scholarly journals Broadening the functional and evolutionary understanding of postnatal neurogenesis using reptilian models

2020 ◽  
Vol 223 (15) ◽  
pp. jeb210542
Author(s):  
Lara D. LaDage
Keyword(s):  
Adult Neurogenesis ◽  
Brain Plasticity ◽  
Adult Brain ◽  
Postnatal Neurogenesis ◽  
Late 20Th Century ◽  
Neural Processes ◽  
Wide Range ◽  
Evolutionary Context ◽  
Similarities And Differences ◽  
Taxonomic Groups

ABSTRACTThe production of new neurons in the brains of adult animals was first identified by Altman and Das in 1965, but it was not until the late 20th century when methods for visualizing new neuron production improved that there was a dramatic increase in research on neurogenesis in the adult brain. We now know that adult neurogenesis is a ubiquitous process that occurs across a wide range of taxonomic groups. This process has largely been studied in mammals; however, there are notable differences between mammals and other taxonomic groups in how, why and where new neuron production occurs. This Review will begin by describing the processes of adult neurogenesis in reptiles and identifying the similarities and differences in these processes between reptiles and model rodent species. Further, this Review underscores the importance of appreciating how wild-caught animals vary in neurogenic properties compared with laboratory-reared animals and how this can be used to broaden the functional and evolutionary understanding of why and how new neurons are produced in the adult brain. Studying variation in neural processes across taxonomic groups provides an evolutionary context to adult neurogenesis while also advancing our overall understanding of neurogenesis and brain plasticity.

scholarly journals Cellular Mechanisms Participating in Brain Repair of Adult Zebrafish and Mammals After Injury

2020 ◽  
Author(s):  
Batoul Ghaddar ◽  
Luisa Lübke ◽  
David COURET ◽  
Sepand Rastegar ◽  
Nicolas Diotel
Keyword(s):  
Stem Cells ◽  
Adult Neurogenesis ◽  
Brain Plasticity ◽  
Adult Zebrafish ◽  
Cellular Mechanisms ◽  
Regenerative Capacity ◽  
Brain Repair ◽  
Cellular Events ◽  
Similarities And Differences ◽  
The Brain

Adult neurogenesis is an evolutionary conserved process occurring in all vertebrates. However, striking differences are observed between the taxa, considering the number of neurogenic niches, the neural stem cell (NSC) identity and brain plasticity under constitutive and injury-induced conditions. Zebrafish has become a popular model for the investigation of the molecular and cellular mechanisms involved in adult neurogenesis. Compared to mammals, the adult zebrafish displays a high number of neurogenic niches distributed throughout the brain. Furthermore, it exhibits a strong regenerative capacity without scar formation or any obvious disabilities. In this review, we will first discuss the similarities and differences regarding (i) the distribution of neurogenic niches in the brain of adult zebrafish and mammals (mainly mouse) and (ii) the nature of the neural stem cells within the main telencephalic niches. In the second part, we will describe the cascade of cellular events occurring after telencephalic injury in zebrafish and mouse. Our study clearly shows that most early events happening right after the brain injury are shared between zebrafish and mouse including cell death, microglia and oligodendrocyte recruitment, as well as injury-induced neurogenesis. In mammals one of the consequences following an injury is the formation of a glial scar that is persistent. This is not the case in zebrafish, which may be one of the main reasons that zebrafish display a higher regenerative capacity.

scholarly journals Focus Groups

Communication ◽  
2017 ◽  
Author(s):  
Kim Hoffman ◽  
Javier Ponce-Terashima
Keyword(s):  
Social Sciences ◽  
Focus Groups ◽  
Research Method ◽  
Qualitative Method ◽  
Qualitative Data ◽  
Late 20Th Century ◽  
Body Of Knowledge ◽  
The Social ◽  
Wide Range ◽  
Similarities And Differences

