scholarly journals Expression and Localization of Kv1.1 and Kv3.1b Potassium Channels in the Cochlear Nucleus and Inferior Colliculus after Long-Term Auditory Deafferentation

2020 ◽  
Vol 10 (1) ◽  
pp. 35 ◽  
Author(s):  
Clara Poveda ◽  
Maria Valero ◽  
Marianny Pernia ◽  
Juan Alvarado ◽  
David Ryugo ◽  
...  
Keyword(s):  
Potassium Channels ◽  
Protein Expression ◽  
Inferior Colliculus ◽  
Auditory Processing ◽  
Cochlear Nucleus ◽  
Auditory Pathway ◽  
Cellular Mechanisms ◽  
Auditory Deprivation ◽  
Central Auditory Neurons

Deafness affects the expression and distribution of voltage-dependent potassium channels (Kvs) of central auditory neurons in the short-term, i.e., hours to days, but the consequences in the expression of Kvs after long-term deafness remain unknown. We tested expression and distribution of Kv1.1 and Kv3.1b, key for auditory processing, in the rat cochlear nucleus (CN), and in the inferior colliculus (IC), at 1, 15 and 90 days after mechanical lesion of the cochlea, using a combination of qRT-PCR and Western blot in the whole CN, along with semi-quantitative immunocytochemistry in the AVCN, where the role of both Kvs in the control of excitability for accurate auditory timing signal processing is well established. Neither Kv1.1/Kv3.1b mRNA or protein expression changed significantly in the CN between 1 and 15 days after deafness. At 90 days post-lesion, however, mRNA and protein expression for both Kvs increased, suggesting that regulation of Kv1.1 and Kv3.1b expression is part of cellular mechanisms for long-term adaptation to auditory deprivation in the CN. Consistent with these findings, immunocytochemistry showed increased labeling intensity for both Kvs in the AVCN at day 90 after cochlear lesion. This increase argues that up-regulation of Kv1.1 and Kv3.1b in AVCN neurons may be required to adapt intrinsic excitability to altered input over the long term after auditory deprivation. Contrary to these findings in the CN, expression levels of Kv1.1 and Kv3.1b in the IC did not undergo major changes after cochlear lesion. In particular, there was no evidence of long-term up-regulation of either Kv1.1 or Kv3.1b, supporting that such post-lesion adaptive mechanism may not be needed in the IC. These results reveal that post-lesion adaptations do not necessarily involve stereotyped plastic mechanisms along the entire auditory pathway.

Effects of L-Baclofen and D-Baclofen on the Auditory System: A Study of Click-Evoked Potentials from the Inferior Colliculus in the Rat

1995 ◽  
Vol 104 (5) ◽  
pp. 399-404 ◽  
Author(s):  
William S. Szczepaniak ◽  
Aage R. Møller
Keyword(s):  
Inferior Colliculus ◽  
Cochlear Nucleus ◽  
Auditory Pathway ◽  
Detectable Effect ◽  
Potential Treatment ◽  
Racemic Form ◽  
System A ◽  
Auditory Disorders ◽  
Severe Tinnitus ◽  
Second Peak

The drug baclofen is a potential treatment for severe tinnitus, but its action in relieving tinnitus is not known. Baclofen is available as an approved drug only in racemic form with about equal content of the two enantiomers. In the present paper we show that l-baclofen causes a considerable (40.7%) suppression of the amplitude of the second peak in the click-evoked response from the cochlear nucleus. Bipolar recordings from the external nucleus of the inferior colliculus showed that l-baclofen caused a reduction in the amplitude of three or four distinct peaks in this response. d-Baclofen had no detectable effect on the response from the cochlear nucleus, and had only a slight effect on one component of the response from the external nucleus of the inferior colliculus. The demonstrated effect of l-baclofen on excitation in the ascending auditory pathway indicates that this drug may be a potential treatment for hyperactive auditory disorders such as tinnitus and hyperacusis.

scholarly journals Acute and Long-Term Effects of Noise Exposure on the Neuronal Spontaneous Activity in Cochlear Nucleus and Inferior Colliculus Brain Slices

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Moritz Gröschel ◽  
Jana Ryll ◽  
Romy Götze ◽  
Arne Ernst ◽  
Dietmar Basta
Keyword(s):  
Hearing Loss ◽  
Spontaneous Activity ◽  
Inferior Colliculus ◽  
Cochlear Nucleus ◽  
Noise Exposure ◽  
Brain Slices ◽  
Noise Induced Hearing Loss ◽  
Long Term Effects ◽  
Noise Trauma

Noise exposure leads to an immediate hearing loss and is followed by a long-lasting permanent threshold shift, accompanied by changes of cellular properties within the central auditory pathway. Electrophysiological recordings have demonstrated an upregulation of spontaneous neuronal activity. It is still discussed if the observed effects are related to changes of peripheral input or evoked within the central auditory system. The present study should describe the intrinsic temporal patterns of single-unit activity upon noise-induced hearing loss of the dorsal and ventral cochlear nucleus (DCN and VCN) and the inferior colliculus (IC) in adult mouse brain slices. Recordings showed a slight, but significant, elevation in spontaneous firing rates in DCN and VCN immediately after noise trauma, whereas no differences were found in IC. One week postexposure, neuronal responses remained unchanged compared to controls. At 14 days after noise trauma, intrinsic long-term hyperactivity in brain slices of the DCN and the IC was detected for the first time. Therefore, increase in spontaneous activity seems to develop within the period of two weeks, but not before day 7. The results give insight into the complex temporal neurophysiological alterations after noise trauma, leading to a better understanding of central mechanisms in noise-induced hearing loss.

