MULTISENSORY CONVERGENCE AND INTEGRATION IN THE NEOSTRIATUM AND GLOBUS-PALLIDUS OF THE RAT

The extracellular response properties of neurons in the caudate-putame n (CPu), globus pallidus (GP) and lateral amygdaloid nucleus (La) evok ed by auditory and somatosensory stimuli were investigated. A total of 61 neurons in these areas responded either singly to somatosensory st imulation (unisensory), or to both somatosensory and auditory stimulat ion (multisensory). Higher rates of somatosensory stimulation reduced the response magnitude of CPu neurons more than that of GP neurons. In multisensory neurons, combined somatosensory and auditory stimulation compared to unisensory stimulation resulted in three characteristic r esponse patterns: enhancement, depression or interaction. Temporal mis alignment of the peak frequency latencies evoked by auditory and somat osensory stimulation altered the response magnitude in the majority of neurons. The response properties and anatomical connectivity of CPu a nd GP neurons suggest that the observed multisensory integrative effec ts may be used to facilitate motor responses to low intensity stimuli.