Chapter 24 Functional anatomy of nociceptive neurones in rat superior colliculus

Publisher Summary This chapter focuses on the role of superior colliculus (SC) in determining the animals' immediate reactions to sudden novel events, including the activation of emotional motor mechanisms. The role of the SC in visual orienting has been widely recognized. More recently, its role in the production of orienting movements to a wide range of innocuous multimodal stimuli has been emphasized. The present results demonstrate that the orientation-approach role of the SC is not limited to innocuous stimuli. Rather, the SC plays a significant role in organizing approach responses to persistent noxious stimuli when immediate withdrawal responses prove to be ineffective in ameliorating discomfort. The neural basis by which the initial withdrawal and escape behaviors, that are appropriate in certain situations, are converted to more adaptive approach and orient behaviors that are required when dealing with a persistent noxious stimulus, as well as how this relates to the circuitry of the SC, remains far from clear.