title: Long-lasting suppression of acoustic startle response after mild traumatic brain injury.
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.
authors.affiliation: 1Neurobehavioral Research Lab, Department of Veteran Affairs Medical Center-New Jersey Health Care System, East Orange, New Jersey.|2Stress and Motivated Behavior Institute, New Jersey Medical School-Rutgers Biomedical and Health Sciences, Newark, New Jersey.|3Department of Neurology and Neurosciences, New Jersey Medical School-Rutgers Biomedical and Health Sciences, Newark, New Jersey.|4Graduate School of Biomedical Sciences, New Jersey Medical School-Rutgers Biomedical and Health Sciences, Newark, New Jersey.
authors.forename: Kevin C H
authors.initials: KC
authors.lastname: Pang
authors.affiliation: 2Stress and Motivated Behavior Institute, New Jersey Medical School-Rutgers Biomedical and Health Sciences, Newark, New Jersey.|4Graduate School of Biomedical Sciences, New Jersey Medical School-Rutgers Biomedical and Health Sciences, Newark, New Jersey.
authors.forename: Swamini
authors.initials: S
authors.lastname: Sinha
authors.affiliation: 2Stress and Motivated Behavior Institute, New Jersey Medical School-Rutgers Biomedical and Health Sciences, Newark, New Jersey.|4Graduate School of Biomedical Sciences, New Jersey Medical School-Rutgers Biomedical and Health Sciences, Newark, New Jersey.
authors.forename: Pelin
authors.initials: P
authors.lastname: Avcu
authors.affiliation: 2Stress and Motivated Behavior Institute, New Jersey Medical School-Rutgers Biomedical and Health Sciences, Newark, New Jersey.|3Department of Neurology and Neurosciences, New Jersey Medical School-Rutgers Biomedical and Health Sciences, Newark, New Jersey.
authors.forename: Jessica J
authors.initials: JJ
authors.lastname: Roland
authors.affiliation: 6B.S./M.D. Program, The College of New Jersey, Ewing, New Jersey.
authors.forename: Neil
authors.initials: N
authors.lastname: Nadpara
authors.affiliation: 5Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, New Jersey.
authors.forename: Bryan
authors.initials: B
authors.lastname: Pfister
authors.affiliation: 4Graduate School of Biomedical Sciences, New Jersey Medical School-Rutgers Biomedical and Health Sciences, Newark, New Jersey.|5Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, New Jersey.
authors.forename: Mathew
authors.initials: M
authors.lastname: Long
authors.affiliation: 3Department of Neurology and Neurosciences, New Jersey Medical School-Rutgers Biomedical and Health Sciences, Newark, New Jersey.|4Graduate School of Biomedical Sciences, New Jersey Medical School-Rutgers Biomedical and Health Sciences, Newark, New Jersey.
authors.forename: Vijayalakshmi
authors.initials: V
authors.lastname: Santhakumar
authors.affiliation: 1Neurobehavioral Research Lab, Department of Veteran Affairs Medical Center-New Jersey Health Care System, East Orange, New Jersey.|2Stress and Motivated Behavior Institute, New Jersey Medical School-Rutgers Biomedical and Health Sciences, Newark, New Jersey.|3Department of Neurology and Neurosciences, New Jersey Medical School-Rutgers Biomedical and Health Sciences, Newark, New Jersey.|4Graduate School of Biomedical Sciences, New Jersey Medical School-Rutgers Biomedical and Health Sciences, Newark, New Jersey.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Servatius
mesh_terms: D000818:Animals; D001930:Brain Injuries / Q000473:pathology* / Q000503:physiopathology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013216:Reflex, Startle / Q000502:physiology*; D013997:Time Factors
keywords: concussion; lateral fluid percussion; memory; pons; spatial learning