scholarly journals Running Promotes Spatial Bias Independently of Adult Neurogenesis

2017 ◽  
Author(s):  
Jason S. Snyder ◽  
Shaina P. Cahill ◽  
Paul W. Frankland

ABSTRACTDifferent memory systems offer distinct advantages to navigational behavior. The hippocampus forms complex associations between environmental stimuli, enabling flexible navigation through space. In contrast, the dorsal striatum associates discrete cues and favorable behavioral responses, enabling habit-like, automated navigation. While these two systems often complement one another, there are instances where striatal-dependent responses (e.g. approach a cue) conflict with hippocampal representations of spatial goals. In conflict situations, preference for spatial vs. response strategies varies across individuals and depends on previous experience, plasticity and the integrity of these two memory systems. Here, we investigated the role of adult hippocampal neurogenesis and exercise on mouse search strategies in a water maze task that can be solved with either a hippocampal-dependent place strategy or a striatal-dependent cue-response strategy. We predicted that inhibiting adult neurogenesis would impair hippocampal function and shift behavior towards striatal-dependent cue responses. However, blocking neurogenesis in a transgenic nestin-TK mouse did not affect strategy choice. We then investigated whether a pro-neurogenic stimulus, running, would bias mice towards hippocampal-dependent spatial strategies. While running indeed promoted spatial strategies, it did so even when neurogenesis was inhibited in nestin-TK mice. These findings indicate that exercise-induced increases in neurogenesis are not always required for enhanced cognitive function. Furthermore, our data identify exercise as a potentially useful strategy for promoting flexible, cognitive forms of memory in habit-related disorders that are characterized by excessive responding to discrete cues.

2014 ◽  
Vol 2014 ◽  
pp. 1-20 ◽  
Author(s):  
Suk-yu Yau ◽  
Joana Gil-Mohapel ◽  
Brian R. Christie ◽  
Kwok-fai So

Cumulative evidence has indicated that there is an important role for adult hippocampal neurogenesis in cognitive function. With the increasing prevalence of cognitive decline associated with neurodegenerative diseases among the ageing population, physical exercise, a potent enhancer of adult hippocampal neurogenesis, has emerged as a potential preventative strategy/treatment to reduce cognitive decline. Here we review the functional role of adult hippocampal neurogenesis in learning and memory, and how this form of structural plasticity is altered in neurodegenerative diseases known to involve cognitive impairment. We further discuss how physical exercise may contribute to cognitive improvement in the ageing brain by preserving adult neurogenesis, and review the recent approaches for measuring changes in neurogenesis in the live human brain.


2021 ◽  
Vol 22 (14) ◽  
pp. 7339
Author(s):  
Julia Leschik ◽  
Beat Lutz ◽  
Antonietta Gentile

Newborn neurons in the adult hippocampus are regulated by many intrinsic and extrinsic cues. It is well accepted that elevated glucocorticoid levels lead to downregulation of adult neurogenesis, which this review discusses as one reason why psychiatric diseases, such as major depression, develop after long-term stress exposure. In reverse, adult neurogenesis has been suggested to protect against stress-induced major depression, and hence, could serve as a resilience mechanism. In this review, we will summarize current knowledge about the functional relation of adult neurogenesis and stress in health and disease. A special focus will lie on the mechanisms underlying the cascades of events from prolonged high glucocorticoid concentrations to reduced numbers of newborn neurons. In addition to neurotransmitter and neurotrophic factor dysregulation, these mechanisms include immunomodulatory pathways, as well as microbiota changes influencing the gut-brain axis. Finally, we discuss recent findings delineating the role of adult neurogenesis in stress resilience.


2003 ◽  
Vol 18 (10) ◽  
pp. 2803-2812 ◽  
Author(s):  
Klaus Fabel ◽  
Konstanze Fabel ◽  
Betty Tam ◽  
Daniela Kaufer ◽  
Armin Baiker ◽  
...  

2021 ◽  
Vol 13 ◽  
Author(s):  
Domenica Donatella Li Puma ◽  
Roberto Piacentini ◽  
Claudio Grassi

