Synaptic theory of working memory

G Mongillo, O Barak, M Tsodyks - Science, 2008 - science.org
Science, 2008science.org
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 …
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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