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Hearing Research Jun 2011Sound localization requires precise and specialized neural circuitry. A prominent and well-studied specialization is found in the mammalian auditory brainstem. Globular... (Review)
Review
Sound localization requires precise and specialized neural circuitry. A prominent and well-studied specialization is found in the mammalian auditory brainstem. Globular bushy cells of the ventral cochlear nucleus (VCN) project contralaterally to neurons of the medial nucleus of the trapezoid body (MNTB), where their large axons terminate on cell bodies of MNTB principal neurons, forming the calyces of Held. The VCN-MNTB pathway is necessary for the accurate computation of interaural intensity and time differences; MNTB neurons provide inhibitory input to the lateral superior olive, which compares levels of excitation from the ipsilateral ear to levels of tonotopically matched inhibition from the contralateral ear, and to the medial superior olive, where precise inhibition from MNTB neurons tunes the delays of binaural excitation. Here we review the morphological and physiological aspects of the development of the VCN-MNTB pathway and its calyceal termination, along with potential mechanisms that give rise to its precision. During embryonic development, VCN axons grow towards the midline, cross the midline into the region of the presumptive MNTB and then form collateral branches that will terminate in calyces of Held. In rodents, immature calyces of Held appear in MNTB during the first few days of postnatal life. These calyces mature morphologically and physiologically over the next three postnatal weeks, enabling fast, high fidelity transmission in the VCN-MNTB pathway.
Topics: Aging; Animals; Auditory Pathways; Axons; Cochlear Nerve; Cochlear Nucleus; Embryonic Development; Humans; Pons; Synaptic Transmission; Time Factors
PubMed: 21093567
DOI: 10.1016/j.heares.2010.11.004 -
Anatomical Science International Mar 2019The inner structure of the pons contains several layers of transverse and vertical fibers and many nuclei. The vertical bundles are described as fibers of the...
The inner structure of the pons contains several layers of transverse and vertical fibers and many nuclei. The vertical bundles are described as fibers of the corticospinal tract, corticonuclear tract, frontopontine tract and parieto-temporopontine tract organized in three layers. The aim of this study was to investigate the structure of the vertical bundles in the ventral pons using the modified Klingler method. Ten brain stem specimens were investigated. Specimens were fixed in 10% formalin, frozen for 24 h to separate nerve fibers by ice crystals, and then unfrozen again in 10% formalin solution. Afterwards, the specimens were dissected using a sharpened spatula. Results point to the existence of three main layers of vertical bundles and a small, constant, and superficial fourth fascicle that is yet to be described in the literature. We propose the name fasciculus longitudinalis superficialis (superficial longitudinal fascicle) for this group of vertical fibers of the pons.
Topics: Adult; Aged; Anatomy; Dissection; Female; Humans; Male; Middle Aged; Nerve Fibers; Pons; Pyramidal Tracts; White Matter; Young Adult
PubMed: 30370477
DOI: 10.1007/s12565-018-0465-7 -
The European Journal of Neuroscience Jan 2002Using positron emission tomographic measurements of regional cerebral blood flow, we report activation of a medial pons area in humans during acoustic startle...
Using positron emission tomographic measurements of regional cerebral blood flow, we report activation of a medial pons area in humans during acoustic startle stimulation. Eight healthy volunteers were scanned during rest and when presented startle-eliciting stimuli. We performed a theory-driven directed search for activity in the nucleus reticularis pontis caudalis, situated in the pons. Because habituation of cerebellar activity during acoustic startle repetition has been reported [Timmann, D., Musso, C., Kolb, F.P., Rijntjes, M., Juptner, M., Muller, S.P., Diener, H.C. & Weiller, C. (1998) J. Neurol. Neurosurg. Psychiatry 65, 771-773], we also predicted habituation in the cerebellum and in the pons as a function of startle repetition. Measurements of eye electromyography validated the presence of a startle response and its habituation. Analysis of regional cerebral blood flow revealed higher neural activity during startle stimulation than at rest in a medial pons area consistent with the location of the pontine reticular nucleus. As a consequence of startle repetition, regional cerebral blood flow increased in the medial cerebellum, and habituated in the ventral cerebellum and in a ventral pons area separate from the pontine reticular nucleus. In the ventral pons, but not in the pontine reticular nucleus, regional cerebral blood flow and the startle reflex were positively correlated. In the cerebellum both positive and negative correlations with the startle reflex were observed. Thus we conclude that the neurofunctional correlates of the startle circuit and its habituation in humans are similar to that previously described in animals.
