China
Africa
Explore chapters and articles related to this topic
Principles of neuromotor development
Published in Mijna Hadders-Algra, Kirsten R. Heineman, The Infant Motor Profile, 2021
Mijna Hadders-Algra, Kirsten R. Heineman
The development of the cerebellum has its own timing. Cells in the cerebellum originate from two proliferative zones: (1) the ventricular zone which brings forth the deep cerebellar nuclei and the Purkinje cells, and (2) the external granular layer originating from the rhombic lip (Volpe 2009b). Cell proliferation in the cerebellum starts at 11 weeks PMA in the ventricular zone and at 15 weeks in the external granular layer. The external granular layer is a transient structure reaching its peak thickness between 28 and 34 weeks PMA. It produces the most numerous cells of the cerebellum, the granule cells. These cells migrate from the external granular layer inward to their final destination in the internal granular layer. The latter grows most prominently between mid-gestation and three months post-term. The external granular layer shrinks, in particular between two and three months post-term. However, it takes until the second half of the first postnatal year for the external granular layer to dissolve entirely (Hadders-Algra 2018a).
General Synonyms
Published in Terence R. Anthoney, Neuroanatomy and the Neurologic Exam, 2017
For labelling layers of cortex. 1a. inner granular layer (M&M, p. 57 [Fig. 27])1b. internal granular layer (B&K, p. 224)2a. inner pyramidal layer (M&M, p. 57 [Fig. 27])2b. internal pyramidal layer (B&K, p. 224)
Gangliocytoma and Lhermitte–Duclos Disease
Published in Dongyou Liu, Tumors and Cancers, 2017
LDD (dysplastic cerebellar gangliocytoma) is a rare, benign lesion (WHO Grade I) that is confined to the cerebellum. LLD is characterized by enlarged cerebellar folia with striking “inverted” architecture and replacement of the internal granular layer by dysplastic ganglion cells. Intermediate zones between the normal and abnormal cerebellar tissues display gradual transitions of large dysplastic cells replacing the small granule cells. Dysplastic areas contain rich vascularization and numerous interstitial vacuoles. Associated with Cowden syndrome, LDD demonstrates very low proliferative activity, although progression to malignant and other benign tumors such as anaplastic ganglioglioma and dysembryoplastic neuroepithelial tumor has been reported in a few cases [2,3].
Effects of pyrethroids on the cerebellum and related mechanisms: a narrative review
Published in Critical Reviews in Toxicology, 2023
Fei Hao, Ye Bu, Shasha Huang, Wanqi Li, Huiwen Feng, Yuan Wang
There is some debate as to whether DM has an effect on the morphogenesis of the molecular layer or the Purkinje cell layer. Patro and Patro (2005) conducted the first morphological study on the effects of DM on the developing cerebellum in 2005. In that study, the administration of 0.7 mg/kg DM to rats for five consecutive days on their ninth postnatal day (PD) had an impact on cerebellar layer morphogenesis. However, the effect was temporary and was observed up to PD21 but not on PD30. It is worth mentioning that the difference in measured body weight in that study was large, but there was no weight change after DM exposure in the 2010 study. Asari et al. (2010) revealed that neonatal administration of 1 mg/kg DM had no effect on morphogenesis and thickness of the cerebellar external granular layer or internal granular layer. The study suggested that the current dosage of DM did not significantly affect granule cell migration or proliferation. Similarly, DM had no influence on morphogenesis in the molecular layer or purkinje cell layer.
Glycyrrhizic acid and silymarin alleviate the neurotoxic effects of aluminum in rats challenged with fructose-induced insulin resistance: possible role of toll-like receptor 4 pathway
Published in Drug and Chemical Toxicology, 2019
Noura M. Ali, Amr A. A. Mahmoud, Mona F. Mahmoud, Hassan M. El Fayoumi
Normal rats showed normal pia mater containing blood vessels followed by the molecular layer, external granular layer, external pyramidal layer, and internal granular layer (Figure 6(a)). In addition, they showed normal pyramidal cells (Figure 6(b)). On the other hand, FR-treated rats showed dilated and congested blood vessels as well as multiple shrunken pyramidal cells surrounded by empty spaces (Figure 6(c,d)). Rats treated with AL showed also dilated and congested blood vessel as well as marked mononuclear cellular infiltration, shrunken pyramidal cells surrounded by empty spaces, and many apoptotic cells having small darkly stained nuclei (Figure 6(e,f)). In a similar way, FRAL-treated rats showed markedly dilated and congested blood vessels, along with marked mononuclear cellular infiltration in the molecular and external granular layers, shrunken pyramidal cells surrounded by empty spaces, and many apoptotic cells (Figure 6(g,h)). Cerebral cortex sections from rats that received GAM showed normal pyramidal cells with only few dilated and congested blood vessels (Figure 6(i,j)). SLY-treated rats had dilated and congested blood vessel as well as marked mononuclear cellular infiltration, multiple shrunken pyramidal cells and large area of hemorrhage (Figure 6(k,l)).
The possible protective effect of N-acetyl-L-cysteine and folic acid in combination against aspartame-induced cerebral cortex neurotoxicity in adult male rats: a light and transmission electron microscopic study
Published in Ultrastructural Pathology, 2018
Hala F. Abd-Ellah, Nadia R. A. Abou-Zeid, Nadia M. Nasr
By light microscopy, using H&E-stained sections, the cerebral cortices of group I (control rats) and group II (rats treated with NAC+FA) are similar and showed their well-known normal general histological architecture. The cerebral cortex is covered by pia matter and is formed of six layers from outside inwards. These layers are the outer molecular layer, external granular layer, external pyramidal layer, internal granular layer, internal pyramidal layer and finally the multiform layer (Figure 1(a)). The common cells inside these layers are the nerve cells (especially pyramidal cells) and granule cells, in addition to neuroglial cells (Figure 1(a,b)). The nerve cells have large rounded vesicular nuclei, basophilic cytoplasm, and processes (Figure 1(b)). Granule cells appear with open face vesicular nuclei and prominent nucleoli (Figure 1(b)). The pink-stained background; the neuropil, contains nerve fibers, scattered small-sized neuroglial cells, and blood vessels (Figure 1(a,b)).