Blast Exposure Disrupts the Tonotopic Frequency Map in the Primary Auditory Cortex

Masri, Samer; Zhang, Li S.; Luo, Hao; Pace, Edward; Zhang, Jinsheng; Bao, Suqing

doi:10.1016/j.neuroscience.2018.03.041

Cited by 17 publications

(11 citation statements)

References 55 publications

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“…In vivo electrophysiological recording and sensory stimuli methods have been described previously 67 . In this study, two anesthetics were used to eliminate potential influence of anesthetics.…”

Section: Methodsmentioning

confidence: 99%

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Increasing endogenous activity of NMDARs on GABAergic neurons increases inhibition, alters sensory processing and prevents noise-induced tinnitus

Deng

Masri

Yao

et al. 2020

Sci Rep

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Selective enhancement of GABAergic inhibition is thought to impact many vital brain functions and interferes with the genesis and/or progression of numerous brain disorders. Here, we show that selectively increasing nMDA receptor activity in inhibitory neurons using an nMDAR positive allosteric modulator (pAM) elevates spiking activity of inhibitory neurons in vitro and in vivo. in vivo infusion of pAM increases spontaneous and sound-evoked spiking in inhibitory and decreases spiking in excitatory neurons, and increases signal-to-noise ratio in the primary auditory cortex. in addition, pAM infusion prior to noise trauma prevents the occurrence of tinnitus and reduction in GABAergic inhibition. these results reveal that selectively enhancing endogenous nMDAR activity on the GABAergic neurons can effectively enhance inhibitory activity and alter excitatory-inhibitory balance, and may be useful for preventing diseases that involve reduced inhibition as the major cause.

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Section: Methodsmentioning

confidence: 99%

“…After 20 min of baseline recording, M-8324 was infused into lateral ventricle at 0.5 µL/min for 10 min. Data analysis was done off-line with custom MATLAB programs 67 .…”

Section: Methodsmentioning

confidence: 99%

Increasing endogenous activity of NMDARs on GABAergic neurons increases inhibition, alters sensory processing and prevents noise-induced tinnitus

Deng

Masri

Yao

et al. 2020

Sci Rep

Self Cite

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“…Of particular interest in the paired‐VNS t paradigm is the observation that noise and blast‐induced hearing loss can alter downstream tonotopic properties of auditory cortex, well beyond the so‐called “critical period;” a time frame in early development during which the central nervous system is most malleable to change 5,46‐49 . As a phenomenological aspect of this effect, reactive neuroanatomical and neurophysiological changes to tonotopic areas of auditory cortex can take the form of expansion or contraction of specific anatomical spatial/frequency bandwidth relative to their “normal” unaffected neighboring regions.…”

Section: Introductionmentioning

confidence: 99%

Vagus nerve stimulation paired with tones for tinnitus suppression: Effects on voice and hearing

Kochilas

Cacace

Arnold

et al. 2020

Laryngoscope Investig Oto

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Objective: In individuals with chronic tinnitus, our interest was to determine whether daily low-level electrical stimulation of the vagus nerve paired with tones (paired-VNSt) for tinnitus suppression had any adverse effects on motor-speech production and physiological acoustics of sustained vowels. Similarly, we were also interested in evaluating for changes in pure-tone thresholds, word-recognition performance, and minimum-masking levels.Both voice and hearing functions were measured repeatedly over a period of 1 year. Study design: Longitudinal with repeated-measures.Methods: Digitized samples of sustained frontal, midline, and back vowels (/e/, /o/, /ah/) were analyzed with computer software to quantify the degree of jitter, shimmer, and harmonic-to-noise ratio contained in these waveforms. Pure-tone thresholds, monosyllabic word-recognition performance, and MMLs were also evaluated for VNS alterations. Linear-regression analysis was the benchmark statistic used to document change over time in voice and hearing status from a baseline condition.Results: Most of the regression functions for the vocal samples and audiometric variables had slope values that were not significantly different from zero. Four of the nine vocal functions showed a significant improvement over time, whereas three of the pure tone regression functions at 2-4 kHz showed some degree of decline; all changes observed were for the left ear, all were at adjacent frequencies, and all were ipsilateral to the side of VNS. However, mean pure-tone threshold changes did not exceed 4.29 dB from baseline and therefore, would not be considered clinically significant. In some individuals, larger threshold shifts were observed. No significant regression/slope effects were observed for word-recognition or MMLs.Meeting information: Portions of this study were presented at

