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Lehtonen SM, Puumalainen V, Nokia MS, Lensu S. Effects of unilateral hippocampal surgical procedures needed for calcium imaging on mouse behavior and adult hippocampal neurogenesis. Behav Brain Res 2024; 468:115042. [PMID: 38723676 DOI: 10.1016/j.bbr.2024.115042] [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: 11/13/2023] [Revised: 04/17/2024] [Accepted: 05/03/2024] [Indexed: 05/16/2024]
Abstract
Hippocampus is essential for episodic memory formation, lesion studies demonstrating its role especially in processing spatial and temporal information. Further, adult hippocampal neurogenesis (AHN) in the dentate gyrus (DG) has also been linked to learning. To study hippocampal neuronal activity during events like learning, in vivo calcium imaging has become increasingly popular. It relies on the use of adeno-associated viral (AAV) vectors, which seem to lead to a decrease in AHN when applied on the DG. More notably, imaging requires the implantation of a relatively large lens into the tissue. Here, we examined how injection of an AAV vector and implantation of a 1-mm-diameter lens into the dorsal DG routinely used to image calcium activity impact the behavior of adult male C57BL/6 mice. To this aim, we conducted open-field, object-recognition and object-location tasks at baseline, after AAV vector injection, and after lens implantation. Finally, we determined AHN from hippocampal slices using a doublecortin-antibody. According to our results, the operations needed for in vivo imaging of the dorsal DG did not have adverse effects on behavior, although we noticed a decrease in AHN ipsilaterally to the operations. Thus, our results suggest that in vivo imaging can be safely used to, for example, correlate patterns of calcium activity with learned behavior. One should still keep in mind that the defects on the operated side might be functionally compensated by the (hippocampus in the) contralateral hemisphere.
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Affiliation(s)
- Suvi-Maaria Lehtonen
- Department of Psychology and Centre for Interdisciplinary Brain Research, University of Jyvaskyla, Finland.
| | - Veera Puumalainen
- Department of Psychology and Centre for Interdisciplinary Brain Research, University of Jyvaskyla, Finland
| | - Miriam S Nokia
- Department of Psychology and Centre for Interdisciplinary Brain Research, University of Jyvaskyla, Finland
| | - Sanna Lensu
- Department of Psychology and Centre for Interdisciplinary Brain Research, University of Jyvaskyla, Finland
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Kim K, Nokia MS, Palva S. Distinct Hippocampal Oscillation Dynamics in Trace Eyeblink Conditioning Task for Retrieval and Consolidation of Associations. eNeuro 2024; 11:ENEURO.0030-23.2024. [PMID: 38627063 PMCID: PMC11046259 DOI: 10.1523/eneuro.0030-23.2024] [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: 01/24/2023] [Revised: 04/04/2024] [Accepted: 04/10/2024] [Indexed: 04/28/2024] Open
Abstract
Trace eyeblink conditioning (TEBC) has been widely used to study associative learning in both animals and humans. In this paradigm, conditioned responses (CRs) to conditioned stimuli (CS) serve as a measure for retrieving learned associations between the CS and the unconditioned stimuli (US) within a trial. Memory consolidation, that is, learning over time, can be quantified as an increase in the proportion of CRs across training sessions. However, how hippocampal oscillations differentiate between successful memory retrieval within a session and consolidation across TEBC training sessions remains unknown. To address this question, we recorded local field potentials (LFPs) from the rat dorsal hippocampus during TEBC and investigated hippocampal oscillation dynamics associated with these two functions. We show that transient broadband responses to the CS were correlated with memory consolidation, as indexed by an increase in CRs across TEBC sessions. In contrast, induced alpha (8-10 Hz) and beta (16-20 Hz) band responses were correlated with the successful retrieval of the CS-US association within a session, as indexed by the difference in trials with and without CR.
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Affiliation(s)
- Kayeon Kim
- Neuroscience Center, Helsinki Institute of Life Sciences, University of Helsinki, Helsinki FI-00014, Finland
- Department of Neuroscience, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen N DK-2200, Denmark
| | - Miriam S Nokia
- Department of Psychology, University of Jyväskylä, Jyväskylä FI-40014, Finland
| | - Satu Palva
- Neuroscience Center, Helsinki Institute of Life Sciences, University of Helsinki, Helsinki FI-00014, Finland
- Centre for Cognitive Neuroscience, School of Psychology and Neuroscience, University of Glasgow, Glasgow G12 8QQ, Scotland
- Division of psychology, VISE, Faculty of Education and Psychology, University of Oulu, Oulu, Ostrobothnia FI-90014, Finland
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3
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Chang Y, Wang X, Liao J, Chen S, Liu X, Liu S, Ming D. Temporal hyper-connectivity and frontal hypo-connectivity within gamma band in schizophrenia: A resting state EEG study. Schizophr Res 2024; 264:220-230. [PMID: 38183959 DOI: 10.1016/j.schres.2023.12.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 11/12/2023] [Accepted: 12/16/2023] [Indexed: 01/08/2024]
Abstract
OBJECTIVE The brain network serves as the physiological foundation for information processing of the brain. Many studies have reported abnormalities of gamma oscillations in Schizophrenia. The aim of this study was to investigate the gamma-band connectivity in Schizophrenia patients. METHODS We recorded the resting state electroencephalogram (EEG) for 15 schizophrenia patients with refractory auditory hallucinations and 14 healthy controls, with eyes open and closed. The brain network was constructed based on weighted phase lag index for gamma band. Whole scalp metrics (clustering coefficient, global efficiency and local efficiency) and local region metrics (degree and betweenness centrality) in the frontal and temporal lobes were computed. Correlation analyses between network metrics and symptom scales were examined to find associations with symptom severity. RESULTS Schizophrenia patients had larger global efficiency and local efficiency (p < 0.05) with eyes closed, probably representing greater brain activity and information exchange. For degree and betweenness centrality, schizophrenia patients showed an increase (p < 0.05) in the temporal lobe but a decrease (p < 0.05) in the frontal lobe with eyes closed and open, potentially account for the patients' symptoms such as hallucinations and thought disorders. Local efficiency and frontal lobe degree were positively and negatively correlated with the scales, respectively (both p < 0.05). CONCLUSIONS Altered connectivity of the resting state brain network has been revealed and may be associated with the core symptoms of schizophrenia. Our study provides promising evidence for the investigation of the pathological basis of Schizophrenia and could aid in objective diagnosis.
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Affiliation(s)
- Yuan Chang
- Tianjin University, Academy of Medical Engineering and Translational Medicine, Tianjin, China
| | - Xiaojuan Wang
- Tianjin University, Academy of Medical Engineering and Translational Medicine, Tianjin, China
| | - Jingmeng Liao
- Tianjin University, Academy of Medical Engineering and Translational Medicine, Tianjin, China
| | - Sitong Chen
- Tianjin University, Academy of Medical Engineering and Translational Medicine, Tianjin, China
| | - Xiaoya Liu
- Tianjin University, Academy of Medical Engineering and Translational Medicine, Tianjin, China
| | - Shuang Liu
- Tianjin University, Academy of Medical Engineering and Translational Medicine, Tianjin, China.
