Graduation Year

2003

Document Type

Dissertation

Degree

Au.D.

Degree Granting Department

Audiology

Major Professor

Hurley, Raymond M.

Co-Major Professor

Willott, James F.

Keywords

acoustic startle response, prepulse inhibition

Abstract

This study examined the effects of genetic background on the acoustic startle response (ASR) and its modulation by prepulse inhibition (PPI) by comparing nine inbred strains of mice. The ASR, a jerk-like motor reflex, is elicited by bursts of noise or tones with sound pressure levels of 80-90 dB and greater. PPI is a type of modulation of the ASR, requires no training, and results in observable response in both mice and humans. Data were obtained from nine inbred mouse strains, sixteen per strain, which were shipped at approximately 3-5 weeks old from The Jackson Laboratory. In general, ASRs were generally smaller when the startle stimulus was less intense. PPI was relatively weak for the 4 kHz prepulse, and stronger with prepulses of 12 kHz and 20 kHz. However, means varied widely across strains for both ASR and PPI, suggesting a strong influence of genetic background on these behaviors.

In addition to genetic influences, peripheral hearing loss and central auditory processing factors must be taken into consideration.

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