Focus groups are a research method using multi-person interviews to generate qualitative data from participants’ interaction. The purpose is to induce conversation between participants to answer questions relevant to the study goals. In contrast to one-on-one interviews that are also widely used in qualitative research, the source of the data is in the “interaction” between participants, including similarities and differences between their experiences, opinions, and perceptions. This helps researchers understand not just what the participants think about a topic, but also why they think that way. Focus groups can cover a wide range of topics that are skillfully “moderated” by the researcher. The earliest known focus groups can be traced to Bogardus in 1926 and Robert Merton and Paul Lazarsfeld in 1941 but did not take hold as a qualitative method in the social sciences for another twenty-five years. Since then, a significant body of knowledge has been created; since the late 20th century, more than twenty-five thousand peer-reviewed, published articles using focus groups have been published. This article will focus on uses within the realm of published scholarly research although focus groups are routinely used within the field of market and consumer research, and additional gray literature may be found in other sources.

scholarly journals The PSA-NCAM-Positive “Immature” Neurons: An Old Discovery Providing New Vistas on Brain Structural Plasticity

Cells ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2542
Author(s):  
Luca Bonfanti ◽  
Tatsunori Seki
Keyword(s):  
Adult Neurogenesis ◽  
Brain Plasticity ◽  
Mammalian Brain ◽  
Biological Processes ◽  
Wide Range ◽  
Immature Neurons ◽  
Large Populations ◽  
Long Time ◽  
History Of ◽  
Synaptic Changes

Studies on brain plasticity have undertaken different roads, tackling a wide range of biological processes: from small synaptic changes affecting the contacts among neurons at the very tip of their processes, to birth, differentiation, and integration of new neurons (adult neurogenesis). Stem cell-driven adult neurogenesis is an exception in the substantially static mammalian brain, yet, it has dominated the research in neurodevelopmental biology during the last thirty years. Studies of comparative neuroplasticity have revealed that neurogenic processes are reduced in large-brained mammals, including humans. On the other hand, large-brained mammals, with respect to rodents, host large populations of special “immature” neurons that are generated prenatally but express immature markers in adulthood. The history of these “immature” neurons started from studies on adhesion molecules carried out at the beginning of the nineties. The identity of these neurons as “stand by” cells “frozen” in a state of immaturity remained un-detected for long time, because of their ill-defined features and because clouded by research ef-forts focused on adult neurogenesis. In this review article, the history of these cells will be reconstructed, and a series of nuances and confounding factors that have hindered the distinction between newly generated and “immature” neurons will be addressed.

scholarly journals Proliferation, neurogenesis and regeneration in the non-mammalian vertebrate brain

2007 ◽  
Vol 363 (1489) ◽  
pp. 101-122 ◽  
Author(s):  
Jan Kaslin ◽  
Julia Ganz ◽  
Michael Brand
Keyword(s):  
Olfactory Bulb ◽  
Adult Neurogenesis ◽  
Brain Plasticity ◽  
Brain Regions ◽  
Adult Brain ◽  
Mammalian Brain ◽  
Embryonic Neurogenesis ◽  
Vertebrate Brain ◽  
Multipotent Progenitor Cells

Post-embryonic neurogenesis is a fundamental feature of the vertebrate brain. However, the level of adult neurogenesis decreases significantly with phylogeny. In the first part of this review, a comparative analysis of adult neurogenesis and its putative roles in vertebrates are discussed. Adult neurogenesis in mammals is restricted to two telencephalic constitutively active zones. On the contrary, non-mammalian vertebrates display a considerable amount of adult neurogenesis in many brain regions. The phylogenetic differences in adult neurogenesis are poorly understood. However, a common feature of vertebrates (fish, amphibians and reptiles) that display a widespread adult neurogenesis is the substantial post-embryonic brain growth in contrast to birds and mammals. It is probable that the adult neurogenesis in fish, frogs and reptiles is related to the coordinated growth of sensory systems and corresponding sensory brain regions. Likewise, neurons are substantially added to the olfactory bulb in smell-oriented mammals in contrast to more visually oriented primates and songbirds, where much fewer neurons are added to the olfactory bulb. The second part of this review focuses on the differences in brain plasticity and regeneration in vertebrates. Interestingly, several recent studies show that neurogenesis is suppressed in the adult mammalian brain. In mammals, neurogenesis can be induced in the constitutively neurogenic brain regions as well as ectopically in response to injury, disease or experimental manipulations. Furthermore, multipotent progenitor cells can be isolated and differentiated in vitro from several otherwise silent regions of the mammalian brain. This indicates that the potential to recruit or generate neurons in non-neurogenic brain areas is not completely lost in mammals. The level of adult neurogenesis in vertebrates correlates with the capacity to regenerate injury, for example fish and amphibians exhibit the most widespread adult neurogenesis and also the greatest capacity to regenerate central nervous system injuries. Studying these phenomena in non-mammalian vertebrates may greatly increase our understanding of the mechanisms underlying regeneration and adult neurogenesis. Understanding mechanisms that regulate endogenous proliferation and neurogenic permissiveness in the adult brain is of great significance in therapeutical approaches for brain injury and disease.

