Single Unit Activity in Cat Prefrontal and Parietal Cortex During Performance of a Symmetrically Reinforced Go-No go Task

Abstract

Relationships between the performance in a symmetrically reinforced go-no go task and cellular firing patterns in prefrontal and parietal association areas of the neocortex were studied in six cats. During recordings, animals lay in a box, with their heads fixed to a stereotaxic frame, and performed an auditory go-no go task by pressing a retractable lever in front of them. Units obtained were classified into eight types according to the correlation of their activity changes with aspects of the task and/or with sensory stimuli. These types were (1) (poly-) sensory, (2) reward related, (3) EMG-related, (4) EOG-related, (5) event-related, (6) movement-initiating, (7) expressing expectancy or novelty, and (8) nonspecific or task-unrelated active units. Between the two recording areas a considerable degree of similarity was obtained in unit firing patterns. It was concluded that within the cerebral cortex, and especially within its association areas, a considerable functional overlap exists, that neurons may be involved in the processing of several and rather different phenomena, and that the processing of information at this level of the brain is generally done via widespread, interwoven neuronal nets so that only the average network activity, but not that of a particular, single neuron, represents a stimulus or an event.

Key Words:

• single unit recording
• prefrontal cortex
• parietal cortex
• go-no go task
• cat