Chronic increases in spontaneous multiunit activity can be induced in the dorsal cochlear nucleus (DCN) of hamsters by intense sound exposure (Kaltenbach and McCaslin, 1996). It has been hypothesized that this hyperactivity may represent a neural code that could underlie the sound percepts of tinnitus. The goal of the present study was to determine whether hyperactivity could be demonstrated in animals that had previously been tested for tinnitus, and, if so, whether animals differing in their behavioral evidence for tinnitus also differ in their levels of spontaneous activity. The results showed not only that levels of activity in exposed animals were higher than those in control animals, but the degree to which the activity was increased was related to the strength of the behavioral evidence for tinnitus. These findings are consistent with the hypothesis that hyperactivity in the DCN may be a physiological correlate of noise-induced tinnitus.
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http://dx.doi.org/10.1016/j.neulet.2003.10.038 | DOI Listing |
PLoS Comput Biol
December 2024
School of Life and Environmental Sciences, University of Lincoln, Lincoln, United Kingdom.
Mammalian hearing operates on three basic steps: 1) sound capturing, 2) impedance conversion, and 3) frequency analysis. While these canonical steps are vital for acoustic communication and survival in mammals, they are not unique to them. An equivalent mechanism has been described for katydids (Insecta), and it is unique to this group among invertebrates.
View Article and Find Full Text PDFJ Comp Neurol
December 2024
School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.
A gene cadre orchestrates the normal development of sensory and non-sensory cells in the inner ear, segregating the cochlea with a distinct tonotopic sound frequency map, similar brain projection, and five vestibular end-organs. However, the role of genes driving the ear development is largely unknown. Here, we show double deletion of the Iroquois homeobox 3 and 5 transcription factors (Irx3/5 DKO) leads to the fusion of the saccule and the cochlear base.
View Article and Find Full Text PDFNeuroscience
January 2025
Laboratory of Neurophysiology and Synapse, Department of Physiology, School of Medicine of Ribeirão Preto, Ribeirão Preto, SP, Brazil. Electronic address:
Cartwheel (CW) neurons are glycinergic interneurons in the dorsal cochlear nucleus (DCN) that exhibit spontaneous firing, resulting in potent tonic inhibition of fusiform neurons. CW neurons expressing open ATP-sensitive potassium (K) channels do not fire spontaneously, and activation of K channels halts spontaneous firing in these neurons. However, the conditions that regulate K channel opening in CW neurons remain unknown.
View Article and Find Full Text PDFDev Sci
January 2025
State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China.
To reveal the formation process of speech processing with early hearing experiences, we tracked the development of functional connectivity in the auditory and language-related cortical areas of 84 (36 female) congenitally deafened toddlers using repeated functional near-infrared spectroscopy for up to 36 months post cochlear implantation (CI). Upon hearing restoration, the CI children lacked the modular organization of the mature speech-processing network and demonstrated a higher degree of immaturity in temporo-parietal than temporo-frontal connections. The speech-processing network appeared to form rapidly with early CI experiences, with two-thirds of the developing connections following nonlinear trajectories reflecting possibly more than one synaptogenesis-pruning cycle.
View Article and Find Full Text PDFAnn Med
December 2024
The Six Medical Center, PLA General Hospital, Beijing, PR China.
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