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On Tue 17 Sep, Jacob Drollinger wrote: > Dear friends, > > What I would like to know is this: Why would a typical P.D.er benefit from > having the signals to the pallidus blocked, such as in a pallidotomy and/or a > pallidal stimulation, when that brain structure is what controls the > reception of dopamine, and injury to such would leave one in my condition. > confounds me. Maybe it has to do with there being less dopamine to receive, > and the receptors are going haywire trying to receive dopamine that isn't > there? > If somebody could help me out, it might add some understanding to all of our > conditions. > Hello Jacob As you said, we are not neurologists, so what we think is the answer may be only a part of it. Anyway, here is my contribution. The movement of our limbs is actually a complex system of orders to move, which are associated with the cerebral cortex area of the brain, and feedback systems which tell the brain that the limb has reached the desired position. The feedback signals are involved with the globus pallidus area of the brain. This feedback system is like a finely tuned electronic system - If you tamper with either the control signal or the feedback signal, the system can become unstable, and the output can 'hunt' for a stable position, but not find it. In the case of a person with PD, the motor commands (the 'go' signal) become very faint or weak due to the lack of the neurotransmitter Dopamine, but the feedback system is still shouting at full volume, and instability (tremor) results. To fix the problem, you can either boost the control signal by supplying extra dopamine ( e.g. Sinemet) OR - you can weaken the feedback signals so that they balance the motor signals once again, and stability is returned. The weakening of the feedback system signals is what is going on in the Pallidotomy operation. So, you can get stability with two strong signals, or two weak ones. It bothers me that we seem to be using two 'wrongs' to make a 'right', but there is no doubt that in many cases substantial relief is obtained by the Pallidotomy operation. I hope you can follow that( and I hope I got it roughly right! Regards Brian Collins <[log in to unmask]>