Acoustic signaling in teleost fishes: Model systems for vertebrate vocalization

Abstract

Teleost fishes can vocalize by contracting striated muscles attached to the lateral walls of their swimbladder. The rhythmic, oscillatory‐like, firing properties of a brain‐stem sonic motor circuit determine the fundamental frequency of the acoustic signals. In the midshipman Porichthys notatus only large, nest‐building, egg‐guarding males generate long duration (up to 1 h) “hums” that attract females to the nests. Females, and smaller, “sneak‐spawning” males, do not hum. Behavorial sex differences in sound production are correlated with: (a) the soma‐dendritic dimensions and discharge frequency of individual sonic motoneurons and their presynaptic pacemaker neurons, (b) the functional architecture of sonic muscle fibers and myofibrils, and (c) the density of neuromodulator inputs to the sonic motor nucleus. The sonic motor circuit can serve as a “simple” model system for a detailed analysis of the synaptic and electro‐responsive properties of single neurons controlling the generation of sex‐ and species‐typical acoustic communication signals. The collaboration of Harriet Baker, Robert Baker, Richard Brantley, and Margaret Marchaterre is acknowledged. [Work supported by NSF, NIH, and Hatch Grants.]