance of task-relevant sensory features, specifically enhancing discrimination of trained examples. These
results suggest mechanisms by which cortical reorganization allows flexible improvement in task performance
while maintaining perceptual stability.
1:40 2:10 Simon Peron
New York University
Barrel cortex dynamics during optical microstimulation task training
During the lifetime of an animal, sensory cortex often experiences repeated presentation of a novel input
pattern. Theoretical studies of cortical plasticity have predicted that repeated presentation of novel input
should drive a range of changes in primary sensory cortex, but plasticity at other processing stages
complicates interpretation of existing experimental data. Here, we use direct optogenetic stimulation of layer
(L) 2/3 pyramidal neurons in primary vibrissal somatosensory cortex (vS1) of mice as they learn to report
whether the number of light pulses is below or above a threshold. Consequently, vS1 L2/3 experiences a
consistent, novel neural activity pattern that the animal must attend to. We use two-photon imaging in
transgenic mice expressing GCaMP6s to track vS1 neural dynamics as mice learn this task. We find that the
directly driven population sparsens rapidly over the course of learning. At the same time, we find a small
subset of neurons whose activity increases over the first few days and remains stable throughout the
remainder of training. This is consistent with theoretical models of repeated cortical stimulation showing
increased feedback inhibition for highly responsive neurons, combined with tuning-specific increases in
recurrent excitation.
2:10 2:40 Carsen Stringer
Janelia Research Campus
A neural atlas of multi-dimensional behavioral representations
Neuronal populations in sensory cortex produce variable responses to sensory stimuli and exhibit intricate
spontaneous activity even without external sensory input. Recording more than 10,000 neurons in mouse
visual cortex, we observed that spontaneous activity reliably encoded a high-dimensional latent state, which
was partially related to the mouse’s ongoing behavior and was represented not just in visual cortex but also
across the forebrain. Sensory inputs did not interrupt this ongoing signal but added onto it a representation of
external stimuli in orthogonal dimensions. Thus, visual cortical population activity, despite its apparently noisy
structure, reliably encodes an orthogonal fusion of sensory and multidimensional behavioral information. It is
unknown whether different mice represent this behavioral information in their brains in similar ways. Therefore,
we are characterizing the similarity of neural-behavioral representations across mice by mapping mouse
behavioral movements into a common coordinate framework.
2:40 3:00 Discussion
3:00 3:20 Coffee Break
Short Platform Talks 3 (10 min including questions)
Moderated by Robert Sachdev (Humboldt University)
19
3:20 3:30 Nathaniel C. Wright, Peter Y. Borden, Yi Juin Liew, Michael F. Bolus, William A. Stoy,
Craig R. Forest, Garrett B. Stanley
Georgia Institute of Technology, Emory University
Rapid sensory adaptation in the mouse thalamocortical circuit during
wakefulness, and the relative contribution of thalamic state
Rapid sensory adaptation is ubiquitous across sensory systems, but the mechanistic basis is poorly
understood. A wide range of (primarily in vitro and anesthetized) studies have uncovered rapid adaptation
effects in the thalamocortical circuit, which may underlie adaptive changes in perception. Yet it is unclear
whether the circuit can be appreciably adapted during wakefulness, when baseline firing rates are higher, or
what role various candidate mechanisms play. To address these unknowns, we recorded spiking activity in
VPm and S1 of the awake mouse, and quantified responses to punctate whisker deflections delivered either
in isolation or embedded in adapting sensory white noise. We found that cortical sensory responses were
indeed adapted by sensory white noise; putative excitatory firing was profoundly adapted, and inhibitory firing
only modestly adapted. Further optogenetic manipulation experiments and network modeling suggest this
largely reflects adaptive changes in thalamic “state” (rate, tonic/burst firing, and synchrony) and robust
feedforward inhibition, with little contribution from synaptic depression. Taken together, these results suggest
that ethologically-relevant changes in thalamic state during normal behavior have major impacts for cortical
sensory representations and perception. Funding: NIH BRAIN NINDS-R01NS104928 (Stanley), NIMH-