| | - Dong Ming
- Tianjin University, Academy of Medical Engineering and Translational Medicine, Tianjin, China
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Yang CCH, Kuo TBJ, Chen CH, Li WY, Hung CT, Li JY. Older rats show slow modulation of hippocampal theta rhythm during voluntary running. Exp Gerontol 2023; 173:112092. [PMID: 36669709 DOI: 10.1016/j.exger.2023.112092] [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: 08/07/2022] [Revised: 12/18/2022] [Accepted: 01/16/2023] [Indexed: 01/19/2023]
Abstract
Aging causes brain function degeneration and slows many motor and behavioural responses. The hippocampal theta rhythm (4-12 Hz) is related to cognition and locomotion. However, the findings on aging-related changes in the frequency and amplitude of hippocampal theta oscillations have been inconsistent. We hypothesized that older rats have slower responses in terms of hippocampal theta rhythm during voluntary wheel running than do young adult rats. By simultaneously recording electroencephalography and physical activity (PA), we evaluated theta oscillations in 8-week-old (young adult) and 60-week-old (middle-aged) rats before and during wheel running, which was conducted only during the rats' 12-h dark period. To test the alterations of hippocampal theta rhythm in voluntary wheel running, we analyzed the signals without (8-s) or with (2-s) chronological order. No significant difference was observed in total frequency (TP, 4-12 Hz), low-frequency (LT, 4-6.5 Hz), or high-frequency (9.5-12 Hz) theta activity between active waking and overall running in either group. The theta oscillations were slower in the middle-aged rats than in the young adult rats during wheel running but increased during running for both age groups. During wheel running, the middle-aged rats exhibited an increased LT, which was related to PA. On the basis of the chronological order of running, the young adult rats exhibited increased TP, and the middle-aged rats exhibited significant increases in middle-frequency (MT, 6.5-9.5 Hz) theta activity. The dominant modulations of MT in the middle-aged rats may have caused nonsignificant changes in total activity. These between-group differences in theta rhythm characteristics during voluntary running provide insights into age-related brain function decline.
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Affiliation(s)
- Cheryl C H Yang
- Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei, Taiwan; Sleep Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan; Department of Education and Research, Taipei City Hospital, Taipei, Taiwan; Brain Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Terry B J Kuo
- Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei, Taiwan; Sleep Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan; Department of Education and Research, Taipei City Hospital, Taipei, Taiwan; Clinical Research Center, Tsoutun Psychiatric Center, Ministry of Health and Welfare, Nantou, Taiwan
| | - Chun-Hsiu Chen
- Department of Health and Leisure Management, Yuanpei University of Medical Technology, Hsinchu, Taiwan
| | - Wei-Yi Li
- Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Chang-Tsen Hung
- Department of Health and Leisure Management, Yuanpei University of Medical Technology, Hsinchu, Taiwan
| | - Jia-Yi Li
- Sleep Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan; Department of Health and Leisure Management, Yuanpei University of Medical Technology, Hsinchu, Taiwan.
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Lu Z, Wang H, Gu J, Gao F. Association between abnormal brain oscillations and cognitive performance in patients with bipolar disorder; Molecular mechanisms and clinical evidence. Synapse 2022; 76:e22247. [PMID: 35849784 DOI: 10.1002/syn.22247] [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: 02/20/2022] [Revised: 05/23/2022] [Accepted: 06/20/2022] [Indexed: 11/10/2022]
Abstract
Brain oscillations have gained great attention in neuroscience during recent decades as functional building blocks of cognitive-sensory processes. Research has shown that oscillations in "alpha," "beta," "gamma," "delta," and "theta" frequency windows are highly modified in brain pathology, including in patients with cognitive impairment like bipolar disorder (BD). The study of changes in brain oscillations can provide fundamental knowledge for exploring neurophysiological biomarkers in cognitive impairment. The present article reviews findings from the role and molecular basis of abnormal neural oscillation and synchronization in the symptoms of patients with BD. An overview of the results clearly demonstrates that, in cognitive-sensory processes, resting and evoked/event-related electroencephalogram (EEG) spectra in the delta, theta, alpha, beta, and gamma bands are abnormally changed in patients with BD showing psychotic features. Abnormal oscillations have been found to be associated with several neural dysfunctions and abnormalities contributing to BD, including abnormal GABAergic neurotransmission signaling, hippocampal cell discharge, abnormal hippocampal neurogenesis, impaired cadherin and synaptic contact-based cell adhesion processes, extended lateral ventricles, decreased prefrontal cortical gray matter, and decreased hippocampal volume. Mechanistically, impairment in calcium voltage-gated channel subunit alpha1 I, neurotrophic tyrosine receptor kinase proteins, genes involved in brain neurogenesis and synaptogenesis like WNT3 and ACTG2, genes involved in the cell adhesion process like CDH12 and DISC1, and gamma-aminobutyric acid (GABA) signaling have been reported as the main molecular contributors to the abnormalities in resting-state low-frequency oscillations in BD patients. Findings also showed the association of impaired synaptic connections and disrupted membrane potential with abnormal beta/gamma oscillatory activity in patients with BD. Of note, the synaptic GABA neurotransmitter has been found to be a fundamental requirement for the occurrence of long-distance synchronous gamma oscillations necessary for coordinating the activity of neural networks between various brain regions. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Zhou Lu
- Department of Neurosurgery, The Affiliated People's Hospital of NingBo University, NingBo, 315000, China
| | - Huixiao Wang
- Department of Neurosurgery, The Affiliated People's Hospital of NingBo University, NingBo, 315000, China
| | - Jiajie Gu
- Department of Neurosurgery, The Affiliated People's Hospital of NingBo University, NingBo, 315000, China
| | - Feng Gao
- Department of Neurosurgery, The Affiliated People's Hospital of NingBo University, NingBo, 315000, China
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Zhang TR, Guilherme E, Kesici A, Ash AM, Vila-Rodriguez F, Snyder JS. Electroconvulsive Shock, but Not Transcranial Magnetic Stimulation, Transiently Elevates Cell Proliferation in the Adult Mouse Hippocampus. Cells 2021; 10:2090. [PMID: 34440859 PMCID: PMC8391684 DOI: 10.3390/cells10082090] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 07/27/2021] [Accepted: 08/10/2021] [Indexed: 12/12/2022] Open
Abstract
Hippocampal plasticity is hypothesized to play a role in the etiopathogenesis of depression and the antidepressant effect of medications. One form of plasticity that is unique to the hippocampus and is involved in depression-related behaviors in animal models is adult neurogenesis. While chronic electroconvulsive shock (ECS) strongly promotes neurogenesis, less is known about its acute effects and little is known about the neurogenic effects of other forms of stimulation therapy, such as repetitive transcranial magnetic stimulation (rTMS). Here, we investigated the time course of acute ECS and rTMS effects on markers of cell proliferation and neurogenesis in the adult hippocampus. Mice were subjected to a single session of ECS, 10 Hz rTMS (10-rTMS), or intermittent theta burst stimulation (iTBS). Mice in both TMS groups were injected with BrdU 2 days before stimulation to label immature cells. One, 3, or 7 days later, hippocampi were collected and immunostained for BrdU + cells, actively proliferating PCNA + cells, and immature DCX + neurons. Following ECS, mice displayed a transient increase in cell proliferation at 3 days post-stimulation. At 7 days post-stimulation there was an elevation in the number of proliferating neuronal precursor cells (PCNA + DCX +), specifically in the ventral hippocampus. iTBS and rTMS did not alter the number of BrdU + cells, proliferating cells, or immature neurons at any of the post-stimulation time points. Our results suggest that neurostimulation treatments exert different effects on hippocampal neurogenesis, where ECS may have greater neurogenic potential than iTBS and 10-rTMS.
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Affiliation(s)
- Tian Rui Zhang
- Department of Psychology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (T.R.Z.); (A.K.); (A.M.A.)
- Non-Invasive Neurostimulation Therapies Laboratory, Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 1Z3, Canada;
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Evelyn Guilherme
- Department of Physiotherapy, Federal University of Sao Carlos, Sao Carlo 13565-905, SP, Brazil;
| | - Aydan Kesici
- Department of Psychology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (T.R.Z.); (A.K.); (A.M.A.)
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Alyssa M. Ash
- Department of Psychology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (T.R.Z.); (A.K.); (A.M.A.)
