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Anatomy of the head and neck
Published in Helen Whitwell, Christopher Milroy, Daniel du Plessis, Forensic Neuropathology, 2021
The dorsal surface of the brainstem is marked by a continuation of the median sulcus extending upwards from the spinal cord into the medulla. Internally, within its caudal two-thirds is a closed central canal. This canal moves to a more a posterior position in the more rostral medulla, eventually opening as the fourth ventricle, deep to the cerebellum. Its floor is the dorsal surface of the rostral medulla and, dorsolaterally, it is dominated by the inferior cerebellar peduncle. Nerve fibres pass through the inferior cerebellar peduncle from the medulla to the cerebellum.
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.
Giuseppe Moruzzi (1910–1986) and Horace Winchell Magoun (1907–1991)
Published in Andrew P. Wickens, Key Thinkers in Neuroscience, 2018
On his arrival at Northwestern, Moruzzi accepted Magoun’s invitation to take part in studies on the cerebellum. Their original intent was to electrically stimulate the superior cerebellar peduncle – a major output pathway of the cerebellum, which passes through the lower midbrain to the ipsilateral ventrolateral nuclei of the thalamus. From here, the cerebellar input is able to influence the planning and execution of voluntary movement through its connection with the motor cortex in the frontal lobe’s precentral gyrus. Moruzzi and Magoun’s intention was to record from the surface of the motor cortex with EEG electrodes after stimulating the peduncle. This experimental procedure, however, produced some unexpected results. More specifically, when Moruzzi and Magoun stimulated the cerebellar peduncle in anaesthetised cats, they found that the EEG responses obtained from the motor cortex changed from a regular slow pattern (characteristic of a sleeping or anaesthetised animal) to one where the EEG was desynchronised and composed of low-voltage fast activity – a response very reminiscent of an arousal reaction in an alert animal. This effect was so unexpected that Moruzzi and Magoun, at first, thought their measurements were faulty – but the change in EEG response turned out to be a genuine consequence of their stimulation.
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).
Modification of CSF findings in multiple sclerosis in the era of rapidly expanding treatment options
Published in Expert Review of Neurotherapeutics, 2019
Ioanna Giotaki, Peter Lange, Martin S. Weber
The third case is a 44-year-old female patient with relapsing-remitting (RR-) MS, diagnosed in 2008 (Figure 3). The initial symptoms were retrobulbar neuritis and a mild left hemiparesis. At the time of diagnosis, the MRI showed 23 supratentorial lesions and at least one infratentorial lesion located in the left cerebellar peduncle. Following gadolinium administration, an enhancement was detectable in two of these lesions. The CSF elaboration revealed CSF-specific OCB and a positive MRZ reaction for measles (antibody index 3.9). The patient was initially treated with beta-interferon 1b and later on with glatiramer acetate. Due to two severe relapses in the following year, the patient was transitioned to natalizumab in March 2009. The following years, the patient was completely stable with no further relapses, disability progression or MRI detectable disease activity. The EDSS gradually improved from 6.0 to 4.0 between 2011 and 2013. Throughout these years, two additional lumbar punctures were performed. While in 2011 the measles index was still indicating a weakened intrathecal production of antibodies in the absence of detectable CSF-specific OCB, in 2013 all CSF findings had completely regressed to non-inflammatory values, apart from a formally positive measles antibody index value of 1.6.
Pseudobulbar affect after stroke: a narrative review
Published in Topics in Stroke Rehabilitation, 2018
Tarun Girotra, Forrest Lowe, Wuwei Feng
Wang et al highlighted the strategic location of the pons when they compared 112 stroke survivors (56 with PBA and 56 without PBA). They observed that patients with PBA are more likely to have pontine lesions than the control group (56.3% vs 17.9%, p < 0.01) and this association was stronger with bilateral pontine lesions (86.7% vs 20%, p < 0.01).15 In the multivariate analysis, pontine lesions with or without other lesions were significantly associated with a greater likelihood for having PBA [odd’s ratio (OR) 12.24, 95% CI: 2.99–58.66].15 This observation is logical as the descending fibers converge at the pons before passing into the cerebellum through the middle cerebellar peduncle. A specific lesion in the pons can have a higher chance for disrupting this network described by Parvizi.