The Experts below are selected from a list of 576 Experts worldwide ranked by ideXlab platform

Sung Ho Jang - One of the best experts on this subject based on the ideXlab platform.

  • relationship between ataxia and Inferior Cerebellar Peduncle injury in patients with cerebral infarct
    Medicine, 2020
    Co-Authors: Sung Ho Jang, Han Do Lee
    Abstract:

    Introduction The Inferior Cerebellar Peduncle (ICP) is a major neural tract in the cerebellum and is involved in coordination of movement and proprioceptive; therefore, ICP injury can be accompanied by poor coordination of movement, including ataxia. In this study, using diffusion tensor tractography (DTT), we investigated the relationship between ataxia and ICP injury in patients with cerebral infarct. Methods We recruited 14 stroke patients with ataxia after the onset of stroke and 12 normal subjects. The Score of Assessment and Rating of Ataxia (SARA) was used to evaluate ataxia. The values of fractional anisotropy (FA), apparent diffusion coefficient, and fiber number (FN) of the ICP were measured for the diffusion tensor imaging parameters. Results Significant differences were observed in the FA and FN values of the ICP in the affected hemisphere between the patient and control groups (P .05). Conclusion We found that the ataxia severity was closely related to the severity of ICP injury in patients with cerebral infarct. Our results suggest that evaluation of the ICP using DTT would be useful for patients with ataxia after cerebral infarct.

  • injury of the Inferior Cerebellar Peduncle in patients with mild traumatic brain injury a diffusion tensor tractography study
    Brain Injury, 2016
    Co-Authors: Sung Ho Jang, Hyeok Gyu Kwon
    Abstract:

    AbstractObjectives: No study on injury of the Inferior Cerebellar Peduncle (ICP) in patients with mild traumatic brain injury (mTBI) has been reported. This study, using diffusion tensor tractography (DTT), attempted to demonstrate injury of the ICP in patients with mTBI.Methods: Three patients with mTBI resulting from a car accident and 18 normal healthy control subjects were enrolled in this study. Diffusion tensor imaging data were acquired at 2 months (patient 1) and 3 months (patients 2 and 3) after onset and the ICP was reconstructed. The Balance Error Scoring System was used for evaluation of balance at the same time diffusion tensor imaging scanning was performed.Results: The ICPs were discontinued at the upper portion of the vertical Cerebellar branch and the transverse Cerebellar branch (patient 1) and the proximal portion of the transverse Cerebellar branch (patients 2 and 3) compared to the normal control subjects. Regarding DTT parameters, in the three patients, the fibre number of the ICPs w...

  • Cerebellar Peduncle injury in patients with ataxia following diffuse axonal injury.
    Brain Research Bulletin, 2009
    Co-Authors: Ji Heon Hong, Oh Lyong Kim, Seong Ho Kim, Mi Young Lee, Sung Ho Jang
    Abstract:

    No diffusion tensor imaging (DTI) study has yet investigated ataxia in diffuse axonal injury (DAI). In the current study, we used DTI to investigate Cerebellar Peduncle lesions of patients who showed severe ataxia following DAI. Six patients with severe ataxia following DAI and six age-and sex-matched control subjects were recruited. DTIs were acquired using a sensitivity-encoding head coil on a 1.5T system. Using DTI-Studio software, three Cerebellar Peduncles (superior Cerebellar Peduncle, SCP; middle Cerebellar Peduncle, MCP; Inferior Cerebellar Peduncle, ICP) were evaluated. In each Cerebellar Peduncle, fractional anisotropy was estimated using the regions of interest method. We defined a lesion as a fractional anisotropy value two standard deviations below that of normal controls. All six patients had an average of 6.3 lesions (range 3-12). Twenty of 36 total Cerebellar Peduncles revealed more than one lesion (SCP: 8, ICP: 7, MCP: 5). In each of the 20 Cerebellar Peduncles, all the lesions displaying the lowest FA values relative to that of normal controls (11 Peduncles; 55%) were located in the junction between brain stem and cerebellum and post-junctional area (nine Peduncles; 45%). The junction and peri-junctional areas between the brain stem and cerebellum appear to be the most vulnerable area by DAI, with the order of incidence SCP, ICP, and MCP. Evaluation of the Cerebellar Peduncles using DTI can be helpful in patients with ataxia following DAI.

