Talk by Raoul-Martin Memmesheimer (CSN Virtual Seminar)

We hereby announce the next talk in the 'CSN Virtual Seminar'

Drifting assemblies for persistent memory: Neuron transitions and unsupervised compensation

by Prof. Raoul-Martin Memmesheimer, University of Bonn


Abstract
Change is ubiquitous in living beings. In particular, the connectome and neural representations can change. Nevertheless behaviors and memories often persist over long times. In a standard model, associative memories are represented by assemblies of strongly interconnected neurons. For faithful storage these assemblies are assumed to consist of the same neurons over time. We propose a contrasting memory model with complete temporal remodeling of assemblies, based on experimentally observed changes of synapses and neural representations. The assemblies drift freely as noisy autonomous network activity or spontaneous synaptic turnover induce neuron exchange. The exchange can be described analytically by reduced, random walk models derived from spiking neural network dynamics or from first principles. The gradual exchange allows activity-dependent and homeostatic plasticity to conserve the representational structure and keep inputs, outputs and assemblies consistent. This leads to persistent memory. Our findings explain recent experimental results on temporal evolution of fear memory representations and suggest that memory systems need to be understood in their completeness as individual parts may constantly change.


You can dial in using the following zoom room information:
https://zoom.us/j/99314955130?pwd=YXkvaW1wY2s2OHJsMFRWVDNtcERiUT09
Meeting ID: 993 1495 5130
Passcode: 4pM2Z8