Molecular and Structural Changes in the Cochlear Nucleus in Response to Hearing Loss

2018 ◽  
pp. 142-162
Author(s):  
Maria E. Rubio
Keyword(s):  
Hearing Loss ◽  
Cochlear Nucleus ◽  
Structural Changes ◽  
Auditory Pathway ◽  
The United States ◽  
Cellular Mechanisms ◽  
Auditory Experience ◽  
Central Auditory Pathway ◽  
The Brain

Hearing loss is the third most common health problem in the United States. It can affect the quality of life and relationships. About 48 million Americans have lost some hearing. Age, illness, and genetics contribute to the generation of hearing loss. During development, auditory synaptic circuitries are highly plastic and able to adapt to fluctuations in auditory experience. Whether this is so for mature auditory nerve synapses and circuitries within nuclei along the central auditory pathway is less understood. Daily fluctuations in auditory experience can lead to hearing deficits, including hearing loss and/or deafness, Therefore, understanding the cellular mechanisms that occur in mature central auditory synaptic circuitries that lead and/or contribute to hearing loss is important. This chapter focuses on published studies using animal models describing structural and molecular changes that occur in the cochlear nucleus in response to hearing loss, the first gateway of sound processing in the brain.

scholarly journals Somatosensory context alters auditory responses in the cochlear nucleus

2011 ◽  
Vol 105 (3) ◽  
pp. 1063-1070 ◽  
Author(s):  
Patrick O. Kanold ◽  
Kevin A. Davis ◽  
Eric D. Young
Keyword(s):  
Auditory Processing ◽  
Cochlear Nucleus ◽  
Acoustic Stimulus ◽  
Electrical Stimulus ◽  
Dorsal Column ◽  
Dorsal Cochlear Nucleus ◽  
Initial Stimulus ◽  
Stimulus Pulse

The cochlear nucleus, the first central auditory structure, performs initial stimulus processing and segregation of information into parallel ascending pathways. It also receives nonauditory inputs. Here we show in vivo that responses of dorsal cochlear nucleus (DCN) principal neurons to sounds can change significantly depending on the presence or absence of inputs from the somatosensory dorsal column nucleus occurring before the onset of auditory stimuli. The effects range from short-term suppression of spikes lasting a few milliseconds at the onset of the stimulus to long-term increases or decreases in spike rate that last throughout the duration of an acoustic stimulus (up to several hundred milliseconds). The long-term effect requires only a single electrical stimulus pulse to initiate and seems to be similar to persistent activity reported in other parts of the brain. Among the DCN inhibitory interneurons, only the cartwheel cells show a long-term rate decrease that could account for the rate increases (but not the decreases) of DCN principal cells. Thus even at the earliest stages of auditory processing, the represented information is dependent on nonauditory context, in this case somatosensory events.

Auditory Selective Attention Modulates Activation of Human Inferior Colliculus

2008 ◽  
Vol 100 (6) ◽  
pp. 3323-3327 ◽  
Author(s):  
Teemu Rinne ◽  
Marja H. Balk ◽  
Sonja Koistinen ◽  
Taina Autti ◽  
Kimmo Alho ◽  
...  
Keyword(s):  
Inferior Colliculus ◽  
Neural Activity ◽  
Auditory Processing ◽  
Auditory Pathway ◽  
Auditory Attention ◽  
The Other ◽  
Auditory Selective Attention ◽  
Attention Tasks ◽  
External Connections

Selective auditory attention powerfully modulates neural activity in the human auditory cortex (AC). In contrast, the role of attention in subcortical auditory processing is not well established. Here, we used functional MRI (fMRI) to examine activation of the human inferior colliculus (IC) during strictly controlled auditory attention tasks. The IC is an obligatory midbrain nucleus of the ascending auditory pathway with diverse internal and external connections. The IC also receives a massive descending projection from the AC, suggesting that cortical processes affect IC operations. In this study, 21 subjects selectively attended to left-ear or right-ear sounds and ignored sounds delivered to the other ear. IC activations depended on the direction of attention, indicating that auditory processing in the human IC is not only determined by acoustic input but also by the current behavioral goals.

scholarly journals Changes in microRNA Expression in the Cochlear Nucleus and Inferior Colliculus after Acute Noise-Induced Hearing Loss

