Activity in the pontine reticular nuclei scales with handgrip force in humans.

The neural pathways that contribute to force production in humans are currently poorly understood, as the relative roles of the corticospinal tract and brainstem pathways, such as the reticulospinal tract (RST), vary substantially across species. Using functional magnetic resonance imaging (fMRI), we aimed to measure activation in the pontine reticular nuclei (PRN) during different submaximal handgrip contractions to determine the potential role of the PRN in force modulation. Thirteen neurologically intact participants (age: 28 ± 6 yr) performed unilateral handgrip contractions at 25%, 50%, 75% of maximum voluntary contraction during brain scans. We quantified the magnitude of PRN activation from the contralateral and ipsilateral sides during each of the three contraction intensities. A repeated-measures ANOVA demonstrated a significant main effect of force (P = 0.012, [Formula: see text] = 0.307) for PRN activation, independent of side (i.e., activation increased with force for both contralateral and ipsilateral nuclei). Further analyses of these data involved calculating the linear slope between the magnitude of activation and handgrip force for each region of interest (ROI) at the individual-level. One-sample t tests on the slopes revealed significant group-level scaling for the PRN bilaterally, but only the ipsilateral PRN remained significant after correcting for multiple comparisons. We show evidence of task-dependent activation in the PRN that was positively related to handgrip force. These data build on a growing body of literature that highlights the RST as a functionally relevant motor pathway for force modulation in humans.NEW & NOTEWORTHY In this study, we used a task-based functional magnetic resonance imaging (fMRI) paradigm to show that activity in the pontine reticular nuclei scales linearly with increasing force during a handgrip task. These findings directly support recently proposed hypotheses that the reticulospinal tract may play an important role in modulating force production in humans.

Pontine tegmental cap dysplasia: the role of diffusion tensor imaging.

Pontine tegmental cap dysplasia (PTCD) is a rare hindbrain malformation syndrome. Recurrent aspiration pneumonia is a major cause of death during a first year of life. We report the case of month-old child with an inability to suck milk since birth and multiple convulsions. PTCD was identified using tractography and MRI. This case report describes the imaging findings, the role of diffusion tensor imaging in PTCD and its differentiating features from Joubert syndrome and related disorders (JSRDs). The constellation of imaging features in PTCD includes a midbrain appearance resembling a molar tooth, a flattened anterior pontine belly, hypoplastic middle cerebellar peduncles and dorsal pontine tegmental cap. 'Tegmental cap' is a transversely oriented abnormal bundle of fibres with absent superior cerebellar peduncle decussation. Accurate diagnosis with MRI and tractography and differentiating PTCD from JSRD would help the clinician for appropriate genetic counselling and prognosis.

A Case Report of Wall-Eyed Bilateral Internuclear Ophthalmoplegia with Bilateral Facial Palsy.

Case reports of bilateral facial palsy with horizontal gaze restriction are rare. A 62-year-old woman experienced sudden onset of bilateral adduction deficits, bilateral abducting nystagmus accompanied with facial diplegia. We confirmed acute ischemic stroke in the midline dorsal pons, where medial longitudinal fasciculus (MLF) and facial nerve fascicles are located. This can be explained by vascular variation of pontine perforating arteries.

'Twenty syndrome' in neuromyelitis optica spectrum disorder.

A 30-year-old woman presented with recurrent hiccups, vomiting and painful diminution of vision and gait instability for 1 day. She had one-and-a-half syndrome, bilateral seventh cranial nerve paresis with bilateral symptomatic optic neuritis and left-sided ataxic haemiparesis. We described her disorder as the 'twenty syndrome' (11/2+7+7+2+2+½=20). MRI of her brain revealed demyelination predominantly in right posterolateral aspect of pons, medulla and bilateral optic nerves. Serum antiaquaporin-4 antibody came out positive. Thus, she was diagnosed as neuromyelitis optica spectrum disorder (NMOSD). She responded brilliantly to immunosuppressive therapy. This is the first ever reported case of the 'twenty syndrome' secondary to cerebral NMOSD.

Neuronophagia and microglial nodules in a SARS-CoV-2 patient with cerebellar hemorrhage.

We document the neuropathologic findings of a 73-year old man who died from acute cerebellar hemorrhage in the context of relatively mild SARS-CoV2 infection. The patient developed sudden onset of headache, nausea, and vomiting, immediately followed by loss of consciousness on the day of admission. Emergency medical services found him severely hypoxemic at home, and the patient suffered a cardiac arrest during transport to the emergency department. The emergency team achieved return of spontaneous circulation after over 17 min of resuscitation. A chest radiograph revealed hazy bilateral opacities; and real-time-PCR for SARS-CoV-2 on the nasopharyngeal swab was positive. Computed tomography of the head showed a large right cerebellar hemorrhage, with tonsillar herniation and intraventricular hemorrhage. One day after presentation, he was transitioned to comfort care and died shortly after palliative extubation. Autopsy performed 3 h after death showed cerebellar hemorrhage and acute infarcts in the dorsal pons and medulla. Remarkably, there were microglial nodules and neuronophagia bilaterally in the inferior olives and multifocally in the cerebellar dentate nuclei. This constellation of findings has not been reported thus far in the context of SARS-CoV-2 infection.

