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Anatomy and Embryology 1987The present study provides data on temporal factors that may play a role in the development of precerebellar-cerebellar circuits in the North American opossum. In this...
The present study provides data on temporal factors that may play a role in the development of precerebellar-cerebellar circuits in the North American opossum. In this study the basilar pons and cerebellum are analyzed from birth, 12-13 days after conception, to approximately postnatal day (PD) 80 at which time the brainstem and cerebellum have a mature histological appearance. In Nissl preparations, the basilar pons was first seen at PD 7 as a small cluster of tightly packed cells. Analysis of Golgi impregnations revealed that dendritic growth occurred between PD 25-80. During this period, dendrites gradually increased in length and in the complexity of their branching pattern. Horseradish peroxidase (HRP) was placed into the cerebellar and cerebral cortices in order to examine the development of efferent and afferent projections of the basilar pons, respectively. Evidence for the growth of pontine axons into the cerebellum was first detected on PD 17. Neurons located dorsally within the basilar pons appear to be the first neurons retrogradely labeled with horseradish peroxidase. By PD 27 retrogradely labeled neurons are found throughout the basilar pons. Afferent fibers from the cerebral cortex are not seen within the neuropil of the nucleus until after PD 25 and by PD 29, they have greatly expanded their terminal fields. Degeneration techniques reveal that afferent fibers from the cerebellum arrive by PD 19 and increase in number until PD 30 when their adult distribution is achieved. These data suggest that the time of afferent arrival from the cerebral cortex and deep cerebellar nuclei is closely correlated in time with the initiation of dendritic maturation and the outgrowth of pontocerebellar axons. Afferent axons from the cerebral cortex and deep cerebellar nuclei reach the basilar pons and afferents from the basilar pons grow into the cerebellum when the dendrites of the respective target neurons are very immature. Thus, the time of axon arrival in these circuits may be an important factor in determining their synaptic location on individual neurons. The data derived from the present study is compared to those obtained in previous studies on the inferior olive. The results of this comparison provide evidence for a similar sequence of events, but a differential timetable for the development of specific connections within precerebellar-cerebellar circuits.
Topics: Afferent Pathways; Aging; Animals; Animals, Newborn; Axonal Transport; Brain; Horseradish Peroxidase; Opossums; Pons
PubMed: 2441628
DOI: 10.1007/BF00310052 -
Clinical Neuroradiology Mar 2014
Topics: Aged; Central Nervous System Venous Angioma; Cerebral Veins; Female; Humans; Magnetic Resonance Imaging; Pons; Tomography, X-Ray Computed
PubMed: 23397208
DOI: 10.1007/s00062-013-0206-1 -
Journal of Neurophysiology Jul 19951. Mechanisms of neural coding of gustatory stimuli were studied in the nucleus of the solitary tract (NTS), the first relay in the neural pathway for gustation, in...