W Mrowczynski - One of the best experts on this subject based on the ideXlab platform.

  • neurones in the cervical enlargement of the cat spinal cord antidromically activated from sacral segments and the Inferior Cerebellar Peduncle
    Neuroscience Research, 2001
    Co-Authors: W Mrowczynski, Kazimierz Grottel, Piotr Krutki
    Abstract:

    Abstract The electrophysiological investigation of neurones located in the cervical enlargement of the spinal cord was performed in eight-chloralose anaesthetized cats. Neurones were recorded intracellularly or extracellularly and identified by antidromic stimulation. The main purpose of the study was to test whether these neurones give off collateral branches ascending to the Inferior Cerebellar Peduncle and descending to the sacral segments (S1/S2). Recordings were made from 78 neurones located in medial and central parts of Rexed's laminae VII and VIII of C6/C7 segments. Four subpopulations could be distinguished from their patterns of propriospinal or supraspinal projections: (a) ascending/descending neurones with axons ascending to RB and descending to S1/S2 (23%); (b) ascending/descending neurones projecting to RB and the level of Th13 (14%); (c) propriospinal neurones descending to Th13 (15%); (d) propriospinal neurones descending to S1/S2 (48%). Within these groups, ipsilateral, contralateral and bilateral descending projections were observed. The mean axonal conduction velocities for descending and ascending collaterals of bidirectional neurones were 59 and 39 m/s, respectively. Results suggest that parallel transmission of information to supraspinal and spinal centres plays an important role in the process of movement coordination.

  • bidirectional neurones in the cervical enlargement of the cat spinal cord with axons descending to sacral segments and ascending to the cerebellum and the lateral reticular nucleus
    Experimental Physiology, 1999
    Co-Authors: Kazimierz Grottel, Piotr Krutki, W Mrowczynski
    Abstract:

    SUMMARY Neurones located in cervical segments (C6/C7) of the spinal cord were investigated electrophysiologically in cats deeply anaesthetized with α-chloralose. Extracellular recordings of antidromic action potentials were performed in order to establish whether long descending propriospinal neurones projecting to sacral segments could have collateral axonal branches ascending to supraspinal centres. The effects of stimulation of the lateral reticular nucleus (LRN) and the Inferior Cerebellar Peduncle (restiform body, RB), as well as the thirteenth thoracic (Th13) and sacral (S1/S2) segments of the spinal cord were tested in 93 cells. Two main groups of cells were identified: 54% of the total sample were classified as purely propriospinal and 46% as bidirectional neurones. Various patterns of projections, as well as the ipsi-, contra- or bilateral courses of axons in the lateral funiculi of the spinal cord, enabled several types of neurones to be distinguished within the above groups. Comparison between particular types showed no significant difference with respect to location in the grey matter (predominantly Rexed's laminae VII-VIII) and the conduction velocities of descending axons. However, the mean axonal conduction velocities of branches ascending to LRN and/or RB were significantly lower in comparison to those measured for spinal collaterals. The hypothetical function of the neurones examined is discussed. Since the same information can be conveyed simultaneously by these branching neurones to lower spinal segments and supraspinal centres, an integrative role in the system of motor control is suggested.

Flavio Dell'acqua - One of the best experts on this subject based on the ideXlab platform.

  • Drum training induces long-term plasticity in the cerebellum and connected cortical thickness
    Scientific Reports, 2020
    Co-Authors: Muriel Bruchhage, Ali Amad, Stephen Draper, Jade Seidman, Luis Lacerda, Pedro Luque Laguna, Ruth Lowry, James Wheeler, Andrew Robertson, Flavio Dell'acqua
    Abstract:

    It is unclear to what extent Cerebellar networks show long-term plasticity and accompanied changes in cortical structures. Using drumming as a demanding multimodal motor training, we compared Cerebellar lobular volume and white matter microstructure, as well as cortical thickness of 15 healthy non-musicians before and after learning to drum, and 16 age matched novice control participants. After 8 weeks of group drumming instruction, 3 ×30 minutes per week, we observed the cerebellum significantly changing its grey (volume increase of left VIIIa, relative decrease of VIIIb and vermis Crus I volume) and white matter microstructure in the Inferior Cerebellar Peduncle. These plastic Cerebellar changes were complemented by changes in cortical thickness (increase in left paracentral, right precuneus and right but not left superior frontal thickness), suggesting an interplay of Cerebellar learning with cortical structures enabled through Cerebellar pathways.