U01MH106027 (Stanley, Forest), NIH NINDS F31NS098691 (Borden), NIH R01EY023173 (Forest), NSF
GRF (Stoy)
3:30 3:40 Jan Jabłonka, Marcin Kaźmierczak, Maria Sadowska, Władysław Średniawa,
Paulina Urban
University of Warsaw
Interhemispheric interactions participate in the cortical plasticity
The two hemispheres of the brain are commonly treated as independent structures when peripheral or even
cortical manipulations are applied to one of them. We present results suggesting that cortical, experience-
dependent plasticity (ExDP) is not a unilateral, independent process but rather a combination of a variety of
interactions between the two hemispheres. We mapped metabolic brain activity with 2-[14C] deoxyglucose
(2DG) following ExDP induction by unilateral, partial whiskers deprivation, which resulted in the band of cortical
representation widening by ~45%. Here we show that the width of 2DG visualised representation is much
smaller (~20%) when unilateral stimulation of the spared whiskers is applied than following bilateral
stimulation. The Kernel Electrical Source Imaging (kCSD) was performed for current flow reconstruction from
electrocorticograms (ECoGs) registered across the rows of whiskers representations. The width of sinks and
sources were measured. Both the metabolic and kCSD visualisation of the cortical activity mappings confirm
the inconsistent response to the uni- vs bilateral stimulation in deprived animals. The results suggested that
ExDP that leads to cortical maps rearrangement depends on the contralateral hemisphere as well. The
response observed in 2DG brain mapping in deprived animals after canonically performed, synchronous
bilateral whiskers stimulation is therefore composed of at least two separately activated plasticity mechanisms.
3:40 3:50 Jason M. Guest, Arco Bast, Marcel Oberlaender
Max Planck Society, Research Center caesar
Thalamus gates top-down modulation of cortical output
How can pyramidal tract neurons integrate sensory information from thalamocortical and intracortical
populations with contextual information from top-down corticocortical pathways? Based on recently reported
and ongoing work in my lab, I will we show how input from primary thalamus enables pyramidal tract neurons
to integrate the current state of their respective local and long-range input populations with stimulus
information. Sensory-evoked thalamocortical gating of cortical output may thereby provide subcortical circuits
with an integrated efference copy that reflects sensory input and context. Funding was provided from the
Center of Advanced European Studies and Research, the European Research Council (grant agreement
633428), the German Federal Ministry of Education and Research (grants BMBF/FKZ 01GQ1002 and
01IS18052), and the Deutsche Forschungsgemeinschaft (SFB 1089 and SPP 2041).
20
Moderated by Kate Hong (Carnegie Mellon University)
3:50 4:00 Mikkel Vestergaard*, M. Carta*, J.F.A. Poulet. *Co-first author
Max-Delbrück Center (MDC), Charité-Universitätsmedizin Berlin, Interdisciplinary
Institute for Neuroscience, University of Bordeaux, CNRS
The cellular coding of temperature in the mammalian cortex
Thermosensation is a key sense required for object identification during haptic exploration, accurate
monitoring of environmental temperature and the perception of pain. The neural encoding of temperature has
been addressed in the sensory periphery, but, unlike almost all other sensory modalities, a central cortical
area for temperature processing has not been identified. It has been suggested that insular cortex and
primary somatosensory cortex (S1) play a role, however, using calcium imaging in awake mice, we show that
S1 only responds to skin cooling but not warming. In contrast, a posterior region of insular cortex (pIC)
contains a somatotopic representation of warm and cool with heterogeneously arranged, thermally-tuned
cells with distinct coding properties. Furthermore, reversible optogenetic manipulations show strong impact of
pIC on thermal perception. Together, this work locates a thermal cortex and identifies fundamental encoding
schemes of temperature in central circuits. This work was supported by the European Research Council
(ERC-2015-CoG-682422, J.F.A.P.), the European Union (3x3Dimaging 323945, J.F.A.P.), the Deutsche
Forschungsgemeinschaft (DFG, FOR 2143, J.F.A.P., SFB 1315, J.F.A.P.), the Helmholtz Society (J.F.A.P.),
the Centre National de la Recherche Scientifique (CNRS) (M.C.) and the Independent Research Fund
Denmark (M.V.).
4:00 4:10 Clément Brunner*, Micheline Grillet*, Arnau Sans-Dublanc, Karl Farrow, Théo
Lambert, Emilie Macé, Gabriel Montaldo & Alan Urban. *Authors contributed
equally.
