Search results for "Auditory Pathways"

The location by early auditory evoked potentials (EAEP) of acoustic nerve and brainstem demyelination in multiple sclerosis (MS).

1980

Tone pips of suprathreshold intensities elicit an acoustic nerve response (I) and six low amplitude brainstem potentials (II-VII) during the initial 10 ms. Seven waves were studied in 40 control subjects and 5 waves (I-V) in 47 patients with MS. The results suggest involvement of the auditory pathway of 24 of 27 patients in the clinically "definite", of 5 of 9 cases in the "probable" and in none of 5 patients in the "possible" MS groups. EAEPs were normal in 6 cases with a spinal form with one exception where changes of potential were indicative of a midbrain lesion. Dysfunction within the acoustic pathway was observed at the level of the acoustic nerve and in the medulla oblongata, pons an…

Introduction to the superior olivary complex

2000

The brainstem efferent acoustic chiasm in pigmented and albino rats

2015

Abstract The present study examined whether structural peculiarities in the brain-efferent pathway to the organ of Corti may underlie functional differences in hearing between pigmented and albino individuals of the same mammalian species. Pigmented Brown-Norway rats and albino Wistar rats received unilateral injections of an aqueous solution of the retrograde neuronal tracer Fluorogold (FG) into the scala tympani of the cochlea to identify olivocochlear neurons (OCN) in the brainstem superior olivary complex. After five days, brains were perfusion-fixed and brainstem sections were cut and analyzed with respect to retrogradely labeled neurons. Intrinsic neurons of the lateral system were lo…

Age-related changes of NADPH-diaphorase-positive neurons in the rat inferior colliculus and auditory cortex

2007

Nitric oxide (NO) has been implied in age-related changes of the central nervous system (CNS) and the central auditory pathway. The present study was conducted to investigate whether the number of NO-producing cells and their morphometric characteristics in the inferior colliculus (IC) and the auditory cortex (AC) are changed with the increasing age of the subjects. IC and AC sections of adult and senile Wistar rats were studied using the histochemical detection of NADPH-diaphorase activity (NADPH-d), a marker for neurons containing nitric oxide synthase (NOS). Our results showed a decreased area of the somas of NADPH-d-positive neurons in the dorsal cortex (DC) of the IC and a diffuse loss…

Immunfluorescence study of neuropeptides in identified neurons of the rat auditory superior olivary complex.

1999

The present study was conducted to investigate the distribution and immunohistochemical characteristics of ascending and descending projection neurons of the rat superior olivary complex (SOC), a group of interrelated brainstem nuclei. Ascending neurons were identified by injection of cholera toxin B subunit (CTB) into the central nucleus of the inferior colliculus (IC), descending neurons were labeled by application of Fluoro-Gold (FG) into the scala tympani of the cochlea, ipsilaterally to the IC injection. In accordance with the literature, we observed neurons innervating the IC located in the lateral superior olivary nucleus (LSO) and dorsal periolivary groups (DPO) on both sides, in th…

Change detection to tone pairs during the first year of life – Predictive longitudinal relationships for EEG-based source and time-frequency measures

2019

Abstract Brain responses related to auditory processing show large changes throughout infancy and childhood with some evidence that the two hemispheres might mature at different rates. Differing rates of hemispheric maturation could be linked to the proposed functional specialization of the hemispheres in which the left auditory cortex engages in analysis of precise timing information whereas the right auditory cortex focuses on analysis of sound frequency. Here the auditory change detection process for rapidly presented tone-pairs was examined in a longitudinal sample of infants at the age of 6 and 12 months using EEG. The ERP response related to change detection of a frequency contrast, i…

Nitric oxide synthase in identified olivocochlear projection neurons in rat and guinea pig.

1999

Nitric oxide (NO) is thought to be involved in the effects of amino acids at the level of cochlear hair cell afferents. Recently, the isoform of the NO-producing enzyme, neuronal NO synthase (nNOS), has been demonstrated in neuronal structures of the cochlea in rats and guinea pigs histochemically and immunohistochemically. To investigate the sources of cochlear NO, we injected Fluoro-Gold (FG) into the cochlea of rats and guinea pigs. Upon terminal uptake of the tracer and neuronal transport we observed FG in terminals at the base of inner (IHC) and outer hair cells (OHC) and in neurons of the spiral ganglion. Ganglion cells and terminals at the IHC were clearly nNOS-positive, while termin…

Evidence for increased nitric oxide production in the auditory brain stem of the aged dwarf hamster (Phodopus sungorus): an NADPH-diaphorase histoche…

2000

Age-related changes of the auditory system such as presbyacusis are believed to be due, at least in part, to alterations of central structures. The superior olivary complex (SOC), a group of interrelated brain stem nuclei, projects to a variety of neuronal structures including the cochlea and the inferior colliculus (IC). The soluble gas nitric oxide (NO), believed to function as a neuroactive substance within the SOC and cochlea, is thought to be involved in ageing processes. Since it is unknown whether NO-production is altered in the ageing auditory system, the present study was conducted to investigate whether the number of NO-producing cells in the SOC is changed with increasing age. Th…

Projection Neurons in the Superior Olivary Complex of the Rat Auditory Brainstem: A Double Retrograde Tracing Study

1998

The superior olivary complex (SOC), a group of interrelated brainstem nuclei, sends efferents to a variety of neuronal structures including the cochlea and the inferior colliculus (IC). In the present study conducted in rats, we sought to investigate whether single SOC efferent neurons project to both cochlea and IC. These neurons were identified by retrograde axonal transport of the neuronal tracers fluoro-gold upon application to the cochlea and cholera toxin B subunit injected into the central nucleus of the IC. Projections to the cochlea were found to stem predominantly from the ipsilateral lateral superior olive (LSO) and medial superior olive (MSO) as well as from the bilateral superi…

Cognitive control in auditory working memory is enhanced in musicians

2010

Musical competence may confer cognitive advantages that extend beyond processing of familiar musical sounds. Behavioural evidence indicates a general enhancement of both working memory and attention in musicians. It is possible that musicians, due to their training, are better able to maintain focus on task-relevant stimuli, a skill which is crucial to working memory. We measured the blood oxygenation-level dependent (BOLD) activation signal in musicians and non-musicians during working memory of musical sounds to determine the relation among performance, musical competence and generally enhanced cognition. All participants easily distinguished the stimuli. We tested the hypothesis that mus…