Neural control mechanisms for normal versus parkinsonian gait

The non-invasive methods which can be applied to the study of the cerebral control mechanisms for human gait are limited because of technical constraints. In particular, the subject's head has to be fixed for most measurements. Despite this problem, SPECT-detected, rCBF activation studies have shown that the cerebral cortex participates in the control of the normal volitional walking of healthy human subjects. The active brain areas include the foot and trunk regions of the primary sensorimotor cortex, and the supplementary motor area (SMA), lateral premotor cortex, and cingulated gyrus. Selected subcortical structures also exhibit walking-related activity, including the dorsal brainstem and cerebellum. These same regions are active in patients with Parkinson's disease (PD), but significantly less so in the right SMA, left precuneus, and right cerebellar hemisphere. For the "kinesie paradoxale" of PD patients, the right lateral premotor area plays an important role in the visually induced gait improvement brought on by adding transverse lines to the walking path.