Synaptic Theory of Working Memory

This is an article published in Science by Mongillo, Barak, and Tsodyks in 2008.

This is an addition to the reverberation theory about working memory. It adds that working memory is sustained by calcium-mediated synaptic facilitation in the recurrent connections of the neocortical networks. The paper is summarized nicely in the following excerpt from the introduction.

“Here, we present an alternative account based on properties of excitatory synaptic transmission in the prefrontal cortex (PFC). The PFC is a cortical area implicated in WM, and excitatory synaptic transmission in this area can be markedly facilitatory, unlike sensory areas where it is mostly depressing. We therefore propose that an item is maintained in the WM state by short-term synaptic facilitation mediated by increased residual calcium levels at the presynaptic terminals of the neurons that code for this item.”

They used simple integrate-and-fire neurons with the usual resources approach to modeling plasticity in their simulation.

They define the “Reactivation” of memory as occurring when “almost every neuron in the population fires a spike within an interval of about 20 ms”. This is a pretty hand wavy metric for my tastes. I would prefer something a bit more concrete. Perhaps a description of which spatiotemporal pattern of activity represented the memory?


This is a very simple model.

Calcium isn’t explicitly modelled in their formulation.

What about a more detailed model considering the principles involved in sensitization?

Obviously, how does astrocytic involvement in the synaptic activity affect the memories?

This is essentially a simpler version of Izhikevich’s work, just asking different questions.

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