Synaptic dynamics in mouse visual cortex following sensory deprivation
Homeostatic synaptic scaling is thought to occur cell-wide, but recent evidence suggests this form of stabilizing plasticity can be implemented more locally in reduced preparations. To investigate the spatial scales of plasticity in vivo, we used repeated two-photon imaging in mouse visual cortex after sensory deprivation to measure TNF-α dependent increases in spine size as a proxy for synaptic scaling in vivo in both excitatory and inhibitory neurons. We found that after sensory deprivation, increases in spine size are restricted to a subset of dendritic branches, which we confirmed using immunohistochemistry. We found that the dendritic branches that had individual spines that increased in size following deprivation, also underwent a decrease in spine density. Within a given dendritic branch, the degree of spine size increases is proportional to recent spine loss within that branch. Using computational simulations, we show that this compartmentalized form of synaptic scaling better retained the previously established input-output relationship in the cell, while restoring activity levels. We then investigated the relationship between new spines that form after this spine loss and strengthening and find that their spatial positioning facilitates strengthening of maintained synapses.
Date: 19 October 2018, 13:00
Venue: Sherrington Building, off Parks Road OX1 3PT
Venue Details: Large Lecture Theatre
Speaker: Dr Tara Keck (University College London)
Organising department: Department of Physiology, Anatomy and Genetics (DPAG)
Host: Professor Kristine Krug (DPAG, University of Oxford)
Part of: DPAG Head of Department Seminar Series
Booking required?: Not required
Audience: Members of the University only
Editor: Isabella Renehan