Unique oscillatory activity related to visual processing in the temporal pole of monkeys

To examine the role of the temporal pole of monkeys in visual processing, the activity of single neurons was extracellularly recorded while the monkey performed a visual discrimination task. Various colored photographs were used as visual stimuli. We found neurons with oscillatory activity coupled to visual stimuli in the ventral part of the temporal pole. Oscillatory activity tended to be elicited by objects familiar to the monkey, such as familiar human faces, familiar foods and familiar non-food objects related to the experiment. The frequencies of oscillations changed depending upon the nature of the visual stimulus. The results suggest that oscillatory activity generated by the activation of a certain circuit is involved in the recognition of complex visual stimuli, leading to the production of certain psychological states.