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Brain Motor Centers and Pathways
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
The cerebellum is connected to the dorsal aspect of the brainstem by three large fiber bundles on either side, referred to as the cerebellar peduncles, and identified as: the inferior cerebellar peduncle, or restiform body, the middle cerebellar peduncle, or brachium pontis, and the superior cerebellar peduncle, or brachium conjunctivum.
The Cerebellar Ataxias and Hereditary Spastic Paraplegias
Published in John W. Scadding, Nicholas A. Losseff, Clinical Neurology, 2011
The classical Fragile X tremor ataxia syndrome (FXTAS) causing learning disability in boys is associated with a CGG expansion of the normal 7–55 repeats to over 200 repeats within the FMR-1 gene on chromosome Xq27. In about 40 per cent of males who carry a previously asymptomatic premutation of 55–200 CGG repeats, a later onset neurological disorder can develop over the age of 50 years; the features are ataxia, a postural or action tremor, cognitive impairment or parkinsonism. There may be no obvious family history of males with fragile X mental retardation. Brain magnetic resonance scanning may show lesions of the middle cerebellar peduncles. Female premutation carriers can also be affected by FXTAS (in 5–10 per cent) or premature ovarian failure.
Other atypical parkinsonian disorders and their differentiation from dementia with Lewy bodies
Published in John O'Brien, Ian McKeith, David Ames, Edmond Chiu, Dementia with Lewy Bodies and Parkinson's Disease Dementia, 2005
In MSA, one may find supra and/or infratentorial changes (Schrag et al, 2000). The former include a hyperintense slitlike appearance at the lateral border of the putamen, which correlates with the highest ferric iron levels, and microgliosis and astrogliosis. However, this has also been described in some cases with PSP, CBD and Huntington's disease. There may be putaminal atrophy or posterior putaminal hypointensity. Infratentorially, one may see a hyperintense 'cross' appearance in the pons, secondary to pontine atrophy. Degeneration of the pontine nuclei and transverse pontine fibers leads to conspicuous retention of the superior cerebellar peduncles and pyramidal tracts. This appearance may also be found in spinocerebellar ataxias 2 and 3 (SCA2 and SCA3), and has been reported in some patients with PSP, CBD and vasculitis. Hyperintensity of the middle cerebellar peduncles is also common
Cerebellar degeneration in primary lateral sclerosis: an under-recognized facet of PLS
Published in Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration, 2022
Eoin Finegan, We Fong Siah, Stacey Li Hi Shing, Rangariroyashe H. Chipika, Orla Hardiman, Peter Bede
The analyses of white matter diffusion metrics highlight the involvement of the cerebellar peduncles. The superior, middle, and inferior cerebellar peduncles provide the structural connection between the cerebellum and the brainstem. Our region-of-interest diffusivity analyses confirmed increased RD in the bilateral superior and inferior cerebellar peduncles and FA reductions in the inferior cerebellar peduncles. Additionally, our voxelwise analyses detected radial diffusivity alterations in the middle cerebellar peduncles. The superior cerebellar peduncles are the primary output tracts of the cerebellum connecting the cerebellar nuclei to the contralateral cortex via the ventral lateral nuclei, although they also contain spinocerebellar afferents (54,55). It is noteworthy, that the ventral lateral thalamic nuclei have previously been found to be affected in PLS (56,57). Superior cerebellar peduncle involvement has been described in a previous study of 3 PLS patients, in whom significantly lower FA was recorded in comparison with controls (58). Cerebellar peduncle white matter abnormalities have been consistently reported in ALS (59–61) and linked to impaired cerebro-cerebellar connectivity, including projections to the primary and supplementary motor cortices (59). MCP integrity changes have also been consistently described in ALS (59,62). The involvement of the MCP has been demonstrated in PLS patients and has been linked to pseudobulbar affect (PBA), supporting the concept of cerebellar deafferentation in the pathogenesis of PBA (35).
Infratentorial onset of progressive multifocal leukoencephalopathy in a patient with systematic lupus erythematosus complicated with lymphoma: a case report
Published in Modern Rheumatology Case Reports, 2021
Mita Sakuraba, Shinji Watanabe, Yasuhiro Nishiyama, Kenta Takahashi, Kazuo Nakamichi, Mikito Suzuki, Takashi Nawata, Kota Komai, Takahisa Gono, Mitsuhiro Takeno, Tadaki Suzuki, Kazumi Kimura, Masataka Kuwana
There were at least two reasons for the difficulty in diagnosing PML in our patient, even though she had multiple known risk factors for developing PML. Our case had underlying diseases potentially affecting the CNS, including SLE and lymphoma. It was difficult to exclude neuropsychiatric SLE from the differential diagnosis of the localised unilateral cerebellar lesions at presentation, since neuropsychiatric SLE occasionally manifests with cerebellar ataxia caused by focal involvement due to vasculitis or diffuse cerebellar involvement mediated by autoantibodies against the N-methyl-D-aspartate receptor [12]. In addition, the infratentorial localisation of the MRI lesion at the first evaluation of our case was atypical of PML, which generally affects the white matter of the cerebral hemispheres [6]. Nevertheless, the MRI finding of a crescent-shaped lesion in the middle cerebellar peduncle, adjacent pons, and cerebellum is relatively specific to the cerebellar lesion of PML [7]. In 47 HIV-infected patients with PML, 32% of them had infratentorial lesions, but only two (4%) had the disease restricted to infratentorial lesions [13], indicating that the cerebellum and brainstem are possible initial lesions, but this appears to be rare. On the other hand, SLE patients with PML involving the cerebellum and/or brainstem have been described in case reports and case series, and some of them had lesions limited to the infratentorial area [11,14–22]. It is possible that infratentorial involvement of PML might be more frequent in patients with SLE than in those with other immunocompromised conditions.
An exploration of higher-level language comprehension deficits and factors influencing them following blast TBI in US veterans
Published in Brain Injury, 2020
Judith R. Koebli, Venugopal Balasubramanian, Genevieve Pinto Zipp
MacDonald, et al. (26) used DTI to scan 63 US soldiers with a diagnosis of bTBI within 90 days post-injury. These soldiers had been exposed to a primary blast injury, plus a second category of blast injury, such as trajectory. Twenty-one soldiers with no diagnosis of bTBI, but were exposed to a primary blast, served as controls. Results revealed abnormalities in the middle cerebellar peduncles (p < .001), cingulum bundles (p = .002), and right orbitofrontal white matter (p = .007). A more recent study of postmortem autopsies revealed distinct differences between soldiers with blast exposure and a control group. Shively et al. (27) examined five brain specimens of soldiers who had died shortly after a severe blast exposure. They compared these brains with nonmilitary brains with no history of blast exposure but had either chronic impact TBI or chronic exposure to opiates. All five of the blast exposed brains revealed astroglial scarring in the subpial glial plate, grey/white matter junctions and structures lining the ventricles as well as penetrating cortical blood vessels. This specific pattern of scarring may be unique to chronic blast exposure and it lines up with the general principles of blast biophysics.