title: Acoustic response properties of single neurons in the central posterior nucleus of the thalamus of the goldfish, Carassius auratus.
abstract: Acoustic responses were recorded extracellularly from single neurons in the thalamic central posterior nucleus (CP). Spontaneous activity, best sensitivity, and sharpness of tuning (Q10dB) of CP neurons ranged from 0 to 36 spikes/s, -40 to 5 dB re: 1 dyne/cm2, and 0.18 to 1.80, respectively. The distribution of characteristic frequency (CF) was nonuniform with a mode at 195 Hz. Temporal response patterns of CP neurons (N = 60) were categorized into three groups: phasic (25%), tonic chopper-like (22%), and tonic nonchopper-like (53%) on the basis of peri-stimulus time and inter-spike interval histograms. Most CP neurons (90%) did not phase-lock to tones, and none phase-locked strongly. The properties of CP neurons are similar to those of the midbrain torus semicircularis neurons in spontaneous rates, best sensitivities, nonuniform CF distributions, and in exhibiting level-independent best frequencies. Both CP and toral neurons show a diversity of response patterns resembling those found in the mammalian central auditory system. However, CP neurons have broader tuning and less phase-locking than toral neurons, suggesting different roles in auditory processing. While peripheral frequency analysis is enhanced at the midbrain level, the integration of frequency-selective channels in the thalamus may function in the processing of wideband spectra characteristic of natural sound sources.
authors.affiliation: Parmly Hearing Institute, Loyola University Chicago, IL 60626, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Lu
authors.forename: R R
authors.initials: RR
authors.lastname: Fay
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology; D006054:Goldfish / Q000033:anatomy & histology / Q000502:physiology*; D006309:Hearing / Q000502:physiology*; D009475:Neurons, Afferent / Q000502:physiology*; D011930:Reaction Time; D013787:Thalamic Nuclei / Q000166:cytology / Q000502:physiology*