SENSORIMOTOR GATING DEFICIT AFTER LESIONS OF THE SUPERIOR COLLICULUS

THE superior colliculus (SC) is important for the processing of sensor y information of different modalities and for the mediation of adequat e motor responses in mammals. The present study investigated the effec ts of excitotoxic lesions of the SC on two different modulations of th e acoustic startle response (ASR) in rats. Modulations of the ASR (i.e . increase or decrease of the response strength) represent useful mode ls for the study of sensorimotor integration phenomena. Lesions of the SC decreased the prepulse inhibition of the ASR without affecting the baseline startle amplitude or the enhancement of the ASR by footshock sensitization. These results suggest a crucial role of the SC in the prepulse inhibition of the ASR, a model of sensorimotor gating.