Neural activity in monkey amygdala during performance of a multisensory operant task

In this paper, we study the potential involvement of monkey amygdala in the evaluation of value encoding of visual and auditive stimuli associated with reward or no reward. We recorded the activity of 93 extracellular neurons from the monkey right amygdala, while performing a multisensory operant task. The activity of 78 task-related neurons was studied. Of these, 13 neurons (16%) responded to the value of visual stimuli, 22 neurons (28%) responded after the presentation of visual stimuli, 22 neurons (28%) showed an inhibition around the lever-pressing and were classified as action related neurons and 22 neurons (28%) responded after reward delivery. These findings suggest that neurons in the amygdala play a role in encoding value and processing visual information, participate in motor regulation and are sensitive to reward. The activity of these neurons did not change in the evaluation of auditive stimuli. These data support the hypothesis that amygdala neurons are specific to each sensory modality and that different groups of amygdala neurons process visual and auditive information.