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Journal of the Belgian Society of... Jul 2016Hypertrophic olivary degeneration (HOD) is a unique form of transneuronal degeneration caused by a disruption of the dentato-rubro-olivary pathway, also known as the...
Hypertrophic olivary degeneration (HOD) is a unique form of transneuronal degeneration caused by a disruption of the dentato-rubro-olivary pathway, also known as the triangle of Guillain-Mollaret. The triangle of Guillain-Mollaret is involved in fine voluntary motor control and consists of both the inferior olivary nucleus and the red nucleus on one side and the contralateral dentate nucleus. Clinically, patients classically present with symptomatic palatal myoclonus. Typical magnetic resonance imaging findings include T2-hyperintensity and enlargement of the inferior olivary nucleus evolving over time to atrophy with residual T2-hyperintensity. In this article, we provide a case-based illustration of the anatomy of the Guillain-Mollaret-triangle and the typical imaging findings of hypertrophic olivary degeneration.
PubMed: 30151471
DOI: 10.5334/jbr-btr.1065 -
Neurosurgical Review Jul 2023The dentato-rubro-olivary pathway, also known as the Guillain-Mollaret triangle (GMT) or myoclonic triangle, consists of the dentate nucleus, the red nucleus, and the... (Review)
Review
The dentato-rubro-olivary pathway, also known as the Guillain-Mollaret triangle (GMT) or myoclonic triangle, consists of the dentate nucleus, the red nucleus, and the inferior olivary nucleus (ION). GMT is important for motor coordination and control, and abnormalities in this network can lead to various neurological disorders. The present study followed a systematic approach in conducting a review on GMT studies. The inclusion criteria were limited to human subjects with primary objectives of characterizing and evaluating GMT syndromes, and the methodology used was not a determining factor for eligibility. The search strategy used MeSH terms and keywords relevant to the study's objective in various databases until August 2022. A total of 76 studies were included in the review after assessing 527 articles for eligibility based on the final inclusion criteria. Most of the studies evaluated the GMT in human subjects, with the majority utilizing magnetic resonance imaging (MRI), diffusion tensor imaging (DTI), or combination of them. The review found that Hypertrophic olivary degeneration (HOD), a common consequence of GMT damage, has diverse underlying causes, including stroke, brainstem cavernous malformations, and structural impairments. Palatal tremor, ocular myoclonus, ataxia, nystagmus, and vertigo were frequently reported symptoms associated with HOD. This systematic review provides comprehensive insights into the association between GMT and various neurological syndromes, shedding light on the diagnostic, etiological, and prognostic aspects of GMT dysfunction. Understanding the role of the GMT and its implications in movement disorders could pave the way for improved treatment options and better management of neurological conditions related to this critical brainstem pathway.
Topics: Humans; Diffusion Tensor Imaging; Syndrome; Olivary Nucleus; Magnetic Resonance Imaging; Stroke; Hypertrophy
PubMed: 37468768
DOI: 10.1007/s10143-023-02086-1 -
ELife Mar 2023Brainstem olivocochlear neurons (OCNs) modulate the earliest stages of auditory processing through feedback projections to the cochlea and have been shown to influence...
Brainstem olivocochlear neurons (OCNs) modulate the earliest stages of auditory processing through feedback projections to the cochlea and have been shown to influence hearing and protect the ear from sound-induced damage. Here, we used single-nucleus sequencing, anatomical reconstructions, and electrophysiology to characterize murine OCNs during postnatal development, in mature animals, and after sound exposure. We identified markers for known medial (MOC) and lateral (LOC) OCN subtypes, and show that they express distinct cohorts of physiologically relevant genes that change over development. In addition, we discovered a neuropeptide-enriched LOC subtype that produces Neuropeptide Y along with other neurotransmitters. Throughout the cochlea, both LOC subtypes extend arborizations over wide frequency domains. Moreover, LOC neuropeptide expression is strongly upregulated days after acoustic trauma, potentially providing a sustained protective signal to the cochlea. OCNs are therefore poised to have diffuse, dynamic effects on early auditory processing over timescales ranging from milliseconds to days.
