Activity patterns of human somatosensory cortex adapt dynamically to stimulus properties

Long-term synchronous tactile stimulation of two sites of the body results in integrated, overlapping cortical representations whereas asynchronous st imulation leads to segregated representations. To investigate the cortical capacity to adapt dynamically to stimulation properties 22 subjects were st imulated at digits 1. 3 and 5 of both hands in either random or fixed order . Changes in the functional organization of the somatosensory cortex were i nferred by neuromagnetic source analysis based on somatosensory evoked magn etic fields. Compared to the stimulation in random sequence, the stimulatio n in fixed order revealed a reduction in distance between the cortical repr esentation of D1 and D3. We conclude that the pattern of activation in the somatosensory cortex adapts dynamically to the spatio-temporal characterist ics of the stimuli. NeuroReport 11:2977-2980 (C) 2000 Lippincott Williams & Wilkins.