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Marzoog BA. Transcription Factors in Brain Regeneration: A Potential Novel Therapeutic Target. Curr Drug Targets 2024; 25:46-61. [PMID: 38444255 DOI: 10.2174/0113894501279977231210170231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 11/21/2023] [Accepted: 11/23/2023] [Indexed: 03/07/2024]
Abstract
Transcription factors play a crucial role in providing identity to each cell population. To maintain cell identity, it is essential to balance the expression of activator and inhibitor transcription factors. Cell plasticity and reprogramming offer great potential for future therapeutic applications, as they can regenerate damaged tissue. Specific niche factors can modify gene expression and differentiate or transdifferentiate the target cell to the required fate. Ongoing research is being carried out on the possibilities of transcription factors in regenerating neurons, with neural stem cells (NSCs) being considered the preferred cells for generating new neurons due to their epigenomic and transcriptome memory. NEUROD1/ASCL1, BRN2, MYTL1, and other transcription factors can induce direct reprogramming of somatic cells, such as fibroblasts, into neurons. However, the molecular biology of transcription factors in reprogramming and differentiation still needs to be fully understood.
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Affiliation(s)
- Basheer Abdullah Marzoog
- World-Class Research Center, Digital Biodesign and Personalized Healthcare», I.M. Sechenov First Moscow State Medical University (Sechenov University), 119991 Moscow, Russia
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2
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Ding Y, Li L, Wang S, Cao Y, Yang M, Dai Y, Lin H, Li J, Liu Y, Wang Z, Liu W, Tao J. Electroacupuncture promotes neurogenesis in the dentate gyrus and improves pattern separation in an early Alzheimer's disease mouse model. Biol Res 2023; 56:65. [PMID: 38041203 PMCID: PMC10693055 DOI: 10.1186/s40659-023-00472-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 11/03/2023] [Indexed: 12/03/2023] Open
Abstract
BACKGROUND Impaired pattern separation occurs in the early stage of Alzheimer's disease (AD), and hippocampal dentate gyrus (DG) neurogenesis participates in pattern separation. Here, we investigated whether spatial memory discrimination impairment can be improved by promoting the hippocampal DG granule cell neogenesis-mediated pattern separation in the early stage of AD by electroacupuncture (EA). METHODS Five familial AD mutations (5 × FAD) mice received EA treatment at Baihui and Shenting points for 4 weeks. During EA, mice were intraperitoneally injected with BrdU (50 mg/kg) twice a day. rAAV containing Wnt5a shRNA was injected into the bilateral DG region, and the viral efficiency was evaluated by detecting Wnt5a mRNA levels. Cognitive behavior tests were conducted to assess the impact of EA treatment on cognitive function. The hippocampal DG area Aβ deposition level was detected by immunohistochemistry after the intervention; The number of BrdU+/CaR+ cells and the gene expression level of calretinin (CaR) and prospero homeobox 1(Prox1) in the DG area of the hippocampus was detected to assess neurogenesis by immunofluorescence and western blotting after the intervention; The gene expression levels of FZD2, Wnt5a, DVL2, p-DVL2, CaMKII, and p-CaMKII in the Wnt signaling pathway were detected by Western blotting after the intervention. RESULTS Cognitive behavioral tests showed that 5 × FAD mice had impaired pattern separation (P < 0.001), which could be improved by EA (P < 0.01). Immunofluorescence and Western blot showed that the expression of Wnt5a in the hippocampus was decreased (P < 0.001), and the neurogenesis in the DG was impaired (P < 0.001) in 5 × FAD mice. EA could increase the expression level of Wnt5a (P < 0.05) and promote the neurogenesis of immature granule cells (P < 0.05) and the development of neuronal dendritic spines (P < 0.05). Interference of Wnt5a expression aggravated the damage of neurogenesis (P < 0.05), weakened the memory discrimination ability (P < 0.05), and inhibited the beneficial effect of EA (P < 0.05) in AD mice. The expression level of Wnt pathway related proteins such as FZD2, DVL2, p-DVL2, CAMKII, p-CAMKII increased after EA, but the effect of EA was inhibited after Wnt5a was knocked down. In addition, EA could reduce the deposition of Aβ plaques in the DG without any impact on Wnt5a. CONCLUSION EA can promote hippocampal DG immature granule cell neogenesis-mediated pattern separation to improve spatial memory discrimination impairment by regulating Wnt5a in 5 × FAD mice.
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Affiliation(s)
- Yanyi Ding
- The Institute of Rehabilitation Industry, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, 350122, China
| | - Long Li
- The Institute of Rehabilitation Industry, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, 350122, China
| | - Sinuo Wang
- The Institute of Rehabilitation Industry, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, 350122, China
| | - Yajun Cao
- The Institute of Rehabilitation Industry, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, 350122, China
| | - Minguang Yang
- The Institute of Rehabilitation Industry, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, 350122, China
| | - Yaling Dai
- The Institute of Rehabilitation Industry, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, 350122, China
| | - Huawei Lin
- The Institute of Rehabilitation Industry, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, 350122, China
| | - Jianhong Li
- The Institute of Rehabilitation Industry, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, 350122, China
| | - Yulu Liu
- College of Rehabilitation Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, 350122, China
| | - Zhifu Wang
- National-Local Joint Engineering Research Center of Rehabilitation Medicine Technology, Fuzhou, Fujian, 350122, China
- Fujian Key Laboratory of Cognitive Rehabilitation, Affiliated Rehabilitation Hospital of Fujian University of Traditional Chinese Medicine, Fuzhou, 350001, China
| | - Weilin Liu
- The Institute of Rehabilitation Industry, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, 350122, China.
| | - Jing Tao
- College of Rehabilitation Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, 350122, China.
- Fujian Key Laboratory of Rehabilitation Technology, Affiliated Rehabilitation Hospital of Fujian University of Traditional Chinese Medicine, Fuzhou, 350001, China.
- Provincial and Ministerial Co-founded Collaborative Innovation Center of Rehabilitation Technology, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China.
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Homayouni R, Canada KL, Saifullah S, Foster DJ, Thill C, Raz N, Daugherty AM, Ofen N. Age-related differences in hippocampal subfield volumes across the human lifespan: A meta-analysis. Hippocampus 2023; 33:1292-1315. [PMID: 37881160 PMCID: PMC10841547 DOI: 10.1002/hipo.23582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 08/31/2023] [Accepted: 09/28/2023] [Indexed: 10/27/2023]
Abstract
The human hippocampus (Hc) is critical for memory function across the lifespan. It is comprised of cytoarchitectonically distinct subfields: dentate gyrus (DG), cornu ammonis sectors (CA) 1-4, and subiculum, each of which may be differentially susceptible to neurodevelopmental and neurodegenerative mechanisms. Identifying age-related differences in Hc subfield volumes can provide insights into neural mechanisms of memory function across the lifespan. Limited evidence suggests that DG and CA3 volumes differ across development while other regions remain relatively stable, and studies of adulthood implicate a downward trend in all subfield volumes with prominent age effects on CA1. Due to differences in methods and limited sampling for any single study, the magnitude of age effects on Hc subfield volumes and their probable lifespan trajectories remain unclear. Here, we conducted a meta-analysis on cross-sectional studies (n = 48,278 participants, ages = 4-94 years) to examine the association between age and Hc subfield volumes in development (n = 11 studies), adulthood (n = 30 studies), and a combined lifespan sample (n = 41 studies) while adjusting estimates for sample sizes. In development, age was positively associated with DG and CA3-4 volumes, whereas in adulthood a negative association was observed with all subfield volumes. Notably, the observed age effects were not different across subfield volumes within each age group. All subfield volumes showed a nonlinear age pattern across the lifespan with DG and CA3-4 volumes showing a more distinct age trajectory as compared to the other subfields. Lastly, among all the study-level variables, only female percentage of the study sample moderated the age effect on CA1 volume: a higher female-to-male ratio in the study sample was linked to the greater negative association between age and CA1 volume. These results document that Hc subfield volumes differ as a function of age offering broader implications for constructing theoretical models of lifespan memory development.
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Affiliation(s)
- Roya Homayouni
- Institute of Gerontology, Wayne State University, Detroit, Michigan, USA
- Department of Psychology, Wayne State University, Detroit, Michigan, USA
| | - Kelsey L Canada
- Institute of Gerontology, Wayne State University, Detroit, Michigan, USA
| | - Samaah Saifullah
- School of Medicine, Wayne State University, Detroit, Michigan, USA
| | - Da' Jonae Foster
- Department of Psychology, Wayne State University, Detroit, Michigan, USA
| | - Charlotte Thill
- School of Medicine, Wayne State University, Detroit, Michigan, USA
| | - Naftali Raz
- Department of Psychology, Stony Brook University, Stony Brook, New York, USA
- Max Planck Institute for Human Development, Berlin, Germany
| | - Ana M Daugherty
- Institute of Gerontology, Wayne State University, Detroit, Michigan, USA
- Department of Psychology, Wayne State University, Detroit, Michigan, USA
| | - Noa Ofen
- Institute of Gerontology, Wayne State University, Detroit, Michigan, USA
- Department of Psychology, Wayne State University, Detroit, Michigan, USA
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Berdugo‐Vega G, Dhingra S, Calegari F. Sharpening the blades of the dentate gyrus: how adult-born neurons differentially modulate diverse aspects of hippocampal learning and memory. EMBO J 2023; 42:e113524. [PMID: 37743770 PMCID: PMC11059975 DOI: 10.15252/embj.2023113524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 06/19/2023] [Accepted: 08/18/2023] [Indexed: 09/26/2023] Open
Abstract
For decades, the mammalian hippocampus has been the focus of cellular, anatomical, behavioral, and computational studies aimed at understanding the fundamental mechanisms underlying cognition. Long recognized as the brain's seat for learning and memory, a wealth of knowledge has been accumulated on how the hippocampus processes sensory input, builds complex associations between objects, events, and space, and stores this information in the form of memories to be retrieved later in life. However, despite major efforts, our understanding of hippocampal cognitive function remains fragmentary, and models trying to explain it are continually revisited. Here, we review the literature across all above-mentioned domains and offer a new perspective by bringing attention to the most distinctive, and generally neglected, feature of the mammalian hippocampal formation, namely, the structural separability of the two blades of the dentate gyrus into "supra-pyramidal" and "infra-pyramidal". Next, we discuss recent reports supporting differential effects of adult neurogenesis in the regulation of mature granule cell activity in these two blades. We propose a model for how differences in connectivity and adult neurogenesis in the two blades can potentially provide a substrate for subtly different cognitive functions.
