Long-Lasting Suppression of Acoustic Startle Response after Mild Traumatic Brain Injury

Document Type

Article

Publication Date

6-1-2015

Abstract

Abstract Acoustic startle response (ASR) is a defensive reflex that is largely ignored unless greatly exaggerated. ASR is suppressed after moderate and severe traumatic brain injury (TBI), but the effect of mild TBI (mTBI) on ASR has not been investigated. Because the neural circuitry for ASR resides in the pons in all mammals, ASR may be a good measure of brainstem function after mTBI. The present study assessed ASR in Sprague-Dawley rats after mTBI using lateral fluid percussion and compared these effects to those on spatial working memory. mTBI caused a profound, long-lasting suppression of ASR. Both probability of emitting a startle and startle amplitude were diminished. ASR suppression was observed as soon as 1 day after injury and remained suppressed for the duration of the study (21 days after injury). No indication of recovery was observed. mTBI also impaired spatial working memory. In contrast to the suppression of ASR, working memory impairment was transient; memory was impaired 1 and 7 days after injury, but recovered by 21 days. The long-lasting suppression of ASR suggests long-term dysfunction of brainstem neural circuits at a time when forebrain neural circuits responsible for spatial working memory have recovered. These results have important implications for return-to-activity decisions because recovery of cognitive impairments plays an important role in these decisions.

Identifier

84930340660 (Scopus)

Publication Title

Journal of Neurotrauma

External Full Text Location

https://doi.org/10.1089/neu.2014.3451

e-ISSN

15579042

ISSN

08977151

PubMed ID

25412226

First Page

801

Last Page

810

Issue

11

Volume

32

Grant

RO1-NS44373

Fund Ref

National Institute of Neurological Disorders and Stroke

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