Physiology of the human tactile system
Innovations on haptic tactile and impactile interfaces

All experience begins with perception. Man's rational capacities and intelligence enable him to respond in original ways to stimuli from the external environment. Several researchers have attempted to classify modes of perception. One existing classification is that of Sherrington . This classification is based on the separation of two types of sensation, which are neither of the same biological nor physiological type:

• external, conscious, expressible sensitivity, etc. (including proprioception, at least in part);

• an internal, unconscious sensitivity, inexpressible and certainly very poorly understood.