Anatomy for neurotrauma
Hemanshu Prabhakar, Charu Mahajan, Indu Kapoor in Essentials of Anesthesia for Neurotrauma, 2018
The cerebellum is divided into two cerebellar hemispheres connected by a narrow midline vermis. The surface is divided by numerous curved transverse fissures or folia, giving it a laminated appearance. Although being only 10% of the total weight of the total brain volume, it contains 3.6 times as many neurons as in the cortex due to the folded pattern in the cerebellar gray matter. The white matter of the cerebellum is largely made of myelinated nerve fibers to and from the cortex, and is referred to as arbor vitae, due to its branched, tree-like appearance in cross-section. Embedded within the white matter, are four deep gray matter nuclei—dentate, globose, emboliform, and fastigial, which are the main sources of output from the cerebellum.
Station 2: History Taking
Saira Ghafur, Parminder K Judge, Richard Kitchen, Samuel Blows, Fiona Moss in The MRCP PACES Handbook, 2017
How would you identify the site of a cerebellar lesion from clinical findings? The cerebellum is divided into a midline vermis and two cerebellar hemispheres.Disease of the vermis leads to truncal ataxia and ataxic gait.Disease of a hemisphere causes ipsilateral dysmetria, dysdiadochokinesis, an intention tremor and fast-beat nystagmus towards the lesion.Multiple sclerosis (demyelination) can cause a global deficit.
Consequences of Excessive Chronic Alcohol Consumption on Brain Structure and Function
John Brick in Handbook of the Medical Consequences of Alcohol and Drug Abuse, 2012
Findings based on fMRI suggest the importance in alcoholics of cerebellar activation in otherwise frontal lobe functions. This additional activation enabled alcoholics to achieve normal levels of coordinated motor performance despite evidence for cerebellar dysmorphology but at a cost to processing capacity. This functional style observed in alcoholics, although perhaps compensatory, has been characterized as inefficient (Nixon and Parsons, 1991). As noted by Nixon (1993), traditional concepts of processing inefficiency derive from conditions engendering altered speed/accuracy trade-offs. Alcoholics are slower to attain normal accuracy, as we observed in a quantified version of the finger-to-nose test, in which alcoholics achieved equivalent or even smaller trajectory deviations than controls (Sullivan, Desmond, et al., 2002). This performance is symptomatic of cerebellar hemisphere dysfunction, characterized by deliberation of otherwise automatic movements. When automatic processing becomes effortful, it calls on limited processing capacity, which is then unavailable for other tasks. Taken together, these phenomena suggest a common neuropsychological mechanism—processing inefficiency—and perhaps a neural mechanism—degraded white matter microstructure—as underlying these possible instances of impaired neural transmission.
Cortical and cerebellar structural correlates of cognitive-motor integration performance in females with and without persistent concussion symptoms
Published in Brain Injury, 2023
Johanna M. Hurtubise, Diana J. Gorbet, Loriann Hynes, Alison K. Macpherson, Lauren E. Sergio
Lobules VIIIa and VIIIb are located in the inferior posterior cerebellum and are considered part of the cortico-cerebellar motor loop (69,70). It has been suggested that there are two motor representations of the body in the cerebellum, the first located in the anterior lobe, and the second in lobule VIII (71–73). Imaging studies have found that lobule VIII is functionally connected to sensory and motor cortical areas, including the primary motor cortex (M1), primary somatosensory cortex (S1), and the premotor cortex (PMC) (71,74). In addition, activation of both VIIIa and VIIIb has been found during basic sensorimotor tasks and, in particular, hand-reaching tasks (69,71). Anatomically, the posterior lobe of the cerebellum receives fibers from the cortical association areas, including prefrontal (PFC) and posterior parietal cortex (PPC) (72). Specifically, it is the lateral cerebellar hemisphere which is reciprocally and indirectly connected to the cortex, with inputs mostly from the parietal lobe, and outputs terminating in PMC and M1 (66). The majority of these cerebro-cerebellar pathways are contralateral; however, 10–30% of these projections are ipsilateral. As such, the right cerebellar hemisphere is associated with language, while the left is associated with visuospatial performance (69,72). This may explain our findings, in which only the left, and not the right, lobules VIIIa and VIIIb demonstrated differences between groups.
Morphologic characterization of the anterior inferior cerebellar artery: a direct anatomic study
Published in Neurological Research, 2020
L.E. Ballesteros, P.L. Forero, H.Y. Estupiñan
The AICA presents great variability. Our single AICA findings (81%) are concurrent with most reports [2,4,8,12], while Yasalgil et al. [1] a 98% incidence of this structure and Pelcevik et al. [10], only 64%. The presence of duplicate AICA reported in the literature in a range of 3.2–26%, is similar to our observations and to those reported by Pai et al. [2], and Pelcevick et al. [10], and Habibi et al. [3], (3.2–12%); while some authors [1,4] have reported incidences of duplication of AICA in a high range of 20 − 26%. The agenesis of AICA also shows variability, which is expressed in the report by Yasargil et al. (2%) and Pelcevick et al. (36%); whereas our findings are similar with the angiographic study of Akgun et al. [8] (18.2%). In the absence of AICA, the flocculum and petrosal surface of the cerebellar hemisphere was usually irrigated by the lateral branches of the cerebellar posteroinferior or caudal cerebellar artery of the superior cerebellar artery. The wide spectrum of presentation of AICA, observed in the various studies, can be explained by factors such as measurement methodology, the size of the samples and the biological characteristics of each population group evaluated.
Mechanisms of COVID-19-induced cerebellitis
Published in Current Medical Research and Opinion, 2022
Mohammad Banazadeh, Sepehr Olangian-Tehrani, Melika Sharifi, Mohammadreza Malek-Ahmadi, Farhad Nikzad, Nooria Doozandeh-Nargesi, Alireza Mohammadi, Gary J. Stephens, Mohammad Shabani
Some COVID-19 patients show evidence of cerebellar infarction and lesions32; for example, MRI examination in a study on patients with acute ischemic stroke and COVID-19 showed acute infarcts in the right cerebellar hemisphere and acute left posterior inferior cerebellar artery territory infarction with petechial hemorrhage33. Moreover, in MRI of a patient with COVID-19, T2 lesions were seen in the right cerebellum34. In other studies, MRIs of axial T2 showed irregular signal changes in the cerebellar vermis and left cerebellar hemisphere due to posterior circulation infarctions35. In one study, injuries to the left cerebellar hemisphere were confirmed by MRI36. This study demonstrated acute and subacute infarcts using susceptibility-weighted imaging (SWI), an MRI procedure exquisitely sensitive to venous blood, hemorrhage, and iron storage. The same study confirmed multiple microhemorrhages in the left cerebellar hemisphere36. Moreover, brain MRI using gadolinium showed multiple acute ischemic infarctions in the regions of the left posterior inferior cerebellar artery, involving the left cerebellar hemisphere and the cerebellar vermis35.
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