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Poster D in Poster Session D: Wednesday, August 5, 2:00 – 3:45 pm, Kimmel Center, Shorin & Rosenthal Rooms

Modulation of synaptic connectivity by population activity

Tian Qiu¹, Drew B. Headley¹; ¹Rutgers University

Presenter: Tian Qiu

Synaptic integration is fundamental to neuronal processing. While each synapse is often treated as independent of the activities of its neighbors, this neglects features of dendritic integration allowing interactions between them. Such interactions could alter the effective weight of a synaptic connection between a pair of neurons depending on the pattern of adjacent impinging synaptic activities. This pattern will be partly reflected in the ongoing activity of the local network. As a result, synaptic coupling should vary with the state of population activity. We determined if this was the case in rat motor cortex in vivo by tracking the effective strength of putative monosynaptic connections between pairs of single units, and mapping this on to the population activity space. A substantial proportion of excitatory monosynaptic connections were significantly enhanced during specific population activity modes. This suggests that effective connectivity at the lowest level of the cortical microcircuit varies with population state. Such a mechanism opens the door to new computational capabilities in biological neural networks.

Topic Area: Methods, Tools, Theory & Neural Coding