Cross-Modal Interactions of Auditory and Somatic Inputs in the Brainstem and Midbrain and Their Imbalance in Tinnitus and Deafness

Dehmel, Susanne; Cui, Yaqiong; Shore, Susan E.

doi:10.1044/1059-0889(2008/07-0045)

Cited by 115 publications

(96 citation statements)

References 103 publications

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“…Dehmel et al 31 , also found similar results. Further, Cook-Huvnh 32 has indicated that there is an increasing prevalence of hypertension and diabetes mellitus in the adults and geriatrics.…”

Section: Other Risk Factorssupporting

confidence: 76%

One-year prevalence and risk factors of tinnitus in older individuals with otological problems

Thirunavukkarasu¹,

Geetha²

2013

The International Tinnitus Journal

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Objective: The present study was carried out to estimate one year prevalence and risk factors of tinnitus in the older individuals (60 years and above) who reported with the ear and/or hearing related complaint to All India Institute of Speech and hearing, Mysore. Methods: The case files of those who visited the institute during the above said period were reviewed retrospectively. Results: The results of the study revealed that the prevalence of tinnitus was 16.81%.It was also found that 60.9% of the individuals with tinnitus were males. Further, 97.5% of the individuals with tinnitus had hearing loss. In addition, 28.53% of the individuals with tinnitus had moderate degree of hearing loss followed by moderately severe degree of hearing loss. Most of these individuals had sensorineural impairment. Conclusion: It can be concluded that prevalence of tinnitus is quite high in the older individuals with otological problems. The hearing loss, gender, giddiness, headache, hypertension, and diabetes were found to be major risk factors.

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Section: Other Risk Factorssupporting

confidence: 76%

One-year prevalence and risk factors of tinnitus in older individuals with otological problems

Thirunavukkarasu¹,

Geetha²

2013

The International Tinnitus Journal

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“…Therefore, it is possible that deafness-induced changes in somatosensory processing at the sub-cortical level could account for the massive redistribution of that information manifested as cortical cross-modal reorganization. Furthermore, given that the auditory pathways are highly crossed in their projections from brainstem to cortex, deafness-induced somatic inputs to the first station of this relay (40,46) could generate a large proportion of bilateral receptive fields at higher levels, as was observed.…”

Section: Discussionmentioning

confidence: 85%

“…It is well established in hearing animals that somatosensory afferents converge on auditory neurons at various sub-cortical levels within the auditory system, including the cochlear nucleus and inferior colliculus (40,41). In hearing animals, dorsal cochlear nucleus neurons respond to somatosensory stimulation of the pinna, vibrissa, neck, and forelimb (42), and neurons in the external nucleus of the inferior colliculus respond to displacement of hairs and light touch on the bilateral or contralateral body surface, with no apparent somatotopic organization (43)(44)(45).…”

Section: Discussionmentioning

confidence: 99%

Adult deafness induces somatosensory conversion of ferret auditory cortex

Allman

Keniston

Meredith

2009

Proc. Natl. Acad. Sci. U.S.A.