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Affiliation(s)
- Gabriel Berdugo‐Vega
- CRTD‐Center for Regenerative Therapies DresdenTechnische Universität DresdenDresdenGermany
- Present address:
Laboratory of Neuroepigenetics, Brain Mind Institute, School of Life Sciences, École Polytechnique Fédérale Lausanne (EPFL)LausanneSwitzerland
| | - Shonali Dhingra
- CRTD‐Center for Regenerative Therapies DresdenTechnische Universität DresdenDresdenGermany
| | - Federico Calegari
- CRTD‐Center for Regenerative Therapies DresdenTechnische Universität DresdenDresdenGermany
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Phillips TO, Castro M, Vas RK, Ferguson LA, Harikumar A, Leal SL. Perceived antidepressant efficacy associated with reduced negative and enhanced neutral mnemonic discrimination. Front Hum Neurosci 2023; 17:1225836. [PMID: 37701502 PMCID: PMC10494429 DOI: 10.3389/fnhum.2023.1225836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 08/09/2023] [Indexed: 09/14/2023] Open
Abstract
Introduction While antidepressants are one of the first-line treatments for depression, the mechanisms underlying antidepressant action are unclear. Furthermore, the extent to which antidepressants impact emotional and cognitive dysfunction in depression requires more fine-grained approaches toward measuring these impacts in humans. Depression is associated with emotion and mood dysregulation in addition to cognitive deficits. Depressed individuals experience general memory impairment as well as a negativity bias in episodic memory, where negative events are better remembered than positive or neutral events. One potential mechanism hypothesized to underlie the negativity bias in memory is dysfunctional hippocampal pattern separation, in which depressed individuals tend to show impaired general pattern separation but enhanced negative pattern separation. Mnemonic discrimination tasks have been designed to tax hippocampal pattern separation in humans and provide a powerful approach to develop a mechanistic account for cognitive dysfunction in depression. While antidepressants have been examined primarily in rodent models in the context of hippocampal pattern separation, this has yet to be examined in humans. Methods Here, we investigated how antidepressant usage and their perceived efficacy was associated with emotional mnemonic discrimination, given our prior work indicating a negativity bias for mnemonic discrimination in individuals with greater depressive symptoms. Results We found that individuals who reported a greater improvement in their depressive symptoms after taking antidepressants (responders) showed reduced negative and enhanced neutral mnemonic discrimination compared to those with little to no improvement (non-responders). Perceived antidepressant efficacy was the strongest predictor of a reduction in the negativity bias for mnemonic discrimination, even when controlling for current depressive symptoms, antidepressant type, and other relevant factors. Discussion These results suggest that antidepressants, when effective, can shift memory dynamics toward healthy function.
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Affiliation(s)
| | | | | | | | | | - Stephanie L. Leal
- Department of Psychological Sciences, Rice University, Houston, TX, United States
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Anitha A, Thanseem I, Iype M, Thomas SV. Mitochondrial dysfunction in cognitive neurodevelopmental disorders: Cause or effect? Mitochondrion 2023; 69:18-32. [PMID: 36621534 DOI: 10.1016/j.mito.2023.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 12/21/2022] [Accepted: 01/04/2023] [Indexed: 01/07/2023]
Abstract
Mitochondria have a crucial role in brain development and neurogenesis, both in embryonic and adult brains. Since the brain is the highest energy consuming organ, it is highly vulnerable to mitochondrial dysfunction. This has been implicated in a range of brain disorders including, neurodevelopmental conditions, psychiatric illnesses, and neurodegenerative diseases. Genetic variations in mitochondrial DNA (mtDNA), and nuclear DNA encoding mitochondrial proteins, have been associated with several cognitive disorders. However, it is not yet clear whether mitochondrial dysfunction is a primary cause of these conditions or a secondary effect. Our review article deals with this topic, and brings out recent advances in mitochondria-oriented therapies. Mitochondrial dysfunction could be involved in the pathogenesis of a subset of disorders involving cognitive impairment. In these patients, mitochondrial dysfunction could be the cause of the condition, rather than the consequence. There are vast areas in this topic that remains to be explored and elucidated.
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Affiliation(s)
- Ayyappan Anitha
- Dept. of Neurogenetics, Institute for Communicative and Cognitive Neurosciences (ICCONS), Shoranur, Palakkad 679 523, Kerala, India.
| | - Ismail Thanseem
- Dept. of Neurogenetics, Institute for Communicative and Cognitive Neurosciences (ICCONS), Shoranur, Palakkad 679 523, Kerala, India
| | - Mary Iype
- Dept. of Pediatric Neurology, Government Medical College, Thiruvananthapuram 695 011, Kerala, India; Dept. of Neurology, ICCONS, Thiruvananthapuram 695 033, Kerala, India
| | - Sanjeev V Thomas
- Dept. of Neurology, ICCONS, Thiruvananthapuram 695 033, Kerala, India
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Exercise increases information content and affects long-term stability of hippocampal place codes. Cell Rep 2022; 41:111695. [PMID: 36417871 PMCID: PMC9715913 DOI: 10.1016/j.celrep.2022.111695] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 06/14/2022] [Accepted: 10/31/2022] [Indexed: 11/23/2022] Open
Abstract
Physical exercise is known to augment brain functioning, improving memory and cognition. However, while some of the physiological effects of physical activity on the brain are known, little is known about its effects on the neural code. Using calcium imaging in freely behaving mice, we study how voluntary exercise affects the quality and long-term stability of hippocampal place codes. We find that running accelerates the emergence of a more informative spatial code in novel environments and increases code stability over days and weeks. Paradoxically, although runners demonstrated an overall more stable place code than their sedentary peers, their place code changed faster when controlling for code quality level. A model-based simulation shows that the combination of improved code quality and faster representational drift in runners, but neither of these effects alone, could account for our results. Thus, exercise may enhance hippocampal function via a more informative and dynamic place code.
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Zhu L, Li L, Li XZ, Wang L. Mind–Body Exercises for PTSD Symptoms, Depression, and Anxiety in Patients With PTSD: A Systematic Review and Meta-Analysis. Front Psychol 2022; 12:738211. [PMID: 35153889 PMCID: PMC8833099 DOI: 10.3389/fpsyg.2021.738211] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 12/14/2021] [Indexed: 12/12/2022] Open
Abstract
Objectives This study aims to systematically analyze the effects of mind–body exercises on post-traumatic stress disorder (PTSD) symptoms, depression, and anxiety in patients with PTSD. Furthermore, it intends to provide scientific evidence-based exercise prescriptions. Methods Chinese (i.e., China National Knowledge Infrastructure, VIP Database for Chinese Technical Periodicals, and Wanfang) and English (i.e., Web of Science, PubMed, the Cochrane Library, and EMBASE) databases were used as data sources to search for studies on the effects of mind–body exercises on symptoms associated with patients with PTSD from January 1980 to November 2020. After a rigorous screening, 16 eligible randomized controlled trials (RCTs) were included in the meta-analysis. Results Mind–body exercises exerted a significant effect on PTSD symptoms [standard mean difference (SMD) = −0.41, 95% confidence interval (CI) −0.64 to −0.19, p < 0.001], depression (SMD = −0.35, 95% CI: −0.55 to −0.15, p < 0.001), and anxiety (SMD = −0.31, 95% CI: −0.74 to −0.12, p < 0.001) among patients with PTSD. Subgroup analysis demonstrated that 60–150 min per session for 8–16 weeks of mindfulness was more effective in improving symptoms in patients with PTSD under 45 years of age compared with other subgroups. For depression, 150–180 min of yoga exercises once per week was effective. For anxiety, the frequency, timing, duration, and type of mind–body exercises that are most effective in relieving anxiety in patients with PTSD cannot be determined at this time due to the limited number of eligible RCTs. Conclusions Mind–body exercises were found to be significantly effective in improving PTSD symptoms, depression, and anxiety in patients with PTSD. Therefore, they can be used as an adjunct to intervention for symptoms of patients with PTSD. However, this conclusion requires further confirmation through additional scientific and objective RCTs. Systematic Review Registration: Unique Identifier: INPLASY2020120072.
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Affiliation(s)
- Lin Zhu
- School of Wushu and Art, Nanjing Sport Institute, Nanjing, China
| | - Long Li
- School of Wushu and Art, Nanjing Sport Institute, Nanjing, China
- *Correspondence: Long Li
| | - Xiao-zhi Li
- Department of Physical Education, Southeast University, Nanjing, China
| | - Lin Wang
- Department of Physical Education, Wuhan University of Technology, Wuhan, China
- Lin Wang
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9
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Adult hippocampal neurogenesis shapes adaptation and improves stress response: a mechanistic and integrative perspective. Mol Psychiatry 2022; 27:403-421. [PMID: 33990771 PMCID: PMC8960391 DOI: 10.1038/s41380-021-01136-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 04/09/2021] [Accepted: 04/19/2021] [Indexed: 02/03/2023]
Abstract
Adult hippocampal neurogenesis (AHN) represents a remarkable form of neuroplasticity that has increasingly been linked to the stress response in recent years. However, the hippocampus does not itself support the expression of the different dimensions of the stress response. Moreover, the main hippocampal functions are essentially preserved under AHN depletion and adult-born immature neurons (abGNs) have no extrahippocampal projections, which questions the mechanisms by which abGNs influence functions supported by brain areas far from the hippocampus. Within this framework, we propose that through its computational influences AHN is pivotal in shaping adaption to environmental demands, underlying its role in stress response. The hippocampus with its high input convergence and output divergence represents a computational hub, ideally positioned in the brain (1) to detect cues and contexts linked to past, current and predicted stressful experiences, and (2) to supervise the expression of the stress response at the cognitive, affective, behavioral, and physiological levels. AHN appears to bias hippocampal computations toward enhanced conjunctive encoding and pattern separation, promoting contextual discrimination and cognitive flexibility, reducing proactive interference and generalization of stressful experiences to safe contexts. These effects result in gating downstream brain areas with more accurate and contextualized information, enabling the different dimensions of the stress response to be more appropriately set with specific contexts. Here, we first provide an integrative perspective of the functional involvement of AHN in the hippocampus and a phenomenological overview of the stress response. We then examine the mechanistic underpinning of the role of AHN in the stress response and describe its potential implications in the different dimensions accompanying this response.
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Sokołowski DR, Hansen TI, Rise HH, Reitlo LS, Wisløff U, Stensvold D, Håberg AK. 5 Years of Exercise Intervention Did Not Benefit Cognition Compared to the Physical Activity Guidelines in Older Adults, but Higher Cardiorespiratory Fitness Did. A Generation 100 Substudy. Front Aging Neurosci 2021; 13:742587. [PMID: 34867275 PMCID: PMC8637860 DOI: 10.3389/fnagi.2021.742587] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 10/14/2021] [Indexed: 12/13/2022] Open
Abstract
Background: Aerobic exercise is proposed to attenuate cognitive decline in aging. We investigated the effect of different aerobic exercise interventions and cardiorespiratory fitness (CRF) upon cognition throughout a 5-year exercise intervention in older adults. Methods: 106 older adults (52 women, age 70-77 years) were randomized into high-intensity interval training (HIIT; ∼90% peak heart rate), moderate-intensity continuous training (MICT; ∼70% peak heart rate), or control for 5 years. The HIIT and MICT groups performed supervised training twice weekly, while the control group was asked to follow the national physical activity guidelines (30 min of physical activity/day). At baseline, 1-, 3-, and 5-year follow-up, participants partook in cognitive testing (spatial memory, verbal memory, pattern separation, processing speed, working memory, and planning ability), underwent clinical testing, and filled out health-related questionnaires. Linear mixed models were used to assess the effects of the exercise group and CRF (measured as peak and max oxygen uptake) on each cognitive test. The effects of changes in CRF on changes in each cognitive test score throughout the intervention were also assessed. The associations between baseline CRF and cognitive abilities at the follow-ups were investigated using linear regressions. Results: There was no group-by-time interaction on the cognitive measures, and neither HIIT nor MICT participation was associated with better cognitive performance than control at any time point during the 5-year intervention. All groups increased their CRF similarly during the 1st year and subsequently declined back to baseline levels after 5 years. A higher CRF was associated with higher processing speed throughout the intervention while increasing CRF during the intervention was associated with better working memory and worse pattern separation. Higher CRF at baseline predicted consistently better processing speed and verbal memory performance. Conclusion: In this first 5-year randomized controlled trial investigating the effects of HIIT, MICT, and physical activity according to national guidelines on cognition, we observed no effect of exercise intervention group on cognition when compared to following the national physical activity guidelines. Still, the results showed that higher CRF and increasing CRF benefited multiple, but not all, cognitive abilities in older adults. Clinical Trial Registration:www.ClinicalTrials.gov, identifier [NCT01666340].
