Interpretation of the Central Excitatory and Inhibitory States

Abstract

In our scientific vocabulary of today Sherrington’s concepts ‘central excitatory state’ and “central inhibitory state” no longer play the role they used to do. This being the case it is of some interest, historical as well as theoretical, to inquire into the reasons for it. One might imagine that they finally have been replaced by more precise concepts or, again, that they simply have been forgotten. In the middle twenties these concepts were important enough to justify a belated inquiry into their fate and present interpretation. And why were they so important? The answer is simply that the two concepts drew attention to the principle of graded excitability as a function of time, and to Sherrington’s view that c. e. s. and c. i. s. were capable of algebraic summation. Sherrington’s deductions, as formulated in 1925, were rooted in observations over a lifetime including not only reflex work by isometric myography after the first World War, but also experiences from his earlier studies of the scratch reflex, the lengthening and shortening reactions etc.