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Krasnow Seminar: Cheng Ly, 3/14

Monday, March 14, 3pm
Krasnow Institute Room 229
Fairfax Campus

How Firing Rate Heterogeneity is Mediated by Intrinsic and Network Heterogeneity

Cheng Ly
Assistant Professor, Statistics & Operations Research Department
Virginia Commonwealth University

Abstract:
Heterogeneity of neural attributes has recently gained a lot of attention and is increasing recognized as a crucial feature in neural processing. Recent experimental recordings in electric fish indicate that the heterogeneous network input can mediate response heterogeneity of superficial pyramidal cells in a cortical area (Marsat Lab, WVU). These data motivated us to theoretically study how heterogeneity of neural attributes in general alter firing rate heterogeneity. We ask how 2 sources of heterogeneity: network (synaptic heterogeneity) and intrinsic heterogeneity alter response heterogeneity.

First we address this in a canonical recurrent spiking network model with random connectivity (Erdos-Renyi graph). The relationship between intrinsic and network heterogeneity can lead to amplification or attenuation of firing rate heterogeneity, and these effects depend on whether the recurrent network is firing asynchronously or rhythmically. We analyze the system and derive compact analytic formulas to precisely describe the phenomena.

Second, we adapt our theory to a delayed feedforward neural network to better model the electric fish system. The theory is used to demonstrate that a feedforward network with structured connectivity rules exhibit qualitatively similar statistics as the experimental data. Specifically, the stimulus tuning of particular cells is related to the network architecture, i.e., the number of synaptic connections. Thus, the model demonstrates that intrinsic and network attributes do not interact in a linear manner but rather in a complex stimulus-dependent fashion to increase or decrease response heterogeneity and thus shape population codes.

This is joint work with Gary Marsat (West Virginia University).

The Krasnow Institute hosts a seminar at 4:00 p.m. each Monday afternoon during the academic year with invited guest speakers presenting on a topic in the cognitive sciences. Click here for upcoming seminars.