Possible role of tremor in the organisation of the nervous system

The essential feature of tremor is that of an activity which is sustained and regular (pathological tremors do not vary in frequency as observed over periods of several years!). Thus the mechanism responsible has the properties, essential to the workings of any organism, of a generator of motive force and of a clocking function in the sense of prediction (Pellionisz and Llinas, 1982). It is these characteristics that provoke the speculation that the existence of oscillatory rhythms, as coherent properties of CNS neurones, is of theoretical significance beyond their relationship to servo-loops (Marsden, this volume, chapter 4) or as the basis for a central motor generator in swimming and locomotion in vertebrates (Jung, 1941; Gresty and Findley, this volume, chapter 2).