1. Mechanisms of neural coding of gustatory stimuli were studied in the nucleus of the solitary tract (NTS), the first relay in the neural pathway for gustation, in anesthetized rats. Taste-responsive NTS units were identified as "relay" or "nonrelay" based on the electrophysiological response to electrical pulses delivered to the parabrachial nucleus of the pons (PbN), the second relay in the neural pathway for gustation. Coding mechanisms in each group were analyzed separately. 2. Taste responses to sapid solutions of NaCl (0.1 M), HCl (0.01 M), quinine HCl (0.01 M), sucrose (0.5 M) and Na-saccharin (0.004 M) were recorded in single units in the NTS. After gustatory stimulation, electrophysiological responses to electrical stimulation of the taste-responsive part of the ipsilateral PbN were recorded. A 0.2-ms pulse was delivered at 75-250 microA at a rates of 1, 25, 50 and 100 pps through a bipolar stainless steel electrode. An antidromic response was defined as a time-locked spike that occurred at a fixed latency after PbN stimulation that followed high stimulation frequencies. A collision test also was performed. 3. Of 42 taste-responsive NTS units, 19 (45%) were relay units, 22 (52%) were nonrelay and 1 unit was activated orthodromically by PbN stimulation. Latencies of evoked spikes ranged from 1.75 to 4.0 ms 2.1 +/- 0.2 ms (mean +/- SE, median, 1.75 ms). 4. Examination of general response characteristics revealed few differences among relay and nonrelay units.(ABSTRACT TRUNCATED AT 250 WORDS)
Topics: Animals; Male; Neural Pathways; Neurons, Afferent; Pons; Rats; Rats, Sprague-Dawley; Solitary Nucleus; Taste
PubMed: 7472328
DOI: 10.1152/jn.1995.74.1.249 -
Neuroscience Bulletin Dec 2010Surgical accesses to lesions of the posterolateral pontomesencephalic junction (PMJ) region and the posterolateral tentorial gap remain a challenge in the field of... (Review)
Review
Surgical accesses to lesions of the posterolateral pontomesencephalic junction (PMJ) region and the posterolateral tentorial gap remain a challenge in the field of neurosurgery. Since the first report of application of the extreme lateral supracerebellar infratentorial (ELSI) approach in resecting the PMJ lesions in 2000, a few articles concerning the ELSI approach have been published. The present review mainly provided an intimate introduction of the ELSI approach, and evaluated it in facets of patient position, skin incision, craniectomy, draining veins, retraction against the cerebellum, exposure limits, patient healing, as well as advantages and limitations compared with other approaches. The ELSI approach is proposed to be a very young and promising approach to access the lesions of posterolateral PMJ region and the posterolateral tentorial gap. Besides, it has several advantages such as having a shorter surgical pathway, causing less surgical complications, labor-saving, etc. Still, more studies are needed to improve this approach.
Topics: Cerebellum; Craniotomy; Humans; Mesencephalon; Neurosurgical Procedures; Pons; Treatment Outcome
PubMed: 21113199
DOI: 10.1007/s12264-010-1036-7 -
Microscopy Research and Technique Nov 2000The distinctive morphology of the human superior olivary complex reflects its primate origins, but functional evidence suggests that it plays a role in auditory spatial... (Review)
Review
The distinctive morphology of the human superior olivary complex reflects its primate origins, but functional evidence suggests that it plays a role in auditory spatial mapping which is similar to olivary function in other mammalian species. It seems likely that the well-developed human medial olivary nucleus is the basis for extraction of interaural time and phase differences. The much smaller human lateral olivary nucleus probably functions in analysis of interaural differences in frequency and intensity, but the absence of a human nucleus of the trapezoid body implies some difference in the mechanisms of this function. A window on human olivary function is provided by the evoked auditory brainstem response (ABR), including its binaural interaction component (BIC). Anatomical, electrophysiological, and histopathological studies suggest that ABR waves IV and V are generated by axonal pathways at the level of the superior olivary complex. Periolivary cell groups are prominent in the human olivary complex. The cell groups located medial, lateral, and dorsal are similar to periolivary nuclei of other mammals, but the periolivary nucleus at the rostral pole of the human olivary complex is very large by mammalian standards. Within the periolivary system, immunostaining for neurotransmitter-related substances allows us to identify populations of medial and lateral olivocochlear neurons. The human olivocochlear system is unique among mammals in the relatively small size of its lateral efferent component. Some consideration is given to the idea that the integration provided by periolivary cell groups, particularly modulation of the periphery by the olivocochlear system, is an extension of the spatial mapping function of the main olivary nuclei.
