Scientific Understanding of Consciousness
Consciousness as an Emergent Property of Thalamocortical Activity

Synaptic Theory of Working Memory


Calcium-Mediated Synaptic Facilitation


Science 14 March 2008: pp. 1543 - 1546

Synaptic Theory of Working Memory

Gianluigi Mongillo,1 Omri Barak,2 Misha Tsodyks2

1 Group for Neural Theory, Département d'Etudes Cognitives, Ecole Normale Supérieure et Collège-de-France, Paris, France.
2 Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel.


It is usually assumed that enhanced spiking activity in the form of persistent reverberation for several seconds is the neural correlate of working memory. Here, we propose that working memory is sustained by calcium-mediated synaptic facilitation in the recurrent connections of neocortical networks. In this account, the presynaptic residual calcium is used as a buffer that is loaded, refreshed, and read out by spiking activity. Because of the long time constants of calcium kinetics, the refresh rate can be low, resulting in a mechanism that is metabolically efficient and robust. The duration and stability of working memory can be regulated by modulating the spontaneous activity in the network.

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