115

123

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In response to early or developmental lesions, responsiveness of sensory cortex can be converted from the deprived modality to that of the remaining sensory systems. However, little is known about capacity of the adult cortex for cross-modal reorganization. The present study examined the auditory cortices of animals deafened as adults, and observed an extensive somatosensory conversion within as little as 16 days after deafening. These results demonstrate that cortical cross-modal reorganization can occur after the period of sensory system maturation.aging ͉ cross-modal reorganization ͉ hearing loss ͉ plasticity ͉ reorganization T he study of neural plasticity has revealed the considerable vulnerability of the developing brain to altered sensory experience (1). This vulnerability is particularly evident when the loss of peripheral sensory input results in the cross-modal reorganization of cortex. In their classic study, Rauschecker and Korte (2) showed that the ectosylvian visual area responded vigorously to auditory and/or somatosensory stimuli in cats visually deprived from birth. Similar developmental studies have been performed in a variety of species and their common finding was that cortical areas normally devoted to processing one sensory modality were converted to the other sensory systems following early visual deprivation (3-8) or early deafening (9-13, but see 14).In contrast to these established developmental effects, little is known about the potential for cross-modal reorganization from lesions occurring after the sensory systems have matured. The few animal studies of adult cross-modal reorganization have described far less robust effects and collectively appear inconclusive. Blinding of adult rabbits resulted in somatosensory innervation of primary visual cortex near its border with somatosensory cortex (15). However, in deafened auditory cortex (16), visual responses were observed in the primary auditory area of cats deafened at 1 week of age, but not when cats were deafened at a later stage. In humans, regions of multi-sensory cortex become more visually active after late-onset deafness (17), which is not surprising given the presence of visual inputs before the hearing loss.Despite these limited and equivocal results regarding lateonset cross-modal reorganization, there is considerable evidence that the adult cortex is capable of reacting to loss of peripheral input (18,19). Investigations of adult subjects that received peripheral insults such as digit amputation (20), focal retinal lesions (21, 22), and frequency-specific cochlear lesions (23) revealed that the initially silenced cortical locus eventually developed responses similar to those of unaffected neighboring neurons (18,24). Although these effects occurred within the same modality, the fact that intra-modal reorganization had occurred is consistent with the likelihood that the sensory cortices of adults are indeed mutable.Hearing impairment is one of the most prevalent neurological disorders in humans, affecting 16% of adults in the...

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“…Since the excitatory CN-commissural pathway resembles that of non-auditory (somatosensory) projection neurons (Dehmel et al 2008;Haenggeli et al 2005;Wright and Ryugo 1996;Zhou et al 2007;Zhou and Shore 2004), it is likely to have a similar modulatory function as suggested for these non-auditory projections and may be associated with DCN synaptic plasticity under normal-hearing conditions (Tzounopoulos et al 2004;Young et al 1995;Zhou et al 2007). …”

Section: Discussionmentioning

confidence: 98%

Vesicular Glutamate Transporter 2 Is Associated with the Cochlear Nucleus Commissural Pathway

Zhou

Zeng

Cui

et al. 2010

JARO

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The cochlear nucleus (CN) is the first auditory structure to receive binaural information via CN-commissural connections. In spite of an abundance of evidence that CN-commissural neurons are glycinergic and thus inhibitory, physiological, and anatomical evidence suggests that a small group of CN-commissural neurons are excitatory. In this study, we examined the excitatory portion of the CN-commissural pathway by combining anterograde tract tracing with immunohistochemistry of vesicular glutamate transporters (VGLUTs) and retrograde tract tracing with immunohistochemistry of glycine and GABA. VGLUTs accumulate glutamate in synaptic vesicles and are prime markers for glutamatergic neurons. The terminal endings of CN-commissural projections were typically en passant or small terminal boutons, but large, irregular swellings were also observed, confined to the granule cell domain (GCD). Both small and large terminal endings in the GCD colabeled with VGLUT2, but not VGLUT1. In addition, some CN-commissural cells themselves received VGLUT2-positive puncta on their somata. After large injections into the CN, 37% of the total number of retrogradely labeled commissural neurons was immunonegative to glycine or GABA. Retrograde labeling after a restricted GCD injection revealed a majority of putative excitatory CN-commissural neurons as multipolar, in the marginal regions of the ventral CN, medially as well as in the small cell cap region and deep dorsal CN. These results provide direct anatomical evidence that an excitatory commissural projection is present, and VGLUT2 is associated with this pathway both as its source and as a recipient.

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Cross-Modal Interactions of Auditory and Somatic Inputs in the Brainstem and Midbrain and Their Imbalance in Tinnitus and Deafness

Cited by 115 publications

References 103 publications

One-year prevalence and risk factors of tinnitus in older individuals with otological problems

One-year prevalence and risk factors of tinnitus in older individuals with otological problems

Adult deafness induces somatosensory conversion of ferret auditory cortex

Vesicular Glutamate Transporter 2 Is Associated with the Cochlear Nucleus Commissural Pathway

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