scholarly journals Noise Exposure Alters Glutamatergic and GABAergic Synaptic Connectivity in the Hippocampus and Its Relevance to Tinnitus

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Liqin Zhang ◽  
Calvin Wu ◽  
David T. Martel ◽  
Michael West ◽  
Michael A. Sutton ◽  
...  
Keyword(s):  
Protective Factor ◽  
Noise Exposure ◽  
Acoustic Startle ◽  
Brain Structures ◽  
Auditory Pathway ◽  
Inhibitory Synapse ◽  
Synaptic Inputs ◽  
Sound Exposure ◽  
Synapse Density ◽  
High Level

Accumulating evidence implicates a role for brain structures outside the ascending auditory pathway in tinnitus, the phantom perception of sound. In addition to other factors such as age-dependent hearing loss, high-level sound exposure is a prominent cause of tinnitus. Here, we examined how noise exposure altered the distribution of excitatory and inhibitory synaptic inputs in the guinea pig hippocampus and determined whether these changes were associated with tinnitus. In experiment one, guinea pigs were overexposed to unilateral narrow-band noise (98 dB SPL, 2 h). Two weeks later, the density of excitatory (VGLUT-1/2) and inhibitory (VGAT) synaptic terminals in CA1, CA3, and dentate gyrus hippocampal subregions was assessed by immunohistochemistry. Overall, VGLUT-1 density primarily increased, while VGAT density decreased significantly in many regions. Then, to assess whether the noise-induced alterations were persistent and related to tinnitus, experiment two utilized a noise-exposure paradigm shown to induce tinnitus and assessed tinnitus development which was assessed using gap-prepulse inhibition of the acoustic startle (GPIAS). Twelve weeks after sound overexposure, changes in excitatory synaptic terminal density had largely recovered regardless of tinnitus status, but the recovery of GABAergic terminal density was dramatically different in animals expressing tinnitus relative to animals resistant to tinnitus. In resistant animals, inhibitory synapse density recovered to preexposure levels, but in animals expressing tinnitus, inhibitory synapse density remained chronically diminished. Taken together, our results suggest that noise exposure induces striking changes in the balance of excitatory and inhibitory synaptic inputs throughout the hippocampus and reveal a potential role for rebounding inhibition in the hippocampus as a protective factor leading to tinnitus resilience.

Single Olivocochlear Neurons in the Guinea Pig. II. Response Plasticity Due to Noise Conditioning

1998 ◽  
Vol 79 (6) ◽  
pp. 3088-3097 ◽  
Author(s):  
M. C. Brown ◽  
S. G. Kujawa ◽  
M. C. Liberman
Keyword(s):  
Guinea Pig ◽  
Noise Exposure ◽  
Firing Rates ◽  
Sound Exposure ◽  
Discharge Rates ◽  
Efferent Neurons ◽  
Medial Olivocochlear ◽  
High Level ◽  
Binaural Sound

Brown, M. C, S. G. Kujawa, and M. C. Liberman. Single olivocochlear neurons in the guinea pig. II. Response plasticity due to noise conditioning. J. Neurophysiol. 79: 3088–3097, 1998. Previous studies have shown that daily, moderate-level sound exposure, or conditioning, can reduce injury from a subsequent high-level noise exposure. We tested the hypothesis that this conditioning produces an increased activity in the olivocochlear efferent reflex, a reflex known to provide protection to the cochlea. Guinea pigs were conditioned by a 10-day intermittent exposure to 2–4 kHz noise at 85 dB sound pressure level. This conditioning is known to reduce damage from a subsequent high-level exposure to the same noise band. Responses to monaural and binaural sound were recorded from single medial olivocochlear (MOC) efferent neurons, and data from conditioned animals were compared with those obtained from unexposed controls. MOC neurons were classified by their response to noise bursts in the ipsilateral or contralateral ears as ipsi units, contra units, or either-ear units. There were no significant differences in the distributions of these unit types between control and conditioned animals. There were also no differences in other responses to monaural stimuli, including the distribution of characteristic frequencies (CFs), the sharpness of tuning, or thresholds at the CF. For binaural sound at high levels, particularly relevant to sound-evoked activation of the MOC reflex during acoustic overstimulation, the firing rates of MOC neurons with CFs just above the conditioning band showed slight (but statistically significant) elevations relative to control animals. Frequency regions just above the conditioning band also demonstrated maximum conditioning-related protection; thus protection could be due, in part, to long-term changes in MOC discharge rates. For binaural sound at low levels, MOC firing rates in conditioned animals also were increased significantly relative to controls. Again, increases were largest for neurons with CFs just above the conditioning band. For equivalent monaural sound, rates were not significantly increased; thus, conditioning appears to increase binaural facilitation by opposite-ear sound. These data indicate that MOC neurons show long-term plasticity in acoustic responsiveness that is dependent on their acoustic history.

