A mechanism for persistent delayed irregular activity in working memory

D. HANSEL AND G. MATO

Congreso; Dynamics of cortical and cortical-subcortical circuits: Interaction between theory and experiments; 2013

Howard Huhes Medical Institute

Persistent activity in cortex is the neural correlate of working memory (WM). In persistent activity, spike trains are highly irregular, even more than in spontaneous activity. This apparently innocuous feature challenges current understanding that persistent activity is due to the reverberation of activity sustained by linear interactions between neurons that have nonlinear input-output transfer functions. Here we show that to account for the observed irregular firing one must assume that the interactions sustaining persistent activity are nonlinear. We apply this result to propose a novel mechanism of WM in prefrontal cortex (PFC) based on short term facilitation as recently discovered in recurrent synapses between pyramidal cells in PFC. This mechanism is the first to account not only for irregular persistent firing but also for the diversity of neuronal responses in PFC during spatial WM tasks. Our work highlights a new role of nonlinear neuronal interactions in cortical computation.