Holography, information theory, and the cerebral cortex

Abstract

When applying information theory to the study of sensory communication processes, the researcher must provide an exact definition of the physical stimulus—in terms of amplitude, frequency, and phase at the electric level—if the unit of information measurement is to be defined. Detection of the registration of correlates of these three variables in the central nervous system implies communication of all aspects of information available in the stimulus. When this is the case, such a structure might be considered an example of a hologram. When the unit of information measurement is sought in the visual system, however, it appears to be indefinable. The visual system's mechanisms of contrast enhancement act as detection mechanisms but do not convey the registration of quantity. In effect, they answer “yes” or “no”, but do not state “how much.” This gives rise to certain illusions of the Mach band kind. In the auditory system, however, the unit of information has been defined as Δƒ · Δt ⋍ 1. The auditory system, therefore, offers a more convenient sensory system for the researcher who wishes to describe his result in terms of information theory.