Neuro-Electronics Research Flanders, VIB, Imec, KU Leuven, Max Planck Institute of
Neurobiology
A platform for brain-wide functional ultrasound imaging and analysis of
circuit dynamics in behaving mice
Imaging of large-scale circuit dynamics is crucial to gain a better understanding of brain function, but most
techniques have a limited depth of field. Here we describe vfUSI, a platform for brain-wide volumetric
functional ultrasound imaging of hemodynamic activity in awake head-fixed mice. We combined high-
frequency 1024-channel 2D-array transducer with advanced multiplexing and high-performance computing
for real-time 3D Power Doppler imaging at high spatiotemporal resolution (220x280x175-µm3 voxel size, up
to 6 Hz). In addition, we developed a standardized software pipeline for registration and segmentation based
on the Allen Mouse Common Coordinate Framework, allowing for temporal analysis in 268 individual brain
regions. We demonstrate the high sensitivity of vfUSI in multiple experimental situations where stimulus-
evoked activity can be recorded using a minimal number of trials. We also mapped neural circuits in vivo
across the whole brain during optogenetic activation of specific cell-types. Moreover, we revealed the
sequential activation of sensory-motor regions during a grasping water droplet task. vfUSI will become a key
neuroimaging technology because it combines ease of use, reliability, and affordability. Funding This work
was supported by grants from the Leducq Foundation (15CVD02), from FWO (MEDI-RESCU2-AKUL/17/049,
G091719N, and 1197818N), from VIB TechWatch (fUSI-MICE) and from internal NERF TechDev fund (3D-
fUSI project).
4:10 4:20 Yu Ding and Yuri Vlasov
University of Illinois at Urbana-Champaign
High-frequency whisker vibrations above 1KHz - are they relevant to perception?
We performed a systematic study of high -frequency vibrations of rodents whiskers using acoustical methods.
We identified a regular series of higher order modes (up to 30) spanning frequencies up to 10KHz. While
interaction of a whisker with a pole excites mostly lower-order modes (80% of total energy), interaction with a
textured surface redistributes over 60% of these vibrational energy to modes higher than 1KHz. Moreover,
these higher order modes exhibit up to 15X smaller damping ratio and are propagating 4X faster, that makes
them the fastest and the most powerful messengers of shock-wave events during whisker scan over textured
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surfaces. Based on these observations we propose a hypothesis of mechanical transduction that can explain
observation of ultrafast microseconds-scale jitter in response of primary afferents to fast whisker stimulations.
4:20 4:30 Wrap-up discussion & Poll
4:30 6:00 Virtual Poster Session
ADJOURN
Presenter Title Present W Present T Present F Email
Ehud Ahissar What happens when you free the head X X ehud.ahissar@weizmann.ac.il
Alicia Barrientos Examining the relationship between microglia and the perineuronal net during a critical period of somatosensory cortex development X X abarrientos@gradcenter.cuny.edu
Sam Benezra Associative learning enhances sensory representations of layer 5 apical dendrites in primary somatosensory cortex X X sb4096@columbia.edu
Flore Boscher Cortical states during whisking in awake and sleeping mice X X flore.marie.boscher@gmail.com
Thomas Burnett A Barrel-less Somatosensory Cortex: Ferret S1 X X tburnet7@jhmi.edu
Giuseppe Cataldo Functionality of Patterning: Electrophysiological Analysis of the Principle Sensory Nucleus in Prrxl1 Knockout and Barrelless Mice X X mariolz@yahoo.com
Trishala Chari A novel behavioral assay to investigate social touch deficits in mouse models of autism X X tchari2018@g.ucla.edu
Suma Chinta Sensorimotor integration in the superior colliculus during whisker-guided orienting behavior X X chintas@purdue.edu
Yu Ding High-frequency whisker vibrations above 1KHz - are they relevant to perception? X X yud2@illinois.edu
Grzegorz Dobrzański Layer IV (L4) somatostatin interneurons and functional plasticity of the barrel cortex. X X g.dobrzanski@nencki.edu.pl
Arash Fassihi Direct modulation of the perceived duration through optogenetic manipulation of somatosensory cortex X X arfassihi@gmail.com
Ana Inacio Brain-wide neural networks of movement-encoding neurons in the primary somatosensory cortex X X ana.inacio@nih.gov
Daniel Kato Effects of Learning and Experience on Multisensory Integration in Mouse Primary Somatosensory Cortex X X dk2643@columbia.edu
