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Assessing Paediatric Development in Psychiatry
Published in Cathy Laver-Bradbury, Margaret J.J. Thompson, Christopher Gale, Christine M. Hooper, Child and Adolescent Mental Health, 2021
Receptive hair cells located in the centre of the coiled cochlear apparatus are sensitive to sounds of low frequency, whereas the proximal hair cells detect sounds of higher frequencies. This information is relayed to the two primary cortical areas responsible for analysis of basic sound information, auditory I and II, via the inferior colliculus and the medial geniculate nucleus of thalamus. Cells within both the thalamus and the cortical areas associated with hearing organise these inputs in such a way that they have an accurate spatial representation of the location from which the sound originated.
Anatomy of the head and neck
Published in Helen Whitwell, Christopher Milroy, Daniel du Plessis, Forensic Neuropathology, 2021
The midbrain is divided into anterior and posterior portions at the level of the cerebral aqueduct. The anterior portion is termed the ‘tegmentum’ and is bounded by the crus cerebri. The posterior portion is the tectum, made up of the inferior and superior colliculi (corpora quadrigemina). The inferior colliculus forms part of the ascending auditory pathway whereas the superior colliculus is part of the visual system.
Brain Motor Centers and Pathways
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
The inferior colliculus is the main midbrain nucleus of the auditory pathway and receives input from the auditory cortex, from the superior colliculus, and from several peripheral brainstem nuclei in the auditory pathway. It is involved in the binaural localization of sound, in frequency recognition, and pitch discrimination, as well as in the processing of sounds having complex temporal patterns.
Vision Beyond Vision: Lessons Learned from Amblyopia
Published in Journal of Binocular Vision and Ocular Motility, 2023
To explain the impairment of auditory localization in amblyopia, we reviewed the literature, which reveals two crucial pieces of information: the role of the superior colliculus in the developmental calibration of the auditory map and the anatomical arrangement of the retinocollicular pathway. First, in several classic experiments using barn owls, vision has been found to calibrate sound localization during early development.50–52 Two structures in the dorsal midbrain are involved – the superior colliculus that contains a retinotopically-organized visual map and the inferior colliculus that contains a spatially-organized auditory map. During development, vision guides sound localization so that the auditory map in the inferior colliculus is aligned with the visual map in the superior colliculus. However, after the barn owls have been raised wearing prisms, the auditory map in the inferior colliculus is realigned with the optically-displaced visual map in the superior colliculus.
ABI-auditory brainstem implant
Published in Acta Oto-Laryngologica, 2021
Anandhan Dhanasingh, Ingeborg Hochmair
The results of the first patient with IC implant showed substantial benefit from electric stimulation with no complications or side effects. All twelve electrodes produced auditory sensations with no non-auditory responses. The threshold levels were as low as 5nC, indicating the array in excellent position over auditory pathway structures. The patient was able to discriminate multisyllabic words at 80% correct in a five-choice test that was based on prosodic and syllabic cues. Face-to-face communication with the implant demonstrated a significant improvement in speech understanding over lip-reading alone. Recognition of words and sentences increased from 5% and 10% to 80% and 90%, respectively, after the revision surgery. These results indicate that the stimulation on the surface if the inferior colliculus in the auditory midbrain could provide an alternative possibility for auditory prosthetic devices.
Change in gene expression levels of GABA, glutamate and neurosteroid pathways due to acoustic trauma in the cochlea
Published in Journal of Neurogenetics, 2021
Meltem Cerrah Gunes, Murat Salih Gunes, Alperen Vural, Fatma Aybuga, Arslan Bayram, Keziban Korkmaz Bayram, Mehmet Ilhan Sahin, Muhammet Ensar Dogan, Sevda Yesim Ozdemir, Yusuf Ozkul
Gabra1 encodes the gamma-aminobutyric acid type A receptor alpha1 subunit. GABA-A α1 subunit functions in phasic inhibition and phasic inhibition reduces the hyperexcitability of the postsynaptic cell (Guerriero, Giza, & Rotenberg, 2015). It is known that increased GABA inhibition is neuroprotective and decreases excitotoxic neuron death in the acute phase of stroke (Green, Hainsworth, & Jackson., 2000). We found that Gabra1 gene expression was decreased in Post-AT(15) group compared to Post-AT(1) group. In some studies, it has been reported that Gad1 and Gabra1 expression in inferior colliculus decreased after hearing loss (Caspary et al., 1999; Mossop et al., 2000; Suneja et al., 1998). However, in another study performed in inferior colliculus samples with bilateral hearing loss, Gabra1 and GABA receptor β2, β3 and γ2 subunits were also found to be increased on the 3rd and 21st days (Holt et al., 2005). Gabra1 expression varies depending on whether the hearing loss is unilateral or bilateral, how long it has elapsed after hearing loss, and where the samples are removed from such as inferior colliculus, cochlea, auditory cortex (Dong et al., 2010; Manohar, Dahar, Adler, Dalian, & Salvi, 2016). Our study included hair cell-SGN synapses and peripheral nerve endings in the cochlea thus the differences between the results of studies may be related primarily to the difference in tissues.