Misha Tsodyks

Department of Neurobiology
Weizmann Institute of Science

http://www.weizmann.ac.il/home/bnmisha/

Friday, October 16

12:00-1:30 pm

Synaptic theory of working memory

We recently proposed that short-term working memory could be residing in

selective facilitation of recurrent connections in dedicated neocortical

circuits. This mechanism can account for low persistent firing rates

observed in monkeys performing delayed memory tasks, and is robust to

external perturbations. In this presentation I will extend the theory to

the case of continuous variables, such as orientation, and show that

synaptic facilitation can dramatically increase the stability of memory

to random perturbation of connectivity. I will also present our analysis of

recordings of large number of single neurons in prefrontal cortex of

monkeys performing parametric working memory tasks, obtained in the

laboratory of Professor Ranulfo Romo. The results of the analysis show

that information about the stimulus in the delay period is encoded in a

highly dynamic manner, in particular the population activity does not

faithfully represent the stimulus for for a certain period during the

delay. Synaptic facilitation can account for some of the features of the

data.