scholarly journals Newly Generated and Non-Newly Generated “Immature” Neurons in the Mammalian Brain: A Possible Reservoir of Young Cells to Prevent Brain Aging and Disease?

2019 ◽  
Vol 8 (5) ◽  
pp. 685 ◽  
Author(s):  
Chiara La Rosa ◽  
Marco Ghibaudi ◽  
Luca Bonfanti
Keyword(s):  
Neurological Disorders ◽  
Brain Aging ◽  
Brain Plasticity ◽  
Brain Regions ◽  
Mammalian Brain ◽  
Brain Health ◽  
Immature Neurons ◽  
Potential Reservoir ◽  
The Impact ◽  
Stem Cell Niches

Brain plasticity is important for translational purposes since most neurological disorders and brain aging problems remain substantially incurable. In the mammalian nervous system, neurons are mostly not renewed throughout life and cannot be replaced. In humans, the increasing life expectancy explains the increase in brain health problems, also producing heavy social and economic burden. An exception to the “static” brain is represented by stem cell niches leading to the production of new neurons. Such adult neurogenesis is dramatically reduced from fish to mammals, and in large-brained mammals with respect to rodents. Some examples of neurogenesis occurring outside the neurogenic niches have been reported, yet these new neurons actually do not integrate in the mature nervous tissue. Non-newly generated, “immature” neurons (nng-INs) are also present: Prenatally generated cells continuing to express molecules of immaturity (mostly shared with the newly born neurons). Of interest, nng-INs seem to show an inverse phylogenetic trend across mammals, being abundant in higher-order brain regions not served by neurogenesis and providing structural plasticity in rather stable areas. Both newly generated and nng-INs represent a potential reservoir of young cells (a “brain reserve”) that might be exploited for preventing the damage of aging and/or delay the onset/reduce the impact of neurological disorders.

scholarly journals Critical period regulation across multiple timescales

2020 ◽  
Vol 117 (38) ◽  
pp. 23242-23251 ◽  
Author(s):  
Rebecca K. Reh ◽  
Brian G. Dias ◽  
Charles A. Nelson ◽  
Daniela Kaufer ◽  
Janet F. Werker ◽  
...  
Keyword(s):  
Critical Period ◽  
Brain Plasticity ◽  
Gamma Oscillations ◽  
Developmental Time ◽  
Brain Regions ◽  
Inhibitory Neurons ◽  
Critical Periods ◽  
Multiple Timescales ◽  
Fast Spiking ◽  
The Impact

Brain plasticity is dynamically regulated across the life span, peaking during windows of early life. Typically assessed in the physiological range of milliseconds (real time), these trajectories are also influenced on the longer timescales of developmental time (nurture) and evolutionary time (nature), which shape neural architectures that support plasticity. Properly sequenced critical periods of circuit refinement build up complex cognitive functions, such as language, from more primary modalities. Here, we consider recent progress in the biological basis of critical periods as a unifying rubric for understanding plasticity across multiple timescales. Notably, the maturation of parvalbumin-positive (PV) inhibitory neurons is pivotal. These fast-spiking cells generate gamma oscillations associated with critical period plasticity, are sensitive to circadian gene manipulation, emerge at different rates across brain regions, acquire perineuronal nets with age, and may be influenced by epigenetic factors over generations. These features provide further novel insight into the impact of early adversity and neurodevelopmental risk factors for mental disorders.

A longitudinal observational population-based study of brain volume associated with changes in sleep timing from middle to late-life

SLEEP ◽  
2020 ◽  
Author(s):  
Regina E Y Kim ◽  
Hyeon Jin Kim ◽  
Soriul Kim ◽  
Robert D Abbott ◽  
Robert J Thomas ◽  
...  
Keyword(s):  
Brain Aging ◽  
Reference Group ◽  
Gray Matter Volume ◽  
Late Life ◽  
Brain Regions ◽  
Population Based ◽  
Longitudinal Changes ◽  
Sleep Timing ◽  
Brain Structure And Function ◽  
The Impact