Topics: Mice; Animals; Olivary Nucleus; Feedback; Hearing; Hearing Loss, Noise-Induced; Cochlea
PubMed: 36876911
DOI: 10.7554/eLife.83855 -
Cerebellum (London, England) Jun 2024Monocular torsional eye oscillations are a rare form of disconjugate nystagmus and the underlying pathophysiology is not well understood. Here, we present and discuss a...
Monocular torsional eye oscillations are a rare form of disconjugate nystagmus and the underlying pathophysiology is not well understood. Here, we present and discuss a case with disabling torsional oscillopsia in one eye only. The patient exhibited (i) spontaneous pendular torsional nystagmus of the left eye and (ii) rhythmic involuntary movements of the soft palate and uvula, consistent with the syndrome of oculopalatal tremor with monocular nystagmus. Brain MRI revealed an infarct of the left dentate nucleus in the cerebellum and, more caudally, a secondary hypertrophic degeneration of the right inferior olivary nucleus. To account for the presence of torsional nystagmus on the eye contralateral to the side of inferior olivary hypertrophy and ipsilateral to the lesioned dentate nucleus, we discuss the hypothesis of a (inferior olivary nucleus-mediated) malfunctioning adaptation of the anterior canal vestibulo-ocular reflex.
Topics: Humans; Nystagmus, Pathologic; Olivary Nucleus; Magnetic Resonance Imaging; Male; Female; Middle Aged
PubMed: 37889471
DOI: 10.1007/s12311-023-01626-1 -
Movement Disorders Clinical Practice Apr 2021Palatal tremor (PT) is an uncommon movement disorder that may be classified into symptomatic (SPT) or essential (EPT). The etiology of SPT is varied, with involvement of...
BACKGROUND
Palatal tremor (PT) is an uncommon movement disorder that may be classified into symptomatic (SPT) or essential (EPT). The etiology of SPT is varied, with involvement of the Guillain-Mollaret triangle (GMT) and inferior olivary hypertrophy. EPT is associated with ear clicks and normal imaging and may have a functional basis.
OBJECTIVES
This study aims to explore the clinical and radiological features of a large cohort of patients with PT.
METHODS
This is a retrospective chart review of patients with PT who were evaluated by the movement disorders subspeciality of the neurology department. Demographic, clinical, and imaging details of patients with PT were documented.
RESULTS
A total of 22 patients with PT comprising 17 with SPT and 5 with EPT were included in this study. No patient was aware of the PT. Ear clicks were reported in 2 patients with SPT and in 3 patients with EPT. The most common etiology for SPT was vascular, followed by degenerative conditions. Patients with SPT had associated features such as tremor (70.6%), ataxia (64.7%), dystonia (52.9%), myoclonus (17.6%), and eye movement abnormalities (75%). Lesions involving the GMT were found in 82% of patients with SPT. Apart from PT, patients with EPT had no other motor symptoms, and imaging was normal. Of the patients with EPT, 2 had additional functional movement disorders.
CONCLUSION
PT has significant etiological heterogeneity and can be easily missed because of the lack of awareness by patients. Involvement of the inferior olivary nucleus may not be necessarily observed. A functional etiology should be considered in cases of EPT.
PubMed: 33816674
DOI: 10.1002/mdc3.13173 -
Tremor and Other Hyperkinetic Movements... Oct 2020Palatal tremor is involuntary, rhythmic and oscillatory movement of the soft palate. Palatal tremor can be classified into three subtypes; essential, symptomatic and... (Review)
Review
BACKGROUND
Palatal tremor is involuntary, rhythmic and oscillatory movement of the soft palate. Palatal tremor can be classified into three subtypes; essential, symptomatic and palatal tremor associated with progressive ataxia.
METHODS
A thorough Pubmed search was conducted to look for the original articles, reviews, letters to editor, case reports, and teaching neuroimages, with the keywords "essential", "symptomatic palatal tremor", "myoclonus", "ataxia", "hypertrophic", "olivary" and "degeneration".
RESULTS
Essential palatal tremor is due to contraction of the tensor veli palatini muscle, supplied by the 5 cranial nerve. Symptomatic palatal tremor occurs due to the contraction of the levator veli palatini muscle, supplied by the 9% and 10% cranial nerves. Essential palatal tremor is idiopathic, while symptomatic palatal tremor occurs due to infarction, bleed or tumor within the Guillain-Mollaret triangle. Progressive ataxia and palatal tremor can be familial or idiopathic. Symptomatic palatal tremor and sporadic progressive ataxia with palatal tremor show signal changes in inferior olive of medulla in magnetic resonance imaging. The treatment options available for essential palatal tremor are clonazepam, lamotrigine, sodium valproate, flunarizine and botulinum toxin. The treatment of symptomatic palatal tremor involves the treatment of the underlying cause.