2020 ◽  
Vol 21 (22) ◽  
pp. 8792
Author(s):  
Sohyeon Park ◽  
Seung Hee Han ◽  
Byeong-Gon Kim ◽  
Myung-Whan Suh ◽  
Jun Ho Lee ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Inferior Colliculus ◽  
Neural Plasticity ◽  
Cochlear Nucleus ◽  
Organ Of Corti ◽  
Auditory Pathway ◽  
Noise Induced Hearing Loss ◽  
Candidate Mirnas ◽  
Central Auditory Pathway

Noise-induced hearing loss (NIHL) can lead to secondary changes that induce neural plasticity in the central auditory pathway. These changes include decreases in the number of synapses, the degeneration of auditory nerve fibers, and reorganization of the cochlear nucleus (CN) and inferior colliculus (IC) in the brain. This study investigated the role of microRNAs (miRNAs) in the neural plasticity of the central auditory pathway after acute NIHL. Male Sprague–Dawley rats were exposed to white band noise at 115 dB for 2 h, and the auditory brainstem response (ABR) and morphology of the organ of Corti were evaluated on days 1 and 3. Following noise exposure, the ABR threshold shift was significantly smaller in the day 3 group, while wave II amplitudes were significantly larger in the day 3 group compared to the day 1 group. The organ of Corti on the basal turn showed evidence of damage and the number of surviving outer hair cells was significantly lower in the basal and middle turn areas of the hearing loss groups relative to controls. Five and three candidate miRNAs for each CN and IC were selected based on microarray analysis and quantitative reverse transcription PCR (RT-qPCR). The data confirmed that even short-term acoustic stimulation can lead to changes in neuroplasticity. Further studies are needed to validate the role of these candidate miRNAs. Such miRNAs may be used in the early diagnosis and treatment of neural plasticity of the central auditory pathway after acute NIHL.

scholarly journals The Effect of Long-Term Unilateral Deafness on Auditory Performance

2020 ◽  
Vol 63 (12) ◽  
pp. 570-578
Author(s):  
Min Young Kwak ◽  
Dong Hyun Kim ◽  
Hyeon Sik Oh ◽  
Yong-Hwi An ◽  
Jong Ho Won ◽  
...  
Keyword(s):  
Auditory Processing ◽  
Normal Hearing ◽  
Control Group ◽  
Auditory Deprivation ◽  
Unilateral Deafness ◽  
Auditory Performance ◽  
The Right ◽  
And Control ◽  
Auditory Process

Background and Objectives We investigated whether there are differences in auditory performance between the healthy ears of subjects with unilateral deafness (UD) and the control ears of subjects with normal hearing (NH) in both ears.Subjects and Method Sixteen subjects with acquired UD and 16 subjects with NH thresholds for both ears were enrolled. We compared the auditory performance of UD group and control group with NH in both ears.Results We found no meaningful differences in the three measures of psychoacoustic performance between the total healthy ears of subjects with UD and the ears of the control group. However, in the subgroup comparison, the left ears of subjects with right UD showed significantly poorer spectral-ripple discrimination (SRD) than the right ears of the subjects with left UD (<i>p</i>=0.006) and the ears of control subjects with NH (<i>p</i>=0.004).Conclusion Our findings indicate that after unilateral auditory deprivation, auditory processing is differentially affected by the side involved. In the subjects with acquired UD, the longterm hearing deprivation on the right side induced the down-regulation of central auditory process for SRD, but hearing deprivation on the left side did not affect SRD.

Temporal and Frequency Characteristics of Cartwheel Cells in the Dorsal Cochlear Nucleus of the Awake Mouse

2007 ◽  
Vol 98 (2) ◽  
pp. 744-756 ◽  
Author(s):  
Christine V. Portfors ◽  
Patrick D. Roberts
Keyword(s):  
Auditory Processing ◽  
Cochlear Nucleus ◽  
Auditory Nerve ◽  
Active Role ◽  
Auditory Pathway ◽  
Dorsal Cochlear Nucleus ◽  
Central Auditory Processing ◽  
Complex Frequency ◽  
Principal Cells ◽  
Cartwheel Cells

The dorsal cochlear nucleus (DCN) is an initial site of central auditory processing and also the first site of multisensory convergence in the auditory pathway. The auditory nerve imparts a tonotopic frequency organization on the responses of principal cells in the DCN. Cartwheel cells modify the responses of principal cells, but they do not receive direct auditory nerve input. This study shows that cartwheel cells respond well to tonal stimuli in the awake mouse and they have a well-defined characteristic frequency that corresponds to the tonotopic organization of the DCN. The auditory responses of cartwheel cells exhibit complex spectrotemporal responses to tones, with excitation and inhibition modulating the firing patterns in both frequency and time after onset of the stimulus. Temporal responses to best-frequency tones are highly variable between cartwheel cells, but a simple model is used to unify this variability as differences in the timing of synaptic currents. Cartwheel cell responses to two-tone stimuli show that interactions from different frequencies affect the output of cartwheel cells. The results suggest that at this primary auditory structure, processing of sound at one frequency can be modified by sounds of different frequency. These complex frequency and temporal interactions in cartwheel cells suggest that these neurons play an active role in basic sound processing.

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