Pontine Tegmentum Lesions Accompanying Myelitis During an Enterovirus Outbreak: Differential Diagnosis and Outcome.

AIM: To investigate etiology and prognostic significance of pontine tegmentum lesions accompanying a cluster of acute flaccid myelitis. METHOD: We retrospectively examined patients from 6 centers in Turkey who manifested encephalitis or myelitis associated with dorsal pontine lesions on magnetic resonance imaging (MRI) between July 2018 and February 2019. RESULTS: Twenty-two patients were evaluated. Ten of 22 (45%) presented with acute paralysis and 12 of 22 (55%) with brainstem symptoms only. Reverse transcription polymerase chain reaction for enterovirus was positive in 2 patients' respiratory tract. Other etiologic factors were detected in 10 cases. On follow-up, patients presenting with symptoms of myelitis developed motor sequalae although spinal cord lesions on MRI resolved in 5 of 9 (55%). Encephalitic symptoms, present in 17 cases, recovered in 13 (76%), and brain MRI showed complete or near-complete resolution in 11 of 14 (78%). CONCLUSION: Various etiologic agents can be detected in patients with pontine involvement, even in a series collected during an outbreak of EV-D68. Encephalitis has a fair outcome but clinical recovery is slow and motor sequalae are frequent in spinal involvement, irrespective of follow-up spinal MRI findings.

Wall-Eyed Bilateral Internuclear Ophthalmoplegia by Ischemic Stroke: Case Report and Literature Review.

INTRODUCTION: Wall-eyed bilateral internuclear ophthalmoplegia (WEBINO) is a rare symptom. Several studies have reported that a small brainstem lesion could cause WEBINO. CASE REPORT: The authors present the case of an 88-year-old female individual who developed sudden-onset diplopia and gait disturbance. Neurological examination revealed WEBINO with convergence impairment, gaze-evoked upward nystagmus on upward gaze, and bilateral limb ataxia. Brain magnetic resonance imaging revealed a small paramedian pontine tegmentum infarction, responsible for the symptoms. A literature review of WEBINO in ischemic stroke revealed that most patients exhibited impaired convergence and other neurological symptoms. CONCLUSION: Gaze-evoked upward nystagmus on upward gaze and bilateral limb ataxia accompanied by WEBINO due to a small brainstem lesion were the characteristic findings of our case.

The Medial Pontine Mid-Tegmentum Syndrome.

Isolated pontine infarcts are common and are often associated with well-described syndromes that are classified based on their specific clinical presentation and arterial stroke territories. Here we present a case of acute combined diplopia and unilateral lower extremity sensory abnormality. Diffusion-weighted magnetic resonance imaging revealed a punctate area of acute ischemia in the right medial pontine mid-tegmentum. These findings suggest a unique pontine stroke syndrome characterized by acute ischemic injury at the intersection of the medial lemniscus and cranial nerve VI.

Signo de "sal y pimienta" como presentación de una lesión pontina no vascular / "Salt and pepper" sign in the onset of a non-vascular pontine pathology

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Case 266: Pontine Tegmental Cap Dysplasia.

History A 1-year-old boy was referred for cochlear implant assessment after he received a diagnosis of bilateral profound sensorineural hearing loss at neonatal hearing screening shortly after birth. The child was born at term via uneventful delivery, and there was no history of familial hearing loss or maternal illness. Tympanic membranes were normal, and hearing loss was confirmed with auditory brainstem testing, which showed no response from either ear. Hearing aids were provided from 3 months of age, but no behavioral responses were noted when these were worn. He was also noted to have some mild developmental delay throughout his 1st year of life and was slow to crawl, roll over, and stand up. Physical examination showed no syndromic features or physical abnormalities. Ophthalmology confirmed normal vision and visual movements but bilateral anesthetic corneas. He had corneal abrasions due to minor repeated corneal trauma, and left-sided tarsorraphy was performed at 6 months. Facial nerve function, swallow, and voice quality were normal. To assess suitability for a cochlear implant, the patient underwent MRI of the temporal lobe and brain and thin-section CT of the temporal bones. The patient subsequently underwent left cochlear implantation.

Prenatal Imaging Findings of Pontine Tegmental Cap Dysplasia: Report of Four Cases.

