Somatosensory Responses

Abstract This chapter is devoted to task-related neurophysiology of the human somatosensory system from peripheral nerves to the cerebral cortex. After brief outlining of the history of this field, the discussion starts from compound action potentials and fields of peripheral nerves and continues with comparison and discussion of the complementarity of early MEG and EEG responses originating from the primary somatosensory cortex. The responses from the second somatosensory cortex to transient electrical stimulation of peripheral nerves at the wrist and ankle are described, especially illustrating analysis of their source locations, before turning to somatosensory steady-state responses. Considerable lowering of the noise floor of a single-channel magnetometer has allowed high-frequency 600-Hz oscillatory responses to be detected in single-trial recordings from primary somatosensory cortex. The chapter ends with a brief survey of responses related to acute pain and nociception.