Inner hair cell loss and steady-state potentials from the inferior colliculus and auditory cortex of the chinchilla.
Steady-state evoked potentials were measured from unanesthetized chinchillas both before and after carboplatin-induced selective inner hair cell loss. Recordings were made from both the inferior colliculus (IC) and the auditory cortex (AC). The steady-state potential was measured in the form of the envelope following response (EFR), obtained by presenting a two-tone stimulus (f1 = 2000 Hz; f2 = 2020, 2040, 2080, 2160, or 2320 Hz), and measuring the magnitude of the Fourier coefficient at the f2-f1 difference frequency. From the IC, precarboplatin, EFR amplitude vs difference tone frequency showed a bandpass pattern, with maximum amplitude at either 160 or 80 Hz, depending upon stimulus level. Postcarboplatin, the preferred difference frequency was 80 Hz for all stimulus levels. From the AC, EFR amplitude versus difference tone frequency also showed a bandpass pattern, with the maximum amplitude at 80 Hz both pre- and postcarboplatin. EFR amplitude from the IC was decreased for some conditions postcarboplatin, while the amplitude from the AC showed no significant change.
Arnold
Sally
S
Department of Speech-Language Pathology, Buffalo State College, New York 14222-1095, USA. arnoldsa@bscmail.buffalostate.edu
Burkard
Robert
R
D000818:Animals; D001303:Auditory Cortex / Q000187:drug effects*; D001306:Auditory Pathways / Q000187:drug effects; D016190:Carboplatin / Q000633:toxicity*; D002452:Cell Count; D002682:Chinchilla; D005072:Evoked Potentials, Auditory / Q000187:drug effects*; D005583:Fourier Analysis; D006199:Hair Cells, Auditory, Inner / Q000187:drug effects*; D007245:Inferior Colliculi / Q000187:drug effects*; D010897:Pitch Discrimination / Q000187:drug effects; D009435:Synaptic Transmission / Q000187:drug effects
D016190:Carboplatin