OBJECTIVES: To describe the prenatal imaging findings in pontine tegmental cap dysplasia (PTCD), a rare congenital malformation of the hindbrain so far reported postnatally only and characterized by a typical appearance of the pons with malformations of the vermis and the cerebellar peduncles. METHODS: This retrospective multicenter study retrieved 4 cases of PTCD over a 10-year period. Prenatal ultrasonography and fetal magnetic resonance imaging (MRI) findings were reviewed and compared to postnatal or postmortem data. RESULTS: In all cases, the parents were referred between 22 and 27 weeks of gestation for characterization of a small cerebellar diameter <3rd centile. The prenatal diagnosis of PTCD was suspected in 1/4 cases, while in 3/4 cases the suggested prenatal diagnosis was pontocerebellar hypoplasia. In all cases, PTCD was characterized by ventral pontine hypoplasia with absence of bulging of the pons and by the tegmental cap protruding into the fourth ventricle on prenatal MRI. Parents opted for termination of pregnancy in 1 case. In the 3 other cases, the children presented with global developmental delay and multiple cranial nerve impairment. CONCLUSION: PTCD is a differential diagnosis of pontocerebellar hypoplasia and should be discussed on prenatal MRI in the presence of the tegmental cap protruding into the fourth ventricle.

[Nuclear paralysis of the oculomotor nerve within the context of traumatic brain injury]. / Paralisis nuclear del III par craneal en el contexto de un traumatismo craneoencefalico.

TITLE: Paralisis nuclear del III par craneal en el contexto de un traumatismo craneoencefalico.

Eight Syndrome: Horizontal Gaze Palsy Plus Ipsilateral Seventh Nerve Palsy.

A 62-year-old woman developed a right horizontal gaze palsy and ipsilateral facial nerve palsy due to a right pontine tegmentum infarct. This constitutes a forme fruste of the eight-and-a-half syndrome that we have termed the eight syndrome.

Rare occurrence of eight-and-a-half syndrome as a clinically isolated syndrome.

Eight-and-a-half syndrome is a rare condition that is described as a combination of one-and-a-half syndrome and an ipsilateral facial nucleus lesion. We present a clinical case of occurrence of eight-and-a-half syndrome that was caused by a demyelinating lesion in the dorsal pontine tegmentum. A 44-year-old man presented to the hospital with a subacute onset of horizontal diplopia and left-sided facial weakness. MRI revealed a T2 hyperintense lesion in his dorsal pons, which was consistent with a demyelinating pathology. Treatment with intravenous steroids showed significant improvement in his symptoms. In our case, it occurred due to a suspected demyelinating lesion that was this patient's first and only demyelinating event, leaving him with a diagnosis of clinically isolated syndrome. His responsiveness to steroids represents the first case report of an adult patient presenting with an eight-and-a-half syndrome secondary to a suspected demyelinating pathology.

Bilateral surgical damage of the central tegmental tract resulting in bilateral hypertrophic olivary degeneration: An MRI case report.

Hypertrophic olivary degeneration (HOD) is a rare trans-synaptic neuronal degeneration of the inferior olivary nucleus caused by an injury to the dentato-rubro-olivary connection, also known as Guillain-Mollaret triangle. It leads to hypertrophy of the affected nucleus rather than atrophy and is characterized by hyperintensity on T2-weighted images. Unilateral and bilateral cases are described. We present a case of a 70-year-old patient affected by a tumor inside the fourth ventricle who suffered from diplopia and right seventh cranial nerve palsy. He underwent surgery and developed left seventh cranial nerve palsy. Three months after resection, magnetic resonance imaging revealed the appearance of bilateral HOD. This is the first report of bilateral HOD occurrence after surgical bilateral damage of the rubro-olivary fibers running in central tegmental tracts.

Pontine Tegmental Cap Dysplasia in an Extremely Preterm Infant and Review of the Literature.

Pontine tegmental cap dysplasia is a rare hindbrain malformation syndrome with a hypoplastic pons, a tissue protrusion into the fourth ventricle, and cranial nerve dysfunction. We here report clinical, imaging, and genetic findings of the first extremely low-birth-weight preterm infant with pontine tegmental cap dysplasia born at 25 weeks of gestation and provide an overview of 29 sporadic cases. A prenatally diagnosed hypoplastic and rostrally shifted cerebellum was indicative of a hindbrain defect and later identified as an early sign of pontine tegmental cap dysplasia in our patient. The neonate exhibited severe muscle hypotonia, persistent thermolability, and clinical signs of an involvement of facial, cochlear, and hypoglossal nerves. Furthermore, paroxysmal episodes of agonizing pain with facial tics, tonic and clonic muscle contractions, blepharospasm, and singultus are highlighted as new phenotypic features of pontine tegmental cap dysplasia. With our report, we present a severe case of pontine tegmental cap dysplasia and provide a brief overview of current knowledge on this rare disease.