Yonatan Katz Cross-whisker adaptation of neurons in layer 2/3 of the rat barrel cortex X X yon.katz@gmail.com
Jinho Kim Behavioral and neural bases of tactile shape discrimination learning in head-fixed mice X X jinho@usc.edu
Sarah Lutchman Alterations in the Perineuronal Nets, Microglial Cells, and Novel Object Discrimination in Prenatally Restricted Mice X X sarah.lutchman16@qmail.cuny.edu
Eduard Maier An isomorphic three-dimensional cortical model of the pig rostrum X X eduard.maier@bccn-berlin.de
Phillip Maire Automatic whisker contact classification using a convolutional neural network X X maire@usc.edu
Krista Marrero Effects of Prestimulus Activity on Performance of a Selective Detection Task X X kmarr006@ucr.edu
Katherine Matho Genetic dissection of glutamatergic neuron subpopulations and developmental trajectories in the cerebral cortex X X Kmatho@cshl.edu
Hisham Mohammed A Modified Behavioral Test of Forelimb Dexterity in Mice X X Hisham.sys@gmail.com
Aurelie Pala Integration of bilateral tactile signals in somatosensory cortices of the awake mouse X X aurelie.pala@gmail.com
William Olson Jaw movement-modulated activity of sensory neurons in the mesencephlic trigeminal nucleus during a directional licking task X X wolson6@johnshopkins.edu
Hyein Park Cortical circuits unifying bilateral space X X park1223@purdue.edu
Georgia Pierce Not-so-sensory activity in the posterior medial nucleus of the thalamus X X gmp2139@columbia.edu
Rikki Rabinovich Learning-related changes in activity of superficial layer cells in barrel cortex X X rjr2153@columbia.edu
Deepa Ramamurthy Recent trial history cues attentional selection of whisker stimuli in mice X X dlramamurthy@berkeley.edu
Cindy Ritter An isomorphic three-dimensional cortical model of the pig rostrum X X cindy.ritter@bccn-berlin.de
Chris Rodgers Behavioral strategies and neural representations for shape discrimination X X ccr2137@columbia.edu
Isis Wyche Whisker inertia contributes to self-motion encoding in the mouse whisker system X X iwyche1@jhmi.edu
Poster Session Schedule
22
BARRELS XXXIII POSTER ABSTRACTS
23
Ehud Ahissar, Tess Oram, Alon Tenzer, Inbar Saraf-Sinik, Ofer Yizhar
Weizmann Institute of Science
Awakening the POm: What happens when you free the head
Headfixed rats and mice are dramatically restrained in their behavior. Previous studies showed that the paralemniscal
nucleus of the thalamus, the POm, is relatively quiet in this condition. We show that when the mouse is free to move POm
gets back to life, exhibiting robust coding of both whisker and head motion. Optogenetic stimulations further suggest that
both the POm and VPM take active part in the motor-sensory-motor loop controlling head motion.
Alicia C. Barrientos (1), Sara Mroziuk (2), Arya Lahijani (2) and Joshua C. Brumberg,(1,2,3)
[1] The Graduate Center, CUNY Behavioral and Cognitive Neuroscience PhD program; [2] Queens College, CUNY
Dept. of Psychology; [3] Queens College, CUNY Dept. of Biology
Examining the relationship between microglia and the perineuronal net during a critical period of somatosensory
cortex development
Sensory deprivation (SD) during the critical period of development results in behavioral and cognitive abnormalities in
mammals. Previous studies from the laboratory demonstrated that SD via whisker trimming leads to activation of microglia
(MG) in the primary somatosensory cortex (S1) and a reduction of perineuronal nets (PNNs). The current study utilizes
SD in conjunction with pharmacological manipulations to activate or inhibit MG throughout a developmental critical period
within S1. Mice were injected with either saline (control), minocycline (MG inhibitor) or lipopolysaccharide (inflammatory
agent) until post-natal day 30 while another cohort additionally underwent SD. We hypothesized that SD and LPS will
activate MG, which in turn will impact PNN density and integrity. Preliminary data shows that SD impacts MG across all
injection treatments, while also resulting in qualitative changes to the PNN. This study is among the first to show
correlative evidence that MG may be shaping the PNN. Funding: This work is supported by NIH grant NIGMS
1SC3GM122657
Sam Benezra, Elizabeth Hillman, Randy Bruno
Zuckerman Institute, Columbia University
Associative learning enhances sensory representations of layer 5 apical dendrites in primary somatosensory
cortex
Cortical layer 1, comprised mainly of apical tuft dendrites of pyramidal neurons, may be a key site of associative learning.
