scholarly journals An ipsilateral vestibulothalamic tract adjacent to the medial lemniscus in humans

Brain ◽  
2008 ◽  
Vol 131 (11) ◽  
pp. 2928-2935 ◽  
Author(s):  
A. Zwergal ◽  
J. Buttner-Ennever ◽  
T. Brandt ◽  
M. Strupp
2018 ◽  
Vol 9 (1) ◽  
pp. 22-25 ◽  
Author(s):  
Sung Ho Jang ◽  
Hyeok Gyu Kwon

Abstract Although there are a few studies of portions of the vestibular system such as the vestibulocerebellar tract and the neural connectivity of the vestibular nuclei (VN), no study of the ipsilateral vestibulothalamic tract (VTT) (originating from the VN and mainly connecting to the lateral thalami nuclei) has been reported. In the current study, using diffusion tensor tractography (DTT), we investigate the reconstruction method and characteristics of the ipsilateral VTT in normal subjects. Thirty-three subjects were recruited for this study. For the ipsilateral VTT, the seed region of interest (ROI) was placed on the VN, which was isolated on the FA map using adjacent structures as follows: the reticular formation (anterior boundary), posterior margin of medulla and pons (posterior boundary), medial lemniscus (medial boundary) and restiform body (lateral boundary). The target ROI was placed at the lateral thalamic nuclei using known anatomical locations. The DTT parameters of the ipsilateral VTT were measured. The ipsilateral VTTs that originated from the vestibular nuclei ascended postero-laterally to the upper pons and antero-medially to the upper midbrain via the medial longitudinal fasciculus, and terminated the lateral thalamic nuclei. No significant differences were observed in DTT parameters of the ipsilateral VTT between the right and left hemispheres (p > 0.05). Using DTT, we reconstructed the ipsilateral VTT and observed the anatomical characteristics of the ipsilateral VTT in normal subjects. We believe that the methodology and results in this study could be helpful to researchers and clinicians in this field.


Children ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 81
Author(s):  
Su Min Son ◽  
Min Cheol Chang

We describe the successful application of hinged ankle−foot orthoses (AFOs) in a cerebral palsied (CP) patient with gait instability due to a disrupted medial lemniscus (ML). The patient was a 27-month-old male CP child with gait instability who presented with reduced knee flexion and ankle dorsiflexion, with severe genu recurvatum on his right lower extremity during gait. The patient had no motor weakness or spasticity. Conventional magnetic resonance imaging (MRI) revealed no definite abnormal lesion. However, diffusion tensor tractography (DTT) showed disruption of the left ML, consistent with right hemiplegic symptoms. The integrity of the major motor-related neural tracts, including the corticospinal and corticoreticulospinal tracts, was preserved. We considered that the patient’s abnormal gait pattern was related to the disrupted ML state. We applied hinged AFOs, which immediately resulted in a significantly stabilized gait. The angles of knee flexion and ankle dorsiflexion increased. Our findings indicate that the application of hinged AFOs could be a useful therapeutic option for CP patients with gait instability related to ML disruption. In addition, we showed that DTT is a useful tool for identifying the causative brain pathology in CP patients, especially when conventional brain MRIs show no specific lesion.


1948 ◽  
Vol 88 (3) ◽  
pp. 411-424 ◽  
Author(s):  
A. T. Rasmussen ◽  
W. T. Peyton
Keyword(s):  

1997 ◽  
Vol 86 (4) ◽  
pp. 670-685 ◽  
Author(s):  
Giorgio Macchi ◽  
Edward G. Jones

✓ The nomenclature most commonly applied to the motor-related nuclei of the human thalamus differs substantially from that applied to the thalamus of other primates, from which most knowledge of input—output connections is derived. Knowledge of these connections in the human is a prerequisite for stereotactic neurosurgical approaches designed to alleviate movement disorders by the placement of lesions in specific nuclei. Transfer to humans of connectional information derived from experimental studies in nonhuman primates requires agreement about the equivalence of nuclei in the different species, and dialogue between experimentalists and neurosurgeons would be facilitated by the use of a common nomenclature. In this review, the authors compare the different nomenclatures and review the cyto- and chemoarchitecture of the nuclei in the anterolateral aspect of the ventral nuclear mass in humans and monkeys, suggest which nuclei are equivalent, and propose a common terminology. On this basis, it is possible to identify the nuclei of the human motor thalamus that transfer information from the substantia nigra, globus pallidus, cerebellum, and proprioceptive components of the medial lemniscus to prefrontal, premotor, motor, and somatosensory areas of the cerebral cortex. It also becomes possible to suggest the principal functional systems involved in stereotactically guided thalamotomies and the functional basis of the symptoms observed following ischemic lesions in different parts of the human thalamus.


