Bilateral sequential motor cortex stimulation and skilled task performance with non-dominant hand

•Both, contralateral M1 iTBS and ipsilateral M1 cTBS improved non-dominant skilled-task performance.•Bilateral sequential M1 TBS (contralateral cTBS followed by ipsilateral iTBS) improved skilled-task performance more than unilateral or sham TBS.•Bilateral sequential M1 TBS may be particularly effective in improving motor learning, also in the neurorehabilitation setting.

ObjectiveTo check whether bilateral sequential stimulation (BSS) of M1 with theta burst stimulation (TBS), using facilitatory protocol over non-dominant M1 followed by inhibitory one over dominant M1, can improve skilled task performance with non-dominant hand more than either of the unilateral stimulations do. Both, direct motor cortex (M1) facilitatory non-invasive brain stimulation (NIBS) and contralateral M1 inhibitory NIBS were shown to improve motor learning.MethodsForty right-handed healthy subjects were divided into 4 matched groups which received either ipsilateral facilitatory (intermittent TBS [iTBS] over non-dominant M1), contralateral inhibitory (continuous TBS [cTBS] over dominant M1), bilateral sequential (contralateral cTBS followed by ipsilateral iTBS), or placebo stimulation. Performance was evaluated by Purdue peg-board test (PPT), before (T0), immediately after (T1), and 30 min after (T2) an intervention.ResultsIn all groups and for both hands, the PPT scores increased at T1 and T2 in comparison to T0, showing clear learning effect. However, for the target non-dominant hand only, immediately after BSS (at T1) the PPT scores improved significantly more than after either of unilateral interventions or placebo.ConclusionM1 BSS TBS is an effective intervention for improving motor performance.SignificanceM1 BSS TBS seems as a promising tool for motor learning improvement with potential uses in neurorehabilitation.