||Dissociation of mnemonic coding and other functional neuronal processing in the monkey prefrontal cortex.
Single-neuron activity was recorded in the prefrontal cortex of 3 female monkeys during the performance of a spatial delayed alternation (DA) task and during the presentation of a variety of visual, auditory, and somatosensory stimuli. Recordings were performed in both experimental situations from 152 neurons. Thirty- two percent of the neurons fired in relation to the DA task performance and 39% were responsive to sensory stimulation or to movement. Three types of task-related neuronal activity were recorded: delay, delay and movement, and movement related. The majority (73%) of the task-related neurons fired in relation to the delay period. The majority (70%) of the delay-related neurons could not be activated by any of the sensory stimuli used and did not fire in relation to movement. In contrast, the majority (66%) of the movement-related neurons were responsive to sensory stimulation outside of the task context. Most delay-related neurons engaged in the spatial DA task did not respond to extrinsic sensory stimulation. These results indicate that most prefrontal neurons firing selectively during the delay phase of the DA task are highly specialized and process only task-related information. (PsycINFO Database Record (c) 2009 APA, all rights reserved)