scholarly journals Cellular Mechanisms Participating in Brain Repair of Adult Zebrafish and Mammals after Injury

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 391
Author(s):  
Batoul Ghaddar ◽  
Luisa Lübke ◽  
David Couret ◽  
Sepand Rastegar ◽  
Nicolas Diotel
Keyword(s):  
Stem Cells ◽  
Adult Neurogenesis ◽  
Brain Plasticity ◽  
Adult Zebrafish ◽  
Cellular Mechanisms ◽  
Regenerative Capacity ◽  
Brain Repair ◽  
Cellular Events ◽  
Similarities And Differences ◽  
The Brain

Adult neurogenesis is an evolutionary conserved process occurring in all vertebrates. However, striking differences are observed between the taxa, considering the number of neurogenic niches, the neural stem cell (NSC) identity, and brain plasticity under constitutive and injury-induced conditions. Zebrafish has become a popular model for the investigation of the molecular and cellular mechanisms involved in adult neurogenesis. Compared to mammals, the adult zebrafish displays a high number of neurogenic niches distributed throughout the brain. Furthermore, it exhibits a strong regenerative capacity without scar formation or any obvious disabilities. In this review, we will first discuss the similarities and differences regarding (i) the distribution of neurogenic niches in the brain of adult zebrafish and mammals (mainly mouse) and (ii) the nature of the neural stem cells within the main telencephalic niches. In the second part, we will describe the cascade of cellular events occurring after telencephalic injury in zebrafish and mouse. Our study clearly shows that most early events happening right after the brain injury are shared between zebrafish and mouse including cell death, microglia, and oligodendrocyte recruitment, as well as injury-induced neurogenesis. In mammals, one of the consequences following an injury is the formation of a glial scar that is persistent. This is not the case in zebrafish, which may be one of the main reasons that zebrafish display a higher regenerative capacity.

Adult Neurogenesis: From Precursors to Network and Physiology

2005 ◽  
Vol 85 (2) ◽  
pp. 523-569 ◽  
Author(s):  
Djoher Nora Abrous ◽  
Muriel Koehl ◽  
Michel Le Moal
Keyword(s):  
Adult Neurogenesis ◽  
Brain Plasticity ◽  
Current Knowledge ◽  
Hippocampal Formation ◽  
Functional Integration ◽  
Brain Regions ◽  
Biological Properties ◽  
Adult Brain ◽  
Mammalian Brain ◽  
Extrinsic Factors

The discovery that the adult mammalian brain creates new neurons from pools of stemlike cells was a breakthrough in neuroscience. Interestingly, this particular new form of structural brain plasticity seems specific to discrete brain regions, and most investigations concern the subventricular zone (SVZ) and the dentate gyrus (DG) of the hippocampal formation (HF). Overall, two main lines of research have emerged over the last two decades: the first aims to understand the fundamental biological properties of neural stemlike cells (and their progeny) and the integration of the newly born neurons into preexisting networks, while the second focuses on understanding its relevance in brain functioning, which has been more extensively approached in the DG. Here, we propose an overview of the current knowledge on adult neurogenesis and its functional relevance for the adult brain. We first present an analysis of the methodological issues that have hampered progress in this field and describe the main neurogenic sites with their specificities. We will see that despite considerable progress, the levels of anatomic and functional integration of the newly born neurons within the host circuitry have yet to be elucidated. Then the intracellular mechanisms controlling neuronal fate are presented briefly, along with the extrinsic factors that regulate adult neurogenesis. We will see that a growing list of epigenetic factors that display a specificity of action depending on the neurogenic site under consideration has been identified. Finally, we review the progress accomplished in implicating neurogenesis in hippocampal functioning under physiological conditions and in the development of hippocampal-related pathologies such as epilepsy, mood disorders, and addiction. This constitutes a necessary step in promoting the development of therapeutic strategies.

