Thursday, July 03, 2008
Theory of Reflex Action
Descartes diagram of reflex action.The heat from the fire, A, starts a chain of processes that begins at the affected spot of the skin, B, and continues up the nerve tube until a pore of a cavity, F, is opened. Descartes speculated that this opening allowed animal spirits in the cavity to enter the nerve tube with the result that the foot is pulled from the fire. (From Descartes, 1662)
The similarity between this view of bodily action and the automata in the French Royal Gardens is evident. Descartes had a hydraulic model of brain functioning, where the fluid was 'animal spirits' and the relevant spaces were the ventricles.