A feasible detailed probe of the grid cell microcircuit

Ila Fiete

(University of Texas, Austin)

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Date: Wednesday March 4, 2015


The phenomenology of grid cell population activity has rapidly advanced, but with disparate competing possibilities the circuit mechanisms underlying grid cell activity remain almost entirely unresolved. In this talk, I will propose a strategy that combines existing experimental techniques in a way that promises to bring the mechanistic underpinnings of the grid cell response into considerably sharper focus. The strategy is based on the theoretical insight that small global perturbations of circuit activity will result in characteristic quantal shifts in the spatial tuning relationships between cells, which should be observable from multi- single unit recordings of a small subsample of the population. The predicted shifts differ qualitatively across the candidate recurrent network mechanisms, and also distinguish between recurrent versus feedforward mechanisms. I will discuss how, more generally, the proposed strategy demonstrates that sparse neural recordings coupled with global circuit perturbation can reveal much more about cortical circuit mechanism as it relates to function than can full knowledge of the synaptic connectivity matrix or of network activity.

Created: Wednesday, March 4th, 2015