scholarly journals Hearing Loss Alters Serotonergic Modulation of Intrinsic Excitability in Auditory Cortex

2010 ◽  
Vol 104 (5) ◽  
pp. 2693-2703 ◽  
Author(s):  
Deepti Rao ◽  
Gregory J. Basura ◽  
Joseph Roche ◽  
Scott Daniels ◽  
Jaime G. Mancilla ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Auditory Cortex ◽  
Sensorineural Hearing Loss ◽  
Pyramidal Cell ◽  
Receptor Activation ◽  
Sensorineural Hearing ◽  
Receptor Expression ◽  
Intrinsic Excitability ◽  
Receptor Subtypes ◽  
Cell Excitability

Sensorineural hearing loss during early childhood alters auditory cortical evoked potentials in humans and profoundly changes auditory processing in hearing-impaired animals. Multiple mechanisms underlie the early postnatal establishment of cortical circuits, but one important set of developmental mechanisms relies on the neuromodulator serotonin (5-hydroxytryptamine [5-HT]). On the other hand, early sensory activity may also regulate the establishment of adultlike 5-HT receptor expression and function. We examined the role of 5-HT in auditory cortex by first investigating how 5-HT neurotransmission and 5-HT2 receptors influence the intrinsic excitability of layer II/III pyramidal neurons in brain slices of primary auditory cortex (A1). A brief application of 5-HT (50 μM) transiently and reversibly decreased firing rates, input resistance, and spike rate adaptation in normal postnatal day 12 (P12) to P21 rats. Compared with sham-operated animals, cochlear ablation increased excitability at P12–P21, but all the effects of 5-HT, except for the decrease in adaptation, were eliminated in both sham-operated and cochlear-ablated rats. At P30–P35, cochlear ablation did not increase intrinsic excitability compared with shams, but it did prevent a pronounced decrease in excitability that appeared 10 min after 5-HT application. We also tested whether the effects on excitability were mediated by 5-HT2 receptors. In the presence of the 5-HT2-receptor antagonist, ketanserin, 5-HT significantly decreased excitability compared with 5-HT or ketanserin alone in both sham-operated and cochlear-ablated P12–P21 rats. However, at P30–P35, ketanserin had no effect in sham-operated and only a modest effect cochlear-ablated animals. The 5-HT2-specific agonist 5-methoxy- N, N-dimethyltryptamine also had no effect at P12–P21. These results suggest that 5-HT likely regulates pyramidal cell excitability via multiple receptor subtypes with opposing effects. These data also show that early sensorineural hearing loss affects the ability of 5-HT receptor activation to modulate A1 pyramidal cell excitability.

A Spiking Neuron Model of Cortical Correlates of Sensorineural Hearing Loss: Spontaneous Firing, Synchrony, and Tinnitus

2006 ◽  
Vol 18 (12) ◽  
pp. 2942-2958 ◽  
Author(s):  
Melissa Dominguez ◽  
Suzanna Becker ◽  
Ian Bruce ◽  
Heather Read
Keyword(s):  
Hearing Loss ◽  
Auditory Cortex ◽  
Sensorineural Hearing Loss ◽  
Auditory Nerve ◽  
Neuron Model ◽  
Nerve Fibers ◽  
Sensorineural Hearing ◽  
Spontaneous Firing ◽  
Spiking Neuron ◽  
Spiking Neuron Model

Hearing loss due to peripheral damage is associated with cochlear hair cell damage or loss and some retrograde degeneration of auditory nerve fibers. Surviving auditory nerve fibers in the impaired region exhibit elevated and broadened frequency tuning, and the cochleotopic representation of broadband stimuli such as speech is distorted. In impaired cortical regions, increased tuning to frequencies near the edge of the hearing loss coupled with increased spontaneous and synchronous firing is observed. Tinnitus, an auditory percept in the absence of sensory input, may arise under these circumstances as a result of plastic reorganization in the auditory cortex. We present a spiking neuron model of auditory cortex that captures several key features of cortical organization. A key assumption in the model is that in response to reduced afferent excitatory input in the damaged region, a compensatory change in the connection strengths of lateral excitatory and inhibitory connections occurs. These changes allow the model to capture some of the cortical correlates of sensorineural hearing loss, including changes in spontaneous firing and synchrony; these phenomena may explain central tinnitus. This model may also be useful for evaluating procedures designed to segregate synchronous activity underlying tinnitus and for evaluating adaptive hearing devices that compensate for selective hearing loss.

scholarly journals Tonotopic organisation of the auditory cortex in sloping sensorineural hearing loss

2017 ◽  
Vol 355 ◽  
pp. 81-96 ◽  
Author(s):  
Tomasz Wolak ◽  
Katarzyna Cieśla ◽  
Artur Lorens ◽  
Krzysztof Kochanek ◽  
Monika Lewandowska ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Auditory Cortex ◽  
Sensorineural Hearing Loss ◽  
Sensorineural Hearing

scholarly journals Plasticity in the Developing Auditory Cortex: Evidence from Children with Sensorineural Hearing Loss and Auditory Neuropathy Spectrum Disorder

2012 ◽  
Vol 23 (06) ◽  
pp. 396-411 ◽  
Author(s):  
Garrett Cardon ◽  
Julia Campbell ◽  
Anu Sharma
Keyword(s):  
Hearing Loss ◽  
Auditory Cortex ◽  
Sensorineural Hearing Loss ◽  
Hearing Aids ◽  
Auditory Neuropathy ◽  
Sensorineural Hearing ◽  
Spectrum Disorder ◽  
Early Deprivation ◽  
Auditory Neuropathy Spectrum Disorder ◽  
Cortical Input