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Fidel Vila-Rodriguez
- Non-Invasive Neurostimulation Therapies Laboratory, Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 1Z3, Canada;
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Jason S. Snyder
- Department of Psychology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (T.R.Z.); (A.K.); (A.M.A.)
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
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Nokia MS, Waselius T, Sahramäki J, Penttonen M. Most hippocampal CA1 pyramidal cells in rabbits increase firing during awake sharp-wave ripples and some do so in response to external stimulation and theta. J Neurophysiol 2020; 123:1671-1681. [PMID: 32208887 DOI: 10.1152/jn.00056.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hippocampus forms neural representations of real-life events including multimodal information of spatial and temporal context. These representations, i.e., organized sequences of neuronal firing, are repeated during following rest and sleep, especially when so-called sharp-wave ripples (SPW-Rs) characterize hippocampal local field potentials. This SPW-R -related replay is thought to underlie memory consolidation. Here, we set out to explore how hippocampal CA1 pyramidal cells respond to the conditioned stimulus during trace eyeblink conditioning and how these responses manifest during SPW-Rs in awake adult female New Zealand White rabbits. Based on reports in rodents, we expected SPW-Rs to take place in bursts, possibly according to a slow endogenous rhythm. In awake rabbits, half of all SPW-Rs took place in bursts, but no endogenous slow rhythm appeared. Conditioning trials suppressed SPW-Rs while increasing theta for a period of several seconds. As expected based on previous findings, only a quarter of the putative CA1 pyramidal cells increased firing in response to the conditioned stimulus. Compared with other cells, rate-increasing cells were more active during spontaneous epochs of hippocampal theta while response profile during conditioning did not affect firing during SPW-Rs. Taken together, CA1 pyramidal cell firing during SPW-Rs is not limited to cells that fired during the preceding experience. Furthermore, the importance of possible reactivations taking place during theta epochs on memory consolidation warrants further investigation.NEW & NOTEWORTHY We studied hippocampal sharp-wave ripples and theta and CA1 pyramidal cell activity during trace eyeblink conditioning in rabbits. Conditioning trials suppressed ripples while increasing theta for a period of several seconds. A quarter of the cells increased firing in response to the conditioned stimulus and fired extensively during endogenous theta as well as ripples. The role of endogenous theta epochs in off-line memory consolidation should be studied further.
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Affiliation(s)
- Miriam S Nokia
- Department of Psychology, University of Jyväskylä, Jyväskylä, Finland
| | - Tomi Waselius
- Department of Psychology, University of Jyväskylä, Jyväskylä, Finland
| | - Joonas Sahramäki
- Department of Psychology, University of Jyväskylä, Jyväskylä, Finland
| | - Markku Penttonen
- Department of Psychology, University of Jyväskylä, Jyväskylä, Finland
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Kim S, Kim YW, Shim M, Jin MJ, Im CH, Lee SH. Altered Cortical Functional Networks in Patients With Schizophrenia and Bipolar Disorder: A Resting-State Electroencephalographic Study. Front Psychiatry 2020; 11:661. [PMID: 32774308 PMCID: PMC7388793 DOI: 10.3389/fpsyt.2020.00661] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 06/25/2020] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Pathologies of schizophrenia and bipolar disorder have been poorly understood. Brain network analysis could help understand brain mechanisms of schizophrenia and bipolar disorder. This study investigates the source-level brain cortical networks using resting-state electroencephalography (EEG) in patients with schizophrenia and bipolar disorder. METHODS Resting-state EEG was measured in 38 patients with schizophrenia, 34 patients with bipolar disorder type I, and 30 healthy controls. Graph theory based source-level weighted functional networks were evaluated: strength, clustering coefficient (CC), path length (PL), and efficiency in six frequency bands. RESULTS At the global level, patients with schizophrenia or bipolar disorder showed higher strength, CC, and efficiency, and lower PL in the theta band, compared to healthy controls. At the nodal level, patients with schizophrenia or bipolar disorder showed higher CCs, mostly in the frontal lobe for the theta band. Particularly, patients with schizophrenia showed higher nodal CCs in the left inferior frontal cortex and the left ascending ramus of the lateral sulcus compared to patients with bipolar disorder. In addition, the nodal-level theta band CC of the superior frontal gyrus and sulcus (cognition-related region) correlated with positive symptoms and social and occupational functioning scale (SOFAS) scores in the schizophrenia group, while that of the middle frontal gyrus (emotion-related region) correlated with SOFAS scores in the bipolar disorder group. CONCLUSIONS Altered cortical networks were revealed and these alterations were significantly correlated with core pathological symptoms of schizophrenia and bipolar disorder. These source-level cortical network indices could be promising biomarkers to evaluate patients with schizophrenia and bipolar disorder.
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Affiliation(s)
- Sungkean Kim
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States
| | - Yong-Wook Kim
- Clinical Emotion and Cognition Research Laboratory, Inje University, Goyang, South Korea.,Department of Biomedical Engineering, Hanyang University, Seoul, South Korea
| | - Miseon Shim
- Institute of Industrial Technology, Korea University, Sejong, South Korea
| | - Min Jin Jin
- Department of Psychiatry, Wonkwang University Hospital, Iksan, South Korea
| | - Chang-Hwan Im
- Department of Biomedical Engineering, Hanyang University, Seoul, South Korea
| | - Seung-Hwan Lee
- Clinical Emotion and Cognition Research Laboratory, Inje University, Goyang, South Korea.,Department of Psychiatry, Inje University Ilsan Paik Hospital, Ilsan, South Korea
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Dillingham CM, Milczarek MM, Perry JC, Frost BE, Parker GD, Assaf Y, Sengpiel F, O'Mara SM, Vann SD. Mammillothalamic Disconnection Alters Hippocampocortical Oscillatory Activity and Microstructure: Implications for Diencephalic Amnesia. J Neurosci 2019; 39:6696-6713. [PMID: 31235646 PMCID: PMC6703878 DOI: 10.1523/jneurosci.0827-19.2019] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 06/08/2019] [Accepted: 06/10/2019] [Indexed: 01/13/2023] Open
Abstract
Diencephalic amnesia can be as debilitating as the more commonly known temporal lobe amnesia, yet the precise contribution of diencephalic structures to memory processes remains elusive. Across four cohorts of male rats, we used discrete lesions of the mammillothalamic tract to model aspects of diencephalic amnesia and assessed the impact of these lesions on multiple measures of activity and plasticity within the hippocampus and retrosplenial cortex. Lesions of the mammillothalamic tract had widespread indirect effects on hippocampocortical oscillatory activity within both theta and gamma bands. Both within-region oscillatory activity and cross-regional synchrony were altered. The network changes were state-dependent, displaying different profiles during locomotion and paradoxical sleep. Consistent with the associations between oscillatory activity and plasticity, complementary analyses using several convergent approaches revealed microstructural changes, which appeared to reflect a suppression of learning-induced plasticity in lesioned animals. Together, these combined findings suggest a mechanism by which damage to the medial diencephalon can impact upon learning and memory processes, highlighting an important role for the mammillary bodies in the coordination of hippocampocortical activity.SIGNIFICANCE STATEMENT Information flow within the Papez circuit is critical to memory. Damage to ascending mammillothalamic projections has consistently been linked to amnesia in humans and spatial memory deficits in animal models. Here we report on the changes in hippocampocortical oscillatory dynamics that result from chronic lesions of the mammillothalamic tract and demonstrate, for the first time, that the mammillary bodies, independently of the supramammillary region, contribute to frequency modulation of hippocampocortical theta oscillations. Consistent with the associations between oscillatory activity and plasticity, the lesions also result in a suppression of learning-induced plasticity. Together, these data support new functional models whereby mammillary bodies are important for coordinating hippocampocortical activity rather than simply being a relay of hippocampal information as previously assumed.
