INCREASED SENSITIVITY TO IPSILATERAL CUTANEOUS STIMULI FOLLOWING TRANSCRANIAL MAGNETIC STIMULATION OF THE PARIETAL LOBE

Transcranial magnetic stimulation of the sensorimotor cortex results in decreased sensitivity of threshold electrical stimuli to fingers of the contralateral hand. It has been suggested that one factor contributing to neglect contralateral to a unilateral parietal lesion is a release of the normal hemisphere from reciprocal interhemispheric inhibition by the damaged hemisphere. Consistent with this account, the current study demonstrated that transcranial magnetic stimulation over the parietal cortex results in increased sensitivity to cutaneous stimulation ipsilateral to the stimulation. The likely mechanism is a transcranial magnetic stimulation-induced transient dysfunction of the ipsilateral parietal cortex that then results in disinhibition of the contralateral parietal cortex.