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Cerebellum (London, England) Sep 2009We report the results of a retrospective analysis of radiological and clinical findings in 45 cases of midbrain-hindbrain anomalies and review recent advances in... (Review)
Review
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. Twenty-six patients presented with motor-mental retardation, which was the most common clinical finding. Eleven patients were born to consanguineous parents. 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.
Topics: Adolescent; Adult; Child; Child, Preschool; Congenital Abnormalities; Female; Fetus; Humans; Magnetic Resonance Imaging; Male; Mesencephalon; Radiography; Retrospective Studies; Rhombencephalon; Tomography Scanners, X-Ray Computed; Young Adult
PubMed: 19337779
DOI: 10.1007/s12311-009-0104-x -
Current Topics in Developmental Biology 2009In the vertebrate central nervous system, the hindbrain is an important center for coordinating motor activity, posture, equilibrium, sleep patterns, and essential... (Review)
Review
In the vertebrate central nervous system, the hindbrain is an important center for coordinating motor activity, posture, equilibrium, sleep patterns, and essential unconscious functions, such as breathing rhythms and blood circulation. During development, the vertebrate hindbrain depends upon the process of segmentation or compartmentalization to create and organize regional properties essential for orchestrating its highly conserved functional roles. The process of segmentation in the hindbrain differs from that which functions in the paraxial mesoderm to generate somites and the axial skeleton. In the prospective hindbrain, cells in the neural epithelia transiently alter their ability to interact with their neighbors, resulting in the formation of seven lineage-restricted cellular compartments. These different segments or rhombomeres each go on to adopt unique characters in response to environmental signals. The Hox family of transcription factors is coupled to this process. Overlapping or nested patterns of Hox gene expression correlate with segmental domains and provide a combinatorial code and molecular framework for specifying the unique identities of hindbrain segments. The segmental organization and patterns of Hox expression and function are highly conserved among vertebrates and, as a consequence, comparative studies between different species have greatly enhanced our ability to build a picture of the regulatory cascades that control early hindbrain development. The purpose of this chapter is to review what is known about the regulatory mechanisms which establish and maintain Hox gene expression and function in hindbrain development.
Topics: Animals; Body Patterning; Gene Expression Regulation, Developmental; Gene Regulatory Networks; Homeodomain Proteins; Models, Genetic; Rhombencephalon; Vertebrates
PubMed: 19651303
DOI: 10.1016/S0070-2153(09)88004-6 -
Current Opinion in Genetics &... Aug 1993Following neurulation, neural crest cells emerge from the neural tube and undergo extensive migrations. At the onset of migration, multipotent stem cells exist within... (Review)
Review
Following neurulation, neural crest cells emerge from the neural tube and undergo extensive migrations. At the onset of migration, multipotent stem cells exist within the neural crest population. Eventually, these assume one of a number of possible fates, ranging from neurons and glia of the peripheral nervous system to pigment cells and cells of the facial skeleton. Neural crest cells follow migratory pathways and differentiate into derivatives that often are characteristic of their axial level of origin. Based on their stereotyped patterns of migration, limited intermixing and distinct homeobox-gene codes, some populations of neural crest cells may have a rostrocaudal regional identity imprinted prior to their emigration.
Topics: Animals; Genes, Homeobox; Neural Crest; Rhombencephalon
PubMed: 7902150
DOI: 10.1016/0959-437x(93)90101-t -
British Medical Bulletin Oct 1987
Review
Topics: Acoustic Stimulation; Animals; Cochlear Nerve; Humans; Rhombencephalon
PubMed: 3329928
DOI: 10.1093/oxfordjournals.bmb.a072221 -
Current Biology : CB
Review
Topics: Animals; Body Patterning; Drosophila; Embryo, Nonmammalian; Embryonic Induction; Gene Expression Regulation; Hedgehog Proteins; Humans; Neurons; Proteins; Rhombencephalon; Signal Transduction; Spinal Cord; Trans-Activators
PubMed: 10959831
DOI: 10.1016/s0960-9822(00)00615-1 -
Neuropediatrics Aug 2002Rhombencephalosynapsis is a rare congenital abnormality characterised by dorsal fusion of the cerebellar hemispheres, agenesis or hypogenesis of the vermis, fusion of... (Review)
Review
Rhombencephalosynapsis is a rare congenital abnormality characterised by dorsal fusion of the cerebellar hemispheres, agenesis or hypogenesis of the vermis, fusion of dentate nuclei and superior cerebellar peduncles. We describe 9 children, aged 1.5 to 6 years, with rhombencephalosynapsis. Isolated rhombencephalosynapsis was found in 2 patients, hydrocephalus in 3 children and another 3 children had ventriculomegaly. Additional supratentorial abnormalities were documented in 5 patients. Clinical findings ranged from mild truncal ataxia and normal cognitive abilities to severe cerebral palsy and mental retardation. No correlation between clinical findings and magnetic resonance imaging could be established so far.
