The cerebellum
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Review
Malformations of the midbrain and hindbrain: a retrospective study and review of the literature.
We report the results of a retrospective analysis of radiological and clinical findings in 45 cases of midbrain-hindbrain anomalies and review recent advances in embryology and molecular neurogenetics. Among 45 patients with midbrain-hindbrain malformations, 16 cases of molar tooth malformation, 12 of cerebellar hypoplasia, ten of posterior fossa cyst and cerebellar vermian hypoplasia, three of rhombencephalosynapsis, two of Fukuyama congenital muscular dystrophy and two cases of isolated cerebellar dysplasia were identified. ⋯ The correct diagnosis of cerebellar malformation is important for determining prognosis, the risk of recurrence and the need for genetic counselling. Integrated classification of malformations based on morphology, embryology and molecular neurogenetics may be useful.
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Traumatic brain injury (TBI) is a major cause of morbidity and mortality worldwide. Studies of human TBI demonstrate that the cerebellum is sometimes affected even when the initial mechanical insult is directed to the cerebral cortex. Some of the components of TBI, including ataxia, postural instability, tremor, impairments in balance and fine motor skills, and even cognitive deficits, may be attributed in part to cerebellar damage. ⋯ In addition, we describe models that produce direct trauma to the cerebellum as well as those that reproduce specific components of TBI including axotomy, stab injury, in vitro stretch injury, and excitotoxicity. Overall, these models reveal robust characteristics of cerebellar damage including regionally specific Purkinje cell injury or loss, activation of glia in a distinct spatial pattern, and traumatic axonal injury. Further research is needed to better understand the mechanisms underlying the pathogenesis of cerebellar trauma, and the experimental models discussed here offer an important first step toward achieving that objective.
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The Pogo (pogo/pogo) mouse is a naturally occurring neurological mutant from a Korean wild-type mouse characterized by loss of balance and motor coordination due to dysfunction of the cerebellum. The Pogo mutation is believed to be an allele of P/Q-type calcium channel mutants such as tottering, leaner, and rolling mouse Nagoya. These mutants have been served as mouse models for a group of neurodegenerative diseases. ⋯ To address this issue, we first describe the discovery of Pogo mouse and its morphological and behavioral defects. Then, we focus on the abnormal expression of several molecules in the Pogo cerebellum, including tyrosine hydroxylase, glutamate, corticotrophin-releasing factor, and 5-hydroxytryptamine. Much of this review is concerned with the functional implications of these ectopic molecules in the Pogo cerebellum.