31 research outputs found
Osteoporosis medication prescribing in British Columbia and Ontario: impact of public drug coverage
Detection of Apical Inflammatory Root Resorption Associated with Periapical Lesion Using Different Methods
Using Systematic Observation Schedules to Explore Variations in Effective Classroom Practice: Preliminary Results From Analysis of Measures From the International System for Teacher Observation and Feedback (ISTOF) Scale and Quality of Teaching (QoT)Lesson Observation Indicator Working Paper ECP/04
Bi-directional interhemispheric inhibition during unimanual sustained contractions
Abstract
Background
The interaction between homologous muscle representations in the right and left primary motor cortex was studied using a paired-pulse transcranial magnetic stimulation (TMS) protocol known to evoke interhemispheric inhibition (IHI). The timecourse and magnitude of IHI was studied in fifteen healthy right-handed adults at several interstimulus intervals between the conditioning stimulus and test stimulus (6, 8, 10, 12, 30, 40, 50 ms). IHI was studied in the motor dominant to non-dominant direction and vice versa while the right or left hand was at rest, performing isometric contraction of the first dorsal interosseous (FDI) muscle, and isometric contraction of the FDI muscle in the context of holding a pen.
Results
Compared with rest, IHI was reduced at all ISIs during contraction of either type (with or without the context of pen). IHI was reduced bi-directionally without evidence of hemispheric dominance. Further, contraction of the hand contralateral to the conditioning and test pulse yielded similar reductions in IHI.
Conclusion
These data provide evidence for bi-directional reduction of IHI during unimanual contractions. During unimanual, sustained contractions of the hand, the contralateral and ipsilateral motor cortices demonstrate reduced inhibition. The data suggest that unimanual movement decreases inhibition bi-directionally across motor hemispheres and offer one explanation for the observation of ipsilateral M1 activity during hand movements