ADULT NEUROGENESIS: ALTERATIONS WITH AGING AND ALZHEIMER’S DISEASE DEVELOPMENT

2021 ◽  
pp. 1080-1087
Author(s):  
А. О. Бурняшева ◽  
Н. А. Стефанова ◽  
Е. А. Рудницкая
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Adult Neurogenesis ◽  
Neurodegenerative Disorder ◽  
Brain Plasticity ◽  
The Elderly ◽  
Adult Brain ◽  
Molecular Control ◽  
Neurogenic Niche ◽  
Age Related

Нейрогенез в головном мозге взрослого организма - один из важнейших механизмов пластичности, который проявляется увеличением числа клеток, участвующих в структурной перестройке нейрональных сетей и формированием синапсов, и способствует увеличению функциональных возможностей головного мозга. С возрастом и при развитии нейродегенеративных расстройств происходит нарушение микроокружения нейрогенной ниши, ослабление контроля и, как следствие, значительное снижение нейрогенеза, что, в свою очередь, может способствовать ухудшению когнитивных способностей и развитию деменции. Наиболее распространённой сенильной деменцией является болезнь Альцгеймера - неизлечимое заболевание нейродегенеративной природы, при котором одними из первых поражаются гиппокамп и энторинальная кора - ключевые нейрогенные ниши зрелого головного мозга, что приводит к нарушению нейрогенеза и способствует дальнейшей прогрессии дегенеративных процессов. На сегодняшний день механизмы, лежащие в основе сопровождающих развитие болезни Альцгеймера изменений нейрогенеза, остаются до конца неясными и являются предметом интенсивного изучения исследователей во всём мире как потенциальная мишень для коррекции патологических изменений. Adult neurogenesis is one of the key mechanisms of the brain plasticity. Increase in the number of cells participating in the rearrangement of the neuronal circuits and synaptic formation facilitates the increase of brain’s functional capacity. However, aging as well as neurodegenerative disorders lead to the disruption of the neurogenic niche microenvironment and the loss of molecular control, which in turn results in the significant decline of the neurogenesis. These events may contribute to the cognitive decline and the consequent development of dementia. Alzheimer’s disease is a progressive incurable age-related neurodegenerative disorder in the elderly and the most prevalent cause of dementia. Hippocampus and entorhinal cortex are the key neurogenic niches in the adult brain and one of the most vulnerable brain areas during the development of Alzheimer’s disease. Thus, neurodegeneration associated with the development of Alzheimer’s disease affects adult neurogenesis. However, to date the mechanisms underlying this connection are unclear, and the investigation of these mechanisms is a promising strategy to find the approaches to correct the Alzheimer’s disease pathology.

scholarly journals Adult Neurogenesis in the Drosophila Brain: The Evidence and the Void

2020 ◽  
Vol 21 (18) ◽  
pp. 6653
Author(s):  
Guiyi Li ◽  
Alicia Hidalgo
Keyword(s):  
Adult Neurogenesis ◽  
Genetic Manipulation ◽  
Brain Plasticity ◽  
Fruit Fly ◽  
Cell Number ◽  
Adult Brain ◽  
Proliferating Cells ◽  
Drosophila Brain ◽  
The Central Nervous System ◽  
The Brain

