“…They certainly cannot do so when operating in the linear part of their response curve because obviously in the last situation the system is 'bidirectionally' rate sensitive (Franz, 1969), and as a result, the average discharge rate which in all likelihood is the information carrying parameter rather than the instantaneous frequency (Douglas, Ritchie & Schaumann, 1956;Gupta, Henry, Sinclair & Von Baumgarten, 1966;McKean, Poppele, Rosenthal & Terzuolo, 1970;Eysel & GrUsser, 1970) is identical for static and dynamic inputs in agreement with Angell James (1971 a). From this point of view, 'unidirectional' rate sensitivity is not a basic property of the receptors themselves, a notion held by Clynes (1961), it rather is the consequence of the receptor's near-threshold operation.…”