A common method designed to identify if an animal hears tinnitus assumes that tinnitus "fills-in" silent gaps in background sound. This phenomenon has not been reliably demonstrated in humans. One test of the gap-filling hypothesis would be to determine if gap-evoked cortical potentials are absent or attenuated when measured within background sound matched to the tinnitus sensation. However the tinnitus sensation is usually of low intensity and of high frequency, and it is unknown if cortical responses can be measured with such "weak" stimulus properties. Therefore the aim of the present study was to test the plausibility of observing these responses in the EEG in humans without tinnitus. Twelve non-tinnitus participants heard narrowband noises centered at sound frequencies of 5 or 10 kHz at sensation levels of either 5, 15, or 30 dB. Silent gaps of 20 ms duration were randomly inserted into noise stimuli, and cortical potentials evoked by these gaps were measured by 64-channel EEG. Gap-evoked cortical responses were statistically identifiable in all conditions for all but one participant. Responses were not significantly different between noise frequencies or levels. Results suggest that cortical responses can be measured when evoked by gaps in sounds that mirror acoustic properties of tinnitus. This design can validate the animal model and be used as a tinnitus diagnosis test in humans.
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http://dx.doi.org/10.1016/j.heares.2018.04.005 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum 44780, Germany.
The novelty, saliency, and valency of ongoing experiences potently influence the firing rate of the ventral tegmental area (VTA) and the locus coeruleus (LC). Associative experience, in turn, is recorded into memory by means of hippocampal synaptic plasticity that is regulated by noradrenaline sourced from the LC, and dopamine, sourced from both the VTA and LC. Two persistent forms of synaptic plasticity, long-term potentiation (LTP), and long-term depression (LTD) support the encoding of different kinds of spatial experience.
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January 2025
Department of Biochemistry, Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada.
In neurons, the acquisition of a polarized morphology is achieved upon the outgrowth of a single axon from one of several neurites. Small extracellular vesicles (sEVs), such as exosomes, from diverse sources are known to promote neurite outgrowth and thus may have therapeutic potential. However, the effect of fibroblast-derived exosomes on axon elongation in neurons of the central nervous system under growth-permissive conditions remains unclear.
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December 2024
Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA.
Podocytes express large-conductance Ca-activated K channels (BK channels) and at least two different pore-forming KCa1.1 subunit C-terminal splice variants, known as VEDEC and EMVYR, along with auxiliary β and γ subunits. Podocyte KCa1.
View Article and Find Full Text PDFJ Contemp Dent Pract
September 2024
Department of Periodontology, Narsinhbhai Patel Dental College and Hospital, Sankalchand Patel University, Visnagar, Gujarat, India.
Aim: This study aims to evaluate the impact of platelet-rich fibrin (PRF) and platelet-rich plasma (PRP) on pain, swelling, trismus, soft tissue healing and bone regeneration following mandibular third molar extraction.
Material And Methods: A systematic review was conducted from a period of January 2014 to June 2024 using PRISMA guidelines. The search strategy included databases such as Scopus, PubMed, Google Scholar, and Cochrane Central Register of Controlled Trials, using key terms related to "PRF", "PRP", oral surgery, and third molars.
J Alzheimers Dis
January 2025
Department of Gerontology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Background: Urinary formic acid (FA) has been reported to be a biomarker for Alzheimer's disease (AD). However, the association between FA and pathological changes in memory clinic patients is currently unclear.
Objective: This study aims to investigate associations between FA and pathological changes across different cognitive statuses in memory clinic patients.
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