The functions of the somatosensory system are multiple. We use tactile input to localize and experience the various qualities of touch, and proprioceptive information to determine the position of different parts of the body with respect to each other, which provides fundamental information for action. Further, tactile exploration of the characteristics of external objects can result in conscious perceptual experience and stimulus or object recognition. Neuroanatomical studies suggest parallel processing as well as serial processing within the cerebral somatosensory system that reflect these separate functions, with one processing stream terminating in the posterior parietal cortex (PPC), and the other terminating in the insula. We suggest that, analogously to the organisation of the visual system, somatosensory processing for the guidance of action can be dissociated from the processing that leads to perception and memory. In addition, we find a second division between tactile information processing about external targets in service of object recognition and tactile information processing related to the body itself. We suggest the posterior parietal cortex subserves both perception and action, whereas the insula principally subserves perceptual recognition and learning.
Chris Dijkerman is a Senior Lecturer at the Department of Experimental Psychology at Utrecht University. He completed his DPhil in Psychology at the University of Oxford under supervision of Larry Weiskrantz and Faraneh Vargha-Khadem and subsequently worked as a postdoctoral research fellow with David Milner at the University of St. Andrews. His research interests include the neuropsychology of perceptual and sensorimotor processing, hemispatial neglect and motor imagery. He has (co)authored more than 30 scientific papers and book chapters and has held several research grants from the Leverhulme Trust, the Scottish Department of Health, and the Netherlands Research Organisation (NWO). His research is currently funded by a Vidi personal fellowship from NWO.
Edward de Haan is a Full professor of Neuropsychology at Utrecht University. Before his move to Utrecht in 1991, he worked for 10 years at the Ratcliffe Infirmary, Oxford together with Freda Newcombe. He finished his PhD in 1988, co-supervised by Andy Young. His research interests range from applied clinical neuropsychological issues to fundamental neuroscience, particularly perception, memory, emotion, and consciousness. He was Head of the Department of Experimental Psychology at Utrecht University from 1994 to 2001 and subsequently Scientific Director of the Helmholtz School and Institute (2001–2005). He is the founding editor of the Journal of Neuropsychology, has (co)authored more than 150 scientific papers and chapters, and is (co)editor of four books.