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Affiliation(s)
- Christopher M Dillingham
- School of Psychology, Cardiff University, Cardiff CF10 3AT, United Kingdom
- Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland
| | - Michal M Milczarek
- School of Psychology, Cardiff University, Cardiff CF10 3AT, United Kingdom
| | - James C Perry
- School of Psychology, Cardiff University, Cardiff CF10 3AT, United Kingdom
| | - Bethany E Frost
- Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland
| | - Greg D Parker
- EMRIC, Cardiff University, Cardiff CF10 3AX, United Kingdom
| | - Yaniv Assaf
- George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel 6997801, and
| | - Frank Sengpiel
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, United Kingdom
| | - Shane M O'Mara
- Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland
| | - Seralynne D Vann
- School of Psychology, Cardiff University, Cardiff CF10 3AT, United Kingdom,
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Millon EM, Shors TJ. Taking neurogenesis out of the lab and into the world with MAP Train My Brain™. Behav Brain Res 2019; 376:112154. [PMID: 31421141 DOI: 10.1016/j.bbr.2019.112154] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 07/24/2019] [Accepted: 08/13/2019] [Indexed: 01/22/2023]
Abstract
Neurogenesis in the adult hippocampus was rediscovered in the 1990's after being reported in the 1960's. Since then, thousands upon thousands of laboratories have reported on the characteristics and presumed functional significance of new neurons in the adult brain. In 1999, we reported that mental training with effortful learning could extend the survival of these new cells and in the same year, others reported that physical training with exercise could increase their proliferation. Based on these studies and others, we developed MAP Train My Brain™, which is a brain fitness program for humans. The program combines mental and physical (MAP) training through 30-min of effortful meditation followed by 30-min of aerobic exercise. This program, when practiced twice a week for eight weeks reduced depressive symptoms and ruminative thoughts in men and women with major depressive disorder (MDD) while increasing synchronized brain activity during cognitive control. It also reduced anxiety and depression and increased oxygen consumption in young mothers who had been homeless. Moreover, engaging in the program reduced trauma-related cognitions and ruminative thoughts while increasing self-worth in adult women with a history of sexual trauma. And finally, the combination of mental and physical training together was more effective than either activity alone. Albeit effortful, this program does not require inordinate amounts of time or money to practice and can be easily adopted into everyday life. MAP Training exemplifies how we as neuroscientists can take discoveries made in the laboratory out into the world for the benefit of others.
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Affiliation(s)
- Emma M Millon
- Department of Psychology and Center for Collaborative Neuroscience, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Tracey J Shors
- Department of Psychology and Center for Collaborative Neuroscience, Rutgers University, Piscataway, New Jersey 08854, USA.
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11
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Stroke Accelerates and Uncouples Intrinsic and Synaptic Excitability Maturation of Mouse Hippocampal DCX + Adult-Born Granule Cells. J Neurosci 2019; 39:1755-1766. [PMID: 30617211 DOI: 10.1523/jneurosci.3303-17.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 11/05/2018] [Accepted: 11/08/2018] [Indexed: 11/21/2022] Open
Abstract
Stroke robustly stimulates adult neurogenesis in the hippocampal dentate gyrus. It is currently unknown whether this process induces beneficial or maladaptive effects, but morphological and behavioral studies have reported aberrant neurogenesis and impaired hippocampal-dependent memory following stroke. However, the intrinsic function and network incorporation of adult-born granule cells (ABGCs) after ischemia is unclear. Using patch-clamp electrophysiology, we evaluated doublecortin-positive (DCX+) ABGCs as well as DCX- dentate gyrus granule cells 2 weeks after a stroke or sham operation in DCX/DsRed transgenic mice of either sex. The developmental status, intrinsic excitability, and synaptic excitability of ABGCs were accelerated following stroke, while dendritic morphology was not aberrant. Regression analysis revealed uncoupled development of intrinsic and network excitability, resulting in young, intrinsically hyperexcitable ABGCs receiving disproportionately large glutamatergic inputs. This aberrant functional maturation in the subgroup of ABGCs in the hippocampus may contribute to defective hippocampal function and increased seizure susceptibility following stroke.SIGNIFICANCE STATEMENT Stroke increases hippocampal neurogenesis but the functional consequences of the postlesional response is mostly unclear. Our findings provide novel evidence of aberrant functional maturation of newly generated neurons following stroke. We demonstrate that stroke not only causes an accelerated maturation of the intrinsic and synaptic parameters of doublecortin-positive, new granule cells in the hippocampus, but that this accelerated development does not follow physiological dynamics due to uncoupled intrinsic and synaptic maturation. Hyperexcitable immature neurons may contribute to disrupted network integration following stroke.
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Waselius T, Pöllänen E, Wikgren J, Penttonen M, Nokia MS. Hippocampal theta phase-contingent memory retrieval in delay and trace eyeblink conditioning. Behav Brain Res 2018; 337:264-270. [PMID: 28882692 DOI: 10.1016/j.bbr.2017.09.001] [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: 04/26/2017] [Revised: 08/25/2017] [Accepted: 09/01/2017] [Indexed: 10/18/2022]
Abstract
Hippocampal theta oscillations (3-12Hz) play a prominent role in learning. It has been suggested that encoding and retrieval of memories are supported by different phases of the theta cycle. Our previous study on trace eyeblink conditioning in rabbits suggests that the timing of the conditioned stimulus (CS) in relation to theta phase affects encoding but not retrieval of the memory trace. Here, we directly tested the effects of hippocampal theta phase on memory retrieval in two experiments conducted on adult female New Zealand White rabbits. In Experiment 1, animals were trained in trace eyeblink conditioning followed by extinction, and memory retrieval was tested by presenting the CS at troughs and peaks of the theta cycle during different stages of learning. In Experiment 2, animals were trained in delay conditioning either contingent on a high level of theta or at a random neural state. Conditioning was then followed by extinction conducted either at a random state, contingent on theta trough or contingent on theta peak. Our current results indicate that the phase of theta at CS onset has no effect on the performance of the behavioral learned response at any stage of classical eyeblink conditioning or extinction. In addition, theta-contingent trial presentation does not improve learning during delay eyeblink conditioning. The results are consistent with our earlier findings and suggest that the theta phase alone is not sufficient to affect learning at the behavioral level. It seems that the retrieval of recently acquired memories and consequently performing a learned response is moderated by neural mechanisms other than hippocampal theta.
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Affiliation(s)
- Tomi Waselius
- Department of Psychology, P.O. Box 35, 40014, University of Jyvaskyla, Finland; Centre for Interdisciplinary Brain Research, University of Jyvaskyla, Finland.
| | - Eveliina Pöllänen
- Department of Psychology, P.O. Box 35, 40014, University of Jyvaskyla, Finland
| | - Jan Wikgren
- Department of Psychology, P.O. Box 35, 40014, University of Jyvaskyla, Finland; Centre for Interdisciplinary Brain Research, University of Jyvaskyla, Finland
| | - Markku Penttonen
- Department of Psychology, P.O. Box 35, 40014, University of Jyvaskyla, Finland
| | - Miriam S Nokia
- Department of Psychology, P.O. Box 35, 40014, University of Jyvaskyla, Finland
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Developmental Changes in Hippocampal CA1 Single Neuron Firing and Theta Activity during Associative Learning. PLoS One 2016; 11:e0164781. [PMID: 27764172 PMCID: PMC5072650 DOI: 10.1371/journal.pone.0164781] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 10/02/2016] [Indexed: 11/19/2022] Open
Abstract
Hippocampal development is thought to play a crucial role in the emergence of many forms of learning and memory, but ontogenetic changes in hippocampal activity during learning have not been examined thoroughly. We examined the ontogeny of hippocampal function by recording theta and single neuron activity from the dorsal hippocampal CA1 area while rat pups were trained in associative learning. Three different age groups [postnatal days (P)17-19, P21-23, and P24-26] were trained over six sessions using a tone conditioned stimulus (CS) and a periorbital stimulation unconditioned stimulus (US). Learning increased as a function of age, with the P21-23 and P24-26 groups learning faster than the P17-19 group. Age- and learning-related changes in both theta and single neuron activity were observed. CA1 pyramidal cells in the older age groups showed greater task-related activity than the P17-19 group during CS-US paired sessions. The proportion of trials with a significant theta (4-10 Hz) power change, the theta/delta ratio, and theta peak frequency also increased in an age-dependent manner. Finally, spike/theta phase-locking during the CS showed an age-related increase. The findings indicate substantial developmental changes in dorsal hippocampal function that may play a role in the ontogeny of learning and memory.
