Synaptic dynamics in mouse visual cortex following sensory deprivation
Friday 19 October – 1pm at the Large Lecture Theatre, DPAG/Sherrington Bldg
The Cortex Club proudly presents Tara Keck from University College London, who will be talking to us about her research on homeostatic synaptic plasticity. Please join us on October 19th at the Large Lecture Theatre of the Sherrington Building of the Department of Physiology, Anatomy and Genetics.
Prof. Tara Keck has kindly agreed to a Q&A lunch after her talk to which students and stuff are warmly invited. If you would like to join the free sandwich held at the Sherrington Library please sign up at https:// goo.gl/forms/
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.