Topics: Animals; Auditory Pathways; Brain Mapping; Cochlea; Evoked Potentials, Auditory; Humans; Olivary Nucleus; Pons
PubMed: 11071722
DOI: 10.1002/1097-0029(20001115)51:4<403::AID-JEMT8>3.0.CO;2-Q -
RoFo : Fortschritte Auf Dem Gebiete Der... Feb 2017
Review
Topics: Diagnosis, Differential; Humans; Image Enhancement; Magnetic Resonance Imaging; Myelinolysis, Central Pontine; Pons
PubMed: 28142166
DOI: 10.1055/s-0042-120176 -
Respiratory Physiology & Neurobiology Nov 2004Activation of pontomedullary cholinergic neurons may directly and indirectly cause depression of respiratory motoneuronal activity, activation of respiratory premotor... (Review)
Review
Activation of pontomedullary cholinergic neurons may directly and indirectly cause depression of respiratory motoneuronal activity, activation of respiratory premotor neurons and acceleration of the respiratory rate during REM sleep, as well as activation of breathing during active wakefulness. These effects may be mediated by distinct subpopulations of cholinergic neurons. The relative inactivity of cholinergic neurons during slow-wave sleep also may contribute to the depressant effects of this state on breathing. Cholinergic muscarinic and nicotinic receptors are expressed in central respiratory neurons and motoneurons, thus allowing cholinergic neurons to act on the respiratory system directly. Additional effects of cholinergic activation are mediated indirectly by noradrenergic, serotonergic and other neurons of the reticular formation. Excitatory and suppressant respiratory effects with features of natural states of REM sleep or active wakefulness can be elicited in urethane-anesthetized rats by pontine microinjections of the cholinergic agonist, carbachol. Carbachol models help elucidate the neural basis of respiratory disorders associated with central cholinergic activation.
Topics: Acetylcholine; Action Potentials; Animals; Carbachol; Cholinergic Agonists; Electroencephalography; Neural Networks, Computer; Neural Pathways; Neurons; Pons; Receptors, Cholinergic; Respiration; Sleep, REM
PubMed: 15519558
DOI: 10.1016/j.resp.2004.04.017 -
Archives Italiennes de Biologie Feb 2001
Review
Topics: Animals; Humans; Locus Coeruleus; Neurons; Pons; Reticular Formation; Sleep, REM
PubMed: 11256190
DOI: No ID Found -
Respiratory Physiology & Neurobiology Nov 2004Respiratory rhythm generators appear both evolutionarily and developmentally as paired segmental rhythm generators in the reticular formation, associated with the motor... (Review)
Review
Respiratory rhythm generators appear both evolutionarily and developmentally as paired segmental rhythm generators in the reticular formation, associated with the motor nuclei of cranial nerves V, VII, IX, X, and XII. Those associated with the Vth and VIIth motor nuclei are "pontine" in origin and in fishes that employ a buccal suction/force pump for breathing the primary pair of respiratory rhythm generators are associated with the trigeminal nuclei. In amphibians, while the basic respiratory pump remains the same, the dominant site of respiratory rhythm generation has been assumed by the facial, glossopharyngeal and vagal motor nuclei. In reptiles, birds and mammals, in general there is a switch to an aspiration pump driven by thoraco-lumbar muscles innervated by spinal nerves. In these groups, the critical sites necessary for respiratory rhythmogenesis now sit near the ponto-medullary border, in the parafacial region (which may underlie expiratory-dominated, intercostal-abdominal breathing in non-mammalian tetrapods) and in a more caudal region, the preBotzinger complex (which may underlie inspiratory-dominated diaphragmatic breathing in mammals).
Topics: Animals; Humans; Motor Neurons; Periodicity; Phylogeny; Pons; Respiration; Respiratory Physiological Phenomena; Reticular Formation; Species Specificity; Vertebrates
PubMed: 15519560
DOI: 10.1016/j.resp.2004.05.008 -
Brain Research Oct 1971
Topics: Action Potentials; Animals; Cats; Cerebellum; Electric Stimulation; Neural Pathways; Picrotoxin; Pons; Stereotaxic Techniques; Thalamic Nuclei
PubMed: 4940679
DOI: 10.1016/0006-8993(71)90322-2