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Affiliation(s)
- Daniel R Sokołowski
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Radiology and Nuclear Medicine, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Tor I Hansen
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Radiology and Nuclear Medicine, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Henning H Rise
- Department of Radiology and Nuclear Medicine, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Line S Reitlo
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Radiology and Nuclear Medicine, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Ulrik Wisløff
- Cardiac Exercise Research Group, Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway.,School of Human Movement and Nutrition Science, University of Queensland, Brisbane, QLD, Australia
| | - Dorthe Stensvold
- Cardiac Exercise Research Group, Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
| | - Asta K Håberg
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Radiology and Nuclear Medicine, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
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Guzman SJ, Schlögl A, Espinoza C, Zhang X, Suter BA, Jonas P. How connectivity rules and synaptic properties shape the efficacy of pattern separation in the entorhinal cortex-dentate gyrus-CA3 network. NATURE COMPUTATIONAL SCIENCE 2021; 1:830-842. [PMID: 38217181 DOI: 10.1038/s43588-021-00157-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 10/12/2021] [Indexed: 01/15/2024]
Abstract
Pattern separation is a fundamental brain computation that converts small differences in input patterns into large differences in output patterns. Several synaptic mechanisms of pattern separation have been proposed, including code expansion, inhibition and plasticity; however, which of these mechanisms play a role in the entorhinal cortex (EC)-dentate gyrus (DG)-CA3 circuit, a classical pattern separation circuit, remains unclear. Here we show that a biologically realistic, full-scale EC-DG-CA3 circuit model, including granule cells (GCs) and parvalbumin-positive inhibitory interneurons (PV+-INs) in the DG, is an efficient pattern separator. Both external gamma-modulated inhibition and internal lateral inhibition mediated by PV+-INs substantially contributed to pattern separation. Both local connectivity and fast signaling at GC-PV+-IN synapses were important for maximum effectiveness. Similarly, mossy fiber synapses with conditional detonator properties contributed to pattern separation. By contrast, perforant path synapses with Hebbian synaptic plasticity and direct EC-CA3 connection shifted the network towards pattern completion. Our results demonstrate that the specific properties of cells and synapses optimize higher-order computations in biological networks and might be useful to improve the deep learning capabilities of technical networks.
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Affiliation(s)
- S Jose Guzman
- IST Austria, Klosterneuburg, Austria
- Institute of Molecular Biotechnology, Vienna, Austria
| | | | - Claudia Espinoza
- IST Austria, Klosterneuburg, Austria
- Medical University of Austria, Division of Cognitive Neurobiology, Vienna, Austria
| | - Xiaomin Zhang
- IST Austria, Klosterneuburg, Austria
- Brain Research Institute, University of Zürich, Zurich, Switzerland
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Mnemonic Discrimination Deficits in First-Episode Psychosis and a Ketamine Model Suggest Dentate Gyrus Pathology Linked to NMDA Receptor Hypofunction. BIOLOGICAL PSYCHIATRY: COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2021; 6:1185-1192. [PMID: 34649019 DOI: 10.1016/j.bpsc.2021.09.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 08/17/2021] [Accepted: 09/12/2021] [Indexed: 11/23/2022]
Abstract
BACKGROUND Converging evidence from neuroimaging and postmortem studies suggests that hippocampal subfields are differentially affected in schizophrenia. Recent studies report dentate gyrus dysfunction in chronic schizophrenia, but the underlying mechanisms remain to be elucidated. Here, we sought to examine if this deficit is already present in first-episode psychosis and if NMDA receptor hypofunction, a putative central pathophysiological mechanism in schizophrenia, experimentally induced by ketamine, would result in a similar abnormality. METHODS We applied a mnemonic discrimination task selectively taxing pattern separation in two experiments: 1) a group of 23 patients with first-episode psychosis and 23 matched healthy volunteers and 2) a group of 19 healthy volunteers before and during a ketamine challenge (0.27 mg/kg over 10 min, then 0.25 mg/kg/hour for 50 min, 0.01 mL/s). We calculated response bias-corrected pattern separation and recognition scores. We also examined the relationships between task performance and symptom severity as well as ketamine levels. RESULTS We reported a deficit in pattern separation performance in patients with first-episode psychosis compared with healthy volunteers (p = .04) and in volunteers during the ketamine challenge compared with baseline (p = .003). Pattern recognition was lower in patients with first-episode psychosis than in control subjects (p < .01). Exploratory analyses revealed no correlation between task performance and Repeatable Battery for the Assessment of Neuropsychological Status total scores or positive symptoms in patients with first-episode psychosis or with ketamine serum levels. CONCLUSIONS We observed a mnemonic discrimination deficit in both datasets. Our findings suggest a tentative mechanistic link between dentate gyrus dysfunction in first-episode psychosis and NMDA receptor hypofunction.
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Zhu Y, Armstrong JN, Contractor A. Kainate receptors regulate the functional properties of young adult-born dentate granule cells. Cell Rep 2021; 36:109751. [PMID: 34551304 PMCID: PMC8525187 DOI: 10.1016/j.celrep.2021.109751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 07/02/2021] [Accepted: 09/01/2021] [Indexed: 11/06/2022] Open
Abstract
Both inhibitory and excitatory neurotransmitter receptors can influence maturation and survival of adult-born neurons in the dentate gyrus; nevertheless, how these two neurotransmitter systems affect integration of new neurons into the existing circuitry is still not fully characterized. Here, we demonstrate that glutamate receptors of the kainate receptor (KAR) subfamily are expressed in adult-born dentate granule cells (abDGCs) and that, through their interaction with GABAergic signaling mechanisms, they alter the functional properties of adult-born cells during a critical period of their development. Both the intrinsic properties and synaptic connectivity of young abDGCs were affected. Timed KAR loss in a cohort of young adult-born neurons in mice disrupted their performance in a spatial discrimination task but not in a hippocampal-dependent fear conditioning task. Together, these results demonstrate the importance of KARs in the proper functional development of young abDGCs.
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Affiliation(s)
- Yiwen Zhu
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - John N Armstrong
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Anis Contractor
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA; Department of Neurobiology, Northwestern University, Chicago, IL 60611, USA.
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14
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Neonatal Enteropathogenic Escherichia coli Infection Disrupts Microbiota-Gut-Brain Axis Signaling. Infect Immun 2021; 89:e0005921. [PMID: 33820817 DOI: 10.1128/iai.00059-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Diarrheal diseases are a leading cause of death in children under the age of 5 years worldwide. Repeated early-life exposures to diarrheal pathogens can result in comorbidities including stunted growth and cognitive deficits, suggesting an impairment in the microbiota-gut-brain (MGB) axis. Neonatal C57BL/6 mice were infected with enteropathogenic Escherichia coli (EPEC) (strain e2348/69; ΔescV [type III secretion system {T3SS} mutant]) or the vehicle (Luria-Bertani [LB] broth) via orogastric gavage at postnatal day 7 (P7). Behavior (novel-object recognition [NOR] task, light/dark [L/D] box, and open-field test [OFT]), intestinal physiology (Ussing chambers), and the gut microbiota (16S Illumina sequencing) were assessed in adulthood (6 to 8 weeks of age). Neonatal infection of mice with EPEC, but not the T3SS mutant, caused ileal inflammation in neonates and impaired recognition memory (NOR task) in adulthood. Cognitive impairments were coupled with increased neurogenesis (Ki67 and doublecortin immunostaining) and neuroinflammation (increased microglia activation [Iba1]) in adulthood. Intestinal pathophysiology in adult mice was characterized by increased secretory state (short-circuit current [Isc]) and permeability (conductance) (fluorescein isothiocyanate [FITC]-dextran flux) in the ileum and colon of neonatally EPEC-infected mice, along with increased expression of proinflammatory cytokines (Tnfα, Il12, and Il6) and pattern recognition receptors (Nod1/2 and Tlr2/4). Finally, neonatal EPEC infection caused significant dysbiosis of the gut microbiota, including decreased Firmicutes, in adulthood. Together, these findings demonstrate that infection in early life can significantly impair the MGB axis in adulthood.
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15
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Johnston S, Parylak SL, Kim S, Mac N, Lim C, Gallina I, Bloyd C, Newberry A, Saavedra CD, Novak O, Gonçalves JT, Gage FH, Shtrahman M. AAV ablates neurogenesis in the adult murine hippocampus. eLife 2021; 10:59291. [PMID: 34259630 PMCID: PMC8331179 DOI: 10.7554/elife.59291] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 07/13/2021] [Indexed: 12/14/2022] Open
Abstract
Recombinant adeno-associated virus (rAAV) has been widely used as a viral vector across mammalian biology and has been shown to be safe and effective in human gene therapy. We demonstrate that neural progenitor cells (NPCs) and immature dentate granule cells (DGCs) within the adult murine hippocampus are particularly sensitive to rAAV-induced cell death. Cell loss is dose dependent and nearly complete at experimentally relevant viral titers. rAAV-induced cell death is rapid and persistent, with loss of BrdU-labeled cells within 18 hr post-injection and no evidence of recovery of adult neurogenesis at 3 months post-injection. The remaining mature DGCs appear hyperactive 4 weeks post-injection based on immediate early gene expression, consistent with previous studies investigating the effects of attenuating adult neurogenesis. In vitro application of AAV or electroporation of AAV2 inverted terminal repeats (ITRs) is sufficient to induce cell death. Efficient transduction of the dentategyrus (DG)– without ablating adult neurogenesis– can be achieved by injection of rAAV2-retro serotyped virus into CA3. rAAV2-retro results in efficient retrograde labeling of mature DGCs and permits in vivo two-photon calcium imaging of dentate activity while leaving adult neurogenesis intact. These findings expand on recent reports implicating rAAV-linked toxicity in stem cells and other cell types and suggest that future work using rAAV as an experimental tool in the DG and as a gene therapy for diseases of the central nervous system should be carefully evaluated.
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Affiliation(s)
- Stephen Johnston
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, United States.,Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, United States
| | - Sarah L Parylak
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, United States
| | - Stacy Kim
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, United States.,Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Nolan Mac
- Department of Biology, University of California, San Diego, La Jolla, United States
| | - Christina Lim
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, United States
| | - Iryna Gallina
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, United States
| | - Cooper Bloyd
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, United States
| | - Alexander Newberry
- Department of Physics, University of California, San Diego, La Jolla, United States
| | - Christian D Saavedra
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, United States
| | - Ondrej Novak
- Laboratory of Experimental Epileptology, Department of Physiology, Second Faculty of Medicine, Charles University, Prague, United Kingdom
| | - J Tiago Gonçalves
- Ruth L. and David S. Gottesman Institute for Stem Cell Biology and Regenerative Medicine, Albert Einstein College of Medicine, Bronx, United States.,Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, United States
| | - Fred H Gage
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, United States
| | - Matthew Shtrahman
- Department of Neurosciences, University of California, San Diego, La Jolla, United States
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16
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Gozel O, Gerstner W. A functional model of adult dentate gyrus neurogenesis. eLife 2021; 10:66463. [PMID: 34137370 PMCID: PMC8260225 DOI: 10.7554/elife.66463] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 06/16/2021] [Indexed: 12/27/2022] Open
Abstract
In adult dentate gyrus neurogenesis, the link between maturation of newborn neurons and their function, such as behavioral pattern separation, has remained puzzling. By analyzing a theoretical model, we show that the switch from excitation to inhibition of the GABAergic input onto maturing newborn cells is crucial for their proper functional integration. When the GABAergic input is excitatory, cooperativity drives the growth of synapses such that newborn cells become sensitive to stimuli similar to those that activate mature cells. When GABAergic input switches to inhibitory, competition pushes the configuration of synapses onto newborn cells toward stimuli that are different from previously stored ones. This enables the maturing newborn cells to code for concepts that are novel, yet similar to familiar ones. Our theory of newborn cell maturation explains both how adult-born dentate granule cells integrate into the preexisting network and why they promote separation of similar but not distinct patterns.