1982 ◽  
Vol 25 (3) ◽  
pp. 357-363
Author(s):  
James P. Bowman

The extent to which the known trigeminothalamic projections are related to afferents from specific peripheral branches of the trigeminal nerve is not clearly revealed by degeneration studies involving lesions of the various trigeminal nuclei. This study examines the ascending projections related to the lingual branch of the trigeminal nerve using the evoked-potential technique in pentobarbital anesthetized rhesus monkeys. The distribution of potentials within the medulla, pons, and midbrain was determined by recording with macroelectrodes following single-pulse stimulation of the lingual nerve. Results show that two pathways from the main sensory nucleus convey lingual nerve information to the thalamic ventral posteromedial nucleus: an ipsilateral projection which in position corresponds to the dorsal trigeminal tract, and a larger contralateral projection which in position corresponds to the crossed ventral trigeminal tract, or trigeminal lemniscus. Additionally, the spinal trigeminal nucleus contributes fibers of lingual nerve origin to the contralateral medial lemniscus. The role of low-threshold mechanoreceptive information in lingual sensorimotor activity is discussed in relation to current concepts of somatosensory system function.


2019 ◽  
Author(s):  
Joshua Gray ◽  
Matthew Thompson ◽  
Chelsie Benca-Bachman ◽  
Max Michael Owens ◽  
Mikela Murphy ◽  
...  

Chronic cigarette smoking is associated with increased risk for myriad health consequences including cognitive decline and dementia, but research on the link between smoking and brain structure is nascent. We assessed the relationship of cigarette smoking (ever smoked, cigarettes per day, and duration) with gray and white matter using the UK Biobank cohort (gray matter N = 19,615; white matter N = 17,760), adjusting for numerous demographic and health confounders. Ever smoked and duration were associated with smaller total gray matter volume. Ever smoked was associated with reduced volume of the right VIIIa cerebellum, as well as elevated white matter hyperintensity volumes. Smoking duration was associated with reduced total white matter volume. With regard to specific tracts, ever smoked was associated with reduced fractional anisotropy in the left cingulate gyrus part of the cingulum, left posterior thalamic radiation, and bilateral superior thalamic radiation and increased mean diffusivity in the middle cerebellar peduncle, right medial lemniscus, bilateral posterior thalamic radiation, and bilateral superior thalamic radiation. Overall, we found significant associations of cigarette exposure with global measures of gray and white matter. Furthermore, we found select associations of ever smoked, but not cigarettes per day or duration, with specific gray and white matter regions. These findings inform our understanding of the connections between smoking and variation in brain structure and clarify potential mechanisms of risk for common neurological sequelae.


1999 ◽  
Vol 90 (4) ◽  
pp. 791-795 ◽  
Author(s):  
Tsutomu Nakada ◽  
Naoki Nakayama ◽  
Yukihiko Fujii ◽  
Ingrid L. Kwee

✓ The utility of three-dimensional anisotropy contrast (3DAC) magnetic resonance (MR) axonography, a method sensitive to neuronal fibers and their directionality, was investigated in the clinical setting using a 3-tesla MR imaging system based on a General Electric Signa platform. The study focused on healthy volunteers and patients with common structural central nervous system disorders, namely chronic infarction, brainstem cavernous hemangioma, supratentorial meningioma, and astrocytoma. Three orthogonal anisotropic diffusion-weighted images were first obtained. Three primary colors were each assigned to a diffusion-weighted image, respectively, and the images were subsequently combined into a single-color image in full-color spectrum (3DAC MR axonography image). Fiber-tract definition in the cerebral peduncle of the midbrain of healthy volunteers showed intersubject variation, with two general patterns recognized: dispersed (60% of cases) and compact (40% of cases). Pathological alterations in the fiber tracts were readily identified in cases involving wallerian degeneration of the pyramidal tract, as illustrated in the cases of chronic infarction. Displacement of major tracts, such as the medial lemniscus or corticospinal tract, as well as fiber directionality, was also easily recognized in cases of mass lesions. As an imaging method uniquely capable of providing information regarding axonal connectivity, 3DAC MR axonography appears to have promising potential for routine clinical application.


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