We investigated the effects of associative learning on dendritic activity in layer 1 of primary somatosensory cortex by
devising a simplified awake head-fixed mouse conditioning paradigm. Air puffs directed at the whiskers are aimed in either
of two directions: rostrocaudal (backward) or ventrodorsal (upward). One of the directions is paired with a water reward
and thus corresponds to a conditioned stimulus (CS+). No reward is given during puffing of the whiskers in the other
direction (CS-). Using both two-photon microscopy and a new high-speed volumetric imaging method called SCAPE, we
longitudinally tracked calcium activity in apical dendrites as mice learned to associate the CS+ with reward. We found that
in naïve animals, apical responses are largely unselective for conditioned stimuli, but become highly selective for either
the CS+ or CS- as behavioral performance improves. This enhanced sensory representation persists even after rewards
are removed on the last session. Our results demonstrate that classical conditioning has a long lasting effect on the
recruitment of apical dendrites by behaviorally relevant stimuli, and provide an avenue for further investigation of cellular
and circuit mechanisms underlying plasticity induced by perceptual experience and reinforcement.
Flore Boscher and Nadia Urbain
Centre de Recherche en Neurosciences de Lyon, INSERM U1028 CNRS UMR5292, UCB-Lyon1 University
Cortical states during whisking in awake and sleeping mice
A striking feature of the EEG observed during rapid eye movements sleep (REM) is its close resemblance to the EEG
patterns observed during the fundamentally different cognitive state of wakefulness. Investigating how sensory inputs are
processed at the cortical level throughout the sleep-wake cycle is a crucial step towards a better understanding of the
function of sleep. Therefore, we developed a technical approach to perform local field potential recordings in the mouse
primary somatosensory cortex (S1-LFP) combined with the monitoring of the EEG and the electromyogram and video-
tracking of whisker movements. Active cortical states were characterized by small-amplitude fast LFP and EEG
fluctuations, with or without whisking, while quiet wakefulness was characterized by significant larger-amplitude
fluctuations in the 1-6 Hz frequency range. Similarly, we observed that the 1-6 Hz spectral power of S1-LFP recorded in
REM was significantly higher during periods between whisking bouts (REM-Quiet) than during whisking (REM-Whisking).
At the EEG level, we did not observe such a change in low frequency spectral power across REM episodes, but a shift to
higher frequencies in the EEG Theta band in REM-Whisking compared with REM-Quiet, suggesting that cortical state
BARRELS XXXIII POSTER ABSTRACTS
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changes during REM-Whisking is not restricted to S1 cortex, but might involve other brain areas. ANR Grant 17-CE16-
0024. French Ministry fellowship.
Thomas Burnett, Kristina Nielsen, Daniel O'Connor
Johns Hopkins University School of Medicine
A Barrel-less Somatosensory Cortex: Ferret S1
Mammals’ vibrissae hold great importance in navigation and object exploration, but of the thousands of mammal species,
relatively few possess a barrel cortex. How then may whisker tactile inputs be represented? We explore this question in
the non-whisking ferret, Mustela putorius furo, an established neurodevelopmental and sensory model. Through
electrophysiology and histology, we show ferrets definitively lack a barrel cortex, but possess an expanded whisker
representation. Whiskers are somatotopically represented, with a reversal akin to other carnivores. Interestingly, we find
neurons responsive to single whisker and multi-whisker deflections, a potential means of motion integration similar to
barrel cortex. We also present preliminary data suggesting a behavioral deficit from the removal of whiskers. We hope
these findings may provide a new avenue to exploring whisker-mediated behavior and active sensation.
