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Physiology of Hearing
Published in John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed, Paediatrics, The Ear, Skull Base, 2018
Soumit Dasgupta, Michael Maslin
The synaptic architecture of the hair cells and the spiral ganglions is discussed in detail in ‘The cochlea’ above. The cochlear nucleus synapses with the cochlear nerve and is represented tonotopically, which implies that frequency encoding by the cochlea is carried up to the central nervous system to be further analyzed.
Specific Synonyms
Published in Terence R. Anthoney, Neuroanatomy and the Neurologic Exam, 2017
Anterior2 cochlear nucleus4 (G&N. p. 127) Anteroventral and posteroventral cochlear nuclei (C&S, p. 365)Ventral division of the cochlear nucleus (K&S. p. 405)
Physiology of Hearing
Published in James R. Tysome, Rahul G. Kanegaonkar, Hearing, 2015
The auditory pathway is considerably more complex than the visual pathway between receptor and cortex. The primary reason for this is presumably the need to compute the localisation of a sound source from the receptor epithelium of the cochlea, which is tonotopically organised and not spatially organised. The cochlear nucleus is an obligatory synapse for all auditory nerve fibres and has been referred to as the ’retina of the auditory system’. An enormous amount of parallel processing occurs at this point. There are cells in the cochlear nucleus specialised to preserve the timing information present in the auditory nerve input. These cells are characterised by large end-bulb of Held synapses (Figures 2.6A, B); these synapses are amongst the largest in the brain.
Effect of selective attention on auditory brainstem response
Published in Hearing, Balance and Communication, 2023
Sathish Kumar, Srikanth Nayak, Arivudai Nambi Pitchai Muthu
The mean amplitude of peak V in active listening condition was larger than the peak V of passive listening with visual distractor and visual task conditions. However, the statistical difference was observed only in the contralateral response between active listening and passive listening with visual distractor condition. This result evidence the attentional modulation of brainstem activity. Increased peak V amplitude in the active listening condition can be attributed to the enhanced activity in the inferior colliculus due to attention [14]. Using functional Magnetic Resonance Imaging (fMRI) technique [14], demonstrated that attention enhances inferior colliculus activity through indirect activation of the superior colliculus. However, the statistical difference was seen only in the contralateral montage, not in the ipsilateral montage. This result can be attributed to the cross-over of the auditory fibres above the cochlear nucleus [45]. Also, the corticofugal system of the auditory cortex sends more dense projections to the ipsilateral peripheral structures than the contralateral structure [8]. Therefore, the attentional modulational would have more effect on the fibres’ responses crossed over to the other side.
CI in single-sided deafness
Published in Acta Oto-Laryngologica, 2021
Anandhan Dhanasingh, Ingeborg Hochmair
In normal-hearing human subjects with binaural hearing (hearing with two ears), the brain receives and processes auditory input from both ears to separate individual voices and speech from environmental noises. The critical function of the brain at this point is to combine and compare raw acoustic information that comes from two cochleae, and takes place in different cochlear nuclei, particularly in the olivary complex exploiting the sound intensity, timing difference and frequency aspects of what the cochleae have encoded in the auditory nerve action potential. From the output that comes from the olivary complex, the auditory cortex creates a three-dimensional landscape of the acoustic signal. This is an ordinary phenomenon in binaural, normal-hearing human subjects who can localise and understand the speech with no additional effort – the two advantages claimed to be the most important in binaural hearing [4].
A population-based case–control study of the association between cervical spondylosis and tinnitus
Published in International Journal of Audiology, 2021
Yen-Fu Cheng, Sudha Xirasagar, Tzong-Hann Yang, Chuan-Song Wu, Nai-Wen Kuo, Herng-Ching Lin
Tinnitus is commonly linked to damage to the auditory apparatus, most often the cochlea and auditory nerve. Tinnitus can occur in patients with normal cochlear function with or without changes to hearing threshold (Bramhall et al. 2017, 2018; Eggermont 1990; Jastreboff 1990; Kujawa and Liberman 2009). Thus, it may have an origin other than the peripheral auditory system such as medial geniculate body (MGB) and inferior colliculus (IC) (Caspary and Llano 2017; Shore, Roberts, and Langguth 2016). A growing body of evidence suggests that the cochlear nucleus (CN) located in the brainstem portion of the central auditory pathway is involved at the earliest stage of hearing signal processing, and this may play an important role in tinnitus (Costa and Caria 2017; Koehler and Shore 2013; Lanting et al. 2010; Levine 1999; Marks et al. 2018; Ralli et al. 2017; Shore, Roberts, and Langguth 2016; Wu et al. 2016).