Piotr Krutki - One of the best experts on this subject based on the ideXlab platform.

  • neurones in the cervical enlargement of the cat spinal cord antidromically activated from sacral segments and the Inferior Cerebellar Peduncle
    Neuroscience Research, 2001
    Co-Authors: W Mrowczynski, Kazimierz Grottel, Piotr Krutki
    Abstract:

    Abstract The electrophysiological investigation of neurones located in the cervical enlargement of the spinal cord was performed in eight-chloralose anaesthetized cats. Neurones were recorded intracellularly or extracellularly and identified by antidromic stimulation. The main purpose of the study was to test whether these neurones give off collateral branches ascending to the Inferior Cerebellar Peduncle and descending to the sacral segments (S1/S2). Recordings were made from 78 neurones located in medial and central parts of Rexed's laminae VII and VIII of C6/C7 segments. Four subpopulations could be distinguished from their patterns of propriospinal or supraspinal projections: (a) ascending/descending neurones with axons ascending to RB and descending to S1/S2 (23%); (b) ascending/descending neurones projecting to RB and the level of Th13 (14%); (c) propriospinal neurones descending to Th13 (15%); (d) propriospinal neurones descending to S1/S2 (48%). Within these groups, ipsilateral, contralateral and bilateral descending projections were observed. The mean axonal conduction velocities for descending and ascending collaterals of bidirectional neurones were 59 and 39 m/s, respectively. Results suggest that parallel transmission of information to supraspinal and spinal centres plays an important role in the process of movement coordination.

  • bidirectional neurones in the cervical enlargement of the cat spinal cord with axons descending to sacral segments and ascending to the cerebellum and the lateral reticular nucleus
    Experimental Physiology, 1999
    Co-Authors: Kazimierz Grottel, Piotr Krutki, W Mrowczynski
    Abstract:

    SUMMARY Neurones located in cervical segments (C6/C7) of the spinal cord were investigated electrophysiologically in cats deeply anaesthetized with α-chloralose. Extracellular recordings of antidromic action potentials were performed in order to establish whether long descending propriospinal neurones projecting to sacral segments could have collateral axonal branches ascending to supraspinal centres. The effects of stimulation of the lateral reticular nucleus (LRN) and the Inferior Cerebellar Peduncle (restiform body, RB), as well as the thirteenth thoracic (Th13) and sacral (S1/S2) segments of the spinal cord were tested in 93 cells. Two main groups of cells were identified: 54% of the total sample were classified as purely propriospinal and 46% as bidirectional neurones. Various patterns of projections, as well as the ipsi-, contra- or bilateral courses of axons in the lateral funiculi of the spinal cord, enabled several types of neurones to be distinguished within the above groups. Comparison between particular types showed no significant difference with respect to location in the grey matter (predominantly Rexed's laminae VII-VIII) and the conduction velocities of descending axons. However, the mean axonal conduction velocities of branches ascending to LRN and/or RB were significantly lower in comparison to those measured for spinal collaterals. The hypothetical function of the neurones examined is discussed. Since the same information can be conveyed simultaneously by these branching neurones to lower spinal segments and supraspinal centres, an integrative role in the system of motor control is suggested.

The Johns Hopkins School Of Medicine - One of the best experts on this subject based on the ideXlab platform.

  • HINTS exam and saccadic dysmetria in lateral medullary stroke
    Spencer S. Eccles Health Sciences Library University of Utah, 2018
    Co-Authors: Daniel R. Gold, Departments Of Neurology, Otolaryngology Head Neck - & Surgery, Emergency Medicine, And Medicine, The Johns Hopkins School Of Medicine
    Abstract:

    This is a 50-year-old who experienced the abrupt onset of prolonged vertigo following chiropractic therapy 2 months prior. Initial work-up included an MRI and MR angiogram - MR-diffusion weighted imaging showed an acute left lateral medullary stroke and left vertebral artery occlusion, which was thought to be related to a dissection. ; The examination seen here was performed 2 months following his stroke, and there was no spontaneous nystagmus with fixation. When fixation was removed with video infrared goggles, right-beating (with a slight torsional component, top poles beating towards the right ear) nystagmus was apparent. Head impulse testing in the planes of the horizontal canals was normal, which is a "central" sign in patients presenting with acute vertigo and spontaneous nystagmus. He also had a skew deviation with a left (ipsilesional) hypotropia. When the utricle-ocular motor fibers are affected caudal to their decussation as in a lateral medullary stroke, the hypotropic eye will be ipsilesional as in this case. Therefore, the HINTS (Head Impulse, Nystagmus, Test of Skew) exam was consistent with a central localization. ; Additionally, there was saccadic dysmetria, with hypermetric saccades to the (ipsilesional) left side and hypometric saccades to the (contralesional) right side. Although not shown here, there was also leftward ocular lateropulsion, a finding which is usually seen ipsilateral to hypermetric saccades. This is a typical finding in the Wallenberg syndrome, given involvement of the Inferior Cerebellar Peduncle and the climbing fibers that course through it on their way to the ipsilateral dorsal vermis (see normal saccadic pathway https://collections.lib.utah.edu/details?id=1260093, and what happens to saccades with lateral medullary injury https://collections.lib.utah.edu/details?id=1260094)

  • The acute vestibular syndrome with dysarthria, dysphagia, dysphonia, hemi-ataxia, and saccadic dysmetria due to the lateral medullary (Wallenberg) syndrome
    Spencer S. Eccles Health Sciences Library University of Utah, 2017
    Co-Authors: Daniel R. Gold, Departments Of Neurology, Otolaryngology Head Neck - & Surgery, Emergency Medicine, And Medicine, The Johns Hopkins School Of Medicine
    Abstract:

    This is a 50-year-old woman with the acute onset of vertigo, dysarthria, dysphagia and dysphonia/hoarseness (nucleus ambiguus), ptosis and imbalance. Her examination localized to a left lateral medullary (Wallenberg) syndrome - there was decreased sensation on the left side of the face (spinal trigeminal nucleus and tract) and the right arm and leg (spinothalamic tract), a left Horner's syndrome (oculosympathetic tract), left hemi-ataxia (Inferior Cerebellar Peduncle), leftward ocular lateropulsion (apparent throughout the video during blinks - during eyelid closure, there is conjugate deviation to the left, and when the eyelids open, the eyes move to the right into primary gaze) which is usually seen with hypermetric saccades to the left (ipsilateral) and hypometric saccades to the right (contralateral), relating to injury of the climbing fibers traveling through the Inferior Cerebellar Peduncle on the left side. Other ocular motor features commonly seen in a lateral medullary syndrome (not demonstrated in the video) include an ipsiversive ocular tilt reaction (1. skew deviation with a (left) hypotropia ipsilateral to the stroke, 2. ipsilesional (towards the left ear) ocular counterroll, 3. leftward head tilt) due to utricle-ocular motor pathway dysfunction; spontaneous nystagmus which is usually horizontal-torsional or pure torsional due to central semicircular canal pathway dysfunction; gaze-evoked nystagmus due to medial vestibular nucleus dysfunction. [[Number of Videos and legend for each: 1, patient with the acute vestibular syndrome due to left lateral medullary stroke.]

  • Medullary structures relevant to upbeat nystagmus
    Spencer S. Eccles Health Sciences Library University of Utah, 2017
    Co-Authors: Daniel R. Gold, Departments Of Neurology, Otolaryngology Head Neck - & Surgery, Emergency Medicine, And Medicine, The Johns Hopkins School Of Medicine
    Abstract:

    This is an axial section of the medulla, slightly more caudal as compared to (please refer to figure "medullary structures relevant to the ocular motor and vestibular consequences of the lateral medullary (Wallenberg) syndrome). Again seen are the Inferior Cerebellar Peduncle (ICP) and caudal aspect of the vestibular nucleus (medial vestibular nucleus [MVN]), in addition to the nucleus of Roller and nucleus intercalatus. These nuclei normally have an inhibitory influence over the flocculus, and when there is a lesion of Roller/intercalatus, there is less inhibition of the flocculus. The Purkinje cells of the flocculus normally inhibit the anti-gravity/anterior semicircular canal (SCC) pathways. With a lesion of Roller/intercalatus, the flocculus will over-inhibit the anterior SCC pathways, causing relative activation of the posterior SCC pathways which will generate a downward slow phase. The fast/position-reset phase will be upward, and these alternating slow (downward) and fast (upward) phases are responsible for upbeat nystagmus