Topics: Adult; Cerebellum; Cerebrovascular Circulation; Female; Habituation, Psychophysiologic; Humans; Male; Pons; Reflex, Startle; Tomography, Emission-Computed
PubMed: 11849306
DOI: 10.1046/j.0953-816x.2001.01870.x -
Journal of Neurosurgery May 2013
Topics: Animals; Behavior, Animal; Cerebral Hemorrhage; Disease Models, Animal; Male; Pons; Rats, Sprague-Dawley
PubMed: 23776937
DOI: No ID Found -
Progress in Brain Research 1991The dorsolateral pontine tegmentum of the cat is known to contain a large population of catecholaminergic neurons. Additionally, several studies have also shown the... (Review)
Review
The dorsolateral pontine tegmentum of the cat is known to contain a large population of catecholaminergic neurons. Additionally, several studies have also shown the presence of other neurochemicals (acetylcholine, enkephalin, neuropeptide Y, serotonin, somatostatin and substance P). In this study, we have employed retrograde transport of horseradish peroxidase in combination with immunocytochemistry to determine the locations of pontospinal neurons which contain catecholamine, enkephalin, neuropeptide Y, and serotonin. Furthermore, we have combined the retrograde transport of Fast Blue and immunofluorescence histochemistry to determine whether enkephalin-containing neurons are catecholaminergic. All pontospinal neurons, irrespective of the neurochemical content, were observed in the ventral and lateral parts of the dorsolateral pontine tegmentum at coronal levels P1.8-P4.0. These neurons were located in the nuclei locus coeruleus alpha and subcoeruleus and the Kölliker-Fuse nucleus. A high concentration of these neurons was evident in the Kölliker-Fuse nucleus when compared to the nuclei locus coeruleus alpha and subcoeruleus. Quantitative data have revealed that enkephalin is contained in a large proportion of the pontospinal catecholaminergic neurons (75%). The observations suggest that catecholaminergic neurons may contain one or more putative peptide neurotransmitters.
Topics: Animals; Brain Mapping; Cats; Locus Coeruleus; Neurons; Neurotransmitter Agents; Pons; Spinal Cord
PubMed: 1687616
DOI: 10.1016/s0079-6123(08)63802-9 -
Journal of Neurosurgery Sep 2018OBJECTIVE The lateral recess is a unique structure communicating between the ventricle and cistern, which is exposed when treating lesions involving the fourth ventricle...
OBJECTIVE The lateral recess is a unique structure communicating between the ventricle and cistern, which is exposed when treating lesions involving the fourth ventricle and the brainstem with surgical approaches such as the transcerebellomedullary fissure approach. In this study, the authors examined the microsurgical anatomy around the lateral recess, including the fiber tracts, and analyzed their findings with respect to surgical exposure of the lateral recess and entry into the lower pons. METHODS Ten cadaveric heads were examined with microsurgical techniques, and 2 heads were examined with fiber dissection to clarify the anatomy between the lateral recess and adjacent structures. The lateral and medial routes directed to the lateral recess in the transcerebellomedullary fissure approach were demonstrated. A morphometric study was conducted in the 10 cadaveric heads (20 sides). RESULTS The lateral recess was classified into medullary and cisternal segments. The medial and lateral routes in the transcerebellomedullary fissure approach provided access to approximately 140º-150º of the posteroinferior circumference of the lateral recess. The floccular peduncle ran rostral to the lateral recess, and this region was considered to be a potential safe entry zone to the lower pons. By appropriately selecting either route, medial-to-lateral or lateral-to-medial entry axis is possible, and combining both routes provided wide exposure of the lower pons around the lateral recess. CONCLUSIONS The medial and lateral routes of the transcerebellomedullary fissure approach provided wide exposure of the lateral recess, and incision around the floccular peduncle is a potential new safe entry zone to the lower pons.