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14
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Li JY, Kuo TB, Yang CC. Aged rats show dominant modulation of lower frequency hippocampal theta rhythm during running. Exp Gerontol 2016; 83:63-70. [DOI: 10.1016/j.exger.2016.08.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 07/30/2016] [Accepted: 08/02/2016] [Indexed: 10/21/2022]
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15
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Hao S, Tang B, Wu Z, Ure K, Sun Y, Tao H, Gao Y, Patel AJ, Curry DJ, Samaco RC, Zoghbi HY, Tang J. Forniceal deep brain stimulation rescues hippocampal memory in Rett syndrome mice. Nature 2016; 526:430-4. [PMID: 26469053 PMCID: PMC4828032 DOI: 10.1038/nature15694] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 09/08/2015] [Indexed: 12/13/2022]
Abstract
Deep brain stimulation (DBS) has improved the prospects for many individuals with diseases affecting motor control, and recently it has shown promise for improving cognitive function as well. Several studies in individuals with Alzheimer disease and in amnestic rats have demonstrated that DBS targeted to the fimbria-fornix1-3, the region that appears to regulate hippocampal activity, can mitigate defects in hippocampus-dependent memory3-5. Despite these promising results, DBS has not been tested for its ability to improve cognition in any childhood intellectual disability disorder (IDD). IDDs are a pressing concern: they affect as much as 3% of the population and involve hundreds of different genes. We hypothesized that stimulating the neural circuits that underlie learning and memory might provide a more promising route to treating these otherwise intractable disorders than seeking to adjust levels of one molecule at a time. We therefore studied the effects of forniceal DBS in a well-characterized mouse model of Rett Syndrome (RTT), which is a leading cause of intellectual disability in females. Caused by mutations that impair the function of MeCP26, RTT appears by the second year of life, causing profound impairment in cognitive, motor, and social skills along with an array of neurological features7; RTT mice, which reproduce the broad phenotype of this disorder, also show clear deficits in hippocampus-dependent learning and memory and hippocampal synaptic plasticity8-11. Here we show that forniceal DBS in RTT mice rescued contextual fear memory as well as spatial learning and memory. In parallel, forniceal DBS restored in vivo hippocampal long-term potentiation (LTP) and hippocampal neurogenesis. These results indicate that forniceal DBS might mitigate cognitive dysfunction in RTT.
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Affiliation(s)
- Shuang Hao
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Bin Tang
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Zhenyu Wu
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Kerstin Ure
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Yaling Sun
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Huifang Tao
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Yan Gao
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Akash J Patel
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA.,Department of Neurosurgery, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Daniel J Curry
- Department of Neurosurgery, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Rodney C Samaco
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Huda Y Zoghbi
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA.,Program in Developmental Biology, Baylor College of Medicine, Houston, Texas 77030, USA.,Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030, USA.,Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Jianrong Tang
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA
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Russo JF, Sheth SA, McKhann GM. Using Deep Brain Stimulation to Rescue Memory in Rett Syndrome. Neurosurgery 2016; 78:N16-7. [PMID: 26779794 DOI: 10.1227/01.neu.0000479892.25489.0e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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17
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Yu W, Krook-Magnuson E. Cognitive Collaborations: Bidirectional Functional Connectivity Between the Cerebellum and the Hippocampus. Front Syst Neurosci 2015; 9:177. [PMID: 26732845 PMCID: PMC4686701 DOI: 10.3389/fnsys.2015.00177] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 12/02/2015] [Indexed: 01/23/2023] Open
Abstract
There is a growing recognition that the utility of the cerebellum is not limited to motor control. This review focuses on the particularly novel area of hippocampal-cerebellar interactions. Recent work has illustrated that the hippocampus and cerebellum are functionally connected in a bidirectional manner such that the cerebellum can influence hippocampal activity and vice versa. This functional connectivity has important implications for physiology, including spatial navigation and timing-dependent tasks, as well as pathophysiology, including seizures. Moving forward, an improved understanding of the critical biological underpinnings of these cognitive collaborations may improve interventions for neurological disorders such as epilepsy.
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Affiliation(s)
- Wilson Yu
- Department of Neuroscience, University of Minnesota Minneapolis, MN, USA
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18
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Ben-Soussan TD, Glicksohn J, Berkovich-Ohana A. From Cerebellar Activation and Connectivity to Cognition: A Review of the Quadrato Motor Training. BIOMED RESEARCH INTERNATIONAL 2015; 2015:954901. [PMID: 26539545 PMCID: PMC4619922 DOI: 10.1155/2015/954901] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 05/06/2015] [Indexed: 11/18/2022]
Abstract
The importance of the cerebellum is increasingly recognized, not only in motor control but also in cognitive learning and function. Nevertheless, the relationship between training-induced cerebellar activation and electrophysiological and structural changes in humans has yet to be established. In the current paper, we suggest a general model tying cerebellar function to cognitive improvement, via neuronal synchronization, as well as biochemical and anatomical changes. We then suggest that sensorimotor training provides an optimal paradigm to test the proposed model and review supporting evidence of Quadrato Motor Training (QMT), a sensorimotor training aimed at increasing attention and coordination. Subsequently, we discuss the possible mechanisms through which QMT may exert its beneficial effects on cognition (e.g., increased creativity, reflectivity, and reading), focusing on cerebellar alpha activity as a possible mediating mechanism allowing cognitive improvement, molecular and anatomical changes. Using the example of QMT research, this paper emphasizes the importance of investigating whole-body sensorimotor training paradigms utilizing a multidisciplinary approach and its implications to healthy brain development.
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Affiliation(s)
- Tal Dotan Ben-Soussan
- The Leslie and Susan Gonda (Goldschmied) Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan, Israel
- Research Institute for Neuroscience, Education and Didactics, Patrizio Paoletti Foundation, Rome, Italy
| | - Joseph Glicksohn
- The Leslie and Susan Gonda (Goldschmied) Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan, Israel
- Department of Criminology, Bar-Ilan University, Ramat Gan, Israel
| | - Aviva Berkovich-Ohana
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel
- Department of Physiology and Pharmacology, University of Rome “La Sapienza”, Rome, Italy
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19
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Moya MV, Siegel JJ, McCord ED, Kalmbach BE, Dembrow N, Johnston D, Chitwood RA. Species-specific differences in the medial prefrontal projections to the pons between rat and rabbit. J Comp Neurol 2015; 522:3052-74. [PMID: 24639247 DOI: 10.1002/cne.23566] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 01/18/2014] [Accepted: 02/18/2014] [Indexed: 12/19/2022]
Abstract
The medial prefrontal cortex (mPFC) of both rats and rabbits has been shown to support trace eyeblink conditioning, presumably by providing an input to the cerebellum via the pons that bridges the temporal gap between conditioning stimuli. The pons of rats and rabbits, however, shows divergence in gross anatomical organization, leaving open the question of whether the topography of prefrontal inputs to the pons is similar in rats and rabbits. To investigate this question, we injected anterograde tracer into the mPFC of rats and rabbits to visualize and map in 3D the distribution of labeled terminals in the pons. Effective mPFC injections showed labeled axons in the ipsilateral descending pyramidal tract in both species. In rats, discrete clusters of densely labeled terminals were observed primarily in the rostromedial pons. Clusters of labeled terminals were also observed contralateral to mPFC injection sites in rats, appearing as a less dense "mirror-image" of ipsilateral labeling. In rabbits, mPFC labeled corticopontine terminals were absent in the rostral pons, and instead were restricted to the intermediate pons. The densest terminal fields were typically observed in association with the ipsilateral pyramidal tract as it descended ventromedially through the rabbit pons. No contralateral terminal labeling was observed for any injections made in the rabbit mPFC. The results suggest the possibility that mPFC inputs to the pons may be integrated with different sources of cortical inputs between rats and rabbits. The resulting implications for mPFC or pons manipulations for studies of trace eyeblink in each species are discussed.
