Afferent fibers with multiple encoding sites.

Abstract A primary afferent fiber with the capability for initiating impulses at more than one sensory terminal belongs to one of two classes. The first, termed simultaneous reset, appears to be more common in nature, including most, if not all myelinated afferents. Analysis of this class shows that multiple encoding sites increase mean discharge and produce significantly less variability in discharge rate of the parent axon. The second class, termed non-simultaneous reset, is far more difficult to analyze, although multiple encoding sites belonging to this class would appear to be limited to C fibers with large areas of innervation. Some possible utilities of the simultaneous reset class include the allowance for both non-disruptive multiplexing of information from different transducers, and for trophic activities of growth and repair without interfering with ongoing function.