Origins, Development, and Compartmentation of the Granule Cells of the Cerebellum

Granule cells (GCs) are the most numerous cell type in the cerebellum and indeed, in the brain: at least 99% of all cerebellar neurons are granule cells. In this review article, we first consider the formation of the upper rhombic lip, from which all granule cell precursors arise, and the way by which the upper rhombic lip generates the external granular layer, a secondary germinal epithelium that serves to amplify the upper rhombic lip precursors. Next, we review the mechanisms by which postmitotic granule cells are generated in the external granular layer and migrate radially to settle in the granular layer. In addition, we review the evidence that far from being a homogeneous population, granule cells come in multiple phenotypes with distinct topographical distributions and consider ways in which the heterogeneity of granule cells might arise during development.

Persistent vomiting, an alarm sign in children

Brain tumors, the second common cancer following hematological malignancies account for up to 21% of all malignancies below 14 years of age. Medulloblastoma is a common form of Primitive neuro ectodermal tumor and likely arise from either the external granular layer (e.g., desmoplastic variant) or the subependymal matrix cells of the fourth ventricle (e.g., classic variant), or both. The clinical course of the disease is aggressive in children than in adults. The tumor can invade the CSF through the ventricles or even cause metastases to bones and lymph node. With the emergence of advanced technologies and treatment facilities, the morbidity and mortality of the disease is greatly improved with a five-year survival of up to 75%. However, the presence of disease in children <3 years or evidence of dissemination on diagnosis carries poor prognosis. Here we are discussing a case of 5-year-old girl who presented to OPD with vomiting for 1 month.

Prenatal treatment with metronidazole induces cerebellar folia alteration in guinea pig fetuses

The most sensitive period in brain development is during prenatal life. The use of antibiotics in pregnancy is still controversial. Recent studies revealed the high neurotoxic potential of the antibiotic and antiprotozoal medication, metronidazole. However, there are insufficient data from animal studies about prenatal treatment effects. We investigated the effect of prenatal treatment with metronidazole on cerebellar development in guinea pigs. Treatment with metronidazole was performed from the 42nd to the 49th day of gestation. On the 50th day of pregnancy, all dams were killed, and the cerebella of the fetuses were analyzed. Gross cerebellar changes characterized by malposition of the folia with partial atrophy were found in 12 of 19 fetuses in the experimental group, but in none of 20 control fetuses that received saline. The most affected were folia VII with depletion of the areal fraction of the external granular layer, molecular layer and the internal granular layer. Purkinje cells displayed cell distortion with loss of normal dendritic polarity. The investigation revealed cell depletion, with a disturbance of the cytoarchitectonic of the cerebellar cortex and folia alteration.