RAPID COMMUNICATION Multisensory Integration in the Superior Colliculus of the Alert Cat

Wallace, Mark T., M. Alex Meredith, and Barry E. Stein. Multi1989), and in other instances anesthetics can degrade or sensory integration in the superior colliculus of the alert cat. J. eliminate brain stem sensory responses (Kuwada et al. Neurophysiol. 80: 1006–1010, 1998. The modality convergence 1989). Furthermore, anesthetics can significantly affect corpatterns, sensory response properties, and principles governing tical activity (Dougherty et al. 1997; Duncan et al. 1982), multisensory integration in the superior colliculus (SC) of the alert and the integrative properties of SC neurons were shown to cat were found to have fundamental similarities to those in anesthecritically depend on cortical inputs (Wallace and Stein tized animals. Of particular interest was the observation that, in a 1994). The current experiments were initiated to determine manner indistinguishable from the anesthetized animal, combinawhether the sensory convergence patterns, response propertions of two different sensory stimuli significantly enhanced the ties, and multisensory integration capabilities believed to responses of SC neurons above those evoked by either unimodal stimulus. These observations are consistent with the speculation characterize the SC and help mediate overt behaviors are that there is a functional link among multisensory integration in apparent in the alert, untrained animal. An abstract of these individual SC neurons and cross-modality attentive and orientation results was published previously (Meredith et al. 1993). behaviors.