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Affiliation(s)
- Olivia Gozel
- School of Life Sciences and School of Computer and Communication Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Departments of Neurobiology and Statistics, University of Chicago, Chicago, United States.,Grossman Center for Quantitative Biology and Human Behavior, University of Chicago, Chicago, United States
| | - Wulfram Gerstner
- School of Life Sciences and School of Computer and Communication Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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17
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Hiscox LV, Schwarb H, McGarry MDJ, Johnson CL. Aging brain mechanics: Progress and promise of magnetic resonance elastography. Neuroimage 2021; 232:117889. [PMID: 33617995 PMCID: PMC8251510 DOI: 10.1016/j.neuroimage.2021.117889] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/12/2021] [Accepted: 02/15/2021] [Indexed: 02/07/2023] Open
Abstract
Neuroimaging techniques that can sensitivity characterize healthy brain aging and detect subtle neuropathologies have enormous potential to assist in the early detection of neurodegenerative conditions such as Alzheimer's disease. Magnetic resonance elastography (MRE) has recently emerged as a reliable, high-resolution, and especially sensitive technique that can noninvasively characterize tissue biomechanical properties (i.e., viscoelasticity) in vivo in the living human brain. Brain tissue viscoelasticity provides a unique biophysical signature of neuroanatomy that are representative of the composition and organization of the complex tissue microstructure. In this article, we detail how progress in brain MRE technology has provided unique insights into healthy brain aging, neurodegeneration, and structure-function relationships. We further discuss additional promising technical innovations that will enhance the specificity and sensitivity for brain MRE to reveal considerably more about brain aging as well as its potentially valuable role as an imaging biomarker of neurodegeneration. MRE sensitivity may be particularly useful for assessing the efficacy of rehabilitation strategies, assisting in differentiating between dementia subtypes, and in understanding the causal mechanisms of disease which may lead to eventual pharmacotherapeutic development.
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Affiliation(s)
- Lucy V Hiscox
- Department of Biomedical Engineering, University of Delaware, 150 Academy St. Newark, Newark, DE 19716, United States.
| | - Hillary Schwarb
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States; Interdisciplinary Health Sciences Institute, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | | | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, 150 Academy St. Newark, Newark, DE 19716, United States.
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18
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Sossin WS, Anadolu MN, Langille JJ. Neuroscience: A New Pathway to Make Us Smarter and Happier. Curr Biol 2021; 30:R1051-R1054. [PMID: 32961162 DOI: 10.1016/j.cub.2020.07.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Treatments that improve cognition and decrease depression converge on decreasing phosphorylation of eukaryotic elongation factor 2 (eEF2). This decrease is sufficient to lead to altered levels of proteins that cause an increase in new neurons, improved cognition and less depression.
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Affiliation(s)
- Wayne S Sossin
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, Canada.
| | - Mina N Anadolu
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, Canada
| | - Jesse J Langille
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, Canada
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19
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Training level reveals a dynamic dialogue between stress and memory systems in birds. Behav Brain Res 2021; 408:113280. [PMID: 33819534 DOI: 10.1016/j.bbr.2021.113280] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 03/19/2021] [Accepted: 03/30/2021] [Indexed: 02/05/2023]
Abstract
Chronic stress profoundly affects forms of declarative memory, such as spatial memory, while it may spare non-declarative memory, such as cue-based memory. It is known, however, that the effects of chronic stress on memory systems may vary according to the level of training of an individual was submitted. Here, we investigated, in birds, how chronic stress impact spatial and cue-based memories according to training level. For that, control and chronically stressed Japanese quail were trained in a task that could be solved using spatial and cue-based memory and tested for their memory performance after 5 and 15 training days (initial training and overtraining, respectively) and following an emotional challenge (exposure to an open field). Our results showed that, compared to control quail, chronic stress impacted negatively spatial memory performances in stressed birds after initial training, but these differences were lowered after overtraining. Control birds seemed to shift from spatial to cue-based memory to solve the task across overtraining. However, an emotional challenge before testing reinstated the negative impact of chronic stress on spatial memory performances between the groups, revealing that chronic stress/overtraining did not eliminate the spatial memory and differences caused by stressors can reemerge depending on the individual's immediate psychological state. Contrary to spatial memory, cue-based memory was not affected in chronically stressed birds compared to control birds in any test occasion, confirming its resistance against the negative effects of chronic stress. Altogether these findings reveal a dynamic dialogue between stress, training level, and memory systems in birds.
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20
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Büeler H. Mitochondrial and Autophagic Regulation of Adult Neurogenesis in the Healthy and Diseased Brain. Int J Mol Sci 2021; 22:ijms22073342. [PMID: 33805219 PMCID: PMC8036818 DOI: 10.3390/ijms22073342] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/18/2021] [Accepted: 03/19/2021] [Indexed: 02/07/2023] Open
Abstract
Adult neurogenesis is a highly regulated process during which new neurons are generated from neural stem cells in two discrete regions of the adult brain: the subventricular zone of the lateral ventricle and the subgranular zone of the dentate gyrus in the hippocampus. Defects of adult hippocampal neurogenesis have been linked to cognitive decline and dysfunction during natural aging and in neurodegenerative diseases, as well as psychological stress-induced mood disorders. Understanding the mechanisms and pathways that regulate adult neurogenesis is crucial to improving preventative measures and therapies for these conditions. Accumulating evidence shows that mitochondria directly regulate various steps and phases of adult neurogenesis. This review summarizes recent findings on how mitochondrial metabolism, dynamics, and reactive oxygen species control several aspects of adult neural stem cell function and their differentiation to newborn neurons. It also discusses the importance of autophagy for adult neurogenesis, and how mitochondrial and autophagic dysfunction may contribute to cognitive defects and stress-induced mood disorders by compromising adult neurogenesis. Finally, I suggest possible ways to target mitochondrial function as a strategy for stem cell-based interventions and treatments for cognitive and mood disorders.
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Affiliation(s)
- Hansruedi Büeler
- School of Life Sciences and Technology, Harbin Institute of Technology, Harbin 150080, China
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21
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Hippocampal volume and navigational ability: The map(ping) is not to scale. Neurosci Biobehav Rev 2021; 126:102-112. [PMID: 33722618 DOI: 10.1016/j.neubiorev.2021.03.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/19/2021] [Accepted: 03/08/2021] [Indexed: 11/22/2022]
Abstract
A critical question regards the neural basis of complex cognitive skill acquisition. One extensively studied skill is navigation, with evidence suggesting that humans vary widely in navigation abilities. Yet, data supporting the neural underpinning of these individual differences are mixed. Some evidence suggests robust structure-behavior relations between hippocampal volume and navigation ability, whereas other experiments show no such correlation. We focus on several possibilities for these discrepancies: 1) volumetric hippocampal changes are relevant only at the extreme ranges of navigational abilities; 2) hippocampal volume correlates across individuals but only for specific measures of navigation skill; 3) hippocampal volume itself does not correlate with navigation skill acquisition; connectivity patterns are more relevant. To explore this third possibility, we present a model emphasizing functional connectivity changes, particularly to extra-hippocampal structures. This class of models arises from the premise that navigation is dynamic and that good navigators flexibly solve spatial challenges. These models pave the way for research on other skills and provide more precise predictions for the neural basis of skill acquisition.
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22
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Wang J, Feng Z, Ren X, Lu N, Luo J, Sun L. Feature subset and time segment selection for the classification of EEG data based motor imagery. Biomed Signal Process Control 2020. [DOI: 10.1016/j.bspc.2020.102026] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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23
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Luján MÁ, Cantacorps L, Valverde O. The pharmacological reduction of hippocampal neurogenesis attenuates the protective effects of cannabidiol on cocaine voluntary intake. Addict Biol 2020; 25:e12778. [PMID: 31162770 DOI: 10.1111/adb.12778] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 02/26/2019] [Accepted: 05/02/2019] [Indexed: 12/24/2022]
Abstract
The administration of cannabidiol has shown promising evidence in the treatment of some neuropsychiatric disorders, including cocaine addiction. However, little information is available as to the mechanisms by which cannabidiol reduces drug use and compulsive seeking. We investigated the role of adult hippocampal neurogenesis in reducing cocaine voluntary intake produced by repeated cannabidiol treatment in mice. Cocaine intake was modelled using the intravenous cocaine self-administration procedure in CD1 male mice. Cannabidiol (20 mg/kg) reduced cocaine self-administration behaviour acquisition and total cocaine intake and enhanced adult hippocampal neurogenesis. Our results show that a 6-day repeated temozolomide treatment (25 mg/kg/day), a chemotherapy drug that blocks hippocampal neurogenesis, prevented cannabidiol-induced increment in the early stages of neuronal maturation and differentiation, without altering the basal levels of BrdU/NeuN and doublecortin immunostaining. The reduction of total cocaine intake and operant behaviour acquisition observed following cannabidiol exposure was attenuated by temozolomide treatment. Our results also show a similar effect of temozolamide on a cannabidiol-induced improvement of novel object recognition memory, a task influenced by the proneurogenic effects of cannabidiol (10 and 20 mg/kg). The anxiolytic effects of cannabidiol (10 and 20 mg/kg), however, remained unaffected after its proneurogenic effects decreased. The present study confirms that adult hippocampal neurogenesis is one of the mechanisms by which cannabidiol lowers cocaine reinforcement and demonstrates the functional implication of adult hippocampal neurogenesis in cocaine voluntary consumption in mice. Such findings highlight the possible use of cannabidiol for developing new pharmacotherapies to manage cocaine use disorders.
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Affiliation(s)
- Miguel Ángel Luján
- Neurobiology of Behaviour Research Group (GReNeC—NeuroBio), Department of Experimental and Health Sciences Universitat Pompeu Fabra Barcelona Spain
| | - Lídia Cantacorps
- Neurobiology of Behaviour Research Group (GReNeC—NeuroBio), Department of Experimental and Health Sciences Universitat Pompeu Fabra Barcelona Spain
| | - Olga Valverde
- Neurobiology of Behaviour Research Group (GReNeC—NeuroBio), Department of Experimental and Health Sciences Universitat Pompeu Fabra Barcelona Spain
- Neuroscience Research Programme IMIM‐Hospital del Mar Research Institute Barcelona Spain
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24
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Murray KD, Liu XB, King AN, Luu JD, Cheng HJ. Age-Related Changes in Synaptic Plasticity Associated with Mossy Fiber Terminal Integration during Adult Neurogenesis. eNeuro 2020; 7:ENEURO.0030-20.2020. [PMID: 32332082 PMCID: PMC7240290 DOI: 10.1523/eneuro.0030-20.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 03/27/2020] [Accepted: 04/12/2020] [Indexed: 12/17/2022] Open
Abstract
Mouse hippocampus retains the capacity for neurogenesis throughout lifetime, but such plasticity decreases with age. Adult hippocampal neurogenesis (AHN) involves the birth, maturation, and synaptic integration of newborn granule cells (GCs) into preexisting hippocampal circuitry. While functional integration onto adult-born GCs has been extensively studied, maturation of efferent projections onto CA3 pyramidal cells is less understood, particularly in aged brain. Here, using combined light and reconstructive electron microscopy (EM), we describe the maturation of mossy fiber bouton (MFB) connectivity with CA3 pyramidal cells in young adult and aged mouse brain. We found mature synaptic contacts of newborn GCs were formed in both young and aged brains. However, the dynamics of their spatiotemporal development and the cellular process by which these cells functionally integrated over time were different. In young brain newborn GCs either formed independent nascent MFB synaptic contacts or replaced preexisting MFBs, but these contacts were pruned over time to a mature state. In aged brain only replacement of preexisting MFBs was observed and new contacts were without evidence of pruning. These data illustrate that functional synaptic integration of AHN occurs in young adult and aged brain, but with distinct dynamics. They suggest elimination of preexisting connectivity is required for the integration of adult-born GCs in aged brain.