Trishala Chari 1,3; Zoë Dobler 1,3; Carlos Portera-Cailliau 1,2
[1] Dept. of Neurology; [2] Dept. of Neurobiology; [3] Neuroscience Interdepartmental Program David Geffen School of
Medicine UCLA
A novel behavioral assay to investigate social touch deficits in mouse models of autism
We are investigating whether social avoidance in individuals with autism is due to hypersensitivity to social touch using
the genetic Fmr1-/- model of Fragile X Syndrome and the maternal immune activation (MIA) autism model. We designed a
novel assay to investigate the behavioral responses to social touch in mice. A test mouse, head-fixed but free to run on an
air-suspended polystyrene ball, is allowed to voluntarily (whisker-whisker) or forcibly (snout-snout) interact with a stranger
mouse that is head-fixed on a moving platform. We recorded high-speed videos to analyze mouse behavior and pupil size
using MATLAB and DeepLabCut. Repeated bouts of voluntary interactions led to pupil constriction in healthy controls but
not in Fmr1-/- or MIA mice, suggesting persistent hyperarousal. In contrast, all groups showed similar degrees of pupil
constriction to bouts of forced contact. Autism model mice displayed prominent avoidance behaviors, spending more time
running away from the stranger mouse during forced and voluntary interactions compared to healthy controls.
Interestingly, we observed sex differences, with Fmr1-/- and MIA females displaying greater avoidance than males. Both
voluntary and forced touch interactions resulted in facial features representing an aversive emotional state, particularly in
Fmr1-/- mice. This novel assay is a promising tool for investigating social touch deficits in autism mouse models. Funding:
R01 HD054453 (NICHD), R01 NS117597 (NINDS).
Suma Chinta and Scott Pluta
Purdue University, Department of Biology
Sensorimotor integration in the superior colliculus during whisker-guided orienting behavior
Spatial attention involves the parallel integration of multiple, disparately organized neural circuits. These disparate circuits
ultimately converge onto the midbrain superior colliculus (SC), where individual neurons encode the location of stimuli,
sustain working memory and initiate overt movements. However, the role of the SC in active, somatosensory-guided
movements is largely unknown. Since mice do not track objects by moving their eyes, somatosensory-guided whisker
movements provide a unique opportunity for greatly advancing our mechanistic understanding of overt spatial attention.
To probe this topic, we recorded spiking from the SC while mice used their whiskers to explore the surface of a
dynamically moving object. Mice dynamically optimized their whisking set-point and amplitude to track object movement.
Many neurons in the SC responded to surface movement with an increase in spiking, while others decreased their activity,
in a location-specific manner. Overall, we observed a clear preference for a particular trajectory of surface movement.
Trajectory tuning was consistent with neuron-specific preferences for whisker curvature and phase during touch. Spiking
in a subset of neurons located in the deepest, motor layer of the SC predicted whisk amplitude. Overall, these data help
establish the rodent whisker system as a valuable model for dissecting the neural circuits underlying overt spatial
attention.
Dobrzanski G, Lukomska A, Zakrzewska R, Kanigowski D, Kossut M
Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
Layer IV (L4) somatostatin interneurons and functional plasticity of the barrel cortex.
