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Injury May 2002
Topics: Adult; Follow-Up Studies; Humans; Male; Pons; Self-Injurious Behavior; Tomography, X-Ray Computed; Wounds, Stab
PubMed: 12091038
DOI: 10.1016/s0020-1383(02)00024-4 -
Stroke Apr 2023
Topics: Humans; Middle Cerebellar Peduncle; Pons; Cerebellum; Infarction; Magnetic Resonance Imaging
PubMed: 36802764
DOI: 10.1161/STROKEAHA.122.042453 -
Neuroscience Letters May 1994Electrical and chemical lesions in the ventrolateral pons produced apneustic breathing in anesthetized, vagotomized, paralyzed, ventilated adult rats (n = 13). Apneustic...
Electrical and chemical lesions in the ventrolateral pons produced apneustic breathing in anesthetized, vagotomized, paralyzed, ventilated adult rats (n = 13). Apneustic breathing did not develop if the vagi remained intact and was reversed partially with vagal (proximal end) stimulation. Physiologically, these data are similar to those obtained following dorsolateral pontine lesion in rat and other mammalian species and support the hypothesis that pontine neurons influence breathing similarly across mammalian species.
Topics: Animals; Electric Stimulation; Male; Muscimol; Neurons; Phrenic Nerve; Pons; Rats; Rats, Sprague-Dawley; Respiratory Mechanics; Vagotomy
PubMed: 8084539
DOI: 10.1016/0304-3940(94)90664-5 -
Acta Neurochirurgica Mar 2022The horizontal fissure approach is a workhorse for brainstem lesions in the central and dorsolateral pons and middle cerebellar peduncle (MCP). The cerebellopontine...
BACKGROUND
The horizontal fissure approach is a workhorse for brainstem lesions in the central and dorsolateral pons and middle cerebellar peduncle (MCP). The cerebellopontine fissure is a V-shaped fissure with a superior and inferior limb between the cerebellum, pons, and MCP. The horizontal or petrosal fissure is at the apex of the cerebellopontine fissure and extends laterally to divide the petrosal surface of the cerebellum into superior and inferior parts. Splitting this fissure exposes the posterolateral aspect of the MCP without excessive retraction or transgression of the cerebellum.
METHOD
We demonstrate and describe the horizontal fissure operative approach to the middle cerebellar peduncle for resection of a pontine cavernoma with illustrative figures and operative video.
CONCLUSION
Splitting the horizontal (petrosal) fissure of the cerebellum brings the middle cerebellar peduncle into view behind the root entry zone of the trigeminal nerve, providing an expanded, safe corridor to the central and dorsolateral pons.
Topics: Cerebellum; Hemangioma, Cavernous; Humans; Middle Cerebellar Peduncle; Pons; Trigeminal Nerve
PubMed: 34643805
DOI: 10.1007/s00701-021-05015-7 -
BMC Biology Jun 2023Based on their anatomical location, rostral projections of nuclei are classified as ascending circuits, while caudal projections are classified as descending circuits....
BACKGROUND
Based on their anatomical location, rostral projections of nuclei are classified as ascending circuits, while caudal projections are classified as descending circuits. Upper brainstem neurons participate in complex information processing and specific sub-populations preferentially project to participating ascending or descending circuits. Cholinergic neurons in the upper brainstem have extensive collateralizations in both ascending and descending circuits; however, their single-cell projection patterns remain unclear because of the lack of comprehensive characterization of individual neurons.
RESULTS
By combining fluorescent micro-optical sectional tomography with sparse labeling, we acquired a high-resolution whole-brain dataset of pontine-tegmental cholinergic neurons (PTCNs) and reconstructed their detailed morphology using semi-automatic reconstruction methods. As the main source of acetylcholine in some subcortical areas, individual PTCNs had abundant axons with lengths up to 60 cm and 5000 terminals and innervated multiple brain regions from the spinal cord to the cortex in both hemispheres. Based on various collaterals in the ascending and descending circuits, individual PTCNs were grouped into four subtypes. The morphology of cholinergic neurons in the pedunculopontine nucleus was more divergent, whereas the laterodorsal tegmental nucleus neurons contained richer axonal branches and dendrites. In the ascending circuits, individual PTCNs innervated the thalamus in three different patterns and projected to the cortex via two separate pathways. Moreover, PTCNs targeting the ventral tegmental area and substantia nigra had abundant collaterals in the pontine reticular nuclei, and these two circuits contributed oppositely to locomotion.
