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Practical Neurology Nov 2023Classic Raymond syndrome is a rare neurological presentation comprising ipsilateral abducens palsy, contralateral facial paresis and contralateral hemiparesis. We...
Classic Raymond syndrome is a rare neurological presentation comprising ipsilateral abducens palsy, contralateral facial paresis and contralateral hemiparesis. We present a man in his late 60s who presented with diplopia, dysarthria and right-sided limb weakness. This syndrome is one of a group of 'crossed paralyses' of the caudal pons.
Topics: Male; Humans; Brain Ischemia; Stroke; Pons; Facial Paralysis; Paresis; Ischemic Stroke
PubMed: 37524438
DOI: 10.1136/pn-2023-003782 -
The European Journal of Neuroscience Oct 2021Catecholamine neurons of the locus coeruleus (LC) in the dorsal pontine tegmentum innervate the entire neuroaxis, with signaling actions implicated in the regulation of... (Review)
Review
Catecholamine neurons of the locus coeruleus (LC) in the dorsal pontine tegmentum innervate the entire neuroaxis, with signaling actions implicated in the regulation of attention, arousal, sleep-wake cycle, learning, memory, anxiety, pain, mood, and brain metabolism. The co-release of norepinephrine (NE) and dopamine (DA) from LC terminals in the hippocampus plays a role in all stages of hippocampal-memory processing. This catecholaminergic regulation modulates the encoding, consolidation, retrieval, and reversal of hippocampus-based memory. LC neurons in awake animals have two distinct firing modes: tonic firing (explorative) and phasic firing (exploitative). These two firing modes exert different modulatory effects on post-synaptic dendritic spines. In the hippocampus, the firing modes regulate long-term potentiation (LTP) and long-term depression, which differentially regulate the mRNA expression and transcription of plasticity-related proteins (PRPs). These proteins aid in structural alterations of dendritic spines, that is, structural long-term potentiation (sLTP), via expansion and structural long-term depression (sLTD) via contraction of post-synaptic dendritic spines. Given the LC's role in all phases of memory processing, the degeneration of 50% of the LC neuron population occurring in Alzheimer's disease (AD) is a clinically relevant aspect of disease pathology. The loss of catecholaminergic regulation contributes to dysfunction in memory processes along with impaired functions associated with attention and task completion. The multifaceted role of the LC in memory and general task performance and the close correlation of LC degeneration with neurodegenerative disease progression together implicate it as a target for new clinical assessment tools.
Topics: Alzheimer Disease; Animals; Locus Coeruleus; Long-Term Potentiation; Memory; Neurodegenerative Diseases
PubMed: 33190318
DOI: 10.1111/ejn.15045 -
JCI Insight Oct 2023BACKGROUNDThe locus coeruleus (LC) is the primary source of norepinephrine in the brain and regulates arousal and sleep. Animal research shows that it plays important...
BACKGROUNDThe locus coeruleus (LC) is the primary source of norepinephrine in the brain and regulates arousal and sleep. Animal research shows that it plays important roles in the transition between sleep and wakefulness, and between slow wave sleep and rapid eye movement sleep (REMS). It is unclear, however, whether the activity of the LC predicts sleep variability in humans.METHODSWe used 7-Tesla functional MRI, sleep electroencephalography (EEG), and a sleep questionnaire to test whether the LC activity during wakefulness was associated with sleep quality in 33 healthy younger (~22 years old; 28 women, 5 men) and 19 older (~61 years old; 14 women, 5 men) individuals.RESULTSWe found that, in older but not in younger participants, higher LC activity, as probed during an auditory attentional task, was associated with worse subjective sleep quality and with lower power over the EEG theta band during REMS. The results remained robust even when accounting for the age-related changes in the integrity of the LC.CONCLUSIONThese findings suggest that LC activity correlates with the perception of the sleep quality and an essential oscillatory mode of REMS, and we found that the LC may be an important target in the treatment of sleep- and age-related diseases.FUNDINGThis work was supported by Fonds National de la Recherche Scientifique (FRS-FNRS, T.0242.19 & J. 0222.20), Action de Recherche Concertée - Fédération Wallonie-Bruxelles (ARC SLEEPDEM 17/27-09), Fondation Recherche Alzheimer (SAO-FRA 2019/0025), ULiège, and European Regional Development Fund (Radiomed & Biomed-Hub).