scholarly journals Prediction of parental alienation on depression in left-behind children: A 12-month follow-up investigation

2021 ◽  
Vol 30 ◽  
Author(s):  
Xiaoxiao Sun ◽  
Xuemei Qin ◽  
Mengjia Zhang ◽  
Aigang Yang ◽  
Xiaomei Ren ◽  
...  
Keyword(s):  
Life Events ◽  
Protective Factor ◽  
Stressful Life Events ◽  
Parental Alienation ◽  
Left Behind ◽  
Resilience Scale ◽  
Children’S Depression ◽  
Risk Predictor ◽  
High Level

Abstract Aims Alienation towards parents often occurs when parents divorce; however, it can also occur when one or both parents leave for work for more than 6 months. Our previous investigation has confirmed a high level of feelings of alienation towards parents among Chinese left-behind children. However, the longitudinal prediction of alienation on children's mental health outcomes remains largely unknown. This study aims to observe the prediction of alienation towards parents on children's depression 12 months later and potential mediators and moderators. Methods A total of 1090 Chinese left-behind children took part in this 12-month follow-up investigation, using the Chinese version of the Inventory of Alienation towards Parents (IAP), the Children's Depression Inventory (CDI), the Adolescent Self-Rating Life-events Checklist (ASLEC), and the Adolescent Resilience Scale. Results Alienation towards parents was high (16.42 ± 7.27 for mother, 15.63 ± 7.17 for father) in left-behind children, and 21.01% of children reported depression. Alienation towards parents predicted current depression of children directly and later depression indirectly; children's alienation toward their mothers was a stronger predictor of depression than alienation towards fathers. In models, stressful life-events acted as a risk mediator. Previous depression was the strongest risk predictor, resilience was the strongest protective factor, and duration of fathers’ absence and parents’ marital status moderated the predictive effects. Conclusions This study is among the first to longitudinally confirm that alienation towards parents is a predictor of children's later depression. The results provide important suggestions for families and schools; i.e. to prevent depression in left-behind children, parent−child bonds especially alienation towards mothers, should be carefully considered, and individuals with more negative life-events and weaker resilience need further attention.

scholarly journals Alpha2-Adrenoblockers Regulate Development of Oxidative Stress and Cognitive Behaviour of Rats under Chronic Acoustic Stress Conditions

2021 ◽  
Vol 14 (6) ◽  
pp. 529
Author(s):  
Magdalina Melkonyan ◽  
Ashkhen Manukyan ◽  
Lilit Hunanyan ◽  
Artem Grigoryan ◽  
Hayk Harutyunyan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Noise Exposure ◽  
Male Rats ◽  
Behavioral Activity ◽  
Induced Stress ◽  
Y Maze ◽  
Cognitive Behaviour ◽  
The Central Nervous System ◽  
High Level ◽  
Environment Noise

Noise is a wide-spread stress factor in modern life produced by urbanization, traffic, and an industrialized environment. Noise stress causes dysfunction and neurotransmission impairment in the central nervous system, as well as changes in hormone levels. In this study, we have examined the level of α-Tocopherol (α-T) and malondialdehyde (MDA) in plasma and the erythrocytes’ membrane (EM), as well as the behavioral characteristics of a noise-induced stress model in rats. In addition, the modulating effect of α2-adrenoblockers, beditin, and mesedin on the aforementioned parameters has been investigated. For these purposes, albino male rats were divided into four groups: (1) untreated; (2) noise-exposed, (3) noise-exposed and beditin-treated (2 mg/kg, i.p.), and (4) noise-exposed and mesedin-treated (10 mg/kg, i.p.) animals. Noise-exposed groups were treated with 91dBA noise on 60 days with a daily duration of 8 h. Increased MDA and decreased α-T levels in plasma and EM were observed upon chronic high-level noise exposure. Locomotor and behavioral activity assessed with a Y-maze revealed disorientation and increased anxiety under chronic noise exposure. Prominently, α2-adrenoblockers alleviated both behavioral deficits and oxidative stress, providing evidence for the involvement of α2-adrenoceptor in the pathophysiology of noise-induced stress.

scholarly journals Individual synaptic vesicles mediate stimulated exocytosis from cochlear inner hair cells

