Blast-induced tinnitus and spontaneous activity changes in the rat inferior colliculus

Luo, Hao; Pace, Edward; Zhang, Xueguo; Zhang, Jinsheng

doi:10.1016/j.neulet.2014.07.041

Cited by 23 publications

(35 citation statements)

References 26 publications

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“…The GABAergic neurotransmission could have mediated the increased SFRs in the AC. Our recent finding that SFRs in the IC gradually increased after blast exposure suggests a progressive decrease in inhibition (Luo et al, 2014a). Our findings are in line with the notion that tinnitus-related hyperactivity at the cortical level may result from pathologically propagated gain change that is originally developed in the brainstem.…”

Section: Blast-induced Tinnitus and Neural Activity Changes 11supporting

confidence: 91%

Blast-induced tinnitus and hyperactivity in the auditory cortex of rats

2017

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Blast exposure can cause tinnitus and hearing impairment by damaging the auditory periphery and direct impact to the brain, which trigger neural plasticity in both auditory and non-auditory centers. However, the underlying neurophysiological mechanisms of blast-induced tinnitus are still unknown. In this study, we induced tinnitus in rats using blast exposure and investigated changes in spontaneous firing and bursting activity in the auditory cortex (AC) at one day, one month, and three months after blast exposure. Our results showed that spontaneous activity in the tinnitus-positive group began changing at one month after blast exposure, and manifested as robust hyperactivity at all frequency regions at three months after exposure. We also observed an increased bursting rate in the low-frequency region at one month after blast exposure and in all frequency regions at three months after exposure. Taken together, spontaneous firing and bursting activity in the AC played an important role in blast-induced chronic tinnitus as opposed to acute tinnitus, thus favoring a bottom-up mechanism.

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Section: Blast-induced Tinnitus and Neural Activity Changes 11supporting

confidence: 91%

Blast-induced tinnitus and hyperactivity in the auditory cortex of rats

2017

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“…A majority of laboratories use a statistically significant reduction in GPIAS as a criterion for behavioral evidence of tinnitus. Although sometimes not clearly stated in the methods of published work, this criterion is most commonly used for identifying animals with gap detection deficits and/or for the separation of tinnitus positive from tinnitus negative individuals ( 16 , 18 , 20 , 26 , 30 , 33 , 34 , 36 – 40 , 45 , 56 , 58 – 60 ). These reductions in GPIAS typically were observed at a narrow frequency range in salicylate ( 21 , 26 , 30 ) as well as in noise-induced tinnitus animal models ( 37 , 38 , 41 , 43 , 44 ).…”

Section: Criteria For the Presence Of Tinnitusmentioning

confidence: 99%

Gap-Prepulse Inhibition of the Acoustic Startle Reflex (GPIAS) for Tinnitus Assessment: Current Status and Future Directions

Galazyuk

Hébert

2015

Front. Neurol.

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The progress in the field of tinnitus largely depends on the development of a reliable tinnitus animal model. Recently, a new method based on the acoustic startle reflex modification was introduced for tinnitus screening in laboratory animals. This method was enthusiastically adopted and now widely used by many scientists in the field due to its seeming simplicity and a number of advantages over the other methods of tinnitus assessment. Furthermore, this method opened an opportunity for tinnitus assessment in humans as well. Unfortunately, multiple modifications of data collection and interpretation implemented in different labs make comparisons across studies very difficult. In addition, recent animal and human studies have challenged the original “filling-in” interpretation of the paradigm. Here, we review the current literature to emphasize on the commonalities and differences in data collection and interpretation across laboratories that are using this method for tinnitus assessment. We also propose future research directions that could be taken in order to establish whether or not this method is warranted as an indicator of the presence of tinnitus.

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“…Nevertheless, 62% of our blast-exposed rats exhibited tinnitus behavior, which is a similar tinnitus yield to intense noise-exposure studies with baseline ratios predominantly below 0.6 (56% tinnitus yield 69 ; 66% tinnitus yield 66 ). In another study with gap-detection ratio values between 0.6–0.8, we found that 44–67% of rats exhibited lasting tinnitus and expressed significant hyperactivity in the IC and AC compared to tinnitus(−) rats 54, 55 . This, and the fact that the current tinnitus (-) and control animals did not significantly change their gap-detection and PPI ratios over the 5 weeks tested, supports the sensitivity and validity of our behavioral testing for tinnitus.…”

Section: Discussionmentioning

confidence: 78%

“…Recently, our lab found evidence suggesting structural damage and compensatory structural changes in the inferior colliculus (IC) and medial geniculate body (MGB) of rats with blast-induced tinnitus 52 , in addition to acute and chronic hyperactivity or hypoactivity in the dorsal cochlear nucleus (DCN) 53 IC 54 , and auditory cortex (AC) 55 . Notably, some incongruities between blast and noise-induced tinnitus are apparent, such as but not limited to altered neural activity occurring in different frequency regions and time points 53–55 .…”

Section: Introductionmentioning

confidence: 99%

Blast-Induced Tinnitus and Elevated Central Auditory and Limbic Activity in Rats: A Manganese-Enhanced MRI and Behavioral Study

Ouyang

Pace

Lepczyk

et al. 2017

Sci Rep

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Blast-induced tinitus is the number one service-connected disability that currently affects military personnel and veterans. To elucidate its underlying mechanisms, we subjected 13 Sprague Dawley adult rats to unilateral 14 psi blast exposure to induce tinnitus and measured auditory and limbic brain activity using manganese-enhanced MRI (MEMRI). Tinnitus was evaluated with a gap detection acoustic startle reflex paradigm, while hearing status was assessed with prepulse inhibition (PPI) and auditory brainstem responses (ABRs). Both anxiety and cognitive functioning were assessed using elevated plus maze and Morris water maze, respectively. Five weeks after blast exposure, 8 of the 13 blasted rats exhibited chronic tinnitus. While acoustic PPI remained intact and ABR thresholds recovered, the ABR wave P1-N1 amplitude reduction persisted in all blast-exposed rats. No differences in spatial cognition were observed, but blasted rats as a whole exhibited increased anxiety. MEMRI data revealed a bilateral increase in activity along the auditory pathway and in certain limbic regions of rats with tinnitus compared to age-matched controls. Taken together, our data suggest that while blast-induced tinnitus may play a role in auditory and limbic hyperactivity, the non-auditory effects of blast and potential traumatic brain injury may also exert an effect.

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Blast-induced tinnitus and spontaneous activity changes in the rat inferior colliculus

Cited by 23 publications

References 26 publications

Blast-induced tinnitus and hyperactivity in the auditory cortex of rats

Blast-induced tinnitus and hyperactivity in the auditory cortex of rats

Gap-Prepulse Inhibition of the Acoustic Startle Reflex (GPIAS) for Tinnitus Assessment: Current Status and Future Directions

Blast-Induced Tinnitus and Elevated Central Auditory and Limbic Activity in Rats: A Manganese-Enhanced MRI and Behavioral Study

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