Primary sensorimotor cortex activation with task-performance after fatiguing hand exercise.
We have compared functional MRI signals in primary sensorimotor cortex (SM1) during a paced motor task of each hand before and after unimanual (right hand) fatiguing exercise. Our aims were to determine whether the degree of activation is different when a motor task is performed after a fatiguing exercise, and whether there are any differences in activation between movement of the fatigued and non-fatigued hands. There was a significant reduction in the number of voxels activated in SM1 in the hemisphere contralateral to movement of both the fatigued hand (38 +/- 5 pre-exercise versus 21 +/- 3 post-exercise; P<0.05) and the non-fatigued hand (32 +/- 4 pre-exercise vs 18 +/- 4 post-exercise; P<0.05). There was no significant difference in the magnitude of the functional magnetic resonance imaging signal before or after exercise, however, the variance increased significantly after exercise (6.0 +/- 0.5 pre-exercise vs 7.3 +/- 0.6 post-exercise; P<0.01). Reduced functional activation in SM1 may reflect increased variability in the activation rather than a reduction in activation of cortical motor networks after fatigue.
Benwell
Nicola M
NM
Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Queen Elizabeth II Medical Centre, Nedlands, WA, 6009, Australia.
Byrnes
Michelle L
ML
Mastaglia
Frank L
FL
Thickbroom
Gary W
GW
D000328:Adult; D001931:Brain Mapping; D015444:Exercise / Q000502:physiology*; D005221:Fatigue / Q000503:physiopathology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006225:Hand / Q000503:physiopathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D011597:Psychomotor Performance / Q000502:physiology; D013003:Somatosensory Cortex / Q000098:blood supply / Q000502:physiology*; D013647:Task Performance and Analysis
D010100:Oxygen