Topics: Male; Animals; Humans; Female; Aged; Young Adult; Adult; Middle Aged; Sleep, REM; Locus Coeruleus; Wakefulness; Sleep Quality; Sleep
PubMed: 37698926
DOI: 10.1172/jci.insight.172008 -
Tidsskrift For Den Norske Laegeforening... Nov 2023
Topics: Humans; Pons; Demyelinating Diseases
PubMed: 37987074
DOI: 10.4045/tidsskr.23.0479 -
Journal of Stroke and Cerebrovascular... Aug 2022There are scarce data regarding pontine arteries anatomy, which is the basis for ischemic lesions following their occlusion. The aim of this study was to examine pontine...
OBJECTIVES
There are scarce data regarding pontine arteries anatomy, which is the basis for ischemic lesions following their occlusion. The aim of this study was to examine pontine vasculature and its relationships with the radiologic and neurologic features of pontine infarctions.
MATERIALS AND METHODS
Branches of eight basilar arteries and their twigs, including the larger intrapontine branches, were microdissected following an injection of a 10% mixture of India ink and gelatin. Two additional brain stems were prepared for microscopic examination after being stained with luxol fast blue and cresyl violet. Finally, 30 patients with pontine infarctions underwent magnetic resonance imaging (MRI) in order to determine the position and size of the infarctions.
RESULTS
The perforating arteries, which averaged 5.8 in number and 0.39 mm in diameter, gave rise to paramedian and anteromedial branches, and also to anterolateral twigs (62.5%). The longer leptomeningeal and cerebellar arteries occasionally gave off perforating and anterolateral twigs, and either the lateral or posterior branches. Occlusion of some of these vessels resulted in the paramedian (30%), anterolateral (26.7%), lateral (20%), and combined infarctions (23.3%), which were most often isolated and unilateral, and rarely bilateral (10%). They were located in the lower pons (23.3%), middle (10%) or rostral (26.7%), or in two or three portions (40%). Each type of infarction usually produced characteristic neurologic signs. The clinical significance of the anatomic findings was discussed.
CONCLUSIONS
There was a good correlation between the intrapontine vascular territories, the position, size and shape of the infarctions, and the type of neurologic manifestations.
Topics: Basilar Artery; Brain Stem Infarctions; Humans; Infarction; Magnetic Resonance Imaging; Pons
PubMed: 35777083
DOI: 10.1016/j.jstrokecerebrovasdis.2022.106613 -
BMJ Case Reports Sep 2021Eight-and-a-half syndrome is a rare entity characterised by conjugate horizontal gaze palsy, ipsilateral internuclear ophthalmoplegia and ipsilateral lower motor neuron...
Eight-and-a-half syndrome is a rare entity characterised by conjugate horizontal gaze palsy, ipsilateral internuclear ophthalmoplegia and ipsilateral lower motor neuron type facial palsy. It is due to a lesion affecting median longitudinal fasciculus, paramedian pontine reticular formation and facial nerve fascicle on the same side at the level of pons. The diagnosis is easily missed as it needs detailed ocular movement examination. It is mainly caused due to infarction or demyelinating conditions. We are reporting an interesting case of a 54-year-old man with right-side eight-and-a-half syndrome due to acute ischaemic stroke and ST-elevation myocardial infarction of the inferior wall.
Topics: Brain Ischemia; Facial Paralysis; Humans; Male; Middle Aged; Ocular Motility Disorders; Ophthalmoplegia; Pons; Stroke
PubMed: 34479896
DOI: 10.1136/bcr-2021-244338 -
Journal of the Neurological Sciences Aug 2023
Topics: Humans; Child; Inflammation; Encephalitis; Magnetic Resonance Imaging; Pons
PubMed: 37348249
DOI: 10.1016/j.jns.2023.120698 -
World Neurosurgery Jun 2020In this article, we describe a new safe entry point for the posterolateral pons.
OBJECTIVE
In this article, we describe a new safe entry point for the posterolateral pons.
METHODS
To show the adjacent anatomy and measure the part of the interpeduncular sulcus that can be safely accessed, we first performed a review of the literature regarding the pons anatomy and its surgical approaches. Thereafter, 1 human cadaveric head and 15 (30 sides) human brainstems with attached cerebellums were bilaterally dissected with the fiber microdissection technique. A clinical correlation was made with an illustrative case of a dorsolateral pontine World Health Organization grade I astrocytoma.
RESULTS
The safe distance for accessing the interpeduncular sulcus was found to extend from the caudal end of the lateral mesencephalic sulcus to the point at which the intrapontine segment of the trigeminal nerve crosses the interpeduncular sulcus. The mean distance was 8.2 mm (range, 7.15-8.85 mm). Our interpeduncular sulcus safe entry zone can be exposed through a paramedian infratentorial supracerebellar approach. When additional exposure is required, the superior portion of the quadrangular lobule of the cerebellar hemispheric tentorial surface can be removed. In the presented case, surgical resection of the tumor was performed achieving a gross total resection, and the patient was discharged without neurologic deficit.
