Misha Tsodyks

Title: Putative synaptic theory of temporal order encoding in working memory
(Joint work with Gianluigi Mongillo)

Abstract: Overwhelming evidence indicates that working memory automatically encodes incoming stimuli in the correct presentation order. How this is achieved in the brain is however not well understood. We addressed this issue in the framework of our previously proposed synaptic theory, according to which stimuli are encoded in working memory by selective short-term facilitation of corresponding recurrent synaptic connections. We further suggest that if synapses exhibit longer-term forms of facilitation, e.g. synaptic augmentation, encodings acquire a ‘primacy gradient’, i.e. stimuli presented earlier are stronger encoded compared to later presented ones. We propose a simple way the order information can be retrieved. The new model also sheds new light on the important issue of working memory capacity. We suggest that one should distinguish between retrieval capacity which is limited to very few items, and representational capacity that can be significantly larger.