Selective spatial attention induces short-term plasticity in human somatosensory cortex

Early cognitive process in the primary somatosensory cortex (SI) was studie d by measuring somatosensory evoked magnetic fields during selective attent ion tasks. We used vibratory stimuli to the index or middle finger with a f requency of 100 or 400 Hz for selective discrimination of spatial finger an d non-spatial frequency attribute of stimuli. An early M50 component from t he SI cortex indicated that the SI regions for the fingers were specificall y segregated in a finger discrimination task but not in a frequency discrim ination task or in a control condition. The task-dependent and immediate sw itchover of cortical finger representation demonstrates a dynamic SI activa tion for spatial information processing. NeuroReport 12:3133-3136 (C) 2001 Lippincott Williams & Wilkins.