Jill M. Slade1,2, Sean C. Forbes3, Ryan M. Francis3, Robert W. Wiseman1,3, Ronald A. Meyer1,3
1Radiology, Michigan State University, East Lansing, MI, USA; 2Manipulative Medicine, Michigan State University, East Lansing, MI, USA; 3Physiology, Michigan State University, East Lansing, MI, USA
An area of primary sensorimotor cortex in which functional MRI signal changes are highly correlated with the force of isometric handgrip contractions was identified in adult subjects. Activity in this area was then measured during 3 min constant low-force contractions performed either with or without forearm ischemia. The signal increase in the force-correlated region was initially similar in both conditions, but by the end of the contraction was 2-fold greater during ischemia. The results are consistent with the notion that functional MRI of the primary sensorimotor area can be used as an index of central motor drive.