CONCLUSIONS
The interpeduncular sulcus safe entry zone provides an alternative direct route for treating intrinsic pathologic entities situated in the posterolateral tegmen of the pons between the superior and middle cerebellar peduncles. The surgical corridor provided by this entry point avoids most eloquent neural structures, thereby preventing surgical complications.
Topics: Humans; Microdissection; Microsurgery; Middle Cerebellar Peduncle; Neurosurgical Procedures; Pons
PubMed: 32217179
DOI: 10.1016/j.wneu.2020.03.084 -
Nature Communications Mar 2024The "dorsal pons", or "dorsal pontine tegmentum" (dPnTg), is part of the brainstem. It is a complex, densely packed region whose nuclei are involved in regulating many...
The "dorsal pons", or "dorsal pontine tegmentum" (dPnTg), is part of the brainstem. It is a complex, densely packed region whose nuclei are involved in regulating many vital functions. Notable among them are the parabrachial nucleus, the Kölliker Fuse, the Barrington nucleus, the locus coeruleus, and the dorsal, laterodorsal, and ventral tegmental nuclei. In this study, we applied single-nucleus RNA-seq (snRNA-seq) to resolve neuronal subtypes based on their unique transcriptional profiles and then used multiplexed error robust fluorescence in situ hybridization (MERFISH) to map them spatially. We sampled ~1 million cells across the dPnTg and defined the spatial distribution of over 120 neuronal subtypes. Our analysis identified an unpredicted high transcriptional diversity in this region and pinpointed the unique marker genes of many neuronal subtypes. We also demonstrated that many neuronal subtypes are transcriptionally similar between humans and mice, enhancing this study's translational value. Finally, we developed a freely accessible, GPU and CPU-powered dashboard ( http://harvard.heavy.ai:6273/ ) that combines interactive visual analytics and hardware-accelerated SQL into a data science framework to allow the scientific community to query and gain insights into the data.
Topics: Humans; Animals; Mice; In Situ Hybridization, Fluorescence; Pontine Tegmentum; Brain Stem; Locus Coeruleus; Parabrachial Nucleus; Ascomycota
PubMed: 38438345
DOI: 10.1038/s41467-024-45907-7 -
Cephalalgia : An International Journal... May 2023The human in-vivo functional somatotopy of the three branches of the trigeminal (V1, V2, V3) and greater occipital nerve in brainstem and also in thalamus and insula is... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
The human in-vivo functional somatotopy of the three branches of the trigeminal (V1, V2, V3) and greater occipital nerve in brainstem and also in thalamus and insula is still not well understood.
METHODS
After preregistration (clinicaltrials.gov: NCT03999060), we mapped the functional representations of this trigemino-cervical complex non-invasively in 87 humans using high-resolution protocols for functional magnetic resonance imaging during painful electrical stimulation in two separate experiments. The imaging protocol and analysis was optimized for the lower brainstem and upper spinal cord, to identify activation of the spinal trigeminal nuclei. The stimulation protocol involved four electrodes which were positioned on the left side according to the three branches of the trigeminal nerve and the greater occipital nerve. The stimulation site was randomized and each site was repeated 10 times per session. The participants partook in three sessions resulting in 30 trials per stimulation site.
RESULTS
We show a large overlap of peripheral dermatomes on brainstem representations and a somatotopic arrangement of the three branches of the trigeminal nerve along the perioral-periauricular axis and for the greater occipital nerve in brainstem below pons, as well as in thalamus, insula and cerebellum. The co-localization of greater occipital nerve with V1 along the lower part of brainstem is of particular interest since some headache patients profit from an anesthetic block of the greater occipital nerve.
CONCLUSION
Our data provide anatomical evidence for a functional inter-inhibitory network between the trigeminal branches and greater occipital nerve in healthy humans as postulated in animal work. We further show that functional trigeminal representations intermingle perioral and periauricular facial dermatomes with individual branches of the trigeminal nerve in an onion shaped manner and overlap in a typical within-body-part somatotopic arrangement.Trial registration: clinicaltrials.gov: NCT03999060.
Topics: Animals; Humans; Brain Stem; Headache; Pain; Trigeminal Nerve; Trigeminal Nucleus, Spinal
PubMed: 37203351
DOI: 10.1177/03331024231174862