4pPP8. Single unit recordings from directionally sensitive cells of the torus semicircularis of the goldfish (Carassius auratus).

Session: Thursday Afternoon, December 5

Time: 3:45

Author: Diana Ma
Location: Boston Univ. Marine Program, Woods Hole, MA 02543
Author: Richard R. Fay
Location: Parmly Hear. Inst., Chicago, IL


This experiment characterized the directional responses of cells of the auditory midbrain of goldfish. Single units in the midbrain were characterized by their response to whole-body vibratory stimuli of various directions and amplitudes. The animal's head was fixed in a rigid dish that was accelerated using two orthogonal pairs of shakers in the horizontal plane, and one shaker oriented vertically. Three orthogonally oriented accelerometers resolved the dish's motion in azimuth and elevation. Computer-synthesized sinusoids activated the shaker channels with relative phases and amplitudes required to produce linear motion along 12 axes equally spaced over 180(degrees) in each of the horizontal, midsagittal, and frontal planes. Spike rate was plotted as a function of stimulation axis angle in both Cartesian and polar coordinates. Most cells showed strongly directional response patterns with a primarily vertical orientation. Response patterns were classified with respect to the symmetry, sharpness, and the amplitude dependence of these directional features. Models were developed to give possible explanations for the observed responses. Many of the response shapes can be explained by combinations of simple peripheral effects (threshold and saturation) and inhibitory interaction. [Work supported by a Program Project Grant (NIH, NIDCD) to the Parmly Hearing Institute.]

ASA 132nd meeting - Hawaii, December 1996