Data from: MRI-based visualization of rTMS-induced cortical plasticity in the primary motor cortex

Repetitive transcranial magnetic stimulation (rTMS) induces changes in
cortical excitability for minutes to hours after the end of intervention.
However, it has not been precisely determined to what extent cortical
plasticity prevails spatially in the cortex. Recent studies have shown
that rTMS induces changes in “interhemispheric” functional connectivity,
the resting-state functional connectivity between the stimulated region
and the symmetrically corresponding region in the contralateral
hemisphere. In the present study, quadripulse stimulation (QPS) was
applied to the index finger representation in the left primary motor
cortex (M1), while the position of the stimulation coil was constantly
monitored by an online navigator. After QPS application, resting-state
functional magnetic resonance imaging was performed, and the
interhemispheric functional connectivity was compared with that before
QPS. A cluster of connectivity changes was observed in the stimulated
region in the central sulcus. The cluster was spatially extended
approximately 10 mm from the center [half width at half maximum (HWHM):
approximately 3 mm] and was extended approximately 20 mm long in depth
(HWHM: approximately 7 mm). A localizer scan of the index finger motion
confirmed that the cluster of interhemispheric connectivity changes
overlapped spatially with the activation related to the index finger
motion. These results indicate that cortical plasticity in M1 induced by
rTMS was relatively restricted in space and suggest that rTMS can reveal
functional dissociation associated with adjacent small areas by inducing
neural plasticity in restricted cortical regions.