scholarly journals Adult Hippocampal Neurogenesis and Affective Disorders: New Neurons for Psychic Well-Being

2021 ◽  
Vol 15 ◽  
Author(s):  
Walace Gomes-Leal
Keyword(s):  
Cognitive Flexibility ◽  
Affective Disorders ◽  
Granule Cells ◽  
Well Being ◽  
Hippocampal Neurogenesis ◽  
Emotional Behavior ◽  
Adult Hippocampal Neurogenesis ◽  
Pattern Separation ◽  
Mammalian Brain ◽  
New Born

A paradigm shift in neuroscience was the discovery that new neurons are constantly produced in the adult mammalian brain of several species, including Homo sapiens. These new-born cells are formed in some main neurogenic niches, including the subventricular zone (SVZ) at the margin of the lateral ventricle and subgranular zone (SGZ) in the hippocampal dentate gyrus (DG). In the DG, neuroblasts derive from SGZ progenitors and migrate to the hippocampal granular layer becoming adult granule cells, which are integrated into functional adult circuits. It has been confirmed that adult hippocampal neurogenesis (AHN) is a long-lasting phenomenon in the human brain. The functions of hippocampal new-born cells are not fully established. Experimental studies suggest that they have unique electrophysiological properties, including hyperexcitability, which enable them to regulate adult granule cells. Their specific function depends on the anatomical hippocampal location along the hippocampal dorsal-ventral axis. Dorsal hippocampus plays a more defined role on spatial learning and contextual information, while the ventral hippocampus is more related to emotional behavior, stress resilience and social interaction. Several reports suggest a role for AHN in pattern separation, cognitive flexibility, forgetting and reversal learning. It has been proposed that deficits in AHN might impair normal DG function, including pattern separation and cognitive flexibility, which could play a role on the etiology of affective disorders, such as depression, anxiety and post-traumatic stress disorder (PTSD). In this paper, we review recent scientific evidence suggesting that impairment of AHN may underlie the pathophysiology of affective disorders even in humans and that neurogenesis-inspired therapies may be a promising approach to reduce symptoms of affective disorders in humans.

scholarly journals Orexin-A and endocannabinoids are involved in obesity-associated alteration of hippocampal neurogenesis, plasticity, and episodic memory in mice

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nicola Forte ◽  
Serena Boccella ◽  
Lea Tunisi ◽  
Alba Clara Fernández-Rilo ◽  
Roberta Imperatore ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Dentate Gyrus ◽  
Adult Neurogenesis ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Pattern Separation ◽  
Mammalian Brain ◽  
Obese Mice ◽  
Orexin A ◽  
Episodic Memories

AbstractThe mammalian brain stores and distinguishes among episodic memories, i.e. memories formed during the personal experience, through a mechanism of pattern separation computed in the hippocampal dentate gyrus. Decision-making for food-related behaviors, such as the choice and intake of food, might be affected in obese subjects by alterations in the retrieval of episodic memories. Adult neurogenesis in the dentate gyrus regulates the pattern separation. Several molecular factors affect adult neurogenesis and exert a critical role in the development and plasticity of newborn neurons. Orexin-A/hypocretin-1 and downstream endocannabinoid 2-arachidonoylglycerol signaling are altered in obese mice. Here, we show that excessive orexin-A/2-arachidonoylglycerol/cannabinoid receptor type-1 signaling leads to the dysfunction of adult hippocampal neurogenesis and the subsequent inhibition of plasticity and impairment of pattern separation. By inhibiting orexin-A action at orexin-1 receptors we rescued both plasticity and pattern separation impairment in obese mice, thus providing a molecular and functional mechanism to explain alterations in episodic memory in obesity.

scholarly journals The orexigenic hormone acyl-ghrelin increases adult hippocampal neurogenesis and enhances pattern separation

2015 ◽  
Vol 51 ◽  
pp. 431-439 ◽  
Author(s):  
Brianne A. Kent ◽  
Amy L. Beynon ◽  
Amanda K.E. Hornsby ◽  
Pedro Bekinschtein ◽  
Timothy J. Bussey ◽  
...  
Keyword(s):  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Pattern Separation ◽  
Acyl Ghrelin

scholarly journals Shaping hippocampal neurogenesis: exercising the brain with cannabinoids

2020 ◽  
Author(s):  
Rui S Rodrigues ◽  
Joao B. Moreira ◽  
Ana M. Sebastião ◽  
Carlos P. Fitzsimons ◽  
Sara Xapelli
Keyword(s):  
Physical Exercise ◽  
Progenitor Cells ◽  
Neurotrophic Factors ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Fine Tuning ◽  
Mammalian Brain ◽  
Potential Conflict ◽  
Brain Physiology ◽  
The Brain

