neural quantum theory
a theory to explain linear psychophysical functions, which are sometimes obtained instead of the ogival (S-shaped) form, whereby changes in sensation are assumed to occur in discrete steps and not along a continuum, based on the all-or-none law of neural activity. In this context, quantum refers to a functionally distinct unit in the neural mechanisms that mediate sensory experience—that is, a perceptual rather than a physical unit. Also called quantal hypothesis; quantal theory.