Motor effects of cortical stimulation after chronic lesion of medullary pyramid in the dog.

In dogs with unilateral pyramidal lesions the motor cortex on both hemispheres was stimulated under Nembutal anesthesia to study the effects of pyramidotomy upon cortically induced movements. Pyramidal lesions resulted in an almost complete abolition of foretoes flexions and marked reduction of wrist ventriflexions. Other movements were not noticeably affected, except for their increased thresholds. The increase in the thresholds of movements elicited from the affected hemispheres diminished as a function of the length of postoperative survival period, so that 6 mo after pyramidotomy the thresholds on the operated side approximated the values obtained on the normal hemispheres.