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Affiliation(s)
- Maria V Moya
- Center for Learning & Memory, University of Texas at Austin, Austin, Texas, 78712
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20
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Kent BA, Oomen CA, Bekinschtein P, Bussey TJ, Saksida LM. Cognitive enhancing effects of voluntary exercise, caloric restriction and environmental enrichment: a role for adult hippocampal neurogenesis and pattern separation? Curr Opin Behav Sci 2015. [DOI: 10.1016/j.cobeha.2015.06.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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21
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Curlik DM, Weiss C, Nicholson DA, Disterhoft JF. Age-related impairments on one hippocampal-dependent task predict impairments on a subsequent hippocampal-dependent task. Behav Neurosci 2015; 128:676-88. [PMID: 25420127 DOI: 10.1037/bne0000018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Age-related cognitive impairments are particularly prevalent in forms of learning that require a functionally intact hippocampal formation, such as spatial and declarative learning. However, there is notable heterogeneity in the cognitive abilities of aged subjects. To date, few studies have determined whether age-related impairments on one learning task relate to impairments on different learning tasks that engage overlapping cognitive processes. Here, we hypothesized that aged animals that were impaired on 1 hippocampal-dependent behavioral procedure would be impaired on a second hippocampal-dependent procedure. Conversely, aged animals that were unimpaired on 1 hippocampal-dependent task would be unimpaired with a subsequent hippocampal-dependent form of learning. To test these hypotheses, we trained young (2-3 months old) and aged (28-29 months old) F344XBN male rats with trace eyeblink conditioning, followed by the Morris water maze. Half of aged rats were impaired during trace conditioning. Nearly half of aged animals were also impaired during water maze probe testing. Performance during trace conditioning correlated with performance during water maze testing in aged animals. Further analyses revealed that, as a group, aged animals that were impaired on 1 hippocampal-dependent task were impaired on both tasks. Conversely, aged animals that were unimpaired on 1 task were unimpaired on both tasks. Together, these results suggest that aged-related impairments on 1 hippocampal-dependent task predict age-related impairments on a second hippocampal-dependent procedure. These results have implications for assigning personalized therapeutics to ameliorate age-related cognitive decline.
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Affiliation(s)
- Daniel M Curlik
- Department of Physiology, Feinberg School of Medicine, Northwestern University
| | - Craig Weiss
- Department of Physiology, Feinberg School of Medicine, Northwestern University
| | | | - John F Disterhoft
- Department of Physiology, Feinberg School of Medicine, Northwestern University
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22
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Multivariate genetic determinants of EEG oscillations in schizophrenia and psychotic bipolar disorder from the BSNIP study. Transl Psychiatry 2015; 5:e588. [PMID: 26101851 PMCID: PMC4490286 DOI: 10.1038/tp.2015.76] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 04/27/2015] [Accepted: 05/04/2015] [Indexed: 01/18/2023] Open
Abstract
Schizophrenia (SZ) and psychotic bipolar disorder (PBP) are disabling psychiatric illnesses with complex and unclear etiologies. Electroencephalogram (EEG) oscillatory abnormalities in SZ and PBP probands are heritable and expressed in their relatives, but the neurobiology and genetic factors mediating these abnormalities in the psychosis dimension of either disorder are less explored. We examined the polygenic architecture of eyes-open resting state EEG frequency activity (intrinsic frequency) from 64 channels in 105 SZ, 145 PBP probands and 56 healthy controls (HCs) from the multisite BSNIP (Bipolar-Schizophrenia Network on Intermediate Phenotypes) study. One million single-nucleotide polymorphisms (SNPs) were derived from DNA. We assessed eight data-driven EEG frequency activity derived from group-independent component analysis (ICA) in conjunction with a reduced subset of 10,422 SNPs through novel multivariate association using parallel ICA (para-ICA). Genes contributing to the association were examined collectively using pathway analysis tools. Para-ICA extracted five frequency and nine SNP components, of which theta and delta activities were significantly correlated with two different gene components, comprising genes participating extensively in brain development, neurogenesis and synaptogenesis. Delta and theta abnormality was present in both SZ and PBP, while theta differed between the two disorders. Theta abnormalities were also mediated by gene clusters involved in glutamic acid pathways, cadherin and synaptic contact-based cell adhesion processes. Our data suggest plausible multifactorial genetic networks, including novel and several previously identified (DISC1) candidate risk genes, mediating low frequency delta and theta abnormalities in psychoses. The gene clusters were enriched for biological properties affecting neural circuitry and involved in brain function and/or development.
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Nokia MS, Waselius T, Mikkonen JE, Wikgren J, Penttonen M. Phase matters: responding to and learning about peripheral stimuli depends on hippocampal θ phase at stimulus onset. ACTA ACUST UNITED AC 2015; 22:307-17. [PMID: 25979993 PMCID: PMC4436652 DOI: 10.1101/lm.038166.115] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 04/10/2015] [Indexed: 12/21/2022]
Abstract
Hippocampal θ (3-12 Hz) oscillations are implicated in learning and memory, but their functional role remains unclear. We studied the effect of the phase of local θ oscillation on hippocampal responses to a neutral conditioned stimulus (CS) and subsequent learning of classical trace eyeblink conditioning in adult rabbits. High-amplitude, regular hippocampal θ-band responses (that predict good learning) were elicited by the CS when it was timed to commence at the fissure θ trough (Trough group). Regardless, learning in this group was not enhanced compared with a yoked control group, possibly due to a ceiling effect. However, when the CS was consistently presented to the peak of θ (Peak group), hippocampal θ-band responding was less organized and learning was retarded. In well-trained animals, the hippocampal θ phase at CS onset no longer affected performance of the learned response, suggesting a time-limited role for hippocampal processing in learning. To our knowledge, this is the first study to demonstrate that timing a peripheral stimulus to a specific phase of the hippocampal θ cycle produces robust effects on the synchronization of neural responses and affects learning at the behavioral level. Our results support the notion that the phase of spontaneous hippocampal θ oscillation is a means of regulating the processing of information in the brain to a behaviorally relevant degree.
