rkinson's patients hold thei arms rigi they don have spontaneous facial exprsion. theyave a mask-likeface. that's something we do spontaneously. the basal ganglia are involved. these are ma with dopamine. they have gidity. th also have tremor. we knowoughly what parts of the brain are involved, what chemal is missing, you can replace dopammine with dopa. they wl often have -- replace dopamine with l-do. if you ge too much youget tics a grimaces. now theres a promising technie called deep-brain stimulation where y can put an electrode inside the brain and partlly aeviate many ofhe symptoms. that's showing considerae promise. >> charlie: what are wlearning from peoe who in a sense are made toeel betr becauf the psychological benet of counselling? >> oh, i think there is evince that talk thera helps. there is evidenc that prozac help but the effects are quite small. you're talking about -- if you doroo -- placebo, talk your friend, ife take prac, if you talk t yourriend it's 65%. prozac is 75%. lk therapy with a trained therapist can be very helpful toout these are ma