DISCUSSION
Further studies are required to understand the cause and pathophysiology of Essential palatal tremor and progressive ataxia and palatal tremor. Similarly, the link between tauopathy and palatal tremor associated progressive ataxia needs to be explored further. Oscillopsia and progressive ataxia are more debilitating than palatal tremor and needs new treatment approaches.
Topics: Anticonvulsants; Cerebellar Nuclei; Essential Tremor; Humans; Inflammation; Magnetic Resonance Imaging; Neuromuscular Agents; Neurosurgical Procedures; Olivary Nucleus; Palatal Muscles; Red Nucleus; Somatoform Disorders; Tremor
PubMed: 33101766
DOI: 10.5334/tohm.188 -
Journal of Integrative Neuroscience Sep 2020Transsynaptic degeneration in the cerebellum and brainstem may give rise to a rare neurological condition with various clinical manifestations, namely hypertrophic... (Meta-Analysis)
Meta-Analysis
Transsynaptic degeneration in the cerebellum and brainstem may give rise to a rare neurological condition with various clinical manifestations, namely hypertrophic olivary degeneration. The classical manifestations of hypertrophic olivary degeneration comprise myoclonus, palatal tremor, ataxia, and ocular symptoms. Any lesions interrupting the dentate-rubro-olivary pathway, referred to as the anatomic Guillain-Mollaret triangle, contribute to the broad aetiologies of hypertrophic olivary degeneration. The clinical diagnosis depends primarily on the associated symptoms and the characteristic magnetic resonance imaging findings. Concerning treatment and prognosis, there are no widely accepted guidelines. Here, we identified 11 cases of hypertrophic olivary degeneration secondary to brainstem infarction from 1964 to the present. Combined with two of our cases, the clinical and imaging findings of 13 patients with hypertrophic olivary degeneration secondary to brainstem infarction were studied. A meta-analysis of case studies gives the correlation coefficient between infraction location and time to develop hypertrophic olivary degeneration as 0.217 ( = 0.393, > 0.05). At the significance level of < 0.05, there was no significant correlation between information location and time to develop hyperophic olivary degeneration. The χ between infraction location and magnetic resonance imaging findings of hypertrophic olivary degeneration was 8.750 ( = 0.364, > 0.05). At the significance level of < 0.05, there was no significant correlation between infraction location and magnetic resonance imaging findings of hypertrophic olivary degeneration. Conclusion based on the analysis of available data suggests that when newly developed or progressive worsening motor symptoms are presented in patients with previous brainstem infarction, a diagnosis of hypertrophic olivary degeneration should be investigated.
Topics: Adult; Aged; Brain Stem Infarctions; Female; Humans; Hypertrophy; Male; Middle Aged; Neurodegenerative Diseases; Olivary Nucleus
PubMed: 33070531
DOI: 10.31083/j.jin.2020.03.1238 -
Arquivos de Neuro-psiquiatria May 2020Transaxonal degenerations result from neuronal death or the interruption of synaptic connections among neuronal structures. These degenerations are not common but may be... (Review)
Review
UNLABELLED
Transaxonal degenerations result from neuronal death or the interruption of synaptic connections among neuronal structures. These degenerations are not common but may be recognized by conventional magnetic resonance imaging.
OBJECTIVE
The learning objectives of this review include recognition of the imaging characteristics of transaxonal degenerations involving cerebellar connections, the identification of potential encephalic lesions that can lead to these degenerations and correlation of the clinical manifestations with imaging findings that reflect this involvement.
METHODS
In this report, we review the neuroanatomical knowledge that provides a basis for identifying potential lesions that can result in these degenerations involving cerebellar structures.
