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Anatomy
Published in Stanley A. Gelfand, Hearing, 2017
The lateral lemniscus (LL) is the pathway from the lower nuclei of the auditory pathway just described to the level of the inferior colliculus, and has been described in some detail (e.g., Ferraro and Minckler, 1977a; Brunso-Bechtold et al., 1981; Glendenning et al., 1981; Moore, 1987; Schwartz, 1992; Helfert and Aschoff, 1997; Kelly et al., 2009). Each LL includes neural fibers originating from the cochlear nuclei and superior olivary complexes on both sides, as well as fibers arising from the nuclei of the LL itself. Communication between the lateral lemnisci of the two sides occurs via the commissural fibers of Probst. In mammals, the LL typically includes a ventral nucleus (VNLL), a dorsal nucleus (DNLL), and an intermediate nucleus (INLL). However, while the human brain has a rather well-defined DNLL, its VNLL and the INLL are only sparsely represented.
Discussions (D)
Published in Terence R. Anthoney, Neuroanatomy and the Neurologic Exam, 2017
Another change, however, involved identifying various functional tracts within the two lemnisci. One of the main components of the medial lemniscus was ascending somatosensory fibers from cells in the nuclei of the posterior columns. Similarly, one of the main functional components of the lateral lemniscus was ascending auditory fibers. Other ascending fibers were also known or thought to run within the medial or lateral lemniscus; and some were named accordingly. Thus, for example, fibers relaying somatosensory information from cell bodies in the dorsal gray columns of the spinal cord were already called the spinal lemniscus/fillet by Herrick in 1916; and fibers relaying somatosensory information from the trigeminal nuclei were called the trigeminal lemniscus/fillet (P. 334). Although such names may have initially been intended only to label parts of the more inclusive medial or lateral lemniscus/fillet—i.e.. the spinal part of the lemniscus, or the trigeminal part of the lemniscus—they soon became described in some texts as separate lemnisci in their own right (e.g., Herrick, 1916, p. 131, 138–139, 163).
Peripheral and central auditory function in adults with epilepsy and treated with carbamazepine
Published in Hearing, Balance and Communication, 2019
Sherifa A. Hamed, Amira M. Oseily
It is well known that anatomical and functional integrity of the peripheral and central auditory pathway are important for normal hearing. In the last three decades, there is an increasing interest in assessment and monitoring of hearing impairment from any cause using BAEPs [27,28,30,33,41]. BAEPs have proven to be more sensitive in detecting subclinical hearing impairment than PTA. BAEPs (short- and middle-latencies) reflect auditory pathway function starting from the auditory nerve and throughout the brainstem [42]. Results of short and middle BAEPs are interpreted as absolute wave latencies (I–V) and interpeak latencies. Waves I originates from afferent activity of the dendrites of the acoustic nerve fibres (first-order neurons) as they leave the cochlea and enter the internal auditory canal. Wave III shows the activity in superior olivary complex which is intimately related to the trapezoid body. Wave V is associated with the lateral lemniscus, the location is the rostral brainstem in or near the inferior colliculus. The I–III, III–V and I–V interpeak latencies (IPLs) reflect brainstem conduction time [42], while long-latency evoked response (also known as event-related potentials [ERPs]) reflects the function within the auditory cortex [43].
CI in single-sided deafness
Published in Acta Oto-Laryngologica, 2021
Anandhan Dhanasingh, Ingeborg Hochmair
In summary, from both dorsal and ventral CN, some fibres cross the mid-line while others stay on the ipsilateral side – and for that reason, acoustic information from both ears travels bilaterally in each lateral lemniscus, and any supranuclear lesions will not lead to severe hearing impairment. Therefore, hearing problems can only be conductive or sensorineural but are rarely central. Fibres ascending through the lateral lemniscus from both cochlear nuclei and superior olivary nuclei, carrying the auditory information, converge at the inferior colliculus. From there, the fibres project ipsilaterally to the medial geniculate body (MGB) where the auditory information is refined and sent to the auditory cortex, which gives meaningful sound sensation to hearing human subject [1–3].
Effect of selective attention on auditory brainstem response
Published in Hearing, Balance and Communication, 2023
Sathish Kumar, Srikanth Nayak, Arivudai Nambi Pitchai Muthu
The current study results demonstrate the presence of attentional modulation at earlier stages of auditory processing as evidenced by the increased amplitude of peak V. In the current study, attentional modulation was observed only in the contralateral responses, which is consistent with the previous fMRI studies. Future studies may investigate early attentional modulations below the level of lateral lemniscus with careful consideration of the effect of sleep and EEG filtering characteristics.