Adult hippocampal neurogenesis is a physiological mechanism contributing to hippocampal memory formation. Several studies associated altered hippocampal neurogenesis with aging and Alzheimer's disease (AD). However, whether amyloid-β protein (Aβ)/tau accumulation impairs adult hippocampal neurogenesis and, consequently, the hippocampal circuitry, involved in memory formation, or altered neurogenesis is an epiphenomenon of AD neuropathology contributing negligibly to the AD phenotype, is, especially in humans, still debated. The detrimental effects of Aβ/tau on synaptic function and neuronal viability have been clearly addressed both in in vitro and in vivo experimental models. Until some years ago, studies carried out on in vitro models investigating the action of Aβ/tau on proliferation and differentiation of hippocampal neural stem cells led to contrasting results, mainly due to discrepancies arising from different experimental conditions (e.g., different cellular/animal models, different Aβ and/or tau isoforms, concentrations, and/or aggregation profiles). To date, studies investigating in situ adult hippocampal neurogenesis indicate severe impairment in most of transgenic AD mice; this impairment precedes by several months cognitive dysfunction. Using experimental tools, which only became available in the last few years, research in humans indicated that hippocampal neurogenesis is altered in cognitive declined individuals affected by either mild cognitive impairment or AD as well as in normal cognitive elderly with a significant inverse relationship between the number of newly formed neurons and cognitive impairment. However, despite that such information is available, the question whether impaired neurogenesis contributes to AD pathogenesis or is a mere consequence of Aβ/pTau accumulation is not definitively answered. Herein, we attempted to shed light on this complex and very intriguing topic by reviewing relevant literature on impairment of adult neurogenesis in mouse models of AD and in AD patients analyzing the temporal relationship between the occurrence of altered neurogenesis and the appearance of AD hallmarks and cognitive dysfunctions.


2020 ◽  
Vol 29 (12) ◽  
pp. 1950-1968
Author(s):  
Charlotte Castillon ◽  
Laurine Gonzalez ◽  
Florence Domenichini ◽  
Sandrine Guyon ◽  
Kevin Da Silva ◽  
...  

Abstract The link between mutations associated with intellectual disability (ID) and the mechanisms underlying cognitive dysfunctions remains largely unknown. Here, we focused on PAK3, a serine/threonine kinase whose gene mutations cause X-linked ID. We generated a new mutant mouse model bearing the missense R67C mutation of the Pak3 gene (Pak3-R67C), known to cause moderate to severe ID in humans without other clinical signs and investigated hippocampal-dependent memory and adult hippocampal neurogenesis. Adult male Pak3-R67C mice exhibited selective impairments in long-term spatial memory and pattern separation function, suggestive of altered hippocampal neurogenesis. A delayed non-matching to place paradigm testing memory flexibility and proactive interference, reported here as being adult neurogenesis-dependent, revealed a hypersensitivity to high interference in Pak3-R67C mice. Analyzing adult hippocampal neurogenesis in Pak3-R67C mice reveals no alteration in the first steps of adult neurogenesis, but an accelerated death of a population of adult-born neurons during the critical period of 18–28 days after their birth. We then investigated the recruitment of hippocampal adult-born neurons after spatial memory recall. Post-recall activation of mature dentate granule cells in Pak3-R67C mice was unaffected, but a complete failure of activation of young DCX + newborn neurons was found, suggesting they were not recruited during the memory task. Decreased expression of the KCC2b chloride cotransporter and altered dendritic development indicate that young adult-born neurons are not fully functional in Pak3-R67C mice. We suggest that these defects in the dynamics and learning-associated recruitment of newborn hippocampal neurons may contribute to the selective cognitive deficits observed in this mouse model of ID.


Cells ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 125 ◽  
Author(s):  
Marcus Augusto-Oliveira ◽  
Gabriela Arrifano ◽  
João Malva ◽  
Maria Crespo-Lopez

Adult neurogenesis occurs in many species, from fish to mammals, with an apparent reduction in the number of both neurogenic zones and new neurons inserted into established circuits with increasing brain complexity. Although the absolute number of new neurons is high in some species, the ratio of these cells to those already existing in the circuit is low. Continuous replacement/addition plays a role in spatial navigation (migration) and other cognitive processes in birds and rodents, but none of the literature relates adult neurogenesis to spatial navigation and memory in primates and humans. Some models developed by computational neuroscience attribute a high weight to hippocampal adult neurogenesis in learning and memory processes, with greater relevance to pattern separation. In contrast to theories involving neurogenesis in cognitive processes, absence/rarity of neurogenesis in the hippocampus of primates and adult humans was recently suggested and is under intense debate. Although the learning process is supported by plasticity, the retention of memories requires a certain degree of consolidated circuitry structures, otherwise the consolidation process would be hampered. Here, we compare and discuss hippocampal adult neurogenesis in different species and the inherent paradoxical aspects.


