This proposal aims to study the cortical representation of mechanical nociception in primary somatosensory cortex (SI). SI cortex has been proposed to play a role in processing sensory-discriminative aspect of nociceptive information. However, how each of the Areas of 3a, 3b and 1 are involved in nociception is not known. We have hypothesized that mechanical pain and pressure are differently represented in specific areas of SI. Using combined intrinsic optical imaging with electrophysiological methods, we will examine in anesthetized monkey 1) what cortical areas are involved in processing the sensory aspect of nociception, whether the sensory aspects of pain and touch are represented in the same or different cortical areas, and in which area, the amplitude of activation correlates with the intensity of nociceptive stimuli, and 2) whether nociception is topographically represented, and how cortical nociceptive responses relate to the topography of touch in each of Areas 3a, 3b and 1. This study will provide insights into how sensory aspects of nociceptive information are encoded in each area of SI.