Convergence of Information

Abstract

When the magnitude of an external variable is signaled through photons, sound waves, or diffused chemicals, that magnitude must be transduced into a neural signal before the nervous system can act on the information that it represents. Information concerning remote objects is delivered by light as a distribution in space and time of photons that are individually insignificant to the recipient nervous system. Likewise, information delivered as sound is a temporally and spatially distributed pattern of individual molecular impacts that have significance only in the aggregate. Chemical communication is a distribution of specific molecules diffusing in air or water. In these and other inputs, the information delivered to the sensory impulse generators only statistically represents the sensed variable. Thus, for example, the average impact of individual air molecules, which constitutes sound pressure, accumulates at the tympanic membrane before there is any mechanical wave analysis and receptor stimulation. The external quantal elements must be combined as physical signals and then transduced into an equivalent neural impulse signal before they can report the remote condition.