NOTE (This week only): Sensorimotor Journal Club will meet at 10:30am

 

Laterality in motor control is a important area of study, especially as it relates to plasticity and recovery of function. Tomorrow at Sensorimotor Journal Club, Sri Nagarajan will present an article describing a study where TMS was used to temporarily disrupt left dominant function in action selection, which caused rapid changes in right activation even in the absence any behavioral deficits:

 

O'Shea, J., Johansen-Berg, H., Trief, D., Gobel, S., & Rushworth, M. F. S. (2007). Functionally specific reorganization in human premotor cortex. Neuron, 54(3), 479-490. (link to pdf of article)

 

After unilateral stroke, the dorsal premotor cortex (PMd) in the intact hemisphere is often more active during movement of an affected limb. Whether this contributes to motor recovery is unclear. Functional magnetic resonance imaging (fMRI) was used to investigate short-term reorganization in right PMd after transcranial magnetic stimulation (TMS) disrupted the dominant left PMd, which is specialized for action selection. Even when 1 Hz left PMd TMS had no effect on behavior, there was a compensatory increase in activity in right PMd and connected medial premotor areas. This activity was specific to task periods of action selection as opposed to action execution. Compensatory activation changes were both functionally specific and anatomically specific: the same pattern was not seen after TMS of left sensorimotor cortex. Subsequent TMS of the reorganized right PMd did disrupt performance. Thus, this pattern of functional reorganization has a causal role in preserving behavior after neuronal challenge.