Slide 2

Persistent activity during working memory may be generated through a balanced increase in recurrent excitation and inhibition within a subgroup of cortical neurons. A. In one classical paradigm of working memory, the animal is required to fixate a center point and to remember for a few seconds the location of a target that is briefly flashed on screen. After the delay (memory) period, the animal performs a saccade to the target. Neurons in the prefrontal cortex maintain activity at 5-40 Hz during the delay period and this activity is specific for the location of the target to be remembered. B. Models of persistent activity in networks of cortical cells depend on recurrent excitation that is balanced by local inhibition. The cessation of the activity is hypothesized to occur through a strong activition of inhibitory neurons.

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