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The variety of opinion in recent postings here about pallidotomy reflects that in the professional community, where experts not only disagree but just plain don't know how it works. The effect on dyskinesia was discovered quite by accident some time ago, during a brain tumor operation, and although knowledge of the complex neural pathways has grown astoundingly since then, it's still a riddle. A popular hypothesis (and it is only that) is that the kinetic action of acetylcholine in the corpus striatum (of which the globus pallidus, or pale body, is one part) is balanced in normal people by the restraining action of dopamine, and the shortage of dopamine arriving from the substantia nigra (black substance) of the midbrain upsets the balance and causes the dyskinesia of PD. The hypothesis is that destroying the small area of excessive stimulation restores the balance, and it seems to work. But it's not clear why stimulating that same area with an electrical signal at 100 HZ (and other frequencies won't do) has the same beneficial effect as destroying the area. The precise choice of the area to be stimulated or destroyed is still being refined. It has long been known that destroying a small area (the ventral intermediate nucleus) of the thalamus has an equally beneficial effect on another PD symptom, tremor; and recently the effect of electrical stimulation there (at the same 100 HZ) was found to be similar. No doubt the exact mechanism of these phenomena will be unraveled someday; meanwhile take it like chicken soup- you may not know why it's good for you, but enjoy the benefits. Cheers, Joe J. R. Bruman (818) 789-3694 3527 Cody Road Sherman Oaks CA 91403