Somesthesis and the Neurobiology of the Somatosensory Cortex

This volume is a compilation of current research on somatosensation and its underlying mechanisms written by international experts from a broad range of disciplines. It is divided into six sections:· structural basis of information processing and neocortical neurotransmitters · psychophysics of somatosensation · cortical representation of somatosensation · sensory-motor interface · neuronal population behavior · cortical neurocomputation and modelling. It highlights not only important new findings but also novel methods and technologies applied to major unresolved issues in the field of neuroscience. The number of methods for investigating the neural mechanisms of soma-tosensory perception has grown substantially in the last decade. The book encompasses levels of inquiry from ionic channels, single unit recordings of neural activity, and functional brain imaging of the coordinated activity of large neuronal ensembles to human psychophysics of controlled somatic stimulation. This work is of great value for researchers and students interested in the dynamic neuronal mechanisms involved in the complex processes of sensory perception and provides a picture of our present understanding of the neural representation of the external world relayed through the somatosensory system.

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The field of neuroscience is experiencing a period of unprecedented growth. The range of ap­ proaches used to investigate the fundamental mechanisms underlying different aspects of somatosen­ sory perception has expanded substantially since the last International Symposium on Informa­ tion Processing in the Somatosensory System. Diversity of approach has become the hallmark of somatosensory research, and I believe that the impact of this diversity continues to be positive. of this symposium with previous symposia will show that researchers are employing Comparison an array of new methods and technologies and that they are offering new insights into old ques­ tions. The techniques range from studies of ionic channels, single unit recordings, functional brain imaging to psychophysics. A careful reading ofthe chapters reveals subtle and, on occasion, also obvious differences of opinion about experimental outcomes, approaches, and views. These differences are healthy signs of venture into new and uncharted territories. It is my hope that read­ ers will appreciate both the diversity of the research addressing somesthesis, and the personal commitment, enthusiasm, and scientific rigor of the participants who made this symposium and volume meaningful for all involved. We all look forward to tracking the progress of somatosensory research at our next Symposium at the turn of the century. OveFranzen November 1995 xv List of Contributors David T. Blake Harold Burton Krieger MindlBrain Institute Department of Anatomy and Neurobiology Department of Neuroscience Washington University The Johns Hopkins University School of Medicine Baltimore, MD 21218, USA St.

Contenu
Structural basis of information processing and neocortical neurotransmitters.- Divergence of thalamocortical projections and limits on somatosensory cortical plasticity.- Inhibitory circuitry in relation to the functional organization of somatosensory cortex.- Pain, temperature, and the sense of the body.- The functional role of a noninactivating sodium current in neocortical neurons.- Psychophysics of somatosensation.- Information processing channels in the sense of touch.- A novel approach for studying direction discrimination.- Tactile directional sensibility; theoretical and functional aspects.- Experimental assessment of the temporal hypothesis of velocity scaling.- Vibrotactile adaptation of the RA system: A psychophysical analysis.- Tactile neural codes for the shapes and orientations of objects.- Tactual discrimination of softness: Abilities and mechanisms.- Representation of the shape and contact force of handled objects in populations of cutaneous afferents.- Haptic object processing I: Early perceptual features.- Haptic object identification II: Purposive exploration.- Cortical representation of somatosensation.- The somatosensory cortex.- The organization of lateral somatosensory cortex in primates and other mammals.- Serial processing in the somatosensory system of macaques.- Parallel processing in somatosensory areas I and II of the cerebral cortex.- Linearity as the basic law of psychophysics: Evidence from studies of the neural mechanisms of roughness magnitude estimation.- Form processing and attention effects in the somatosensory system.- Functional plasticity of cortical representations of the hand.- Sensory-motor interface.- Somatosensory signals and sensorimotor transformations in reactive control of grasp.- Strain-sensitive mechanoreceptors in thehuman skin provide kinaesthetic information.- A second tactile system in the human skin with unmyelinated primary afferents.- Factors influencing the perception of tactile stimuli during movement.- Changing the intended direction of movement.- Disturbances of motor behavior after parietal lobe lesions in the human.- Neuronal population behavior: Imaging techniques.- PET and fMRI scans of the cerebral cortex in humans and single neuron responses from SI in monkeys to rubbing embossed dot and grating patterns across a fingerpad.- Magnetic resonance functional mapping of cortical activation associated with differing sensorimotor hand paradigms.- Whole-head neuromagnetic recordings of human somatosensory cortical functions.- Optical imaging of intrinsic signals in somatosensory cortex.- Somatosensory and frontal cortical processing during pain experience.- Cortical Neurocomputation and modelling.- Local receptive field diversity within cortical neuronal populations.- Functional segregation and integration in the nervous system: Theory and models.