The results of motor improvement may be due to changes in the noradrenergic-dopaminergic feed-back systems. It is also possible that the autonomic nervous system plays a role in the Parkinson's disease which is still poorly understood.
Relief of extrapyramidal symptoms
by sympathetic block2003-05-17
http://www.privatix.fi/index.shtml?&a=0&s=navig_03&l=en&d=extrapyramidal