Abstract Study Objectives Sleep behaviors are related to brain structure and function, but the impact of long-term changes in sleep timing on brain health has not been clearly addressed. The purpose of this study was to examine the association of longitudinal changes in sleep timing from middle to late-life with gray matter volume (GMV), an important marker of brain aging. Methods We enrolled 1798 adults (aged 49–82 years, men 54.6%) who underwent magnetic resonance imaging (MRI) between 2011 and 2014. Midsleep time (MST) on free days corrected for sleep debt on workdays was adopted as a marker of sleep timing. Data on MST were available at the time of MRI assessment and at examinations that were given 9 years earlier (2003–2004). Longitudinal changes in MST over the 9-year period were derived and categorized into quartiles. Subjects in quartile 1 were defined as “advancers” (MST advanced ≥ 1 h) while those in quartile 4 were defined as “delayers” (MST delayed ≥ 0.2 h). Quartiles 2–3 defined a reference group (MST change was considered modest). The relationship of GMV with MST changes over 9 years was investigated. Results Nine-year change in MST were significantly associated with GMV. Compared to the reference group, advancers had smaller GMVs in the frontal and temporal regions. A delay in MST was also associated with smaller cerebellar GMV. Conclusions In middle-to-late adulthood, the direction of change in MST is associated with GMV. While advancers and delayers in MST tend to present lower GMV, associations appear to differ across brain regions.

scholarly journals PSA Depletion Induces the Differentiation of Immature Neurons in the Piriform Cortex of Adult Mice

2021 ◽  
Vol 22 (11) ◽  
pp. 5733
Author(s):  
Simona Coviello ◽  
Bruno Benedetti ◽  
Dominika Jakubecova ◽  
Maria Belles ◽  
Patrycja Klimczak ◽  
...  
Keyword(s):  
Piriform Cortex ◽  
Adult Brain ◽  
Mammalian Brain ◽  
Extrinsic Factors ◽  
Factors Affecting ◽  
Neuronal Markers ◽  
Adult Mice ◽  
Immature Neurons ◽  
Cortical Regions ◽  
The Impact

Immature neurons are maintained in cortical regions of the adult mammalian brain. In rodents, many of these immature neurons can be identified in the piriform cortex based on their high expression of early neuronal markers, such as doublecortin (DCX) and the polysialylated form of the neural cell adhesion molecule (PSA-NCAM). This molecule plays critical roles in different neurodevelopmental events. Taking advantage of a DCX-CreERT2/Flox-EGFP reporter mice, we investigated the impact of targeted PSA enzymatic depletion in the piriform cortex on the fate of immature neurons. We report here that the removal of PSA accelerated the final development of immature neurons. This was revealed by a higher frequency of NeuN expression, an increase in the number of cells carrying an axon initial segment (AIS), and an increase in the number of dendrites and dendritic spines on the immature neurons. Taken together, our results demonstrated the crucial role of the PSA moiety in the protracted development of immature neurons residing outside of the neurogenic niches. More studies will be required to understand the intrinsic and extrinsic factors affecting PSA-NCAM expression to understand how the brain regulates the incorporation of these immature neurons to the established neuronal circuits of the adult brain.

scholarly journals The Exercising Brain: Changes in Functional Connectivity Induced by an Integrated Multimodal Cognitive and Whole-Body Coordination Training

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Traute Demirakca ◽  
Vita Cardinale ◽  
Sven Dehn ◽  
Matthias Ruf ◽  
Gabriele Ende
Keyword(s):  
Functional Connectivity ◽  
Brain Plasticity ◽  
Brain Regions ◽  
Posterior Cingulate Cortex ◽  
Whole Body ◽  
Before And After ◽  
Coordination Training ◽  
Brain Changes ◽  
The Impact ◽  
The Brain

This study investigated the impact of “life kinetik” training on brain plasticity in terms of an increased functional connectivity during resting-state functional magnetic resonance imaging (rs-fMRI). The training is an integrated multimodal training that combines motor and cognitive aspects and challenges the brain by introducing new and unfamiliar coordinative tasks. Twenty-one subjects completed at least 11 one-hour-per-week “life kinetik” training sessions in 13 weeks as well as before and after rs-fMRI scans. Additionally, 11 control subjects with 2 rs-fMRI scans were included. The CONN toolbox was used to conduct several seed-to-voxel analyses. We searched for functional connectivity increases between brain regions expected to be involved in the exercises. Connections to brain regions representing parts of the default mode network, such as medial frontal cortex and posterior cingulate cortex, did not change. Significant connectivity alterations occurred between the visual cortex and parts of the superior parietal area (BA7). Premotor area and cingulate gyrus were also affected. We can conclude that the constant challenge of unfamiliar combinations of coordination tasks, combined with visual perception and working memory demands, seems to induce brain plasticity expressed in enhanced connectivity strength of brain regions due to coactivation.

