Search results for "Olivary Nucleus"

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…

Computation of inverse functions in a model of cerebellar and reflex pathways allows to control a mobile mechanical segment.

2003

Abstract The command and control of limb movements by the cerebellar and reflex pathways are modeled by means of a circuit whose structure is deduced from functional constraints. One constraint is that fast limb movements must be accurate although they cannot be continuously controlled in closed loop by use of sensory signals. Thus, the pathways which process the motor orders must contain approximate inverse functions of the bio-mechanical functions of the limb and of the muscles. This can be achieved by means of parallel feedback loops, whose pattern turns out to be comparable to the anatomy of the cerebellar pathways. They contain neural networks able to anticipate the motor consequences …

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…

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…

The Lipofuscin Content of Nerve Cells of the Inferior Olivary Nucleus in Alzheimer's Disease

1994

Lipofuscin, the age pigment, is of interest in Alzheimer's disease because of its property to accumulate in neurons and because of the hypothesis that Alzheimer's dementia is a kind of premature ageing. The amount of intraneuronal lipofuscin in the inferior olivary nucleus of 20 brains from patients with histologically confirmed Alzheimer's disease according to the CERAD protocol and of 20 controls has been measured microfluorometrically. Patients and controls were matched for age. The amount of lipofuscin in the neurons of the inferior olivary nucleus did not differ significantly between the cases of Alzheimer's disease and the controls. The result is discussed taking the findings of previ…

Neurochemistry of olivocochlear neurons in the hamster.

2009

The present study was conducted to characterize the superior olivary complex (SOC) of the lower brain stem in the pigmented Djungarian hamster Phodopus sungorus. Using Nissl-stained serial cryostat sections from fresh-frozen brains, we determined the borders of the SOC nuclei. We also identified olivocochlear (OC) neurons by retrograde neuronal tracing upon injection of Fluoro-Gold into the scala tympani. To evaluate the SOC as a putative source of neuronal nitric oxide synthase (nNOS), arginine-vasopressin (AVP), oxytocin (OT), vasoactive intestinal polypeptide (VIP), or pituitary adenylate cyclase-activating polypeptide (PACAP) that were all found in the cochlea, we conducted immunohistoc…

A nitrergic projection from the superior olivary complex to the inferior colliculus of the rat

2003

The present study was conducted to test whether the ascending auditory projection from the superior olivary complex (SOC) of the brainstem to the inferior colliculus (IC) may use nitric oxide (NO) as a neuroactive compound. We identified olivo-collicular projection neurons in subnuclei of the SOC by retrograde neuronal tracing with Fluoro-Gold (FG) injected into the central nucleus of the IC. Sections containing retrograde labelled neurons were subjected to immunohistochemical incubation in an antiserum directed against the enzyme responsible for NO production in nerve cells, neuronal NO synthase (nNOS). The analysis showed that FG-containing neurons as well as nNOS-immunoreactive neurons w…