Sensational science. Sensory Transduction: 45th Annual Symposium of the Society of General Physiologists, Marine Biological Laboratory, Woods Hole, MA, USA, September 5-8, 1991.

In the course of several days of formal and informal talks, in the idyllic setting of Woods Hole, the impression grew among many of the participants that useful common themes have emerged for comparison among sensory transduction systems. Many of these were made explicit in a talk on biophysical principles of sensory transduction by Steven Block (Cambridge, MA, USA). In one hour, Block summarized the rest of the symposium and much more, in a dazzling tour through the senses. One of his points was that all sensory transducers must fulfill common goals: detection of the signal, which involves the functions of collecting, selecting or tuning, and capture of the stimulus; amplification, to raise the signal energy (without adding noise) for transmission to other parts of the organism; adaptation or feedback, to extract behaviorally useful parts of the signal; termination, to re-prime the system for the next signal; and encoding, which puts the information in a useful form for downstream processing or effector elements. Another useful comparison was between quantum-detecting systems, such as photoreception and olfaction, where the energy of the stimulus quantum (photon or odor ligand) is large and a uniform response is desired, and noise-limited systems, such as auditory transduction or magnetoreception, where thermal noise is larger than the smallest stimuli and time-averaging helps pull the signal out of the noise. A third observation from Block was that sensory transduction systems--while often performing at physical limits--have not necessarily been perfected by the process of evolution.(ABSTRACT TRUNCATED AT 250 WORDS)