TY - JOUR
T1 - Task-dependent effects of interhemispheric inhibition on motor control
AU - Fling, Brett W.
AU - Seidler, Rachael D.
N1 - Funding Information:
This work was supported by the National Institutes of Health ( T32-AG00114 ). The authors thank Scott Carr and Yanin Vongkancom for their assistance with equipment fabrication and data collection.
PY - 2012/1/1
Y1 - 2012/1/1
N2 - Interhemispheric communication consists of a complex balance of facilitation and inhibition that is modulated in a task-dependent manner. However, it remains unclear how individual differences in interhemispheric interactions relate to motor performance. To assess interhemispheric inhibition, we utilized the ipsilateral silent period technique (iSP; evoked by suprathreshold transcranial magnetic stimulation), which elicits inhibition of volitional motor activity. Participants performed three force production tasks: (1) unimanual (right hand) constant force, (2) bimanual constant force, (bimanual simultaneous) and (3) bimanual with right hand constant force and left hand sine wave tracking (bimanual independent). We found that individuals with greater IHI capacity demonstrated reduced mirror EMG activity in the left hand during unimanual right hand contraction. However, these same individuals demonstrated the poorest performance during the bimanual independent force production task. We suggest that a high capacity for IHI from one motor cortex to another can effectively prevent "motor overflow" during unimanual tasks, but it can also limit interhemispheric cooperation during independently controlled bimanual tasks.
AB - Interhemispheric communication consists of a complex balance of facilitation and inhibition that is modulated in a task-dependent manner. However, it remains unclear how individual differences in interhemispheric interactions relate to motor performance. To assess interhemispheric inhibition, we utilized the ipsilateral silent period technique (iSP; evoked by suprathreshold transcranial magnetic stimulation), which elicits inhibition of volitional motor activity. Participants performed three force production tasks: (1) unimanual (right hand) constant force, (2) bimanual constant force, (bimanual simultaneous) and (3) bimanual with right hand constant force and left hand sine wave tracking (bimanual independent). We found that individuals with greater IHI capacity demonstrated reduced mirror EMG activity in the left hand during unimanual right hand contraction. However, these same individuals demonstrated the poorest performance during the bimanual independent force production task. We suggest that a high capacity for IHI from one motor cortex to another can effectively prevent "motor overflow" during unimanual tasks, but it can also limit interhemispheric cooperation during independently controlled bimanual tasks.
KW - Force production
KW - Ipsilateral silent period
KW - Motor overflow
UR - http://www.scopus.com/inward/record.url?scp=80054844391&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=80054844391&partnerID=8YFLogxK
U2 - 10.1016/j.bbr.2011.09.018
DO - 10.1016/j.bbr.2011.09.018
M3 - Article
C2 - 21944939
AN - SCOPUS:80054844391
SN - 0166-4328
VL - 226
SP - 211
EP - 217
JO - Behavioural Brain Research
JF - Behavioural Brain Research
IS - 1
ER -