Colloquium Series 2015-2016

Mriganka Sur
Massachusetts Institute of Technology (MIT)

The Functional Logic of Cortical Circuits

Cortical circuits transform simpler inputs into complex outputs that underlie behavior and cognition. Neuronal circuits of the cortex involve feedforward and top-down inputs, connections between specific types of excitatory and inhibitory neurons, and neuromodulatory inputs to specific cell classes. We have utilized novel experimental approaches – including two-photon imaging of neurons across multiple cortical regions in behaving mice, targeted recordings from specific neuron types, and activation and suppression of neuron classes - to analyze circuits that mediate visual perception and behavior. I will describe some recent results demonstrating powerful circuit motifs underlying spatial and temporal processing in the cortex. These include inhibitory computations performed via two fundamental operations, division and subtraction, by  parvalbumin (PV) and somatostatin (SOM) expressing neurons; modulation of temporal processing by acetylcholine via a unique inhibitory-disinhibitory microcircuit; and information flow and attractor dynamics in neuronal populations of the frontal cortex during memory-guided behavior.