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Developmental Diseases of the Nervous System
Published in Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw, Hankey's Clinical Neurology, 2020
James H. Tonsgard, Nikolas Mata-Machado
Formation of the mature nervous system is dependent on the induction or formation of precursor cells, followed by the proliferation and maturation of cells within periventricular germinal centers and finally, migration to their intended sites. A cross section of the developing brain shows that it is initially organized into an outer pial (preplate) or marginal zone (MZ) and inner ventricular zone (VZ) (Figure 9.4a). Stem cells proliferate and differentiate into immature neurons and glial precursors within the VZ and subventricular zone (SVZ). Starting in the seventh fetal week, neuroblasts in the VZ migrate upward to form a subpial preplate zone (PP). Subsequently, neurons migrate into the PP (Figure 9.4c1). These neurons divide, with some forming the superficial molecular layer or MZ (layer I) and others moving to the deep subplate. Thereafter, waves of neurons pass through the subplate, successively forming layers VI, V, IV, III, and II in an inside-out pattern, with the last neurons moving into layer II (Figure 9.4b, c3).
The nervous system and the eye
Published in C. Simon Herrington, Muir's Textbook of Pathology, 2020
James A.R. Nicoll, William Stewart, Fiona Roberts
Central chromatolysis occurs between 5 and 8 days after transection, and is characterized by swelling of the cell body and displacement of the nucleus to the periphery of the cell. The cytoplasm becomes pale and homogeneous and there is dispersion of the Nissl substance – chromatolysis – accompanied by increased synthesis of RNA and protein. This reaction occurs in central and peripheral neurons, but particularly the latter. It may be followed by recovery with or without axonal regeneration, or may proceed to degeneration and ultimate death of the neuron. Effective regeneration is limited to the peripheral nervous system (PNS). In contrast, those neurons with projections lying entirely within the CNS tend to undergo retrograde degeneration and die. However, there is evidence of continuing neurogenesis from a population of stem cells residing in the subventricular zone of the basal ganglia and hippocampi.
Role of Herbs and Their Delivery Through Nanofibers in Pharmacotherapy of Depression
Published in Anne George, Snigdha S. Babu, M. P. Ajithkumar, Sabu Thomas, Holistic Healthcare. Volume 2: Possibilities and Challenges, 2019
Ginpreet Kaur, Mihir Invally, Hiral Mistry, Parnika Dicholkar, Sukhwinder Bhullar
In humans, there are two zones subventricular zone and subgranular zone, an area in brain (hippocampus) is responsible for learning and memory.11,12 Due to aging, there is reduction of postsynaptic density in hippocampus resulting in a decrease in long-term potentiation (LTP) and increase in long-term depression which results in major depression.13,14 SSRIs (selective serotonin reuptake inhibitors) or atypical antidepressants (venlafaxine) in chronic treatment are found to be more beneficial than tricyclic antidepressants (TCAs) because they prevent stress induced LTP.15,16 In hippocampus and Cornu Ammonis pyramidal cells, cellular plasticity increases due to SSRIs (fluoxetine), while this neuroplastic activity is decreased by TCA due to its anticholinergic activity.17-19
Metabolomics reveals the effects of hydroxysafflor yellow A on neurogenesis and axon regeneration after experimental traumatic brain injury
Published in Pharmaceutical Biology, 2023
En Hu, Teng Li, Zhilin Li, Hong Su, Qiuju Yan, Lei Wang, Haigang Li, Wei Zhang, Tao Tang, Yang Wang
Neurogenesis and axon regeneration are the main processes in neural restoration (Chen et al. 2014; Zhang, Bogdanova, et al. 2014; Zhang, Yu, et al. 2014). Neurogenesis supplements the lost neurons (Chen et al. 2014). Axon regeneration can re-establish the communicating network in the injured brain (Zhang, Bogdanova, et al. 2014; Zhang, Yu, et al. 2014). They aid functional reconstruction following TBI (He et al. 2020; Redell et al. 2020). However, the intrinsic extents of neurogenesis and axon regeneration need to be improved for overall functional improvement after TBI (Jarrahi et al. 2020). In the adult mammal brain, the mature neuron cannot proliferate, and neurogenesis is restricted to the subventricular zone and the subgranular zone of the hippocampus (Redell et al. 2020). Axon regeneration in the adult central nervous system (CNS) is also limited, even following the injury stimuli (Ribas et al. 2021). Thus, it is valuable to strengthen neurogenesis and axon regeneration for TBI recovery.
A role for flavonoids in the prevention and/or treatment of cognitive dysfunction, learning, and memory deficits: a review of preclinical and clinical studies
Published in Nutritional Neuroscience, 2023
Matin Ramezani, Arman Zeinaddini Meymand, Fariba Khodagholi, Hamed Mohammadi Kamsorkh, Ehsan Asadi, Mitra Noori, Kimia Rahimian, Ali Saberi Shahrbabaki, Aisa Talebi, Hanieh Parsaiyan, Sepideh Shiravand, Niloufar Darbandi
Accumulating research has provided clear evidence of neurogenesis in subgranular zone (SGZ) and subventricular zone (SVZ). At the SVZ, neural stem cells (NSCs) travel to the rostral migratory stream and differentiate into interneurons in the olfactory bulb. NSCs located in the SGZ give rise to granular neurons that integrate into functional circuits in the hippocampus [36,37]. By activation of neurogenesis, flavonoids such as luteolin [38] and spinosin [39] can have beneficial effects on learning and memory function. Intraperitoneal administration of luteolin in the Ts65Dn mouse model with Down syndrome enhanced hippocampal cell proliferation and neurogenesis and improved cognition, learning and memory [Morris water maze (MWM) and Novel object recognition tasks] [38]. Spinosin administration in male ICR mice promoted the proliferation of NSCs and the survival and differentiation of newborn neurons in the hippocampal DG region and also improved cognitive performance (passive avoidance task) compared with vehicle mice [39].
Response of murine neural stem/progenitor cells to gamma-neutron radiation
Published in International Journal of Radiation Biology, 2022
Galina A. Posypanova, Marya G. Ratushnyak, Yuliya P. Semochkina, Alexander N. Strepetov
The main neurogenic zones of the mammalian brain are the subventricular zone of the lateral ventricles and the dentate gyrus of the hippocampus (Ming and Song 2011). These are the areas of the brain where NSCs were first discovered (Eriksson et al. 1998; Louis et al. 2008). NSCs are characterized as undifferentiated cells capable of unlimited proliferation and self-renewal and possessing multipotency—the ability to generate neurons, astrocytes, and oligodendrocytes. A division of an NSC can either produce two NSCs or give rise to neural progenitor cells (NPCs) capable of proliferation and self-renewal. In recent years, strong evidence has emerged that the NPC population is heterogeneous. Various researchers distinguish from 3 to 8 subpopulations of NPCs possessing pluripotency, bipotency, or unipotency (Codega et al. 2014; Mich et al. 2014; Buono et al. 2015). Each of these populations is characterized by a specific combination of markers. Currently, there is no consensus as to which combination of antigens most specifically characterizes NSCs. Most often, NSCs are defined as nestin+/GFAP+ cells (Fukuda et al. 2003), nestin+/CD133+ cells (Coskun et al. 2008), CD133+/GFAP+/EGFR+ cells (Codega et al. 2014), CD133+/LeX+/NG2ˉ/CD140aˉ cells (Buono et al. 2015).