2018 ◽  
Vol 115 (50) ◽  
pp. 12811-12816 ◽  
Author(s):  
Chad Paul Grabner ◽  
Tobias Moser
Keyword(s):  
Hair Cells ◽  
Synaptic Vesicles ◽  
Basolateral Membrane ◽  
Mean Amplitude ◽  
Auditory Pathway ◽  
Inner Hair Cell ◽  
Excitatory Postsynaptic Currents ◽  
High Level ◽  
High Degree ◽  
Channel Type

Spontaneous excitatory postsynaptic currents (sEPSCs) measured from the first synapse in the mammalian auditory pathway reach a large mean amplitude with a high level of variance (CV between 0.3 and 1). This has led some to propose that each inner hair cell (IHC) ribbon-type active zone (AZ), on average, releases ∼6 synaptic vesicles (SVs) per sEPSC in a coordinated manner. If true, then the predicted change in membrane capacitance (Cm) for such multivesicular fusion events would equate to ∼300 attofarads (aF). Here, we performed cell-attached Cm measurements to directly examine the size of fusion events at the basolateral membrane of IHCs where the AZs are located. The frequency of events depended on the membrane potential and the expression of Cav1.3, the principal Ca2+-channel type of IHCs. Fusion events averaged 40 aF, which equates to a normal-sized SV with an estimated diameter of 37 nm. The calculated SV volumes showed a high degree of variance (CV > 0.6). These results indicate that SVs fused individually with the plasma membrane during spontaneous and evoked release and SV volume may contribute more variability in EPSC amplitude than previously assumed.

Medical Issues in Playing the Oboe: A Literature Review

2017 ◽  
Vol 32 (4) ◽  
pp. 235-246 ◽  
Author(s):  
Sofia Banzhoff ◽  
Maria del Mar Ropero ◽  
Gabriele Menzel ◽  
Tatjana Salmen ◽  
Manfred Gross ◽  
...  
Keyword(s):  
Literature Review ◽  
Disease Transmission ◽  
Protective Factor ◽  
Noise Exposure ◽  
Small Sample ◽  
Cochrane Library ◽  
Physical And Mental Health ◽  
Eligibility Criteria ◽  
Velopharyngeal Incompetence ◽  
Obstructive Sleep

Playing a musical instrument can affect physical and mental health. A literature review was conducted to determine the prevalence of health problems among oboists, which medical conditions can be caused or exacerbated by playing, whether oboe playing can be a protective factor, and whether recommendations are possible as to who should or should not play the oboe. Searches in 7 databases (Medline, Embase, Cochrane Library, Web of Science, SocIndex, PsyIndex, Psychinfo) yielded a total of 950 studies; after exclusion of duplicates and those not meeting eligibility criteria, 37 articles were selected for final analysis. In addition, Google Scholar and a musicology library served as additional sources, revealing another 6 publications for inclusion. As a result, some evidence was found for musculoskeletal problems, focal dystonia, stress velopharyngeal incompetence, increased intraocular pressure and glaucoma, gastroesophageal reflux disease, lower pulmonary function, disease transmission via instruments, and hearing loss due to noise exposure. Playing the oboe may be protective against obstructive sleep apnea. However, due to small sample sizes, uncertain reproducibility of findings, and lack of accurate descriptions of problems reported by oboists, far more evidence would be necessary to answer the research questions conclusively. There was no evidence for causal relationships, and thus no recommendations can be made regarding who should (not) play the oboe. To improve the quality of medical care for these musicians and to implement prevention strategies, future investigations with more in-depth instrument-specific analyses and higher numbers of participants are needed.

scholarly journals The Relationship between Mental Health with the Level of Empathy Among Medical Students in Southern Thailand: A University-Based Cross- Sectional Study

2021 ◽  
Vol 73 (12) ◽  
pp. 832-840
Author(s):  
Katti Sathaporn ◽  
Jarurin Pitanupong
Keyword(s):  
Mental Health ◽  
Medical Students ◽  
Protective Factor ◽  
Cross Sectional Study ◽  
Clinical Group ◽  
Sectional Study ◽  
Cross Sectional ◽  
Factors Associated ◽  
Significant Difference ◽  
High Level

