Functional MRI in human somatosensory cortex activated by touching textured surfaces.

MRI revealed activation foci in human somatosensory cortex during protocols involving stimulation of the fingertips with a textured surface. A 2D T2*-weighted gradient echo sequence was used to acquire images. The imaging protocol included acquiring images while subjects performed specific tactile stimulation paradigms (activation scans) or rested. Three different paradigms were used to produce functional activation using a textured surface to rub the fingertips of one hand. First, motor sensory activation was produced by rubbing the textured surface held in one hand against the fingertips of the opposite hand only during the activation scans. Second, the hand holding the textured surface moved throughout the experiment but touched the fingertips of the opposite hand only during the activation scans. Third, subjects remained still in the magnet throughout the entire study while an investigator rubbed the textured surface against the subjects' fingertips during the activation scans. Images were postprocessed using a cross-correlation scheme. The results revealed multiple foci of motor sensory activation near the central sulcus, postcentral sulcus, and prefrontal cortex.