CONCLUSIONS
Our results suggest that individual PTCNs have abundant axons, and most project to various collaterals in the ascending and descending circuits simultaneously. They target regions with multiple patterns, such as the thalamus and cortex. These results provide a detailed organizational characterization of cholinergic neurons to understand the connexional logic of the upper brainstem.
Topics: Brain Stem; Axons; Pons; Brain; Cholinergic Neurons
PubMed: 37280580
DOI: 10.1186/s12915-023-01625-y -
Microscopy Research and Technique Nov 2000
Review
Topics: Animals; Auditory Pathways; Cochlea; Guinea Pigs; Olivary Nucleus; Pons; Rats
PubMed: 11071715
DOI: 10.1002/1097-0029(20001115)51:4<303::AID-JEMT1>3.0.CO;2-B -
Neurosurgery May 1985We describe a patient with a gunshot wound to the brain that traversed the left cerebellar hemisphere and terminated in the left lateral midpons. The clinical findings,...
We describe a patient with a gunshot wound to the brain that traversed the left cerebellar hemisphere and terminated in the left lateral midpons. The clinical findings, operative course, neuroradiographic features, and evoked potential data are correlated with the functional anatomy of the pons. It is possible to demonstrate that a local lesion in the lateral pons causes a hemiparesis, worse in the upper extremity, thus suggesting a somatotopic localization of the pontine corticospinal tract not previously described.
Topics: Adult; Electroencephalography; Evoked Potentials; Follow-Up Studies; Humans; Male; Neurologic Examination; Pons; Postoperative Complications; Reflex, Abnormal; Wounds, Gunshot
PubMed: 4000432
DOI: 10.1227/00006123-198505000-00004 -
The Journal of Comparative Neurology May 1990Previous light microscopic immunoperoxidase studies of glutamic acid decarboxylase (GAD)-immunoreactive neural elements in the rat basilar pontine nuclei revealed...
Previous light microscopic immunoperoxidase studies of glutamic acid decarboxylase (GAD)-immunoreactive neural elements in the rat basilar pontine nuclei revealed immunocytochemical reaction product in neuronal somata and axon terminals. In the present study, pre-embedding immunoperoxidase labeling of GAD or gamma-aminobutyric acid (GABA) and postembedding immunogold labeling of GABA allowed the ultrastructural visualization of these neural elements in the basilar pontine nuclei of colchicine-treated animals. At the electron microscopic level, immunolabeled neuronal somata exhibited smoothly contoured nuclei, whereas some dendrites also contained reaction product after immunocytochemical treatment and were postsynaptic to both immunoreactive and nonimmunoreactive axon terminals. Synaptic boutons immunoreactive for GAD or GABA exhibited cross-sectional areas that ranged from 0.1 to 3.8 microns 2 and generally appeared round or elongated in most sections. The majority (95%) of immunolabeled boutons contained pleomorphic synaptic vesicles and formed symmetric synapses at their postsynaptic loci; however, boutons exhibiting round vesicles and boutons forming asymmetric synapses (5%) were also immunopositive. Small (less than 1.5 microns 2) GAD- or GABA-labeled axon terminals formed synaptic contact mainly with small dendritic profiles, dendritic spines, and neuronal somata, whereas large labeled boutons (greater than 1.5 microns 2) formed synapses with all sizes of dendritic profiles. Occasionally, a single immunolabeled bouton formed synaptic contact with two separate postsynaptic dendrites. It is suggested that the immunolabeled neuronal somata and dendrites observed in the rat basilar pontine nuclei represent a population of pontine local circuit neurons; however, it is known that GABAergic cell groups extrinsic to the pontine gray provide afferent projections to the basilar pons, and therefore at least some immunoreactive axon terminals present in the pontine nuclei are derived from these extrinsic sources. The ultrastructural observation of GABAergic neural elements in the rat basilar pontine nuclei confirms previous light microscopic findings and provides an anatomical substrate through which GABAergic neurons, whether arising from an intrinsic or extrinsic source, might exert an inhibitory influence on target cells within the pontine nuclei.