Objective: To determine the level of and factors associated with empathy among medical students.Materials and Methods: This cross-sectional study surveyed all first- to sixth-year medical students at the Facultyof Medicines, Prince of Songkla University, at the end of the 2020 academic year. The questionnaires consisted of:1) The personal and demographic information questionnaire, 2) The Toronto Empathy Questionnaire, and 3) ThaiMental Health Indicator-15. Data were analyzed using descriptive statistics, and factors associated with empathylevel were assessed via chi-square and logistic regression analyses.Results: There were 1010 participants with response rate of 94%. Most of them were female (59%). More than half(54.9%) reported a high level of empathy. There was a statistically significant difference in empathy levels betweenpre-clinical and clinical medical students; in regards to empathy subgroups (P-value < 0.001). The assessment ofemotional states in others by demonstrating appropriate sensitivity behavior, altruism, and empathic respondingscores among the pre-clinical group were higher than those of the clinical group. Multivariate analysis indicatedthat female gender, pre-clinical training level, and minor specialty preference were factors associated with empathylevel. The protective factor that significantly improved the level of empathy was having fair to good mental health.Conclusion: More than half of the surveyed medical students reported a high level of empathy. The protective factorthat improved the level of empathy was good mental health. However, future qualitative methods, longitudinalsurveillance, or long-term follow-up designs are required to ensure the trustworthiness of these findings.

scholarly journals Brain ontogeny and life history in Pleistocene hominins

2015 ◽  
Vol 370 (1663) ◽  
pp. 20140062 ◽  
Author(s):  
Jean-Jacques Hublin ◽  
Simon Neubauer ◽  
Philipp Gunz
Keyword(s):  
Life History ◽  
Cognitive Complexity ◽  
Extended Period ◽  
Brain Structures ◽  
Human Model ◽  
Evolutionary Pathway ◽  
Life History Pattern ◽  
Delayed Maturation ◽  
High Level ◽  
The Brain

A high level of encephalization is critical to the human adaptive niche and emerged among hominins over the course of the past 2 Myr. Evolving larger brains required important adaptive adjustments, in particular regarding energy allocation and life history. These adaptations included a relatively small brain at birth and a protracted growth of highly dependent offspring within a complex social environment. In turn, the extended period of growth and delayed maturation of the brain structures of humans contribute to their cognitive complexity. The current palaeoanthropological evidence shows that, regarding life history and brain ontogeny, the Pleistocene hominin taxa display different patterns and that one cannot simply contrast an ‘ape-model’ to a ‘human-model’. Large-brained hominins such as Upper Pleistocene Neandertals have evolved along their own evolutionary pathway and can be distinguished from modern humans in terms of growth pattern and brain development. The life-history pattern and brain ontogeny of extant humans emerged only recently in the course of human evolution.

Numerical simulations of flow induced noise from a dual rotor cooling fan used in electronic cooling systems

2021 ◽  
Vol 263 (5) ◽  
pp. 1308-1319
Author(s):  
Sahan Wasala ◽  
Yutong Xue ◽  
Lon Stevens ◽  
Ted Wiegandt ◽  
Tim Persoons
Keyword(s):  
Noise Exposure ◽  
Acoustic Noise ◽  
High Capacity ◽  
Disk Drive ◽  
Air Cooling ◽  
Noise Sources ◽  
Cooling Systems ◽  
Cooling Fan ◽  
Flow Induced Noise ◽  
High Level

Hard Disk Drive (HDD) system enclosures in a data center require effective cooling systems to avoid HDD overheating. These systems often rely on air cooling because of their cost effciency and maintainability. Air cooling systems typically consist of an array of axial fans which push or pull the air through the system. These fans emit high level tonal noise particularly at high tip speed ratios. High-capacity HDDs, on the other hand, are sensitive to high acoustic noise, which consequently increases the risk of read/write error and deteriorates drive performance. Therefore, cooling fan noise adversely affects the function of the HDD enclosure systems which emphasizes the need to understand the noise sources and develop methods to mitigate HDD noise exposure.

Decrease and increase of spikes in auditory neuron with time-varying synaptic inputs

2019 ◽  
Vol 33 (20) ◽  
pp. 1950216
Author(s):  
Fuqiang Wu ◽  
Kuihua Ma
Keyword(s):  
Dynamic Behavior ◽  
Neuronal Networks ◽  
Auditory Brainstem ◽  
Neuronal Model ◽  
Inhibitory Synapse ◽  
Auditory Neuron ◽  
Time Varying ◽  
Relative Time ◽  
Synaptic Inputs ◽  
Synaptic Model

Precise timing and brief inhibitory synapse associated with excitation, in auditory brainstem circuit, can affect the generation of spikes. Using a lot of principles of synaptic model verified in the experiments, we develop a time varying synaptic model into the auditory neuronal model to explore its dynamic behavior. The controllable relative time between excitation and inhibition can achieve the increase or decrease of spikes in auditory neuronal model, which is consistent with the findings. This phenomenon can take place after a lasting hyperpolarization rebound by observing the phase profiles. Our results provide insights into the further investigation in neuronal networks with time-varying and plastic synapses.

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