  • Saccadic pathways in the brainstem and cerebellum & mechanism for saccadic dysmetria in Wallenberg syndrome - Normal function of the brainstem/Cerebellar saccadic pathways
    Spencer S. Eccles Health Sciences Library University of Utah, 2017
    Co-Authors: Daniel R. Gold, Departments Of Neurology, Otolaryngology Head Neck - & Surgery, Emergency Medicine, And Medicine, The Johns Hopkins School Of Medicine
    Abstract:

    The Inferior Cerebellar Peduncle (ICP) carries climbing fibers to the dorsal vermis, and these fibers have an inhibitory influence over the Purkinje cells. These Purkinje cells normally inhibit the ipsilateral fastigial nucleus, and the fastigial nucleus projects to the contralateral inhibitory burst neurons (IBN) within the paramedian pontine reticular formation (PPRF). The IBN project contralaterally to inhibit the VIth nucleus to prevent unwanted saccades in this direction, while facilitating saccades (via the excitatory burst neurons [EBN]) in the opposite direction. Modified and redrawn with permission from Wolters Kluwer and the American Academy of Neurology. Frohman TC, Graves J, Balcer LJ, Galetta SL, Frohman EM. The neuro-ophthalmology of multiple sclerosis. Continuum (Minneap Minn) 2010;16:122-146

  • Triangle of Guillain-Mollaret
    Spencer S. Eccles Health Sciences Library University of Utah, 2017
    Co-Authors: Daniel R. Gold, Departments Of Neurology, Otolaryngology Head Neck - & Surgery, Emergency Medicine, And Medicine, The Johns Hopkins School Of Medicine
    Abstract:

    Seen here is a schematic representation of the Gullain-Mollaret triangle (Figure 1), also referred to as the dentato-olivary pathway, reflecting the 3 points of this imaginary triangle - 1) dentate nucleus, 2) red nucleus, and 3) Inferior olivary nucleus. The olive sends decussating climbing fibers through the contralateral Inferior Cerebellar Peduncle that travel from the Purkinje cells of the Cerebellar cortex to the dentate nucleus; the dentate sends decussating fibers (via the superior Cerebellar Peduncle) that wrap around the contralateral red nucleus; these fibers descend from red nucleus to the ipsilateral Inferior olive via the central tegmental tract (CTT). Injury to any of these structures may result in oculopalatal tremor (OPT). Generally, OPT develops weeks to months following the inciting event (usually a brainstem hemorrhage), and vertical, vertical-torsional or torsional pendular nystagmus and palatal tremor can usually be appreciated on exam. Since the CTT normally inhibits the ipsilateral Inferior olive, damage to the CTT results in decreased inhibition of the ipsilateral olive resulting from transsynaptic degeneration. Hypertrophic Inferior olivary degeneration occurs as swollen and vacuolated neurons come into contact with each other, and corresponds to MRI T2/FLAIR hyperintensity (Figure 2). Cells of the Inferior olive are electrically coupled by dendrodendritic gap junctions and are normally capable of generating spontaneous oscillations, but are inhibited by the CTT. When olivary denervation occurs, there is aberrant conduction between the soma of adjacent cells, causing synchronized oscillatory signals that are transmitted to the cerebellum where they are modulated and augmented. These rhythmic outputs generate nystagmus and palatal tremor. Nystagmus may be conjugate, dissociated or disjunctive. Nystagmus may be seen without palatal tremor, and palatal tremor may be seen without nystagmus (e.g., progressive ataxia and palatal tremor, PAPT), and synchronous contractions of other muscles from the branchial arches (larynx, pharynx, diaphragm, facial muscles) may also be appreciated. Shaikh AG, et al. Oculopalatal tremor explained by a model of Inferior olivary hypertrophy and Cerebellar plasticity. Brain. 2010 Mar;133(Pt 3):923-40. Tilikete C, Desestret V. Hypertrophic Olivary Degeneration and Palatal or Oculopalatal Tremor. Front Neurol. 2017; 8: 302