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Affiliation(s)
- Miriam S Nokia
- Department of Psychology, University of Jyvaskyla, FI-40014 Jyväskylän, Finland
| | - Tomi Waselius
- Department of Psychology, University of Jyvaskyla, FI-40014 Jyväskylän, Finland
| | - Jarno E Mikkonen
- Department of Psychology, University of Jyvaskyla, FI-40014 Jyväskylän, Finland Centre for Interdisciplinary Brain Research, University of Jyvaskyla, FI-40014 Jyväskylän, Finland
| | - Jan Wikgren
- Department of Psychology, University of Jyvaskyla, FI-40014 Jyväskylän, Finland Centre for Interdisciplinary Brain Research, University of Jyvaskyla, FI-40014 Jyväskylän, Finland
| | - Markku Penttonen
- Department of Psychology, University of Jyvaskyla, FI-40014 Jyväskylän, Finland
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Shors TJ, Olson RL, Bates ME, Selby EA, Alderman BL. Mental and Physical (MAP) Training: a neurogenesis-inspired intervention that enhances health in humans. Neurobiol Learn Mem 2014; 115:3-9. [PMID: 25219804 PMCID: PMC4535923 DOI: 10.1016/j.nlm.2014.08.012] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 08/20/2014] [Accepted: 08/21/2014] [Indexed: 12/20/2022]
Abstract
New neurons are generated in the hippocampus each day and their survival is greatly enhanced through effortful learning (Shors, 2014). The numbers of cells produced can be increased by physical exercise (van Praag, Kempermann, & Gage, 1999). These findings inspired us to develop a clinical intervention for humans known as Mental and Physical Training, or MAP Training. Each session consists of 30min of mental training with focused attention meditation (20min sitting and 10min walking). Meditation is an effortful training practice that involves learning about the transient nature of thoughts and thought patterns, and acquiring skills to recognize them without necessarily attaching meaning and/or emotions to them. The mental training component is followed by physical training with 30min of aerobic exercise performed at moderate intensity. During this component, participants learn choreographed dance routines while engaging in aerobic exercise. In a pilot "proof-of-concept" study, we provided supervised MAP Training (2 sessions per week for 8weeks) to a group of young mothers in the local community who were recently homeless, most of them having previously suffered from physical and sexual abuse, addiction, and depression. Preliminary data suggest that MAP Training improves dependent measures of aerobic fitness (as assessed by maximal rate of oxygen consumed) while decreasing symptoms of depression and anxiety. Similar changes were not observed in a group of recently homeless women who did not participate in MAP Training. It is not currently possible to determine whether new neurons in the human brain increase in number as a result of MAP Training. Rather these preliminary results of MAP Training illustrate how neuroscientific research can be translated into novel clinical interventions that benefit human health and wellness.
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Affiliation(s)
- Tracey J Shors
- Behavioral and Systems Neuroscience, Rutgers University, United States; Department of Psychology, Rutgers University, United States; Center for Collaborative Neuroscience, Rutgers University, United States
| | - Ryan L Olson
- Department of Exercise Science, Rutgers University, United States
| | - Marsha E Bates
- Center of Alcohol Studies, Rutgers University, United States
| | - Edward A Selby
- Department of Psychology, Rutgers University, United States
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25
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Chemotherapy-related cognitive dysfunction: current animal studies and future directions. Brain Imaging Behav 2014; 7:453-9. [PMID: 23949877 DOI: 10.1007/s11682-013-9250-3] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Cognitive impairment is a potential long-term side effect of adjuvant chemotherapy that can have a major impact on the quality of life of cancer survivors. There is a growing number of preclinical studies addressing this issue, thereby extending our knowledge of the mechanisms underlying chemotherapy-induced neurotoxicity. In this review, we will summarize the recent advances and important findings presented in these studies. Emerging challenges, such as the development of neuroprotective strategies, and the role of the blood-brain barrier on cognitive impairment will be described and future directions in this field of investigation will be outlined.
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26
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Curlik DM, Difeo G, Shors TJ. Preparing for adulthood: thousands upon thousands of new cells are born in the hippocampus during puberty, and most survive with effortful learning. Front Neurosci 2014; 8:70. [PMID: 24795549 PMCID: PMC4005956 DOI: 10.3389/fnins.2014.00070] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 03/24/2014] [Indexed: 11/27/2022] Open
Abstract
The dentate gyrus of the hippocampal formation generates new granule neurons throughout life. The number of neurons produced each day is inversely related to age, with thousands more produced during puberty than during adulthood, and many fewer produced during senescence. In adulthood, approximately half of these cells undergo apoptosis shortly after they are generated. Most of these cells can be rescued from death by effortful and successful learning experiences (Gould et al., 1999; Waddell and Shors, 2008; Curlik and Shors, 2011). Once rescued, the newly-generated cells differentiate into neurons, and remain in the hippocampus for at least several months (Leuner et al., 2004). Here, we report that many new hippocampal cells also undergo cell death during puberty. Because the juvenile brain is more plastic than during adulthood, and because many experiences are new, we hypothesized that a great number of cells would be rescued by learning during puberty. Indeed, adolescent rats that successfully acquired the trace eyeblink response retained thousands more cells than animals that were not trained, and those that failed to learn. Because the hippocampus generates thousands more cells during puberty than during adulthood, these results support the idea that the adolescent brain is especially responsive to learning. This enhanced response can have significant consequences for the functional integrity of the hippocampus. Such a massive increase in cell proliferation is likely an adaptive response as the young animal must emerge from the care of its mother to face the dangers, challenges, and opportunities of adulthood.
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Affiliation(s)
- Daniel M Curlik
- Department of Psychology, Behavioral and Systems Neuroscience, Center for Collaborative Neuroscience, Rutgers University Piscataway, NJ, USA
| | - Gina Difeo
- Department of Psychology, Behavioral and Systems Neuroscience, Center for Collaborative Neuroscience, Rutgers University Piscataway, NJ, USA
| | - Tracey J Shors
- Department of Psychology, Behavioral and Systems Neuroscience, Center for Collaborative Neuroscience, Rutgers University Piscataway, NJ, USA
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Chen H, Wang YJ, Yang L, Hu C, Ke XF, Fan ZL, Sui JF, Hu B. Predictive nature of prefrontal theta oscillation on the performance of trace conditioned eyeblink responses in guinea pigs. Behav Brain Res 2014; 265:121-31. [PMID: 24572215 DOI: 10.1016/j.bbr.2014.02.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 02/11/2014] [Accepted: 02/15/2014] [Indexed: 10/25/2022]
Abstract
Stimulus-evoked theta oscillations are observed in the medial prefrontal cortex (mPFC) when executing a variety of learning tasks. Here, we aimed to further determine whether spontaneous theta-band (5.0-10.0 Hz) oscillations in the mPFC predicted the subsequent behavioral performance in trace eyeblink conditioning (TEBC), in which the conditioned stimulus (CS) was separated from the unconditioned stimulus (US) by 500 ms trace interval. By recording local field potentials (LFP) signals in the guinea pigs performing the TEBC task, we found that, a higher mPFC relative theta ratio [theta/(delta+beta)] during the baseline (850-ms period prior to the onset of the CS) was predictive of higher magnitude and more adaptive timing rather than faster acquisition of trace conditioned eyeblink responses (CR). However, the prediction of baseline mPFC theta activity was time-limited to the well-learning stage. Additionally, the relative power of mPFC theta activity did not correlate with the CR performance if the trace interval between the CS and the US was shortened to 100 ms. These results suggest that the brain state in which the baseline mPFC theta activity is present or absent is detrimental for the subsequent performance of trace CRs especially when the asymptotic learning state is achieved.
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Affiliation(s)
- Hao Chen
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, PR China
| | - Yi-jie Wang
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, PR China; Battalion 5 of Cadet Brigade, Third Military Medical University, Chongqing 400038, PR China
| | - Li Yang
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, PR China
| | - Chen Hu
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, PR China; Battalion 8 of Cadet Brigade, Third Military Medical University, Chongqing 400038, PR China
| | - Xian-feng Ke
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, PR China; Battalion 8 of Cadet Brigade, Third Military Medical University, Chongqing 400038, PR China
| | - Zheng-li Fan
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, PR China
| | - Jian-feng Sui
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, PR China; Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, PR China.
| | - Bo Hu
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, PR China.
