Cajal-Retzius cells.

摘要: What is a Cajal-Retzius cell? A transient class of neurons found in the surface developing cerebral cortex mammals. They are named after Santiago Ramon y Cajal and Gustaf Retzius, who first described them at end 19th century. These ‘special cells’, as initially called them, populate marginal zone from early stages development (Figure 1Figure 1), thus have strategic position to influence its organization. cells peculiar morphology with distinctive horizontal dendrites, they release neurotransmitter glutamate. Most eliminated through cell death during postnatal stages.Why important? In contrast most neurons, not known for their role information processing, but rather job ‘project managers’ construction cortex. organization by releasing signals that affect underlying neurons. One these Reelin, an extracellular glycoprotein required normal lamination The absence Reelin or other molecules signaling pathway result severe disruption laminar cortex.Where do come from? Although it was thought originate precursor throughout cortex, actually emerge focal sources located borders pallium (a more general name cortex). main source cortical hem, which caudomedial region pallium, close hippocampal primordium. Other pallial septum ventral pallium. simultaneous production several sites may guarantee complete coverage all regions cortex.Figure 1Distribution embryonic development.(A) — identified here expression mRNA entire this dorsal view E12.5 mouse brain. dotted line indicates midline, rostral left. (B) detail zone, migrate (in red, stained antibodies against calcium binding protein Calretinin). Some also express GFP image. arrowheads point growth cones tipping leading process. Scale bars equal 200 μm (A) 50 (B).View Large Image | View Hi-Res Download PowerPoint SlideAre equal? generated different differ neurochemical content, suggests classes exist. As result, relative contributions each complement vary areas. words, even though up homogenously distributed area contains proportion types cells. This observation has led hypothesis released distinct patterning.How reach final position? Because born restricted locations, must disperse tangentially cover 1). migration seems be highly dependent meninges, system membranes envelopes (e.g. chemokines) promote movement cortex.What happens if screw up? might expected building abnormal generation catastrophic effects: neocortex hippocampus gets completely messed up, numbers. humans, decreased been associated lissencephaly, autism, schizophrenia bipolar disorder.Are unique mammals? seem present reptiles birds, although relatively sparse compared why non-mammalian vertebrates mostly devoid (laminar) structures telencephalon. number morphological intricacy increase parallel complexity neocortex, expanded mammals reaches peak humans.