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“…Increasing clinical (Berger et al, 1997;Cohen et al, 2002;Cave et al, 2007;Ritenour et al, 2008;Lew et al, 2009;Gallun et al, 2012a) and laboratory (Patterson and Hamernik, 1997;Ewert et al, 2012;Cho et al, 2013b;Du et al, 2013;Masri et al, 2018) evidence suggest that both peripheral and central auditory system (CAS) are important blast-susceptible structures, where CAS includes the brainstem, midbrain, thalamus, and cortex. Subcortical CAS such as the auditory brainstem may be particularly vulnerable to blast injury, including hemorrhages, intracranial deformation and blood-brain barrier (BBB) permeability, glutamate excitotoxicity, elevated calcium, as well as elevated markers of oxidative stress and neuroinflammation from near short-term (1-7 days) up to 2 weeks (Knudsen and Øen, 2003;Leung et al, 2008;Säljö et al, 2011;Cho et al, 2013a;Song et al, 2015;Walls et al, 2016;Laplaca et al, 1997;Hamann et al, 2008)).…”

Section: Introductionmentioning

confidence: 99%

“…However, significant hearing difficulties can occur in the absence of peripheral diagnostic indicators such as eardrum rupture or clinical threshold shifts (hearing loss >25 dB), indicating that were not apparent with simple audiological measures (Gallun et al 2012b;Saunders et al 2015;Bressler et al 2017;Kubli et al 2018). However, blast studies in animals rarely go beyond simple auditory stimuli such as clicks, tones and AM modulation in a quiet background (Ewert et al 2012;Race et al 2017;Masri et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Longitudinal Auditory Pathophysiology Following Mild Blast Induced Trauma

Han¹,

Fernandez²,

Swanberg³

et al. 2020

Preprint

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Blast-induced hearing difficulties affect thousands of veterans and civilians. The long-term impact of even a mild blast exposure on the central auditory system (CAS) is hypothesized to contribute to many lasting behavioral complaints associated with mild blast traumatic brain injury (bTBI). Although recovery from mild blast has been studied over different time windows, few, if any, studies have investigated recovery longitudinally over short-term and longer-term (months) time windows. Specifically, many peripheral measures of auditory function either recover almost fully or exhibit subclinical deficits, thus masking deficits in processing complex, real-world stimuli that may recover with different time courses. Thus, examining the acute time course and pattern of neurophysiological impairment using appropriate stimuli is critical to better understanding and intervention of bTBI-induced auditory system impairments. In this study, we compared auditory brainstem response, middle-latency auditory evoked potentials, and envelope following responses. Stimuli were clicks, tone pips, amplitude modulated tones in quiet and in noise, and speech-like stimuli (iterated rippled noise pitch contours) in adult male rats subjected to mild blast and sham exposure over the course of two months. We found that blast animals demonstrated drastic threshold increases and auditory transmission deficits immediately after blast exposure, followed by substantial recovery during the window of 7-14 days post-blast, though with some deficits remaining even after two months. Challenging conditions and speech-like stimuli can better elucidate mild bTBI-induced auditory deficit during this period. Our results indicated multiphasic recovery, suggesting different time windows for treatment, and deficits can be best observed using a small battery of sound stimuli.

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Blast Exposure Disrupts the Tonotopic Frequency Map in the Primary Auditory Cortex

Cited by 17 publications

References 55 publications

Increasing endogenous activity of NMDARs on GABAergic neurons increases inhibition, alters sensory processing and prevents noise-induced tinnitus

Increasing endogenous activity of NMDARs on GABAergic neurons increases inhibition, alters sensory processing and prevents noise-induced tinnitus

Vagus nerve stimulation paired with tones for tinnitus suppression: Effects on voice and hearing

Longitudinal Auditory Pathophysiology Following Mild Blast Induced Trauma

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