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Affiliation(s)
- Karl D Murray
- Center for Neuroscience
- Department of Psychiatry and Behavioral Neuroscience
| | | | | | | | - Hwai-Jong Cheng
- Center for Neuroscience
- Department of Neurobiology, Physiology and behavior
- Department of Pathology and Laboratory Medicine, University of California, Davis, Davis, CA 95618
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25
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Daugherty AM, Schwarb HD, McGarry MDJ, Johnson CL, Cohen NJ. Magnetic Resonance Elastography of Human Hippocampal Subfields: CA3-Dentate Gyrus Viscoelasticity Predicts Relational Memory Accuracy. J Cogn Neurosci 2020; 32:1704-1713. [PMID: 32379003 DOI: 10.1162/jocn_a_01574] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The hippocampus is necessary for binding and reconstituting information in relational memory. These essential memory functions are supported by the distinct cytoarchitecture of the hippocampal subfields. Magnetic resonance elastography is an emerging tool that provides sensitive estimates of microstructure vis-à-vis tissue mechanical properties. Here, we report the first in vivo study of human hippocampal subfield viscoelastic stiffness and damping ratio. Stiffness describes resistance of a viscoelastic tissue to a stress and is thought to reflect the relative composition of tissue at the microscale; damping ratio describes relative viscous-to-elastic behavior and is thought to generally reflect microstructural organization. Measures from the subiculum (combined with presubiculum and parasubiculum), cornu ammonis (CA) 1-2, and CA3-dentate gyrus (CA3-DG) were collected in a sample of healthy, cognitively normal men (n = 20, age = 18-33 years). In line with known cytoarchitecture, the subiculum demonstrated the lowest damping ratio, followed by CA3-DG and then combined CA1-CA2. Moreover, damping ratio of the CA3-DG-potentially reflective of number of cells and their connections-predicted relational memory accuracy and alone replicated most of the variance in performance that was explained by the whole hippocampus. Stiffness did not differentiate the hippocampal subfields and was unrelated to task performance in this sample. Viscoelasticity measured with magnetic resonance elastography appears to be sensitive to microstructural properties relevant to specific memory function, even in healthy younger adults, and is a promising tool for future studies of hippocampal structure in aging and related diseases.
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Hassanpoor H, Saidi M. An investigation into the effective role of astrocyte in the hippocampus pattern separation process: A computational modeling study. J Theor Biol 2020; 487:110114. [PMID: 31836505 DOI: 10.1016/j.jtbi.2019.110114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 11/15/2019] [Accepted: 12/09/2019] [Indexed: 11/29/2022]
Abstract
A physiologically realistic three layer neuron-astrocyte network model is used to evaluate the biological mechanism in pattern separation. The innovative feature of the model is the use of a combination of three elements: neuron, interneuron and astrocyte. In the input layer, a pyramidal neuron receives input patterns from stimulus current, while in the middle layer there are two pyramidal neurons coupled with two inhibitory interneurons and an astrocyte. Finally, in the third layer, a pyramidal neuron produces the output of the model by integrating the output of two neurons from the middle layer resulting from inhibitory and excitatory connections among neurons, interneurons and the astrocyte. Results of computer simulations show that the neuron-astrocyte network within the hippocampal dentate gyrus can generate diverse, complex and different output patterns to given inputs. It is concluded that astrocytes within the dentate gyrus play an important role in the pattern separation process.
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Affiliation(s)
- Hossein Hassanpoor
- Department of Cognitive Science, Dade Pardazi, Shenakht Mehvar, Atynegar (DSA) Institute, Tehran, Iran.
| | - Maryam Saidi
- Department of Cognitive Science, Dade Pardazi, Shenakht Mehvar, Atynegar (DSA) Institute, Tehran, Iran
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27
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Increasing neurogenesis refines hippocampal activity rejuvenating navigational learning strategies and contextual memory throughout life. Nat Commun 2020; 11:135. [PMID: 31919362 PMCID: PMC6952376 DOI: 10.1038/s41467-019-14026-z] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 12/12/2019] [Indexed: 01/24/2023] Open
Abstract
Functional plasticity of the brain decreases during ageing causing marked deficits in contextual learning, allocentric navigation and episodic memory. Adult neurogenesis is a prime example of hippocampal plasticity promoting the contextualisation of information and dramatically decreases during ageing. We found that a genetically-driven expansion of neural stem cells by overexpression of the cell cycle regulators Cdk4/cyclinD1 compensated the age-related decline in neurogenesis. This triggered an overall inhibitory effect on the trisynaptic hippocampal circuit resulting in a changed profile of CA1 sharp-wave ripples known to underlie memory consolidation. Most importantly, increased neurogenesis rescued the age-related switch from hippocampal to striatal learning strategies by rescuing allocentric navigation and contextual memory. Our study demonstrates that critical aspects of hippocampal function can be reversed in old age, or compensated throughout life, by exploiting the brain’s endogenous reserve of neural stem cells. Ageing affects several brain areas causing a decrease in cognitive abilities and memory. We find that increasing the endogenous potential of the hippocampus to generate new neurons throughout life rejuvenates learning and memory, indicating that neural reserves can be exploited during ageing to compensate for age- or disease-related cognitive impairments.
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Akt dependent adult hippocampal neurogenesis regulates the behavioral improvement of treadmill running to mice model of post-traumatic stress disorder. Behav Brain Res 2019; 379:112375. [PMID: 31759046 DOI: 10.1016/j.bbr.2019.112375] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 11/19/2019] [Accepted: 11/19/2019] [Indexed: 02/07/2023]
Abstract
Physical exercise is well-established paradigm for improving adult neurogenesis and brain functions. As considered as an alternative therapeutic strategy, treadmill running could reduce cognitive impairment and psychiatric abnormalities associating post-traumatic stress disorder (PTSD), which might associate with the promote effects to adult neurogenesis. In current study, we aimed to address how treadmill exercise benefit adult hippocampal neurogenesis in PTSD model and the underlying molecular mechanism related with Akt signaling. PTSD was induced by exposure to aggressor and treatments were conducted with different intensity of compulsory treadmill running. We observed treadmill running improved hippocampal neurogenesis including proliferation and neural differentiation of neural stem cells (NSCs). Moreover, behavioral tests showed treadmill could attenuate the cognitive deficit and depressive/anxiety like behaviors in correlating with PTSD model. Moreover, treadmill running recovered the Akt activity in hippocampus. Interrupting treadmill running administrated mice with Akt inhibitor GSK690693 resulted in the blocked the effects of treadmill running to hippocampal neurogenesis and behavioral improvement in PTSD mice model. In conclusion, treadmill running could mediate behavioral functions and improve hippocampal neurogenesis in PTSD model by regulating Akt signaling.
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29
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Terranova JI, Ogawa SK, Kitamura T. Adult hippocampal neurogenesis for systems consolidation of memory. Behav Brain Res 2019; 372:112035. [DOI: 10.1016/j.bbr.2019.112035] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 06/07/2019] [Accepted: 06/11/2019] [Indexed: 12/11/2022]
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30
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Hassevoort KM, Khan NA, Hillman CH, Cohen NJ. Differential development of relational memory and pattern separation. Hippocampus 2019; 30:210-219. [PMID: 31369174 DOI: 10.1002/hipo.23146] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 07/15/2019] [Accepted: 07/19/2019] [Indexed: 11/09/2022]
Abstract
Researchers have taken a number of different approaches in their exploration of hippocampal function. One approach seeks to describe hippocampal function by probing the memory representations that the hippocampus supports. Another approach focuses on the role of the hippocampus in pattern separation and completion. Each of these approaches to understanding hippocampal function utilizes a distinct set of specialized tasks, and both of these task sets are known to be sensitive to changes in hippocampal function with age and disease status. But the question remains whether the tasks utilized in these two approaches tap into the same aspects of hippocampal function. We explored this question in the context of hippocampal development. Preadolescent children (N = 73) and young adults (N = 41) completed an identical battery of cognitive tasks consisting of a spatial reconstruction relational memory task, the mnemonic similarity task (MST)-an object-based pattern separation task, and a novel hybrid task-the Object Discrimination and Distribution (ODD) Task-designed to integrate and simultaneously tax pattern separation and spatial relational memory. Children did not demonstrate impairments in lure discrimination relative to young adults on either the object-based pattern separation task or for aspects of the ODD task that required pattern separation in the absence of relational memory demands but performed more poorly across aspects of tasks that required relational binding.
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Affiliation(s)
- Kelsey M Hassevoort
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Center for Brain Plasticity, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Naiman A Khan
- Department of Kinesiology & Community Health, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Charles H Hillman
- Department of Psychology, Northeastern University, Boston, Massachusetts.,Department of Physical Therapy, Movement, & Rehabilitation Sciences, Northeastern University, Boston, Massachusetts
| | - Neal J Cohen
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Center for Brain Plasticity, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Department of Psychology, University of Illinois at Urbana-Champaign, Urbana, Illinois
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31
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Synaptic properties of newly generated granule cells support sparse coding in the adult hippocampus. Behav Brain Res 2019; 372:112036. [PMID: 31201871 DOI: 10.1016/j.bbr.2019.112036] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 06/06/2019] [Accepted: 06/11/2019] [Indexed: 12/14/2022]
Abstract
In the adult hippocampus new neurons are continuously generated throughout life and integrate into the existing network via the formation of thousands of new synapses. Adult-born granule cells are known to improve learning and memory at about 3-6 weeks post mitosis by enhancing the brains ability to discriminate similar memory items. However, the underlying mechanisms are still controversial. Here we review the distinct functional properties of the newborn young neurons, including enhanced excitability, reduced GABAergic inhibition, NMDA-receptor dependent electrogenesis and enhanced synaptic plasticity. Although these cellular properties provide a competitive advantage for synapse formation, they do not generate 'hyperactivity' of young neurons. By contrast, in vivo evidence from immediate early gene expression and calcium imaging indicates that young neurons show sparse activity during learning. Similarly, in vitro data show a low number of high-impact synapses, leading to activation young cells by distinct subsets of afferent fibers with minimal overlap. Overall, the enhanced excitability of young cells does not generate hyperactivity but rather counterbalance the low number of excitatory input synapses. Finally, sparse coding in young neurons has been shown to be crucial for neurogenesis-dependent improvement of learning behavior. Taken together, converging evidence from cell physiology and behavioral studies suggests a mechanism that can explain the beneficial effects of adult neurogenesis on brain function.
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32
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Ngwenya LB, Danzer SC. Impact of Traumatic Brain Injury on Neurogenesis. Front Neurosci 2019; 12:1014. [PMID: 30686980 PMCID: PMC6333744 DOI: 10.3389/fnins.2018.01014] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 12/17/2018] [Indexed: 12/21/2022] Open
Abstract
New neurons are generated in the hippocampal dentate gyrus from early development through adulthood. Progenitor cells and immature granule cells in the subgranular zone are responsive to changes in their environment; and indeed, a large body of research indicates that neuronal interactions and the dentate gyrus milieu regulates granule cell proliferation, maturation, and integration. Following traumatic brain injury (TBI), these interactions are dramatically altered. In addition to cell losses from injury and neurotransmitter dysfunction, patients often show electroencephalographic evidence of cortical spreading depolarizations and seizure activity after TBI. Furthermore, treatment for TBI often involves interventions that alter hippocampal function such as sedative medications, neuromodulating agents, and anti-epileptic drugs. Here, we review hippocampal changes after TBI and how they impact the coordinated process of granule cell adult neurogenesis. We also discuss clinical TBI treatments that have the potential to alter neurogenesis. A thorough understanding of the impact that TBI has on neurogenesis will ultimately be needed to begin to design novel therapeutics to promote recovery.