Establishing the existence and extent of neurogenesis in the adult brain throughout the animals including humans, would transform our understanding of how the brain works, and how to tackle brain damage and disease. Obtaining convincing, indisputable experimental evidence has generally been challenging. Here, we revise the state of this question in the fruit-fly Drosophila. The developmental neuroblasts that make the central nervous system and brain are eliminated, either through apoptosis or cell cycle exit, before the adult fly ecloses. Despite this, there is growing evidence that cell proliferation can take place in the adult brain. This occurs preferentially at, but not restricted to, a critical period. Adult proliferating cells can give rise to both glial cells and neurons. Neuronal activity, injury and genetic manipulation in the adult can increase the incidence of both gliogenesis and neurogenesis, and cell number. Most likely, adult glio- and neuro-genesis promote structural brain plasticity and homeostasis. However, a definitive visualisation of mitosis in the adult brain is still lacking, and the elusive adult progenitor cells are yet to be identified. Resolving these voids is important for the fundamental understanding of any brain. Given its powerful genetics, Drosophila can expedite discovery into mammalian adult neurogenesis in the healthy and diseased brain.

Role of melatonin in regulating neurogenesis: Implications for the neurodegenerative pathology and analogous therapeutics for Alzheimer’s disease

2020 ◽  
Vol 3 (2) ◽  
pp. 216-242 ◽  
Author(s):  
Mayuri Shukla ◽  
Areechun Sotthibundhu ◽  
Piyarat Govitrapong
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Adult Neurogenesis ◽  
Adult Brain ◽  
Therapeutic Approaches ◽  
Therapeutic Implications ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
Progenitor Cell Proliferation

The revelation of adult brain exhibiting neurogenesis has established that the brain possesses great plasticity and that neurons could be spawned in the neurogenic zones where hippocampal adult neurogenesis attributes to learning and memory processes. With strong implications in brain functional homeostasis, aging and cognition, various aspects of adult neurogenesis reveal exuberant mechanistic associations thereby further aiding in facilitating the therapeutic approaches regarding the development of neurodegenerative processes in Alzheimer’s Disease (AD). Impaired neurogenesis has been significantly evident in AD with compromised hippocampal function and cognitive deficits. Melatonin the pineal indolamine augments neurogenesis and has been linked to AD development as its levels are compromised with disease progression. Here, in this review, we discuss and appraise the mechanisms via which melatonin regulates neurogenesis in pathophysiological conditions which would unravel the molecular basis in such conditions and its role in endogenous brain repair. Also, its components as key regulators of neural stem and progenitor cell proliferation and differentiation in the embryonic and adult brain would aid in accentuating the therapeutic implications of this indoleamine in line of prevention and treatment of AD.   

scholarly journals Early Consumption of Cannabinoids: From Adult Neurogenesis to Behavior

2021 ◽  
Vol 22 (14) ◽  
pp. 7450
Author(s):  
Citlalli Netzahualcoyotzi ◽  
Luis Miguel Rodríguez-Serrano ◽  
María Elena Chávez-Hernández ◽  
Mario Humberto Buenrostro-Jáuregui
Keyword(s):  
Young Adulthood ◽  
Adult Neurogenesis ◽  
Critical Period ◽  
Consumption Rate ◽  
Behavioral Outcomes ◽  
Endocannabinoid System ◽  
Illegal Drug ◽  
Adult Brain ◽  
As Stress

The endocannabinoid system (ECS) is a crucial modulatory system in which interest has been increasing, particularly regarding the regulation of behavior and neuroplasticity. The adolescent–young adulthood phase of development comprises a critical period in the maturation of the nervous system and the ECS. Neurogenesis occurs in discrete regions of the adult brain, and this process is linked to the modulation of some behaviors. Since marijuana (cannabis) is the most consumed illegal drug globally and the highest consumption rate is observed during adolescence, it is of particular importance to understand the effects of ECS modulation in these early stages of adulthood. Thus, in this article, we sought to summarize recent evidence demonstrating the role of the ECS and exogenous cannabinoid consumption in the adolescent–young adulthood period; elucidate the effects of exogenous cannabinoid consumption on adult neurogenesis; and describe some essential and adaptive behaviors, such as stress, anxiety, learning, and memory. The data summarized in this work highlight the relevance of maintaining balance in the endocannabinoid modulatory system in the early and adult stages of life. Any ECS disturbance may induce significant modifications in the genesis of new neurons and may consequently modify behavioral outcomes.

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