| Abstrakt: |
Research in sensory physiology proves the usefulness of describing distinct functions of sensory systems from the point of view of information processing, neglecting energetic (metabolic) processes, which may occur simultaneously. On the other hand, complex metabolic processes play an important role in sensory reception and sensory communication. Adaptation — in quite a few situations resulting in an actual gain of sensory information — is based upon interacting metabolic processes. It is conceivable that various enzyme systems, such as coenzyme B, involved in the building and destruction of a particular exitatory substance, e. g., acetylcholine and cholinesterase, influence the speed of these different metabolic processes within the sensory cells. It is even possible to separate the damage done to these processes by using an electrophysiological recording of combined action potentials on the auditory nerve and accounting for the time course of adaptation according toRanke's adaptation theory. The human central nervous system selects the 100 bit/sec processed for conscious perception from the 109 bit/sec offered from all sensory receptors in two principal ways: (1) “Specific auditory information” is modulated by “unspecific” information processed through the reticular formation of the brain stem; (2) descending fiber systems alter selectively the information flow on every level of the auditory pathway. The filtered information perceived, in turn triggers a set of inborn and learned behavioral responses, such as speech and motor reaction, altogether representing appromaximately 107 bit/sec. Metabolic processes possibly involved in this optimizing system are largely unknown. |
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