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Affiliation(s)
- Laura B Ngwenya
- Department of Neurosurgery, University of Cincinnati, Cincinnati, OH, United States.,Department of Neurology and Rehabilitation Medicine, University of Cincinnati, Cincinnati, OH, United States.,Neurotrauma Center, University of Cincinnati Gardner Neuroscience Institute, Cincinnati, OH, United States
| | - Steve C Danzer
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Department of Anesthesia, University of Cincinnati, Cincinnati, OH, United States.,Center for Pediatric Neuroscience, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Department of Pediatrics, University of Cincinnati, Cincinnati, OH, United States
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33
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Llorens-Martín M. Exercising New Neurons to Vanquish Alzheimer Disease. Brain Plast 2018; 4:111-126. [PMID: 30564550 PMCID: PMC6296267 DOI: 10.3233/bpl-180065] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/21/2018] [Indexed: 02/07/2023] Open
Abstract
Alzheimer disease (AD) is the most common type of dementia in individuals over 65 years of age. The neuropathological hallmarks of the condition are Tau neurofibrillary tangles and Amyloid-β senile plaques. Moreover, certain susceptible regions of the brain experience a generalized lack of neural plasticity and marked synaptic alterations during the progression of this as yet incurable disease. One of these regions, the hippocampus, is characterized by the continuous addition of new neurons throughout life. This phenomenon, named adult hippocampal neurogenesis (AHN), provides a potentially endless source of new synaptic elements that increase the complexity and plasticity of the hippocampal circuitry. Numerous lines of evidence show that physical activity and environmental enrichment (EE) are among the most potent positive regulators of AHN. Given that neural plasticity is markedly decreased in many neurodegenerative diseases, the therapeutic potential of making certain lifestyle changes, such as increasing physical activity, is being recognised in several non-pharmacologic strategies seeking to slow down or prevent the progression of these diseases. This review article summarizes current evidence supporting the putative therapeutic potential of EE and physical exercise to increase AHN and hippocampal plasticity both under physiological and pathological circumstances, with a special emphasis on neurodegenerative diseases and AD.
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Affiliation(s)
- María Llorens-Martín
- Department of Molecular Neuropathology, Centro de Biología Molecular “Severo Ochoa”, CBMSO, CSIC-UAM, Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases CIBERNED, Madrid, Spain
- Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
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Ray S, Corenblum MJ, Anandhan A, Reed A, Ortiz FO, Zhang DD, Barnes CA, Madhavan L. A Role for Nrf2 Expression in Defining the Aging of Hippocampal Neural Stem Cells. Cell Transplant 2018; 27:589-606. [PMID: 29871525 PMCID: PMC6041888 DOI: 10.1177/0963689718774030] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Redox mechanisms are emerging as essential to stem cell function given their capacity to
influence a number of important signaling pathways governing stem cell survival and
regenerative activity. In this context, our recent work identified the reduced expression
of nuclear factor (erythroid-derived 2)-like 2, or Nrf2, in mediating the decline in
subventricular zone neural stem progenitor cell (NSPC) regeneration during aging. Since
Nrf2 is a major transcription factor at the heart of cellular redox regulation and
homeostasis, the current study investigates the role that it may play in the aging of
NSPCs that reside within the other major mammalian germinal niche located in the
subgranular zone (SGZ) of the dentate gyrus (DG) of the hippocampus. Using rats from
multiple aging stages ranging from newborn to old age, and aging Nrf2 knockout mice, we
first determined that, in contrast with subventricular zone (SVZ) NSPCs, Nrf2 expression
does not significantly affect overall DG NSPC viability with age. However, DG NSPCs
resembled SVZ stem cells, in that Nrf2 expression controlled their proliferation and the
balance of neuronal versus glial differentiation particularly in relation to a specific
critical period during middle age. Also, importantly, this Nrf2-based control of NSPC
regeneration was found to impact functional neurogenesis-related hippocampal behaviors,
particularly in the Morris water maze and in pattern separation tasks. Furthermore, the
enrichment of the hippocampal environment via the transplantation of Nrf2-overexpressing
NSPCs was able to mitigate the age-related decline in DG stem cell regeneration during the
critical middle-age period, and significantly improved pattern separation abilities. In
summary, these results emphasize the importance of Nrf2 in DG NSPC regeneration, and
support Nrf2 upregulation as a potential approach to advantageously modulate DG NSPC
activity with age.
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Affiliation(s)
- S Ray
- 1 Department of Neurology, University of Arizona, Tucson, AZ, USA.,2 Undergraduate Biology Research Program, University of Arizona, Tucson, AZ, USA.,3 Neuroscience and Cognitive Science Undergraduate Program, Tucson, AZ, USA
| | - M J Corenblum
- 1 Department of Neurology, University of Arizona, Tucson, AZ, USA
| | - A Anandhan
- 1 Department of Neurology, University of Arizona, Tucson, AZ, USA
| | - A Reed
- 1 Department of Neurology, University of Arizona, Tucson, AZ, USA.,3 Neuroscience and Cognitive Science Undergraduate Program, Tucson, AZ, USA
| | - F O Ortiz
- 1 Department of Neurology, University of Arizona, Tucson, AZ, USA.,3 Neuroscience and Cognitive Science Undergraduate Program, Tucson, AZ, USA
| | - D D Zhang
- 4 Pharmacology and Toxicology, University of Arizona, Tucson, AZ, USA
| | - C A Barnes
- 5 Departments of Psychology & Neuroscience, University of Arizona, Tucson, AZ, USA.,6 Evelyn F. McKnight Brain Institute, University of Arizona, Tucson, AZ, USA
| | - L Madhavan
- 1 Department of Neurology, University of Arizona, Tucson, AZ, USA.,6 Evelyn F. McKnight Brain Institute, University of Arizona, Tucson, AZ, USA
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35
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Kumaran D, Hassabis D, McClelland JL. What Learning Systems do Intelligent Agents Need? Complementary Learning Systems Theory Updated. Trends Cogn Sci 2018; 20:512-534. [PMID: 27315762 DOI: 10.1016/j.tics.2016.05.004] [Citation(s) in RCA: 222] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 04/22/2016] [Accepted: 05/03/2016] [Indexed: 12/17/2022]
Abstract
We update complementary learning systems (CLS) theory, which holds that intelligent agents must possess two learning systems, instantiated in mammalians in neocortex and hippocampus. The first gradually acquires structured knowledge representations while the second quickly learns the specifics of individual experiences. We broaden the role of replay of hippocampal memories in the theory, noting that replay allows goal-dependent weighting of experience statistics. We also address recent challenges to the theory and extend it by showing that recurrent activation of hippocampal traces can support some forms of generalization and that neocortical learning can be rapid for information that is consistent with known structure. Finally, we note the relevance of the theory to the design of artificial intelligent agents, highlighting connections between neuroscience and machine learning.
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Affiliation(s)
- Dharshan Kumaran
- Google DeepMind, 5 New Street Square, London EC4A 3TW, UK; Institute of Cognitive Neuroscience, University College London, 17 Queen Square, WC1N 3AR, UK.
| | - Demis Hassabis
- Google DeepMind, 5 New Street Square, London EC4A 3TW, UK; Gatsby Computational Neuroscience Unit, 17 Queen Square, London WC1N 3AR, UK.
| | - James L McClelland
- Department of Psychology and Center for Mind, Brain, and Computation, Stanford University, 450 Serra Mall, CA 94305, USA.
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36
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Birch AM, Kelly ÁM. Lifelong environmental enrichment in the absence of exercise protects the brain from age-related cognitive decline. Neuropharmacology 2018; 145:59-74. [PMID: 29630903 DOI: 10.1016/j.neuropharm.2018.03.042] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 03/30/2018] [Accepted: 03/31/2018] [Indexed: 12/19/2022]
Abstract
Environmental manipulations enhance neuroplasticity, with enrichment-induced cognitive improvements linked to increased expression of growth factors and enhanced hippocampal neurogenesis. Environmental enrichment (EE) is defined as the addition of social, physical and somatosensory stimulation into an animal's environment via larger group housing, extra objects and, often, running wheels. Previous studies from our laboratory report that physical activity is a potent memory enhancer but that long-term environmental stimulation can be as effective as exercise at ameliorating age-related memory decline. To assess the effects of EE, in the absence of exercise, rats were housed in continuous enriched conditions for 20 months and memory assessed at young, middle aged and aged timepoints. MRI scans were also performed at these timepoints to assess regional changes in grey matter and blood flow with age, and effects of EE upon these measures. Results show an age-related decline in recognition, spatial and working memory that was prevented by EE. A parallel reduction in βNGF in hippocampus, and cell proliferation in the dentate gyrus, was prevented by EE. Furthermore, EE attenuated an age-related increase in apoptosis and expression of pro-inflammatory markers IL-1β and CD68. Long-term EE induced region-specific changes in grey matter intensity and partially rescued age-related reductions in cerebral blood flow. This study demonstrates that sensory enrichment alone can ameliorate many features typical of the ageing brain, such as increases in apoptosis and pro-inflammatory markers. Furthermore, we provide novel data on enrichment-induced regional grey matter alterations and age-related changes in blood flow in the rat. This article is part of the Special Issue entitled "Neurobiology of Environmental Enrichment".
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Affiliation(s)
- Amy M Birch
- Department of Physiology, School of Medicine & Trinity College Institute of Neuroscience & Trinity Biomedical Sciences Institute, University of Dublin, Trinity College, Dublin 2, Ireland
| | - Áine M Kelly
- Department of Physiology, School of Medicine & Trinity College Institute of Neuroscience & Trinity Biomedical Sciences Institute, University of Dublin, Trinity College, Dublin 2, Ireland.
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37
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Kraguljac NV, Carle M, Frölich MA, Tran S, Yassa MA, White DM, Reddy A, Lahti AC. RETRACTED: Mnemonic Discrimination Deficits in First-Episode Psychosis and a Ketamine Model Suggests Dentate Gyrus Pathology Linked to N-Methyl-D-Aspartate Receptor Hypofunction. BIOLOGICAL PSYCHIATRY. COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2018; 3:231-238. [PMID: 29486864 PMCID: PMC5836317 DOI: 10.1016/j.bpsc.2017.02.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 02/19/2017] [Indexed: 01/21/2023]
Abstract
This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). Retraction notice to: “Mnemonic Discrimination Deficits in First-Episode Psychosis and a Ketamine Model Suggests Dentate Gyrus Pathology Linked to N-Methyl-D-Aspartate Receptor Hypofunction” by Nina Vanessa Kraguljac, Matthew Carle, Michael A. Frölich, Steve Tran, Michael A. Yassa, David Matthew White, Abhishek Reddy, and Adrienne Carol Lahti (Biol Psychiatry Cogn Neurosci Neuroimaging 2018; 3:231-238); https://doi.org/10.1016/j.bpsc.2017.02.005. This article has been retracted at the request of Cameron S. Carter, M.D., Editor of Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, with agreement from all authors. The authors discovered an error in the calculation of the response bias–corrected pattern recognition score in this article, which has significantly changed the results for experiment 1. Specifically, the authors discovered that the response bias corrected pattern recognition score was erroneously computed as P(‘old’|target) minus P(‘old’|lure) rather than P(‘old’|target) minus P(‘old’|foil). After re-running statistical analyses with the correct values, the authors found a significant difference in the response bias–corrected pattern recognition score in healthy volunteers (HV) compared with first-episode psychosis (FEP) patients (HV: 84.13 ± 10.96; FEP: 63.70 ± 21.83; t = 4.01; p < .01) in experiment 1. This finding is not consistent with the original report, where the authors reported no group differences in bias-corrected pattern recognition scores (originally reported values: t = 0.93, p = .36). The authors again found no significant correlations between pattern completion scores and BPRS total, positive, or negative symptom scores or RBANS scores, consistent with the original report. In experiment 2, bias-corrected pattern recognition scores did not differ between the saline and ketamine conditions (saline: 78.29 ± 28.04; ketamine: 73.59 ± 18.94; t = 0.81; p = 0.43), which is consistent with the original report (originally reported values: t = −0.69, p = .50). Contrary to the original report, task performance during the saline and ketamine infusions was no longer correlated at trend level for pattern recognition. Repeat analyses showed no correlations between pattern recognition scores during the ketamine challenge and BPRS total, positive, and negative symptom scores, or ketamine plasma levels at either time point, consistent with the original report. The authors have verified that bias-corrected pattern separation scores were calculated correctly for both experiments in the initial report. This error affects the abstract, the results, Figure 1, and discussion of the manuscript. The authors voluntarily informed the Journal of this honest error upon its discovery. Because of the extent and nature of the changes to the paper, the editors and authors concluded that, to ensure maximum clarity and transparency, the only course of action was to retract this version of the paper. The authors are revising the paper, which the Journal will re-review and consider further for publication.
