Increases in multiunit spontaneous activity (hyperactivity) can be induced in the dorsal cochlear nucleus (DCN) by intense sound exposure. This hyperactivity has been observed in the hamster and rat following exposure to a 10 kHz tone at a level of 125-130 dB SPL for a period of 4 h. The present study demonstrates that the onset of this hyperactivity is not immediate, but develops in the DCN between 2 and 5 days after exposure. Mean rates of multiunit spontaneous activity increased sharply from below normal levels at day 2 to higher than normal levels at day 5. The mean magnitude of activity continued to increase more gradually over the next 6 months. During this period, changes in the distribution of hyperactivity across the tonotopic array were also noted. The hyperactivity was more broadly distributed across the DCN at the early post-exposure times (5 and 14 days) than at later post-exposure recovery times (30 and 180 days), and peak activity was found at increasingly more medial positions over this time frame. These changes over time indicate that the mechanisms leading to hyperactivity following intense sound exposure are more complex than previously realized.
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http://dx.doi.org/10.1016/s0378-5955(00)00138-6 | DOI Listing |
Med Phys
January 2025
Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.
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Division of Animal and Dairy Sciences, Chungnam National University, Daejeon 34134, Korea.
Animal-based foods such as meat, dairy, and eggs contain abundant essential proteins, vitamins, and minerals that are crucial for human nutrition. Therefore, there is a worldwide growing demand for animal-based products. Since animal-based foods are vital resources of nutrients, it is essential to ensure their microbial safety which may not be ensured by traditional food preservation methods.
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January 2025
Experimental Otology Group, InnerEarLab, Department of Otolaryngology, University Medical Center Göttingen, Göttingen, Germany.
Noise-induced hearing loss is one of the most common forms of hearing loss in adults and also one of the most common occupational diseases. Extensive previous work has shown that the highly sensitive synapses of the inner hair cells (IHCs) may be the first target for irreparable damage and permanent loss in the noise-exposed cochlea, more precisely in the cochlear base. However, how such synaptic loss affects the synaptic physiology of the IHCs in this particularly vulnerable part of the cochlea has not yet been investigated.
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January 2025
Department of Behavioural Ecology, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 6, Poznan, 61614, Poland.
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View Article and Find Full Text PDFHear Res
January 2025
Institute of Sound and Vibration Research, University of Southampton, Southampton, United Kingdom.
The cortical tracking of the acoustic envelope is a phenomenon where the brain's electrical activity, as recorded by electroencephalography (EEG) signals, fluctuates in accordance with changes in stimulus intensity (the acoustic envelope of the stimulus). Understanding speech in a noisy background is a key challenge for people with hearing impairments. Speech stimuli are therefore more ecologically valid than clicks, tone pips, or speech tokens (e.
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