Somatotopic mapping of the human primary somatosensory cortex by fully automated tactile stimulation using functional magnetic resonance imaging.

The clinical application of functional magnetic resonance imaging (fMRI) requires time-saving protocols insensitive to artifacts that provide robust localization and important information on brain function. A fully automated, pneumatically driven tactile stimulation is presented, that reproducibly localizes postcentral lip, finger and toe representations in contralateral primary somatosensory cortex (SI) with mean correlation coefficients (cc) and relative BOLD signal changes (dS) of cc approximately 0.59, dS approximately 1.95% (fingers); cc approximately 0.52, dS approximately 1.35% (lips); cc approximately 0.47, dS approximately 1.42% (toes). Bilateral somatotopic mapping requires 21 min of scanning time and has become a clinical routine fMRI application in patients with perirolandic tumors. Normative data may also be useful in monitoring cerebral plasticity and reorganization, e.g. in sensorimotor recovery after cerebral ischemia or in understanding mechanisms of supraspinal pain processing.