Adult neural stem/progenitor cells (NSPC) are present in specialized niches of the mammalian brain and their proliferative and differentiative potential is modulated by a myriad of factors. Recent evidence sheds light on the interaction between cannabinoids and neurotrophic factors underlying a major regulative force of adult hippocampal neurogenesis, with important effects upon cognitive plasticity and mood flexibility. Herein, we aimed at evaluating the actions of cannabinoid type 2 receptor (CB2R) together with exercise upon hippocampal neurogenesis and whether this has significant behavioral implications. Our data suggests a participation of CB2Rs in fine-tuning the actions of physical exercise upon adult hippocampal neurogenesis. Specifically, CB2R ligands as well as exercise-regulated neurotrophic factors promote an acceleration in the differentiation of progenitor cells accompanied by an increase in the number of mature neurons in vitro. Moreover, preliminary results show that CB2Rs play an impactful role in controlling cognitive and depressive-like behavior. This is particularly important because brain physiology and mental health are known to be greatly affected by physical exercise, with adult neurogenesis playing a significant role in this process. Ultimately, this work will contribute to unravel the mechanisms behind the actions of cannabinoids and exercise in the brain and to develop strategies utilizing CB2Rs and physical exercise to boost neural stem cell capacity and treat several brain disorders. Acknowledgements: Supported by Fundação para a Ciência e a Tecnologia (FCT), projects SFRH/BD/129710/2017 and IF/01227/2015. No potential conflict of interest.

scholarly journals Differential inhibition onto developing and mature granule cells generates high-frequency filters with variable gain

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
María Belén Pardi ◽  
Mora Belén Ogando ◽  
Alejandro F Schinder ◽  
Antonia Marin-Burgin
Keyword(s):  
Granule Cells ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Information Encoding ◽  
High Frequencies ◽  
Wide Range ◽  
Mature Neurons ◽  
Different Populations ◽  
Immature Cells ◽  
Two Populations

Adult hippocampal neurogenesis provides the dentate gyrus with heterogeneous populations of granule cells (GC) originated at different times. The contribution of these cells to information encoding is under current investigation. Here, we show that incoming spike trains activate different populations of GC determined by the stimulation frequency and GC age. Immature GC respond to a wider range of stimulus frequencies, whereas mature GC are less responsive at high frequencies. This difference is dictated by feedforward inhibition, which restricts mature GC activation. Yet, the stronger inhibition of mature GC results in a higher temporal fidelity compared to that of immature GC. Thus, hippocampal inputs activate two populations of neurons with variable frequency filters: immature cells, with wide‐range responses, that are reliable transmitters of the incoming frequency, and mature neurons, with narrow frequency response, that are precise at informing the beginning of the stimulus, but with a sparse activity.

scholarly journals Energy Restriction Enhances Adult Hippocampal Neurogenesis-Associated Memory after Four Weeks in an Adult Human Population with Central Obesity; a Randomized Controlled Trial

Nutrients ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 638 ◽  
Author(s):  
Curie Kim ◽  
Ana Margarida Pinto ◽  
Claire Bordoli ◽  
Luke Patrick Buckner ◽  
Polly Charlotte Kaplan ◽  
...  
Keyword(s):  
Recognition Memory ◽  
Central Obesity ◽  
Human Study ◽  
Energy Restriction ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Pattern Separation ◽  
Intermittent Fasting ◽  
Ageing Population ◽  
Cognitive Improvement

Adult neurogenesis, the generation of new neurons throughout life, occurs in the subventricular zone of the dentate gyrus in the human hippocampal formation. It has been shown in rodents that adult hippocampal neurogenesis is needed for pattern separation, the ability to differentially encode small changes derived from similar inputs, and recognition memory, as well as the ability to recognize previously encountered stimuli. Improved hippocampus-dependent cognition and cellular readouts of adult hippocampal neurogenesis have been reported in daily energy restricted and intermittent fasting adult mice. Evidence that nutrition can significantly affect brain structure and function is increasing substantially. This randomized intervention study investigated the effects of intermittent and continuous energy restriction on human hippocampal neurogenesis-related cognition, which has not been reported previously. Pattern separation and recognition memory were measured in 43 individuals with central obesity aged 35–75 years, before and after a four-week dietary intervention using the mnemonic similarity task. Both groups significantly improved pattern separation (P = 0.0005), but only the intermittent energy restriction group had a significant deterioration in recognition memory. There were no significant differences in cognitive improvement between the two diets. This is the first human study to investigate the association between energy restriction with neurogenesis-associated cognitive function. Energy restriction may enhance hippocampus-dependent memory and could benefit those in an ageing population with declining cognition. This study was registered on ClinicalTrials.gov (NCT02679989) on 11 February 2016.

scholarly journals Adult hippocampal neurogenesis of mammals: evolution and life history

2008 ◽  
Vol 5 (1) ◽  
pp. 141-144 ◽  
Author(s):  
Irmgard Amrein ◽  
Hans-Peter Lipp
Keyword(s):  
Hippocampal Formation ◽  
Mammalian Species ◽  
Critical Role ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Mammalian Brain ◽  
Spatial Learning And Memory ◽  
Species Specific ◽  
Species Being

Substantial production of new neurons in the adult mammalian brain is restricted to the olfactory system and the hippocampal formation. Its physiological and behavioural role is still debated. By comparing adult hippocampal neurogenesis (AHN) across many mammalian species, one might recognize a common function. AHN is most prominent in rodents, but shows considerable variability across species, being lowest or missing in primates and bats. The latter finding argues against a critical role of AHN in spatial learning and memory. The common functional denominator across all species investigated thus far is a strong decline of AHN from infancy to midlife. As predicted by Altman and colleagues in 1973, this implies a role in transforming juvenile unpredictable to predictable behaviour, typically characterizing mammalian behaviour once reproductive competence has been attained. However, as only a fraction of mammalian species has been investigated, further comparative studies are necessary in order to recognize whether AHN has a common unique function, or whether it mediates species-specific hippocampal functions.

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