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Affiliation(s)
- Nina Vanessa Kraguljac
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Matthew Carle
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Michael A Frölich
- Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Steve Tran
- Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Michael A Yassa
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, California
| | - David Matthew White
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Abhishek Reddy
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Adrienne Carol Lahti
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama.
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38
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Involvement of Nuclear Receptor REV-ERBβ in Formation of Neurites and Proliferation of Cultured Adult Neural Stem Cells. Cell Mol Neurobiol 2018; 38:1051-1065. [PMID: 29397477 DOI: 10.1007/s10571-018-0576-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 01/27/2018] [Indexed: 01/05/2023]
Abstract
Neural stem cells (NSCs) serve as the source of both neurons and support cells, and neurogenesis is reportedly linked to the circadian clock. This study aimed to clarify the functional role of the circadian rhythm-related nuclear receptor, REV-ERBβ, in neurogenesis of NSCs from adult brain. Accordingly, Rev-erbβ expression and the effect of Rev-erbβ gene-specific knockdown on neurogenesis in vitro was examined in adult rodent NSCs. Initial experiments confirmed REV-ERBβ expression in cultured adult NSCs, while subsequent gene expression and gene ontogeny analyses identified functional genes upregulated or downregulated by REV-ERBβ. In particular, expression levels of factors associated with proliferation, stemness, and neural differentiation were affected. Knockdown of Rev-erbβ showed involvement of REV-ERBβ in regulation of cellular proliferation and self-renewal of cultured adult NSCs. Moreover, Rev-erbβ-knockdown cells formed neurons with a slightly shrunken morphology, fewer new primary neurites, and reduced length and branch formation of neurites. Altogether, this suggests that REV-ERBβ is involved in neurite formation during neuronal differentiation of cultured adult NSCs. In summary, REV-ERBβ is a known circadian regulatory protein that appears to be involved in neurogenesis via regulation of networks for cell proliferation and neural differentiation/maturation in adult NSCs.
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39
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Saraulli D, Costanzi M, Mastrorilli V, Farioli-Vecchioli S. The Long Run: Neuroprotective Effects of Physical Exercise on Adult Neurogenesis from Youth to Old Age. Curr Neuropharmacol 2018; 15:519-533. [PMID: 27000776 PMCID: PMC5543673 DOI: 10.2174/1570159x14666160412150223] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 03/08/2016] [Accepted: 03/16/2016] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND The rapid lengthening of life expectancy has raised the problem of providing social programs to counteract the age-related cognitive decline in a growing number of older people. Physical activity stands among the most promising interventions aimed at brain wellbeing, because of its effective neuroprotective action and low social cost. The purpose of this review is to describe the neuroprotective role exerted by physical activity in different life stages. In particular, we focus on adult neurogenesis, a process which has proved being highly responsive to physical exercise and may represent a major factor of brain health over the lifespan. METHODS The most recent literature related to the subject has been reviewed. The text has been divided into three main sections, addressing the effects of physical exercise during childhood/ adolescence, adulthood and aging, respectively. For each one, the most relevant studies, carried out on both human participants and rodent models, have been described. RESULTS The data reviewed converge in indicating that physical activity exerts a positive effect on brain functioning throughout the lifespan. However, uncertainty remains about the magnitude of the effect and its biological underpinnings. Cellular and synaptic plasticity provided by adult neurogenesis are highly probable mediators, but the mechanism for their action has yet to be conclusively established. CONCLUSION Despite alternative mechanisms of action are currently debated, age-appropriate physical activity programs may constitute a large-scale, relatively inexpensive and powerful approach to dampen the individual and social impact of age-related cognitive decline.
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Affiliation(s)
- Daniele Saraulli
- Institute of Cell Biology and Neurobiology, National Research Council, & Fondazione S. Lucia, Rome. Italy
| | - Marco Costanzi
- Department of Human Sciences, LUMSA University, Rome. Italy
| | - Valentina Mastrorilli
- Institute of Cell Biology and Neurobiology, National Research Council, & Fondazione S. Lucia, Rome. Italy
| | - Stefano Farioli-Vecchioli
- Institute of Cell Biology and Neurobiology, National Research Council, Via del Fosso di Fiorano 64, 00143 Rome. Italy
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40
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Beining M, Mongiat LA, Schwarzacher SW, Cuntz H, Jedlicka P. T2N as a new tool for robust electrophysiological modeling demonstrated for mature and adult-born dentate granule cells. eLife 2017; 6:e26517. [PMID: 29165247 PMCID: PMC5737656 DOI: 10.7554/elife.26517] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 11/21/2017] [Indexed: 12/18/2022] Open
Abstract
Compartmental models are the theoretical tool of choice for understanding single neuron computations. However, many models are incomplete, built ad hoc and require tuning for each novel condition rendering them of limited usability. Here, we present T2N, a powerful interface to control NEURON with Matlab and TREES toolbox, which supports generating models stable over a broad range of reconstructed and synthetic morphologies. We illustrate this for a novel, highly detailed active model of dentate granule cells (GCs) replicating a wide palette of experiments from various labs. By implementing known differences in ion channel composition and morphology, our model reproduces data from mouse or rat, mature or adult-born GCs as well as pharmacological interventions and epileptic conditions. This work sets a new benchmark for detailed compartmental modeling. T2N is suitable for creating robust models useful for large-scale networks that could lead to novel predictions. We discuss possible T2N application in degeneracy studies.
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Affiliation(s)
- Marcel Beining
- Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck SocietyFrankfurtGermany
- Frankfurt Institute for Advanced StudiesFrankfurtGermany
- Institute of Clinical Neuroanatomy, Neuroscience CenterGoethe UniversityFrankfurtGermany
- Faculty of BiosciencesGoethe UniversityFrankfurtGermany
| | - Lucas Alberto Mongiat
- Instituto de Investigación en Biodiversidad y MedioambienteUniversidad Nacional del Comahue-CONICETSan Carlos de BarilocheArgentina
| | | | - Hermann Cuntz
- Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck SocietyFrankfurtGermany
- Frankfurt Institute for Advanced StudiesFrankfurtGermany
| | - Peter Jedlicka
- Institute of Clinical Neuroanatomy, Neuroscience CenterGoethe UniversityFrankfurtGermany
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41
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Scharfman HE, MacLusky NJ. Sex differences in hippocampal area CA3 pyramidal cells. J Neurosci Res 2017; 95:563-575. [PMID: 27870399 DOI: 10.1002/jnr.23927] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Revised: 08/14/2016] [Accepted: 08/24/2016] [Indexed: 11/07/2022]
Abstract
Numerous studies have demonstrated differences between males and females in hippocampal structure, function, and plasticity. There also are many studies about the different predisposition of a males and females for disorders where the hippocampus plays an important role. Many of these reports focus on area CA1, but other subfields are also very important, and unlikely to be the same as area CA1 based on what is known. Here we review basic studies of male and female structure, function, and plasticity of area CA3 pyramidal cells of adult rats. The data suggest that the CA3 pyramidal cells of males and females are distinct in structure, function, and plasticity. These sex differences cannot be simply explained by the effects of circulating gonadal hormones. This view agrees with previous studies showing that there are substantial sex differences in the brain that cannot be normalized by removing the gonads and depleting peripheral gonadal hormones. Implications of these comparisons for understanding sex differences in hippocampal function and dysfunction are discussed. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Helen E Scharfman
- Department of Child and Adolescent Psychiatry, Physiology and Neuroscience, and Psychiatry, New York University Langone Medical Center, New York, New York.,Department of Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York
| | - Neil J MacLusky
- Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada
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42
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Neural mechanisms underlying GABAergic regulation of adult hippocampal neurogenesis. Cell Tissue Res 2017; 371:33-46. [PMID: 28948349 DOI: 10.1007/s00441-017-2668-y] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 07/01/2017] [Indexed: 12/25/2022]
Abstract
Within the dentate gyrus of the adult hippocampus is the subgranular zone, which contains a neurogenic niche for radial-glia like cells, the most primitive neural stem cells in the adult brain. The quiescence of neural stem cells is maintained by tonic gamma-aminobutyric acid (GABA) released from local interneurons. Once these cells differentiate into neural progenitor cells, GABA continues to regulate their development into mature granule cells, the principal cell type of the dentate gyrus. Here, we review the role of GABA circuits, signaling, and receptors in regulating development of adult-born cells, as well as the molecular players that modulate GABA signaling. Furthermore, we review recent findings linking dysregulation of adult hippocampal neurogenesis to the altered GABAergic circuitry and signaling under various pathological conditions.
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Yu T, Tensaouti Y, Bagha ZM, Davidson R, Kim A, Kernie SG. Adult newborn neurons interfere with fear discrimination in a protocol-dependent manner. Brain Behav 2017; 7:e00796. [PMID: 28948089 PMCID: PMC5607558 DOI: 10.1002/brb3.796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 06/27/2017] [Accepted: 07/02/2017] [Indexed: 12/25/2022] Open
Abstract
INTRODUCTION Significant enhancement of neurogenesis is known to occur in response to a variety of brain insults such as traumatic brain injury. Previous studies have demonstrated that injury-induced newborn neurons are required for hippocampus-dependent spatial learning and memory tasks like the Morris water maze, but not in contextual fear conditioning that requires both the hippocampus and amygdala. Recently, the dentate gyrus, where adult hippocampal neurogenesis occurs, has been implicated in processing information to form specific memory under specific environmental stimuli in a process known as pattern separation. METHODS To test whether injury-induced newborn neurons facilitate pattern separation, hippocampus-dependent contextual fear discrimination was performed using delta-HSV-TK transgenic mice, which can temporally inhibit injury-induced neurogenesis under the control of ganciclovir. RESULTS We observed that impaired neurogenesis enhanced the ability to distinguish aversive from naïve environments. In addition, this occurs most significantly following injury, but only in a context-dependent manner whereby the sequence of introducing the naïve environment from the aversive one affected the performance differentially. CONCLUSIONS Temporal impairment of both baseline and injury-induced adult neurogenesis enhances performance in fear discrimination in a context-dependent manner.
