Responses to auditory stimuli in macaque lateral intraparietal area II. Behavioral modulation

The lateral intraparietal area (LIP), a region of posterior parietal cortex , was once thought to be unresponsive to auditory stimulation. However, rec ent reports have indicated that neurons in area LIP respond to auditory sti muli during an auditory-saccade task. To what extent are auditory responses in area LIP dependent on the performance of an auditory-saccade task? To a ddress this question, recordings were made from 160 LIP neurons in two monk eys while the animals performed auditory and visual memory-saccade and fixa tion tasks. Responses to auditory stimuli were significantly stronger durin g the memory-saccade task than during the fixation task, whereas responses to visual stimuli were not. Moreover, neurons responsive to auditory stimul i tended also to be visually responsive and to exhibit delay or saccade act ivity in the memory-saccade task. These results indicate that, in general, auditory responses in area LIP are modulated by behavioral context, are ass ociated with visual responses, and are predictive of delay or saccade activ ity. Responses to auditory stimuli in area LIP may therefore be best interp reted as supramodal responses, and similar in nature to the delay activity, rather than as modality-specific sensory responses. The apparent link betw een auditory activity and oculomotor behavior suggests that the behavioral modulation of responses to auditory stimuli in area LIP reflects the select ion of auditory stimuli as targets for eye movements.