Development/Plasticity/Repair Repetitive Transcranial Magnetic Stimulation-Induced Changes in Sensorimotor Coupling Parallel Improvements of Somatosensation in Humans

Repetitive transcranialmagnetic stimulation (rTMS) is an established technique fornon-invasive stimulationof humancortex.Although studies have shown an influence of rTMS on single cortical regions and on simple behavioral response patterns, its influences on the dynamics of task-related activity in cortical networks have not been characterized.We provide such a characterization by showing that 5 Hz rTMS over primary somatosensory cortex (SI) induces a reconfiguration of activity patterns in a sensorimotor network, comprising the stimulated region and ipsilateral primarymotor cortex (MI). These plastic changes endure for up to 120min and are correlated with behavioral improvement in discrimination. Dynamic causal modeling showed that this reconfiguration could be explained by an rTMS-induced increase in SI excitability (self-connection) and an increase in the effective connectivity from SI to MI. Thus, our data demon-strate that rTMS can temporarily induce behaviorally relevant reorganization within a complex cortical network underlying human somatosensory experience. Key words: functional magnetic resonance imaging; repetitive transcranial stimulation; sensorimotor coupling; effective connectivity; plasticity; perceptio