Latency alterations of the auditory brainstem response in audiogenic seizure-prone Long-Evans rats

Audiogenic seizure susceptibility in the normally seizure-resistant Long-Ev ans rat may result from altered processing in the auditory pathway. Represe ntative waveform latencies of the auditory brainstem responses (ABR) were r ecorded to examine generator alterations at different levels of the auditor y neuraxis. male Long-Evans rats primed for audiogenic seizures (AGS) on PN D 14 with a 10 kHz pure tone at 120 dB SPL for 8 min were tested for AGS on PND 28 with 120 dB SPL continuous white noise. Primed subjects displayed w ild running culminating in clonic convulsions. Following behavioral testing at 4-6 months, vertex recordings of ABR waves Ia-VI were made in anestheti zed subjects using pure tone stimulus bursts. AGS subjects showed marginall y elevated ABR thresholds. Shorter ABR wave latencies were elicited in AGS subjects for peripheral and central auditory components with stimulus inten sities above 50 dB PeSPL at 8 and 40 kHz. Interpeak intervals were reduced for waves Ia-V and III-V in AGS subjects. These results reveal that intense sound stimulation during a sensitive period of development later reduces p rocessing time at higher intensity levels. (C) 1999 Elsevier Science B.V. A ll rights reserved.