Transcranial magnetic stimulation (TMS) of the motor cortex of one hemisphere (conditioning stimulus, CS) inhibits EMG responses evoked in distal hand muscles by a magnetic stimulus given at appropriate interval later over the opposite hemisphere (test stimulus, TS). The common interpretation attributes this effect to an inhibition produced at cortical level via a transcallosal route. The variability of cortical excitability as measured by the interhemispheric paired-pulse (PP) technique has been assessed in healthy subjects in order to compare sub- and supra-threshold intensity of CS (80% versus 120% of individual motor threshold, MT). Within- and between-subject variability relating, respectively, to interhemispheric and gender differences were also assessed. Results point to an efficacy of a magnetic CS on one hemisphere in inhibiting EMG responses of the abductor digiti minimi (ADM) stimulated by a TS delivered over the opposite hemisphere in a range of intervals centered at 12ms. These reductions were produced by the 120% suprathreshold CS, while the 80% subthreshold CS did not affect EMG responses. Females showed a higher transcallosal inhibition than males, suggesting gender differences in interhemispheric connectivity that concern the anterior half of the trunk of the corpus callosum
Titolo: | Callosal effects of trancranial magnetic stimulation (TMS): The influence of gender and stimulus parameter |
Autori: | |
Data di pubblicazione: | 2004 |
Rivista: | |
Abstract: | Transcranial magnetic stimulation (TMS) of the motor cortex of one hemisphere (conditioning stimulus, CS) inhibits EMG responses evoked in distal hand muscles by a magnetic stimulus given at appropriate interval later over the opposite hemisphere (test stimulus, TS). The common interpretation attributes this effect to an inhibition produced at cortical level via a transcallosal route. The variability of cortical excitability as measured by the interhemispheric paired-pulse (PP) technique has been assessed in healthy subjects in order to compare sub- and supra-threshold intensity of CS (80% versus 120% of individual motor threshold, MT). Within- and between-subject variability relating, respectively, to interhemispheric and gender differences were also assessed. Results point to an efficacy of a magnetic CS on one hemisphere in inhibiting EMG responses of the abductor digiti minimi (ADM) stimulated by a TS delivered over the opposite hemisphere in a range of intervals centered at 12ms. These reductions were produced by the 120% suprathreshold CS, while the 80% subthreshold CS did not affect EMG responses. Females showed a higher transcallosal inhibition than males, suggesting gender differences in interhemispheric connectivity that concern the anterior half of the trunk of the corpus callosum |
Handle: | http://hdl.handle.net/11697/12006 |
Appare nelle tipologie: | 1.1 Articolo in rivista |