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Affiliation(s)
- Tzong‐Shiue Yu
- Department of PediatricsColumbia University College of Physicians and SurgeonsNew YorkNYUSA
| | - Yacine Tensaouti
- Department of PediatricsColumbia University College of Physicians and SurgeonsNew YorkNYUSA
| | - Zohaib M. Bagha
- Department of PediatricsColumbia University College of Physicians and SurgeonsNew YorkNYUSA
| | - Rina Davidson
- Department of PediatricsColumbia University College of Physicians and SurgeonsNew YorkNYUSA
| | - Ahleum Kim
- Department of PediatricsColumbia University College of Physicians and SurgeonsNew YorkNYUSA
| | - Steven G. Kernie
- Department of PediatricsColumbia University College of Physicians and SurgeonsNew YorkNYUSA
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Voluntary Running Exercise-Mediated Enhanced Neurogenesis Does Not Obliterate Retrograde Spatial Memory. J Neurosci 2017; 36:8112-22. [PMID: 27488632 DOI: 10.1523/jneurosci.0766-16.2016] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 06/09/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Running exercise (RE) improves cognition, formation of anterograde memories, and mood, alongside enhancing hippocampal neurogenesis. A previous investigation in a mouse model showed that RE-induced increased neurogenesis erases retrograde memory (Akers et al., 2014). However, it is unknown whether RE-induced forgetting is common to all species. We ascertained whether voluntary RE-induced enhanced neurogenesis interferes with the recall of spatial memory in rats. Young rats assigned to either sedentary (SED) or running exercise (RE) groups were first subjected to eight learning sessions in a water maze. A probe test (PT) conducted 24 h after the final training session confirmed that animals in either group had a similar ability for the recall of short-term memory. Following this, rats in the RE group were housed in larger cages fitted with running wheels, whereas rats in the SED group remained in standard cages. Animals in the RE group ran an average of 78 km in 4 weeks. A second PT performed 4 weeks after the first PT revealed comparable ability for memory recall between animals in the RE and SED groups, which was evidenced through multiple measures of memory retrieval function. The RE group displayed a 1.5- to 2.1-fold higher hippocampal neurogenesis than SED rats. Additionally, both moderate and brisk RE did not interfere with the recall of memory, although increasing amounts of RE proportionally enhanced neurogenesis. In conclusion, RE does not impair memory recall ability in a rat model despite substantially increasing neurogenesis. SIGNIFICANCE STATEMENT Running exercise (RE) improves new memory formation along with an increased neurogenesis in the hippocampus. In view of a recent study showing that RE-mediated increased hippocampal neurogenesis promotes forgetfulness in a mouse model, we ascertained whether a similar adverse phenomenon exists in a rat model. Memory recall ability examined 4 weeks after learning confirmed that animals that had run a mean of 78 km and displayed a 1.5- to 2.1-fold increase in hippocampal neurogenesis demonstrated similar proficiency for memory recall as animals that had remained sedentary. Furthermore, both moderate and brisk RE did not interfere with memory recall, although increasing amounts of RE proportionally enhanced neurogenesis, implying that RE has no adverse effects on memory recall.
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França TFA, Bitencourt AM, Maximilla NR, Barros DM, Monserrat JM. Hippocampal neurogenesis and pattern separation: A meta-analysis of behavioral data. Hippocampus 2017; 27:937-950. [PMID: 28597491 DOI: 10.1002/hipo.22746] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 05/09/2017] [Accepted: 05/26/2017] [Indexed: 12/16/2022]
Abstract
The generation of new neurons in the hippocampus of adult mammals has become a widely accepted phenomenon, but the functional significance of the adult neurogenesis in the hippocampus is not fully understood. One of the main hypotheses currently investigated suggests that neurogenesis contributes to pattern separation in the dentate gyrus. Many behavioral studies were conducted aiming to test this hypothesis using rodents as animal model. In those studies, researches ablated neurogenesis in the animals and subsequently evaluate them in tests of behavioral pattern separation, that is, behaviors that are thought to rely on the computational process of pattern separation. The results of these studies are varied, with most supporting a role for neurogenesis in pattern separation, but some others not. To address this controversy we performed a systematic review and meta-analysis of studies evaluating the effect of neurogenesis ablation on behavioral pattern separation. Analysis results indicated that most of the literature in the topic is surprisingly consistent and, although there are two studies with divergent results, the bulk of the literature supports an effect of hippocampal neurogenesis on behavioral pattern separation. We discuss those findings in light of other behavioral effects of hippocampal neurogenesis ablation, limitations of behavioral data and other lines of evidence about the effect of hippocampal neurogenesis in the dentate gyrus.
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Affiliation(s)
- Thiago F A França
- Programa de Pós-graduação em Ciências Fisiológicas, Universidade Federal do Rio Grande-FURG, Rio Grande, RS, Brazil
| | - Alexandre M Bitencourt
- Programa de Pós-graduação em Ciências Fisiológicas, Universidade Federal do Rio Grande-FURG, Rio Grande, RS, Brazil
| | - Naiana R Maximilla
- Curso de graduação em Ciências Biológicas, Universidade Federal do Rio Grande-FURG, Rio Grande, RS, Brazil
| | - Daniela M Barros
- Programa de Pós-graduação em Ciências Fisiológicas, Universidade Federal do Rio Grande-FURG, Rio Grande, RS, Brazil.,Instituto de Ciências Biológicas, Universidade Federal do Rio Grande (FURG), Rio Grande, RS, Brazil
| | - José M Monserrat
- Programa de Pós-graduação em Ciências Fisiológicas, Universidade Federal do Rio Grande-FURG, Rio Grande, RS, Brazil.,Instituto de Ciências Biológicas, Universidade Federal do Rio Grande (FURG), Rio Grande, RS, Brazil
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47
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Daugherty AM, Flinn R, Ofen N. Hippocampal CA3-dentate gyrus volume uniquely linked to improvement in associative memory from childhood to adulthood. Neuroimage 2017; 153:75-85. [PMID: 28342999 PMCID: PMC5477670 DOI: 10.1016/j.neuroimage.2017.03.047] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2016] [Revised: 03/10/2017] [Accepted: 03/20/2017] [Indexed: 12/17/2022] Open
Abstract
Associative memory develops into adulthood and critically depends on the hippocampus. The hippocampus is a complex structure composed of subfields that are functionally-distinct, and anterior-posterior divisions along the length of the hippocampal horizontal axis that may also differ by cognitive correlates. Although each of these aspects has been considered independently, here we evaluate their relative contributions as correlates of age-related improvement in memory. Volumes of hippocampal subfields (subiculum, CA1-2, CA3-dentate gyrus) and anterior-posterior divisions (hippocampal head, body, tail) were manually segmented from high-resolution images in a sample of healthy participants (age 8-25 years). Adults had smaller CA3-dentate gyrus volume as compared to children, which accounted for 67% of the indirect effect of age predicting better associative memory via hippocampal volumes. Whereas hippocampal body volume demonstrated non-linear age differences, larger hippocampal body volume was weakly related to better associative memory only when accounting for the mutual correlation with subfields measured within that region. Thus, typical development of associative memory was largely explained by age-related differences in CA3-dentate gyrus.
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Affiliation(s)
- Ana M Daugherty
- Institute of Gerontology, Wayne State University, Detroit, MI 48202, USA; Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
| | - Robert Flinn
- Institute of Gerontology, Wayne State University, Detroit, MI 48202, USA
| | - Noa Ofen
- Institute of Gerontology, Wayne State University, Detroit, MI 48202, USA; Department of Psychology, Wayne State University, Detroit, MI 48202, USA.
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48
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Swart CC, Wattenberger A, Hackett A, Isaman D. Lifelong neurogenesis in the cerebral ganglion of the Chinese mud snail, Cipangopaludina chinensis. Brain Behav 2017; 7:e00652. [PMID: 28413703 PMCID: PMC5390835 DOI: 10.1002/brb3.652] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 12/06/2016] [Accepted: 12/18/2016] [Indexed: 02/02/2023] Open
Abstract
INTRODUCTION A small group of Gastropods possessing giant neurons have long been used to study a wide variety of fundamental neurophysiological phenomena. However, the majority of gastropods do not have large neurons but instead have large numbers of small neurons and remain largely unstudied. We explored neuron size and rate of increase in neuron numbers in the Chinese mud snail, Cipangopaludina chinensis. METHODS Using histological sections and whole mounts of the cerebral ganglia, we collected cross-sectional data on neuron number and size across the lifespan of this animal. Neurogenesis was verified using Click-it EdU staining. RESULTS We found that total neuron number in the cerebral ganglia increases throughout the lifespan of this species at a constant rate. New neurons arise primarily near the nerve roots. Females live longer (up to 7 years) than males (up to 5 years) and thus achieve larger numbers of neurons in the cerebral ganglion. Neuron size is consistently small (<10 μm) in the cerebral ganglia at all ages, however, cells in the posterior section of the cerebral ganglia are modestly but significantly larger than cells at the anterior. CONCLUSIONS These features suggest that C. chinensis and similar species of Caenogastropoda are good candidates for studying gastropod neurogenesis, senescence, and sex differences in the nervous system.
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Chavlis S, Poirazi P. Pattern separation in the hippocampus through the eyes of computational modeling. Synapse 2017; 71. [PMID: 28316111 DOI: 10.1002/syn.21972] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 03/02/2017] [Accepted: 03/14/2017] [Indexed: 12/24/2022]
Abstract
Pattern separation is a mnemonic process that has been extensively studied over the years. It entails the ability -of primarily hippocampal circuits- to distinguish between highly similar inputs, via generating different neuronal activity (output) patterns. The dentate gyrus (DG) in particular has long been hypothesized to implement pattern separation by detecting and storing similar inputs as distinct representations. The ways in which these distinct representations can be generated have been explored in a number of theoretical and computational modeling studies. Here, we review two categories of pattern separation models: those that address the phenomenon in an abstract mathematical fashion and those that delve into the underlying biological mechanisms by taking into account the anatomy and/or physiology of hippocampal circuits. We summarize the strategies, findings and limitations of these modeling approaches in the light of new experimental findings and propose a unifying framework whereby different network, cellular and sub-cellular mechanisms converge to a common goal: controlling sparsity, the key determinant of pattern separation in the DG.
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Affiliation(s)
- Spyridon Chavlis
- Institute of Molecular Biology & Biotechnology (IMBB), Foundation for Research and Technology - Hellas (FORTH), N. Plastira 100, Heraklion, Crete, 70013, Greece.,Department of Biology, University of Crete, Vasilika Vouton, P.O. Box 2208, Heraklion, Crete, 71409, Greece
| | - Panayiota Poirazi
- Institute of Molecular Biology & Biotechnology (IMBB), Foundation for Research and Technology - Hellas (FORTH), N. Plastira 100, Heraklion, Crete, 70013, Greece
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50
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Pedraza LK, Sierra RO, Crestani AP, Quillfeldt JA, de Oliveira Alvares L. Sequential learning during contextual fear conditioning guides the rate of systems consolidation: Implications for consolidation of multiple memory traces. Hippocampus 2017; 27:518-528. [DOI: 10.1002/hipo.22708] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Revised: 01/05/2017] [Accepted: 01/12/2017] [Indexed: 11/10/2022]
Affiliation(s)
- Lizeth K. Pedraza
- Laboratório de Neurobiologia da Memória; Biophysics Department, Biosciences Institute, Universidade Federal do Rio Grande do Sul; Porto Alegre RS, Brazil
- Institute of Health Sciences, Graduate Program in Neuroscience; Universidade Federal do Rio Grande do Sul; Porto Alegre RS, Brazil
| | - Rodrigo O. Sierra
- Institute of Health Sciences, Graduate Program in Neuroscience; Universidade Federal do Rio Grande do Sul; Porto Alegre RS, Brazil
- Laboratório de Psicobiologia e Neurocomputação, Biophysics Department; Biosciences Institute, Universidade Federal do Rio Grande do Sul; Porto Alegre Brazil
| | - Ana P. Crestani
- Institute of Health Sciences, Graduate Program in Neuroscience; Universidade Federal do Rio Grande do Sul; Porto Alegre RS, Brazil
- Laboratório de Psicobiologia e Neurocomputação, Biophysics Department; Biosciences Institute, Universidade Federal do Rio Grande do Sul; Porto Alegre Brazil
| | - Jorge A. Quillfeldt
- Institute of Health Sciences, Graduate Program in Neuroscience; Universidade Federal do Rio Grande do Sul; Porto Alegre RS, Brazil
- Laboratório de Psicobiologia e Neurocomputação, Biophysics Department; Biosciences Institute, Universidade Federal do Rio Grande do Sul; Porto Alegre Brazil
| | - Lucas de Oliveira Alvares
- Laboratório de Neurobiologia da Memória; Biophysics Department, Biosciences Institute, Universidade Federal do Rio Grande do Sul; Porto Alegre RS, Brazil
- Institute of Health Sciences, Graduate Program in Neuroscience; Universidade Federal do Rio Grande do Sul; Porto Alegre RS, Brazil
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