2010 ◽  
Vol 22 (7) ◽  
pp. 1362-1372 ◽  
Author(s):  
Lars Schwabe ◽  
Hartmut Schächinger ◽  
E. Ron de Kloet ◽  
Melly S. Oitzl

Stress and corticosteroid hormones are known to affect learning and memory processes. In this study, we examined whether stress and corticosteroids are capable of facilitating the switch between multiple memory systems in mice. For this purpose, we designed a task that allowed measurement of nucleus caudate-based stimulus–response and hippocampus-based spatial learning strategies. Naive mice used spatial strategies to locate an exit hole on a circular hole board at a fixed location flagged by a proximal stimulus. When the mice were either stressed or administered corticosterone before the task, 30–50% of the mice switched to a stimulus–response strategy. This switch between learning strategies was accompanied by a rescue of performance, whereas performance declined in the stressed mice that kept using the spatial strategy. Pretreatment with a mineralocorticoid receptor antagonist prevented the switch toward the stimulus–response strategy but led to deterioration of hippocampus-dependent performance. These findings (i) show that corticosteroids promote the transition from spatial to stimulus–response memory systems, (ii) provide evidence that the mineralocorticoid receptor underlies this corticosteroid-mediated switch, and (iii) suggest that a stress-induced switch from hippocampus-based to nucleus caudate-based memory systems can rescue performance.


2017 ◽  
Vol 28 (7) ◽  
pp. 693-703 ◽  
Author(s):  
Lina Sun ◽  
Qingshan Sun ◽  
Jinshun Qi

AbstractDepression is a prevalent devastating mental disorder that affects the normal life of patients and brings a heavy burden to whole society. Although many efforts have been made to attenuate depressive/anxiety symptoms, the current clinic antidepressants have limited effects. Scientists have long been making attempts to find some new strategies that can be applied as the alternative antidepressant therapy. Exercise, a widely recognized healthy lifestyle, has been suggested as a therapy that can relieve psychiatric stress. However, how exercise improves the brain functions and reaches the antidepressant target needs systematic summarization due to the complexity and heterogeneous feature of depression. Brain plasticity, especially adult neurogenesis in the hippocampus, is an important neurophysiology to facilitate animals for neurogenesis can occur in not only humans. Many studies indicated that an appropriate level of exercise can promote neurogenesis in the adult brains. In this article, we provide information about the antidepressant effects of exercise and its implications in adult neurogenesis. From the neurogenesis perspective, we summarize evidence about the effects of exercise in enhancing neurogenesis in the hippocampus through regulating growth factors, neurotrophins, neurotransmitters and metabolism as well as inflammations. Taken together, a large number of published works indicate the multiple benefits of exercise in the brain functions of animals, particularly brain plasticity like neurogenesis and synaptogenesis. Therefore, a new treatment method for depression therapy can be developed by regulating the exercise activity.


eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Hongsheng Zhang ◽  
Anupama Sathyamurthy ◽  
Fang Liu ◽  
Lei Li ◽  
Lei Zhang ◽  
...  

Adult neurogenesis in the hippocampus may represent a form of plasticity in brain functions including mood, learning and memory. However, mechanisms underlying neural stem/progenitor cells (NSPCs) proliferation are not well understood. We found that Agrin, a factor critical for neuromuscular junction formation, is elevated in the hippocampus of mice that are stimulated by enriched environment (EE). Genetic deletion of the Agrn gene in excitatory neurons decreases NSPCs proliferation and increases depressive-like behavior. Low-density lipoprotein receptor-related protein 4 (Lrp4), a receptor for Agrin, is expressed in hippocampal NSPCs and its mutation blocked basal as well as EE-induced NSPCs proliferation and maturation of newborn neurons. Finally, we show that Lrp4 interacts with and activates receptor tyrosine kinase-like orphan receptor 2 (Ror2); and Ror2 mutation impairs NSPCs proliferation. Together, these observations identify a role of Agrin-Lrp4-Ror2 signaling for adult neurogenesis, uncovering previously unexpected functions of Agrin and Lrp4 in the brain.


2020 ◽  
Author(s):  
Sara Zocher ◽  
Rupert W Overall ◽  
Gabriel Berdugo-Vega ◽  
Nicole Rund ◽  
Anne Karasinsky ◽  
...  

SummaryDynamic DNA methylation controls gene-regulatory networks underlying cell fate specification. How DNA methylation patterns change during adult hippocampal neurogenesis and their relevance for adult neural stem cell differentiation and related brain function has, however, remained unknown. Here, we show that neurogenesis-associated de novo DNA methylation is critical for maturation and functional integration of adult-born hippocampal neurons. Cell stage-specific bisulfite sequencing revealed a pronounced gain of DNA methylation at neuronal enhancers, gene bodies and binding sites of pro-neuronal transcription factors during adult neurogenesis, which mostly correlated with transcriptional up-regulation of the associated loci. Inducible deletion of both de novo DNA methyltransferases Dnmt3a and Dnmt3b in adult neural stem cells specifically impaired dendritic outgrowth and synaptogenesis of new-born neurons, resulting in reduced hippocampal excitability and specific deficits in hippocampus-dependent learning and memory. Our results highlight that, during adult neurogenesis, remodeling of neuronal methylomes is fundamental for proper hippocampal function.


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