Enlargement of functional representation of whiskers can be induced in two experimental models: sensory deprivation
sparing selected whiskers and fear learning where stimulation of selected whiskers is the conditioned stimulus. The plastic
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change of cortical representation of cognate whiskers is detected with [14C]-2-deoxyglucose (2DG) autoradiography
mainly in barrel cortex L4. Such plasticity was linked to the action of somatostatin interneurons (SOM-INs). We examined
how formation of the plastic change is affected by modulation of L4 SOM-INs activity. Using cell-specific transduction and
layer-targeted injections we introduced DREADDs to SOM-INs with cell bodies localized mainly in L4 and modulated their
activity in both experimental models. After procedure completion, selected whiskers were stimulated and 2DG mapping
was performed. L4 SOM-INs inhibition during learning, selectively in representation of the conditioned row of whiskers
prevents plasticity formation. SOM-INs blockade in deprived barrels (but not in spared one) adjacent to the spared one,
decreases sensory deprivation-induced plasticity of spared whisker representation. L4 SOM-INs may monitor and adjust
thalamic inputs-dependent neuronal activity in L4. Under important environmental circumstances may support conveying
information about salient stimuli or brain states across the cortical column, contributing to plasticity formation. Funding:
Polish National Science Centre Grant to GD (2017/27/N/NZ4/02639)
Arash Fassihi (2), Sebastian Reinartz (1), Alessandro Toso (1), Francesca Pulecchi (1) , Mathew E. Diamond (1)
[1] International School for Advanced Studies, Trieste, Italy; [2] Department of Physics, Section of Neurobiology,
University of California, San Diego
Direct modulation of the perceived duration through optogenetic manipulation of somatosensory cortex
In humans and rats, when subjects judged the duration of a vibration applied to the fingertip (human) or whiskers (rat),
increasing stimulus amplitude led to increased perceived duration. Symmetrically, increasing vibration duration led to
increasing perceived intensity. We hypothesized that this mechanism is the leaky integration of sensory input. We first
asked whether the amplitude-dependent bias in the perceived duration can be replicated by integrating the vibrissal
somatosensory cortex (vS1) activity. We recorded vibration-evoked neuronal activity from the vS1 of awake, behaving
rats. We then inserted the spiking activity as the sensory input into the leaky integrator model and could generate
neurometric functions that replicated rats' actual psychophysical functions. Second, we confirmed by targeted optogenetic
manipulation that the amplitude-dependent bias is originated within vS1. Finally, we show that animals' choice bias could
be predicted by leaky integration of the optogenetic modulation activity in vS1.
Ana R Inacio (1), Francisco Pereira (2), Charles R Gerfen (3), and Soohyun Lee (1)
[1] Unit on Functional Neural Circuits, [2] Machine Learning Team, [3] Section on Neuroanatomy, National Institute of
Mental Health, National Institutes of Health
Brain-wide neural networks of movement-encoding neurons in the primary somatosensory cortex
Principal neurons in the primary sensory cortices exhibit heterogeneous patterns of activity, not only in response to
sensory stimuli but also, during spontaneous movements. Yet, how these heterogeneous, behavioral state-dependent
patterns of activity arise is largely unknown. Longitudinal two-photon calcium imaging uncovered a remarkably stable
correlation between the activity of principal neurons in layers II/III of primary somatosensory cortex and spontaneous
movements. This population activity could reliably predict spontaneous movements, but with a subset of neurons
accounting for most of the prediction accuracy. The activity of movement-encoding neurons cannot be explained by
sensory feedback, as paralysis of the contralateral whisker pad did not disrupt correlation with ipsilateral whisker
movements and locomotion. During pharmacological blockade of neuromodulators, the activity levels were altered, but the
correlation of neuronal activity with spontaneous movements was largely maintained. By contrast, glutamatergic
transmission blockers nearly abolished this correlation. Single cell-initiated monosynaptic retrograde tracing and whole-
brain presynaptic network analysis revealed that movement-encoding neurons receive characteristic subcortical inputs.
Our study provides a connectivity rule that supports the representation of spontaneous movements in the primary
somatosensory cortex. Funding: NIH Intramural Research Program.
Daniel D. Kato, Randy M. Bruno
Zuckerman Institute, Columbia University
Effects of Learning and Experience on Multisensory Integration in Mouse Primary Somatosensory Cortex
Primary sensory cortical areas have historically been considered uni-sensory, but an emerging body of evidence suggests
that multi-sensory integration (MSI) occurs even in these early stages of cortical information processing. However, the
effect of learning and experience on these early cortical multi-sensory responses remains unclear. To address this
question, we used in vivo 2-photon imaging to measure the activity of layer 2/3 barrel field neurons over the course of
several days during which a tactile stimulus was paired with a specific auditory stimulus, both in a passive and a rewarded
context. We found that a subset of S1 cells nonlinearly integrated auditory and tactile information in an auditory stimulus-
specific manner even in naïve mice, suggesting a role in representing specific conjunctions of sensory features. Pairing a
tactile and an auditory stimulus in a passive setting did not lead to higher trial-averaged responses to the either auditory
stimulus alone or to the conjunctive auditory-tactile stimulus. Performing the same experiment in a rewarded setting led to
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a non-selective increase in responses to all stimuli. We are currently investigating whether experience causes S1
responses to different auditory-tactile stimulus conjunctions to overlap more (pattern completion) or less (pattern
separation).
