Abstract
Posterior cingulate cortex (CGp) is strongly connected with areas involved in vision, attention, and eye movements. Furthermore, CGp neurons respond both to visual stimulation and after gaze shifts, and the strength of visual responses predicts saccade accuracy. These observations suggest that CGp neurons may signal covert processes associated with orienting. The goal of the present study was to determine quantitatively whether neuronal activity in CGp persists during delays when the saccade target is no longer visible. Single CGp cells were studied in monkeys (M. mulatta) performing memory saccade trials in which the saccade target was extinguished 200–600 ms before the cue to shift gaze to the remembered location of the target. For many neurons, firing rate increased following target onset, transiently decreased after target offset, and increased again during the memory delay prior to movement. Spatial selectivity for remembered target locations was similar to that for visible targets. These data suggest a role for CGp in covert processes associated with spatial orienting.
Supported by the McDonnell-Pew Program in Cognitive Neuroscience, the Whitehall Foundation, EY013496 (MLP), and F31-NS-046193 (HLD).