Topics: Cerebellum; Child; Child, Preschool; Cognition Disorders; Female; Humans; Infant; Magnetic Resonance Imaging; Male; Nervous System Diseases; Rhombencephalon
PubMed: 12368992
DOI: 10.1055/s-2002-34498 -
Current Opinion in Cell Biology Dec 2001Proper craniofacial development requires the orchestrated integration of multiple specialized tissue interactions. Recent analyses suggest that craniofacial development... (Review)
Review
Proper craniofacial development requires the orchestrated integration of multiple specialized tissue interactions. Recent analyses suggest that craniofacial development is not dependent upon neural crest pre-programming as previously thought but is regulated by a more complex integration of cell and tissue interactions. In the absence of neural crest cells it is still possible to obtain normal arch patterning indicating that neural crest is not responsible for patterning all of arch development. The mesoderm, endoderm and surface ectoderm tissues play a role in the patterning of the branchial arches, and there is now strong evidence that Hoxa2 acts as a selector gene for the pathways that govern second arch structures.
Topics: Animals; Body Patterning; Bone and Bones; Branchial Region; Ectoderm; Endoderm; Gene Expression Regulation, Developmental; Head; Homeodomain Proteins; Mesoderm; Models, Biological; Neural Crest; Rhombencephalon
PubMed: 11698185
DOI: 10.1016/s0955-0674(00)00273-8 -
Experimental Brain Research 1989The topographical mapping of glial fibrillary acidic protein (GFAP)-immunoreactivity was performed in coronal serial sections of the rat mesencephalon, rhombencephalon...
The topographical mapping of glial fibrillary acidic protein (GFAP)-immunoreactivity was performed in coronal serial sections of the rat mesencephalon, rhombencephalon and spinal cord. Relative to a background of poor or moderate overall staining of the mesencephalon, the interpeduncular nucleus, substantia nigra and the periaqueductal grey matter were prominent by their intense GFAP-immunoreactivity. The pons and particularly the medulla contained more GFAP-labelled elements compared with the mesencephalon. The spinal trigeminal nucleus and Rolando substance were distinguished by their intense staining. Large fibre tracts were usually poor in immunoreactive GFAP. In a concluding discussion, findings relevant to the GFAP-mapping of the whole rat CNS are evaluated with regard to possible reasons underlying the observed differential distribution of GFAP-immunoreactivity.
Topics: Animals; Astrocytes; Female; Glial Fibrillary Acidic Protein; Immunohistochemistry; Male; Mesencephalon; Rats; Rhombencephalon; Spinal Cord
PubMed: 2591510
DOI: 10.1007/BF00230695 -
Journal of Neuroscience Research 1988Rhombencephala from rat embryos were processed as whole-mounts for immunocytochemical detection of monoaminergic cell populations, using antibodies to tyrosine...
Rhombencephala from rat embryos were processed as whole-mounts for immunocytochemical detection of monoaminergic cell populations, using antibodies to tyrosine hydroxylase (TH) and serotonin (5-HT). Specific advantages of the whole-mount technique over the classical serial-section method were that even isolated immunoreactive (IR) cells could be detected easily, and three-dimensional relationships could be ascertained without the need for serial reconstruction. Embryos between embryonic days (E) 12 and 16 (the day following nocturnal mating being considered as E1) were used in this study. Both TH and 5-HT immunoreactivities were already detectable at E12, even in the smallest embryos (crown-rump length: 6 mm), but there was a striking difference in the number and regional distribution of these two types of IR cells. TH was expressed in several cell groups located in the rostral rhombencephalon (the presumed anlage of the A4-7 complex) as well as in the caudal rhombencephalon (the presumed anlagen of groups A1-2 and C1-3), whereas 5-HT was expressed in very few cells located near the rostral border of the rhombencephalon (presumed anlage of the B4-9 complex). Although the three-dimensional distribution of the TH-IR cell groups underwent some modifications during the period studied, its general pattern remained relatively stable after E12. This contrasted with the sequential appearance of the 5-HT-IR cell groups and their spatial transformations during this period. Using the rhombencephalic isthmus as a landmark, we found that conspicuous 5-HT-IR fibre bundles penetrated into the mesencephalon from E13 onwards, but that the 5-HT IR cell bodies were exclusively located caudal to the borderline between the mesencephalon and the rhombencephalon (the rhombencephalic isthmus). We therefore suggest the term "rostral rhombencephalic raphe nuclei" for the rostral 5-HT cell groups instead of "mesencephalic raphe nuclei," which is a misnomer. Close spatial association between TH and 5-HT-IR elements was observed mainly in the caudal rhombencephalon, where 5-HT-IR fibres coursed through an area containing numerous TH-IR cell bodies (the presumed anlagen of groups A1-2 and C1-3).
Topics: Animals; Embryonic and Fetal Development; Gestational Age; Immunohistochemistry; Rats; Rats, Inbred Strains; Rhombencephalon; Serotonin; Tyrosine 3-Monooxygenase
PubMed: 2902232
DOI: 10.1002/jnr.490200210 -
Frontiers in Neural Circuits 2016Spontaneous activity in the developing central nervous system occurs before the brain responds to external sensory inputs, and appears in the hindbrain and spinal cord... (Review)
Review
Spontaneous activity in the developing central nervous system occurs before the brain responds to external sensory inputs, and appears in the hindbrain and spinal cord as rhythmic electrical discharges of cranial and spinal nerves. This spontaneous activity recruits a large population of neurons and propagates like a wave over a wide region of the central nervous system. Here, we review spontaneous activity in the chick hindbrain by focusing on this large-scale synchronized activity. Asynchronous activity that is expressed earlier than the above mentioned synchronized activity and activity originating in midline serotonergic neurons are also briefly mentioned.
Topics: Animals; Birds; Chick Embryo; Nerve Net; Rhombencephalon
PubMed: 27570506
DOI: 10.3389/fncir.2016.00063