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Christian Machens

Cold Spring Harbor Laboratory, USA


Wednesday 8 November 2006, 16:00


FIL Seminar Room, 4th Floor

Alexandra House, 12 Queen Square, London, WC1N 3AR



Reconstruction of network dynamics in the prefrontal cortex during a two-interval discrimination task


I will talk about the progress we have made in understanding how the primate brain solves a classical, psychophysical task. In this task, a subject must first perceive a brief stimulus (f1), maintain it in short-term memory for several seconds, and then compare it with a brief second stimulus (f2), to immediately decide which of the two stimuli was larger (f1>f2?). Electrophysiological recordings from neurons in the primate prefrontal cortex show a large variety of task-related neural activities, including correlates of the short-term memory of f1 and the monkey's decision (f1>f2?). Using phase space embedding methods, I here report that this diversity of neural activities is due to random combinations of a few fundamental components. These components suggest a slow reorganization of the short-term memory representation of f1 during the delay period of the task. I will discuss these results in relation to simple network models previously developed by us. [joint work with Ranulfo Romo and Carlos Brody].