The developing auditory cortex is highly plastic. As such, the cortex is both primed to mature normally and at risk for reorganizing abnormally, depending upon numerous factors that determine central maturation. From a clinical perspective, at least two major components of development can be manipulated: (1) input to the cortex and (2) the timing of cortical input. Children with sensorineural hearing loss (SNHL) and auditory neuropathy spectrum disorder (ANSD) have provided a model of early deprivation of sensory input to the cortex and demonstrated the resulting plasticity and development that can occur upon introduction of stimulation. In this article, we review several fundamental principles of cortical development and plasticity and discuss the clinical applications in children with SNHL and ANSD who receive intervention with hearing aids and/or cochlear implants.

scholarly journals Altered Brain Activity and Functional Connectivity in Unilateral Sudden Sensorineural Hearing Loss

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Jiawei Chen ◽  
Bo Hu ◽  
Peng Qin ◽  
Wei Gao ◽  
Chengcheng Liu ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Visual Cortex ◽  
Functional Connectivity ◽  
Auditory Cortex ◽  
Sensorineural Hearing Loss ◽  
Brain Regions ◽  
Sudden Sensorineural Hearing Loss ◽  
Sensorineural Hearing ◽  
Angular Gyrus ◽  
Precentral Gyrus

Background. Sudden sensorineural hearing loss (SSNHL) is an otologic emergency and could lead to social difficulties and mental disorders in some patients. Although many studies have analyzed altered brain function in populations with hearing loss, little information is available about patients with idiopathic SSNHL. This study is aimed at investigating brain functional changes in SSNHL via functional magnetic resonance imaging (fMRI). Methods. Thirty-six patients with SSNHL and thirty well-matched normal hearing individuals underwent resting-state fMRI. Amplitude of low-frequency fluctuation (ALFF), fractional ALFF (fALFF), and functional connectivity (FC) values were calculated. Results. In the SSNHL patients, ALFF and fALFF were significantly increased in the bilateral putamen but decreased in the right calcarine cortex, right middle temporal gyrus (MTG), and right precentral gyrus. Widespread increases in FC were observed between brain regions, mainly including the bilateral auditory cortex, bilateral visual cortex, left striatum, left angular gyrus (AG), bilateral precuneus, and bilateral limbic lobes in patients with SSNHL. No decreased FC was observed. Conclusion. SSNHL causes functional alterations in brain regions, mainly in the striatum, auditory cortex, visual cortex, MTG, AG, precuneus, and limbic lobes within the acute period of hearing loss.

scholarly journals Functional Magnetic Resonance Imaging Reveals Early Connectivity Changes in the Auditory and Vestibular Cortices in Idiopathic Sudden Sensorineural Hearing Loss With Vertigo: A Pilot Study

2021 ◽  
Vol 15 ◽  
Author(s):  
Qiuxia Wang ◽  
Qingguo Chen ◽  
Ping Liu ◽  
Jing Zhang ◽  
Liangqiang Zhou ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Hearing Loss ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Auditory Cortex ◽  
Sensorineural Hearing Loss ◽  
Sudden Sensorineural Hearing Loss ◽  
Sensorineural Hearing ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging

The underlying pathophysiology of idiopathic sudden sensorineural hearing loss (ISSNHL) with vertigo has yet to be identified. The aims of the current study were (1) to elucidate whether there are functional changes of the intrinsic brain activity in the auditory and vestibular cortices of the ISSNHL patients with vertigo using resting-state functional magnetic resonance imaging (rs-fMRI) and (2) whether the connectivity alterations are related to the clinical performance associated with ISSNHL with vertigo. Twelve ISSNHL patients with vertigo, eleven ISSNHL patients without vertigo and eleven healthy subjects were enrolled in this study. Rs-fMRI data of auditory and vestibular cortices was extracted and regional homogeneity (ReHo) and seed-based functional connectivity (FC) were evaluated; the chi-square test, the ANOVA and the Bonferroni multiple comparison tests were performed. Significantly decreased ReHo in the ipsilateral auditory cortex, as well as increased FC between the inferior parietal gyrus and the auditory cortex were found in the ISSNHL with vertigo groups. These findings contribute to a characterization of early plastic changes in ISSNHL patients with vertigo and cultivate new insights for the etiology research.

Functional Connectivity in Patients With Sensorineural Hearing Loss Using Resting-State MRI

2015 ◽  
Vol 24 (2) ◽  
pp. 145-152 ◽  
Author(s):  
Bin Liu ◽  
Yuan Feng ◽  
Ming Yang ◽  
Jing-ya Chen ◽  
Jing Li ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Functional Connectivity ◽  
Auditory Cortex ◽  
Sensorineural Hearing Loss ◽  
Resting State ◽  
Region Of Interest ◽  
Primary Auditory Cortex ◽  
Sensorineural Hearing ◽  
Control Group ◽  
Resting State Functional Connectivity

Purpose This study was undertaken to evaluate whole-brain functional connectivity changes related to auditory cortex in patients with left-sided sensorineural hearing loss (SNHL) using resting-state functional connectivity magnetic resonance imaging. Method Imaging was performed in 19 patients with left-sided SNHL and 35 individuals in the control group without SNHL. Data were collected and analyzed to map functional connectivity using the left/right primary auditory cortex as the region of interest to identify global differences between patients with SNHL and the control group. Results In comparison to the control group, the SNHL group was found to have significant functional connectivity changes in the auditory system, recognition network, visual cortex, and language network. Conclusion These findings suggest that functional brain alterations in unilateral SNHL patients may indicate reorganizations that occur in response to auditory deficits.

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