Topics: Brain Stem; Cisterna Magna; Fourth Ventricle; Humans; Microsurgery; Pons
PubMed: 29148902
DOI: 10.3171/2017.5.JNS17251 -
Respiratory Physiology & Neurobiology Feb 2011The purpose of this retrospective study was to gain insight into the contribution of the dorsolateral pons to the coordination of swallowing and breathing in awake...
The purpose of this retrospective study was to gain insight into the contribution of the dorsolateral pons to the coordination of swallowing and breathing in awake goats. In 4 goats, cannulas were chronically implanted bilaterally through the lateral (LPBN) and medial (MPBN) parabrachial nuclei just dorsal to the Kölliker-Fuse nucleus (KFN). After >2weeks recovery from this surgery, the goats were studied for 5½h on a control day, and on separate days after receiving 1 and 10μl injections of ibotenic acid (IA) separated by 1week. The frequency of swallows did not change during the control and 1μl IA studies, but after injection of 10μl IA, there was a transient 65% increase in frequency of swallows (P<0.05). Under control conditions swallows occurred throughout the respiratory cycle, where late-E swallows accounted for 67.6% of swallows. The distribution of swallow occurrence throughout the respiratory cycle was unaffected by IA injections. Consistent with the concept that swallowing is dominant over breathing, we found that swallows increased inspiratory (T(I)) and expiratory (T(E)) time and decreased tidal volume (V(T)) of the breath of the swallow (n) and/or the subsequent (n+1) breath. Injections of 10μl IA attenuated the normal increases in T(I) and T(E) and further attenuated V(T) of the n breath. Additionally, E and I swallows reset respiratory rhythm, but injection of 1 or 10μl IA progressively attenuated this resetting, suggesting a decreased dominance over respiratory motor output with increasing IA injections. Post mortem histological analysis revealed about 50% fewer (P<0.05) neurons remained in the KFN, LPBN, and MPBN in lesioned compared to control goats. We conclude that dorsolateral pontine nuclei have a modulatory role in a hypothesized holarchical neural network regulating swallowing and breathing particularly contributing to the normal dominance of swallowing over breathing in both rhythm and motor pattern generation.
Topics: Animals; Deglutition; Female; Goats; Ibotenic Acid; Pons; Pulmonary Ventilation; Respiration; Retrospective Studies; Wakefulness
PubMed: 21145433
DOI: 10.1016/j.resp.2010.12.002 -
Operative Neurosurgery (Hagerstown, Md.) Jul 2021
Topics: Hemangioma, Cavernous; Humans; Pons
PubMed: 34018002
DOI: 10.1093/ons/opab159 -
Stroke Oct 1988
Topics: Hemorrhage; Humans; Male; Middle Aged; Pons; Radiography
PubMed: 3176093
DOI: 10.1161/01.str.19.10.1307 -
Progress in Neurobiology 1991In an effort to account for a large number of reported functions mediated by a small portion of the midbrain, a hypothesis is advanced as a basis for discussion and not... (Review)
Review
In an effort to account for a large number of reported functions mediated by a small portion of the midbrain, a hypothesis is advanced as a basis for discussion and not as established fact and is guided by reports from a large number of laboratories working on the same region but using widely disparate preparations. Overall, the hypothesized model suggests an underlying mechanism of action for what is essentially the ascending reticular activating system. The model proposed will hopefully be tested stringently in order to arrive at a better understanding of brain stem mechanisms modulating a host of rhythmic functions.
Topics: Humans; Male; Mesencephalon; Periodicity; Pons
PubMed: 1887068
DOI: 10.1016/0301-0082(91)90016-t