scholarly journals Beyond Alzheimer’s Disease: Bilingualism and Other Types of Neurodegeneration

2019 ◽  
Author(s):  
Toms Voits ◽  
Christos Pliatsikas ◽  
Holly Robson ◽  
Jason Rothman
Keyword(s):  
Neurodegenerative Disorders ◽  
Brain Structure ◽  
Neurological Disorders ◽  
Brain Regions ◽  
Future Research ◽  
Healthy Children ◽  
Relevant Evidence ◽  
Children And Young Adults ◽  
The Impact ◽  
Ageing Populations

Bilingualism has been argued to have an impact on cognition and brain structure. Such effects have been reported in healthy children and young adults, but also in ageing adults, including clinical ageing populations. For example, bilingualism may significantly contribute to the delaying of the expression of Alzheimer’s dementia symptoms. If bilingualism plays an ameliorative role against neurodegeneration, it is possible that it would have similar effects for other neurodegenerative disorders, including Multiple Sclerosis, Parkinson’s and Huntington’s Diseases; however, relevant evidence remains limited. Herein, we provide a focused literature review on the effects of these progressive neurological disorders on cognition and brain structure, examine how the affected functions and brain regions map to those suggested to be impacted by bilingualism, and report the limited evidence of the impact of bilingualism on these conditions. We then examine the value of making links across neurodegenerative disorders and bilingualism, proposing that available evidence warrants claims for bilingualism- related effects more generally, with an eye at future research to fill in gaps in our understanding.

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 Social reprogramming in ants induces longevity-associated glia remodeling

2019 ◽  
Author(s):  
Lihong Sheng ◽  
Emily J. Shields ◽  
Janko Gospocic ◽  
Karl M. Glastad ◽  
Puttachai Ratchasanmuang ◽  
...  
Keyword(s):  
Social Insects ◽  
Brain Function ◽  
Brain Aging ◽  
Cellular Level ◽  
Brain Health ◽  
Glia Cells ◽  
Single Cell Rna Sequencing ◽  
Extended Lifespan ◽  
The Impact ◽  
Phenotypic State

ABSTRACTHealthy brain aging is of crucial societal importance; however, the mechanisms that regulate it are largely unknown. Social insects are an outstanding model to study the impact of environment and epigenetics on brain function and aging because workers and queens arise from the same genome but display profound differences in behavior and longevity. In Harpegnathos saltator ants, adult workers can transition to a queen-like phenotypic state called gamergate. This caste transition results in reprogramming of social behavior and lifespan extension. Whether these changes in brain function and physiology cause brain remodeling at the cellular level is not known. Using single-cell RNA-sequencing of Harpegnathos brains undergoing caste transition, we uncovered shifts in neuronal and glial populations. In particular, the conversion of workers into long-lived gamergates caused the expansion of ensheathing glia, which maintain brain health by phagocytosing damaged neuronal structures. These glia cells were lost during aging in normal workers but not in longer-lived gamergates. We observed similar caste- and age-associated differences in ensheathing glia in other Hymenoptera as well as Drosophila melanogaster. We propose that enhanced glia-based neuroprotection promotes healthy brain aging and contributes to the extended lifespan of the reproductive caste in social insects.

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.

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.

Musical Anhedonia

2020 ◽  
Vol 31 (2) ◽  
pp. 62-68
Author(s):  
Sara E. Holm ◽  
Alexander Schmidt ◽  
Christoph J. Ploner
Keyword(s):  
Quality Of Life ◽  
Nucleus Accumbens ◽  
Brain Damage ◽  
Parietal Cortex ◽  
Neurological Disorders ◽  
Brain Regions ◽  
Precise Information ◽  
Exact Localization ◽  
High Prevalence

Abstract. Some people, although they are perfectly healthy and happy, cannot enjoy music. These individuals have musical anhedonia, a condition which can be congenital or may occur after focal brain damage. To date, only a few cases of acquired musical anhedonia have been reported in the literature with lesions of the temporo-parietal cortex being particularly important. Even less literature exists on congenital musical anhedonia, in which impaired connectivity of temporal brain regions with the Nucleus accumbens is implicated. Nonetheless, there is no precise information on the prevalence, causes or exact localization of both congenital and acquired musical anhedonia. However, the frequent involvement of temporo-parietal brain regions in neurological disorders such as stroke suggest the possibility of a high prevalence of this disorder, which leads to a considerable reduction in the quality of life.

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