Topics: Animals; Female; Glutamate Decarboxylase; Immunohistochemistry; Male; Microscopy, Electron; Pons; Rats; gamma-Aminobutyric Acid
PubMed: 2341630
DOI: 10.1002/cne.902950111 -
Journal of the Neurological Sciences May 2013The paramedian tract (PMT) neurons, a group of neurons associated with eye movement that project into the cerebellar flocculus, are present in or near the medial...
Downbeat nystagmus associated with damage to the medial longitudinal fasciculus of the pons: a vestibular balance control mechanism via the lower brainstem paramedian tract neurons.
The paramedian tract (PMT) neurons, a group of neurons associated with eye movement that project into the cerebellar flocculus, are present in or near the medial longitudinal fasciculus (MLF) in the paramedian region of the lower brainstem. A 66-year-old man with multiple sclerosis in whom downbeat nystagmus appeared along with right MLF syndrome due to a unilateral pontomedullary lesion is described. In light of these findings, a possible schema for the vestibular balance control mechanism circuit of the PMT neurons via the flocculus is presented. Damage to the PMT neurons impaired the elective inhibitory control mechanism of the anterior semicircular canal neural pathway by the flocculus. This resulted in the appearance of anterior semicircular canal-dominant vestibular imbalance and the formation of downbeat nystagmus. From the pathogenesis of this vertical vestibular nystagmus, the action of the PMT neurons in the vestibular eye movement neuronal pathway to maintain vestibular balance was conjectured to be as follows. PMT neurons transmit vestibular information from the anterior semicircular canals to the cerebellum, forming a cerebellum/brainstem feedback loop. Vestibular information from that loop is integrated in the cerebellum, inhibiting only the anterior semicircular canal neuronal pathway via the flocculus and controlling vestibular balance.
Topics: Aged; Dominance, Ocular; Electric Stimulation; Eye Movements; Humans; Magnetic Resonance Imaging; Male; Neurons; Nystagmus, Pathologic; Pons; Vestibular Nuclei
PubMed: 23510567
DOI: 10.1016/j.jns.2013.02.017 -
Brain & Development 1986In the acute precollicular-postmammillary decerebrate cat, stimulation of the mesencephalic locomotor region (MLR) induces "controlled locomotion" on a moving treadmill....
In the acute precollicular-postmammillary decerebrate cat, stimulation of the mesencephalic locomotor region (MLR) induces "controlled locomotion" on a moving treadmill. Stimulation of the dorsal area and of the ventral area of the pons at its midline elicited a long-lasting decrease and an increase in the tone of the hindlimb extensor muscles, respectively. By selecting the stimulus strength according to the stimulus site, it was possible to set the extensor muscle tone level, that is the "background excitability" of the brain stem and the spinal cord. Locomotor effects induced by MLR stimulation were greatly modified by the set level of background excitability. When the background excitability was high, MLR stimulation evoked "spastic" locomotor movement, while "atonic" locomotor movement was evoked when it was low. Furthermore, stimulation of the ventral area alone also evoked "spastic" locomotor movement. During locomotion in intact cats, stimulation of the dorsal area evoked a series of postural changes. Within a few seconds from the beginning of stimulation, the cat ceased to walk, but maintained a standing posture with or without a locomotor figure. With continuation of this stimulation, it squatted and then lay down on the floor in a sequential manner. Stimulation of the ventral area of the pons evoked an almost opposite series of postural changes. Within a few seconds from the beginning of stimulation, the cat changed from a lying to a squatting posture, and then stood, started to walk and continued to walk during the period of stimulation. All these results demonstrate that an increase in extensor muscle tone and activation of the spinal stepping generator are not separate phenomena, and suggest that integration of neuronal mechanisms involved in the setting of the background excitability and in locomotor movement is a prerequisite for successful expression of locomotor behavior both in decerebrate and intact cats.
Topics: Animals; Cats; Decerebrate State; Efferent Pathways; Electric Stimulation; Locomotion; Pons; Posture; Psychomotor Performance
PubMed: 3799910
DOI: 10.1016/s0387-7604(86)80062-6