title: Acousticolateral processing in the torus semicircularis of the trout Salmo gairdneri.
abstract: Characteristics of single units in the trout torus semicircularis to acousticolateral stimulation were investigated with tone bursts. Auditory (A) units (33%, N = 67), exclusively sensitive to frequencies higher than 125 Hz, and low frequency (L, 12%) units responding to tones up to 125 Hz were found next to the third type, the broadband (B,55%) unit, sensitive to both low and high frequencies. For many B units sensitivity to intermediate frequencies is absent. The sensitivity range of 85% of the units does not exceed 450 Hz. Most units (70%) show an increase in spike firing during the tone burst irrespective of frequency (ON units), but for a minority (9%) firing is maximal in the silent intervals (OFF units). OFF units are mostly found among A units. All L units are ON units. The remaining ON/OFF (ON behaviour for some and OFF behaviour for other frequencies) or ON + OFF (ON and OFF behaviour for all frequencies) units are all B units. Tonic ON units are most common. Some units show habituation and only sensitive ones may exhibit phase-locking. The different behaviour of some B units for low versus high frequencies, as expressed in their ON and OFF behaviour and latencies, presumably reflects convergence of inputs from acousticolateral subsystems with distinct properties.
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D006185:Habituation, Psychophysiologic; D006735:Horseradish Peroxidase; D008636:Mesencephalon / Q000502:physiology*; D012487:Salmonidae / Q000502:physiology*; D012684:Sensory Thresholds; D013016:Sound; D013997:Time Factors; D014337:Trout / Q000502:physiology*
chemical_list: D006735:Horseradish Peroxidase