RESULTS
Hypertrophic olivary degeneration results from an injury that interrupts any of the components of the Guillain-Mollaret triangle. In this work, we describe cases of lesions in the dentate nucleus and central tegmental tract. The crossed cerebellar diaschisis presents specific imaging findings and clinical correlations associated with its acute and chronic phases. The Wallerian degeneration of the middle cerebellar peduncle is illustrated by fiber injury of the pontine cerebellar tracts. A T2-hyperintensity in the dentate nucleus due to a thalamic acute lesion (in ventral lateral nuclei) is also described. Each condition described here is documented by MRI images and is accompanied by teaching points and an anatomical review of the pathways involved.
CONCLUSION
Neurologists and radiologists need to become familiar with the diagnosis of these conditions since their presentations are peculiar and often subtle, and can easily be misdiagnosed as ischemic events, degenerative disease, demyelinating disease or even tumors.
Topics: Brain; Cerebellum; Magnetic Resonance Imaging; Olivary Nucleus; Pons
PubMed: 32490959
DOI: 10.1590/0004-282x20200021 -
The Journal of Comparative Neurology Apr 2018The cerebrocerebellar circuit is a feedback circuit that bidirectionally connects the neocortex and the cerebellum. According to the classic view, the cerebrocerebellar... (Review)
Review
The cerebrocerebellar circuit is a feedback circuit that bidirectionally connects the neocortex and the cerebellum. According to the classic view, the cerebrocerebellar circuit is specifically involved in the functional regulation of the motor areas of the neocortex. In recent years, studies carried out in experimental animals by morphological and physiological methods, and in humans by magnetic resonance imaging, have indicated that the cerebrocerebellar circuit is also involved in the functional regulation of the nonmotor areas of the neocortex, including the prefrontal, associative, sensory and limbic areas. Moreover, a second type of cerebrocerebellar circuit, bidirectionally connecting the hypothalamus and the cerebellum, has been detected, being specifically involved in the regulation of the hypothalamic functions. This review analyzes the morphological features of the centers and pathways of the cerebrocerebellar circuits, paying particular attention to their organization in different channels, which separately connect the cerebellum with the motor areas and nonmotor areas of the neocortex, and with the hypothalamus. Actually, a considerable amount of new data have led, and are leading, to profound changes on the views on the anatomy, physiology, and pathophysiology of the cerebrocerebellar circuits, so much they may be now considered to be essential for the functional regulation of many neocortex areas, perhaps all, as well as of the hypothalamus and of the limbic system. Accordingly, clinical studies have pointed out an involvement of the cerebrocerebellar circuits in the pathophysiology of an increasing number of neuropsychiatric disorders.
Topics: Animals; Cerebellum; Humans; Neocortex; Neural Pathways
PubMed: 29238972
DOI: 10.1002/cne.24361 -
Scientific Reports Jun 2024Based on the auditory periphery and the small head size, Etruscan shrews (Suncus etruscus) approximate ancestral mammalian conditions. The auditory brainstem in this...
Based on the auditory periphery and the small head size, Etruscan shrews (Suncus etruscus) approximate ancestral mammalian conditions. The auditory brainstem in this insectivore has not been investigated. Using labelling techniques, we assessed the structures of their superior olivary complex (SOC) and the nuclei of the lateral lemniscus (NLL). There, we identified the position of the major nuclei, their input pattern, transmitter content, expression of calcium binding proteins (CaBPs) and two voltage-gated ion channels. The most prominent SOC structures were the medial nucleus of the trapezoid body (MNTB), the lateral nucleus of the trapezoid body (LNTB), the lateral superior olive (LSO) and the superior paraolivary nucleus (SPN). In the NLL, the ventral (VNLL), a specific ventrolateral VNLL (VNLLvl) cell population, the intermediate (INLL) and dorsal (DNLL) nucleus, as well as the inferior colliculus's central aspect were discerned. INLL and VNLL were clearly separated by the differential distribution of various marker proteins. Most labelled proteins showed expression patterns comparable to rodents. However, SPN neurons were glycinergic and not GABAergic and the overall CaBPs expression was low. Next to the characterisation of the Etruscan shrew's auditory brainstem, our work identifies conserved nuclei and indicates variable structures in a species that approximates ancestral conditions.
Topics: Animals; Shrews; Superior Olivary Complex; Auditory Pathways; Neurons; Inferior Colliculi; Calcium-Binding Proteins; Brain Stem; Male; Olivary Nucleus
PubMed: 38926520
DOI: 10.1038/s41598-024-65451-0