Event Details:
Are neurons soloists or obedient members of a large orchestra? This is a key question in systems neuroscience, and this talk will answer it: the relationship of neurons to the overall population lies along a continuum, from cells whose firing is strongly correlated with it (“choristers”), to others that fire independently of it (“soloists”). This relationship is invariant to visual stimuli, is causal, and is rooted in robust differences in synaptic connectivity. Moreover, this relationship is central to explaining seemingly complex population patterns.
And what kind of signals do distant cortical neurons share? To answer this question we used optogenetics to cause activity in a local region of mouse primary visual cortex (V1), and measured its effects at distal V1 locations. These effects depended on visual contrast: at low contrast there was activation, whereas at higher contrast there was suppression. The balance between the two depends on visual contrast just as predicted by a simple equation, “divisive normalization”. Intracellular measurements reveal that it arises from relative changes in synaptic excitation and inhibition.
Dinner will be provided at 6:30pm.
RSVP for the Monday, March 30 Dinner to lehope@stanford.edu by Tuesday, March 24