SWC (Hybrid) Seminar - Dr Carl Schoonover and Dr Andrew Fink

SWC (Hybrid) Seminar - Dr Carl Schoonover, Allen Institute, and Dr Andrew Fink, and Northwestern University

This event will take place on Thursday 16 October 2025 at 1:15pm

The seminar will be held at 25 Howland Street, London, W1T 4JG. This central location provides easy access for attendees.

Talk Title: A network mechanism for perceptual learning

Abstract

Part 1: Organisms continually tune their perceptual systems to the features they encounter in their environment. We have studied how this experience reorganizes the synaptic connectivity of neurons in the olfactory (piriform) cortex of the mouse. We developed an approach to measure synaptic connectivity in vivo, training a deep convolutional network to reliably identify monosynaptic connections from the spike-time cross-correlograms of 4.4 million single-unit pairs. This revealed that excitatory piriform neurons with similar odor tuning are more likely to be connected. We asked whether experience enhances this like-to-like connectivity, but found that it was unaffected by odor exposure. Experience did, however, alter the logic of interneuron connectivity. Following repeated encounters with a set of odorants, inhibitory neurons that responded differentially to these stimuli exhibited a high degree of both incoming and outgoing synaptic connections within the cortical network. This reorganization depended only on the odor tuning of the inhibitory interneuron and not on the tuning of its pre- or postsynaptic partners. A computational model of this reorganized connectivity predicts that it increases the dimensionality of the entire network’s responses to familiar stimuli, thereby enhancing their discriminability. We confirmed that this network-level property is present in physiological measurements, which showed increased dimensionality and separability of the evoked responses to familiar versus novel odorants. Thus a simple, non-Hebbian reorganization of interneuron connectivity may selectively enhance an organism’s discrimination of the features of its environment.

Part 2: TBD (behaviour)

About the speaker: Dr Schnoonover and Dr Fink

Carl Schoonover. I am Senior Scientist at the Allen Institute for Neural Dynamics. My postdoctoral work was under Richard Axel, my doctoral work under Randy Bruno. Before that I took a master’s degree in cognitive science (École Normale Supérieure) and a bachelor’s degree in philosophy (Harvard College).

Andrew Fink. I am an Assistant Professor of Neurobiology at Northwestern University. My post-doctoral work was under Richard Axel and my graduate training under Thomas Jessell. I was a Fulbright fellow in Berlin in non-linear dynamics and linguistics and majored in physics at Carleton College.

RSVP Reserve a place by registering via Eventbrite.