Remote changes in cortical excitability after stroke

摘要: Changes in the cerebral metabolism and excitability of brain areas remote from an ischaemic lesion have been reported animals humans implicated as a mechanism relevant to functional recovery. The aim present study was determine whether changes inhibitory excitatory activity motor cortex non-affected hemisphere are stroke patients, these related extent patients' recovery function. Transcranial magnetic stimulation (TMS) used first dorsal interosseus muscle (FDI) hand 13 patients with good function after stroke, compared left hemispheric healthy age-matched volunteers. In experiment, paired-pulse TMS conditioning stimulus (CS) set at 80% subject's threshold (MT) interstimulus intervals (ISIs) 2, 3, 10 15 ms used. second different intensities CS were its effect on succeeding suprathreshold test ISI that kept constant 2 ms. third rise evoked potential (MEP) amplitudes increasing measured. two additional control experiments, versus right normal volunteers poor studied. MT, mean MEP recruitment curves similar those recovery, increased ISIs 3 ms, When tested subjects small intensities, but faded rapidly higher patients. contrast, this increase cortical not seen. similarity indicates overall corticomotoneuronal has changed low subjects, steeper conditioned amplitude recovering suggest contralesional balance shifted towards neuronal circuits This shares similarities mechanisms for reorganizational processes experimental injury may be stroke. absence supports relevance our findings