Intrinsic Signal Imaging of Somatosensory Function in Nonhuman Primates

Optical imaging studies of somatosensory cortex (SI) in primates has led to re-evaluation of our understanding of cortical functional organization. This chapter describes findings showing that somatosensory topography, long a foundation of cortical function, may not be as precise in the awake monkey, suggesting a re-evaluation of the relationship between topographic representation and sensory precision. Optical maps of the tactile funneling illusion, which demonstrate a map of how tactile stimuli are perceived rather than a map of skin topography, call for a re-evaluation of topographic representation in SI as a body map. With respect to representation of sensory submodalities, optical images of vibrotactile pressure, flutter, and vibration domains reveal striking similarities and differences between modality maps in visual and somatosensory cortices.