title: Auditory evoked potentials from medulla and midbrain in the clawed frog, Xenopus laevis laevis.
abstract: Auditory evoked potentials (AEPs) to clicks and tonal pulses were recorded from medulla and midbrain in Xenopus laevis laevis. They comprise three components: an initial peak (I) at 2.2-3 ms latency, a fast series of peaks (F) at 5-15 ms latency, and a slow negative wave (S) at 20-40 ms latency. In medullary recordings, the initial peak was largest, whereas in midbrain recordings typically the two other components prevailed. For all components and animals, response threshold at 4 clicks/s was approximately 69 dB SPL. In response to tonal stimuli, AEP amplitudes were maximal at 1.3-2.0 and 3.5 kHz. Raising the click rate to 100/s gradually reduced the amplitude of the I and the first F peaks, whereas later F peaks and the S wave virtually disappeared at 20-40 clicks/s. On the other hand, extending the plateau duration of tonal stimuli from 4 to 10 ms hardly affected the I and F peaks but doubled the S amplitude. This suggests two systems for stimulus processing, a fast system capable to follow clicks up to high repetition rates and a slow system with longer integration time.
authors.affiliation: N.N. Andreyev Inst., Acoustics Acad. Sci., Moscow, Russia.
authors.forename: Nikolay G
authors.initials: NG
authors.lastname: Bibikov
authors.forename: Andreas
authors.initials: A
authors.lastname: Elepfandt
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D001300:Audiometry, Evoked Response; D001309:Auditory Threshold; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D008297:Male; D008526:Medulla Oblongata / Q000502:physiology*; D008636:Mesencephalon / Q000502:physiology*; D011930:Reaction Time; D014982:Xenopus laevis / Q000502:physiology*