Quantitative assessment of the effect of basal ganglia lesions on the stretch reflex in primates.

The effect of basal ganglia stereotactic lesions on motor tone in 3 primates was quantitated. The elastic and neurogenic forces generated with a controlled stretch of each animal's upper extremities were measured pre- and postlesion, and compared to previous studies. The techniques were sensitive to subtle changes in motor tone that were not clinically apparent. The results suggest that the basal ganglia, through the outflow path of the globus pallidus, is important in controlling the sensitivity of both flexors and extensors to stretch. These quantification techniques also have promise in evaluating treatment regimens for spasticity, rigidity, and other conditions with abnormal motor tone.