Chris, Thank you for the explanation. It looks like the next part of my question would be harder to answer, given what you said. Can this knowledge be used as the basis of any form of therapy to control tremor? Are there drugs which stimulate the reticular formation(without causing instant sleep!)or preferably, can it be reached by induced mental activity such as hypnosis or meditation? As an observation, I find that I have no tremor on awakening and, provided that I remain inactive and relaxed, it does not appear. As soon as I contemplate starting my daily activities, the tremor begins (paradoxically, as it is a 'rest' tremor). Maybe this is simply the result of a lower demand for dopamine in the inactive state as another respondent suggested. But, if it is triggered by more alert mental activity, it might be auto-controllable. regards Alf Adelaide, Aus