Yonatan Katz and Ilan Lampl
Weizmann Institute of Science, Israel
Cross-whisker adaptation of neurons in layer 2/3 of the rat barrel cortex
Neurons in the barrel cortex respond preferentially to stimulation of one principal whisker and weakly to several adjacent
whiskers. Such integration exists already in layer 4, the pivotal recipient layer of thalamic inputs. Previous studies show
that cortical neurons gradually adapt to repeated whisker stimulations and that layer 4 neurons exhibit whisker specific
adaptation, showing no apparent interactions with other whiskers. The aim of this intracellular study was to determine
whether layer 2 /3 cortical cells exhibit whisker specific adaptation. Towards this aim we compared the synaptic response
of neurons to repetitive stimulation of either one of two responsive whiskers or when stimulation of the two whiskers was
interleaved. We found that in most layer 2/3 cells adaptation is whisker specific. These findings indicate that despite the
multi-whisker receptive fields in the cortex, the adaptation process for each whisker is independent of other whiskers,
perhaps allowing high responsiveness in complex environments.
Jinho Kim, Andrew Erskine, Jonathan A. Cheung, Samuel Andrew Hires
Department of Biological Sciences, Section of Neurobiology, University of Southern California
Behavioral and neural bases of tactile shape discrimination learning in head-fixed mice
Tactile three-dimensional shape recognition requires perception of object surface angles. We investigated how object
surface angles are represented in the brain, how this representation is constructed from sensory inputs, and it reorganizes
across learning. Head-fixed mice learned to discriminate object angles by active exploration with one whisker. Calcium
imaging of excitatory neurons in layers 2-4 of barrel cortex revealed maps of object-angle tuning before and after learning.
Three-dimensional whisker tracking demonstrated that the sensory input components that best discriminate angle (vertical
bending and slide distance) also have the greatest influence on object-angle tuning. Despite high turnover in active
ensemble membership across learning, both the population distribution of object-angle tuning preferences and individual
preferences remained stable. Motor strategy and sensory inputs were not changed across learning, but population
response from touch-response neurons better discriminated object angle after learning. These results show how
discrimination training enhances stimulus selectivity in primary somatosensory cortex while maintaining perceptual
stability.
Sarah Lutchman, Kathleen Berta, Joshua C. Brumberg
Queens College, CUNY
Alterations in the Perineuronal Nets, Microglial Cells, and Novel Object Discrimination in Prenatally Restricted
Mice
Inadequate food consumption during pregnancy can negatively impact fetal brain development, which is mediated in part
by perineuronal nets and microglial cells. Perineuronal nets are a neuronal specific form of the extracellular matrix which
envelop the cell bodies and proximal processes of predominantly GABAergic interneurons. As specialized macrophages,
microglia clear dead neurons and other cellular debris to maintain CNS health. To study how low food consumption
impacts offspring, adult female CD-1 mice were placed on a calorically restricted diet before and during pregnancy. Pups
produced from this group were compared to pups born from ad libitum-fed mothers. Perineuronal nets and microglia in
pups were visualized using histochemistry to better understand how maternal caloric restriction impacts offspring brain
development. A novel object paradigm was also conducted in which mice were allowed to explore two objects of the same
texture. Mice that were calorically restricted in utero had significantly fewer perineuronal nets compared to non-restricted
mice. There was also a sex difference with female offspring being more affected by maternal caloric restriction than male
offspring. The microglia of prenatally restricted mice were more ramified compared to non-restricted mice. Prenatally
restricted pups also spent less time engaging with the novel object in the behavioral paradigm compared to the control
pups. Funding: NIGMS SC3GM122657
Phillip Maire, Jonathan Cheung, Jonathan Sy, Samuel Andrew Hires
University of Southern California
Automatic whisker contact classification using a convolutional neural network
Many labs use tasks that involve whisker active touch against thin movable poles to study diverse questions of sensory
and motor coding. Since neurons operate at temporal resolutions of milliseconds, determining precise whisker contact
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periods is essential. Yet, accurately classifying the precise moment of touch is time-consuming and labor intensive.
Current classification techniques rely on semi-automated curation, infrared beam crossings, or hard coded distance to
object thresholds. All involve substantial tradeoffs in analysis time or accuracy. We propose the use of convolutional
neural networks to fully automate the identification of whisker