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28
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Tronel S, Lemaire V, Charrier V, Montaron MF, Abrous DN. Influence of ontogenetic age on the role of dentate granule neurons. Brain Struct Funct 2014; 220:645-61. [PMID: 24510284 DOI: 10.1007/s00429-014-0715-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 01/24/2014] [Indexed: 12/20/2022]
Abstract
New neurons are continuously produced in the adult dentate gyrus of the hippocampus, a key structure in learning and memory. It has been shown that adult neurogenesis is crucial for normal memory processing. However, it is not known whether neurons born during the developmental period and during adulthood support the same functions. Here, we demonstrate that neurons born in neonates (first postnatal week) are activated in different memory processes when they are mature compared to neurons born in adults. By imaging the activation of these two different neuron generations in the same rat and using the IEG Zif268 and Fos, we show that these neurons are involved in discriminating dissimilar contexts and spatial problem solving, respectively. These findings demonstrate that the ontogenetic stage during which neurons are generated is crucial for their function within the memory network.
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29
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Pereira Dias G, Hollywood R, Bevilaqua MCDN, da Luz ACDDS, Hindges R, Nardi AE, Thuret S. Consequences of cancer treatments on adult hippocampal neurogenesis: implications for cognitive function and depressive symptoms. Neuro Oncol 2014; 16:476-92. [PMID: 24470543 DOI: 10.1093/neuonc/not321] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The human brain is capable of generating new functional neurons throughout life, a phenomenon known as adult neurogenesis. The generation of new neurons is sustained throughout adulthood due to the proliferation and differentiation of adult neural stem cells. This process in humans is uniquely located in the subgranular zone of the dentate gyrus in the hippocampus. Adult hippocampal neurogenesis (AHN) is thought to play a major role in hippocampus-dependent functions, such as spatial awareness, long-term memory, emotionality, and mood. The overall aim of current treatments for cancer (such as radiotherapy and chemotherapy) is to prevent aberrant cell division of cell populations associated with malignancy. However, the treatments in question are absolutist in nature and hence inhibit all cell division. An unintended consequence of this cessation of cell division is the impairment of adult neural stem cell proliferation and AHN. Patients undergoing treatment for cancerous malignancies often display specific forms of memory deficits, as well as depressive symptoms. This review aims to discuss the effects of cancer treatments on AHN and propose a link between the inhibition of the neurogenetic process in the hippocampus and the advent of the cognitive and mood-based deficits observed in patients and animal models undergoing cancer therapies. Possible evidence for coadjuvant interventions aiming to protect neural cells, and subsequently the mood and cognitive functions they regulate, from the ablative effects of cancer treatment are discussed as potential clinical tools to improve mental health among cancer patients.
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Affiliation(s)
- Gisele Pereira Dias
- Institute of Psychiatry, King's College London, The James Black Centre, London, UK (G.P.D., R.H., S.T.); Translational Neurobiology Unit, Laboratory of Panic and Respiration, Institute of Psychiatry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil (G.P.D., M.C.N.B., A.C.D.dS.d.L., A.E.N.); MRC Centre for Developmental Neurobiology, King's College London, London, UK (M.C.N.B., R.H.)
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30
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Nokia MS, Wikgren J. Phase-locked hippocampal theta-band responses are related to discriminative eyeblink conditioned responding. Behav Brain Res 2013; 256:575-9. [PMID: 24029698 DOI: 10.1016/j.bbr.2013.09.011] [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: 05/31/2013] [Revised: 08/16/2013] [Accepted: 09/02/2013] [Indexed: 11/17/2022]
Abstract
Hippocampal electrophysiological oscillatory activity is undoubtedly related to learning and memory. The relative power of spontaneously occurring hippocampal theta (∼4-8 Hz) oscillations predicts how fast and how well an animal will learn: more theta predicts faster acquisition of the conditioned response in eyeblink conditioning in both rats and rabbits. Here, our aim was to study how hippocampal theta-band responses to conditioned stimuli elicited during very-long delay discrimination eyeblink conditioning relate to the accompanying conditioned behavior. We trained adult male New Zealand White rabbits using 1500-ms auditory stimuli as conditioned stimuli and a 100-ms airpuff as an unconditioned stimulus. The reinforced conditioned stimulus overlapped and co-terminated with the unconditioned stimulus whereas the non-reinforced conditioned stimulus was always presented alone. Consistent with previous results, hippocampal theta-band responses to the conditioned stimuli diminished in amplitude across training. Interestingly, hippocampal theta-band responses were most consistently time-locked when a well-trained animal failed to suppress behavioral learned responses to the non-reinforced conditioned stimulus. We suggest that phase-locking of hippocampal theta-band oscillations in response to external stimuli reflects retrieval of the dominant memory trace (adaptive or not) along with initiating the most prominent action scheme related to that memory trace.
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Affiliation(s)
- Miriam S Nokia
- Department of Psychology, P.O. Box 35, FI-40014 University of Jyväskylä, Finland
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31
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Patrício P, Mateus-Pinheiro A, Sousa N, Pinto L. Re-cycling paradigms: cell cycle regulation in adult hippocampal neurogenesis and implications for depression. Mol Neurobiol 2013; 48:84-96. [PMID: 23471746 PMCID: PMC3718990 DOI: 10.1007/s12035-013-8422-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Accepted: 02/05/2013] [Indexed: 02/08/2023]
Abstract
Since adult neurogenesis became a widely accepted phenomenon, much effort has been put in trying to understand the mechanisms involved in its regulation. In addition, the pathophysiology of several neuropsychiatric disorders, such as depression, has been associated with imbalances in adult hippocampal neurogenesis. These imbalances may ultimately reflect alterations at the cell cycle level, as a common mechanism through which intrinsic and extrinsic stimuli interact with the neurogenic niche properties. Thus, the comprehension of these regulatory mechanisms has become of major importance to disclose novel therapeutic targets. In this review, we first present a comprehensive view on the cell cycle components and mechanisms that were identified in the context of the homeostatic adult hippocampal neurogenic niche. Then, we focus on recent work regarding the cell cycle changes and signaling pathways that are responsible for the neurogenesis imbalances observed in neuropathological conditions, with a particular emphasis on depression.
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Affiliation(s)
- Patrícia Patrício
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.
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Curlik DM, Maeng LY, Agarwal PR, Shors TJ. Physical skill training increases the number of surviving new cells in the adult hippocampus. PLoS One 2013; 8:e55850. [PMID: 23437067 PMCID: PMC3577803 DOI: 10.1371/journal.pone.0055850] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 01/04/2013] [Indexed: 02/05/2023] Open
Abstract
The dentate gyrus is a major site of plasticity in the adult brain, giving rise to thousands of new neurons every day, through the process of adult neurogenesis. Although the majority of these cells die within two weeks of their birth, they can be rescued from death by various forms of learning. Successful acquisition of select types of associative and spatial memories increases the number of these cells that survive. Here, we investigated the possibility that an entirely different form of learning, physical skill learning, could rescue new hippocampal cells from death. To test this possibility, rats were trained with a physically-demanding and technically-difficult version of a rotarod procedure. Acquisition of the physical skill greatly increased the number of new hippocampal cells that survived. The number of surviving cells positively correlated with performance on the task. Only animals that successfully mastered the task retained the cells that would have otherwise died. Animals that failed to learn, and those that did not learn well did not retain any more cells than those that were untrained. Importantly, acute voluntary exercise in activity wheels did not increase the number of surviving cells. These data suggest that acquisition of a physical skill can increase the number of surviving hippocampal cells. Moreover, learning an easier version of the task did not increase cell survival. These results are consistent with previous reports revealing that learning only rescues new neurons from death when acquisition is sufficiently difficult to achieve. Finally, complete hippocampal lesions did not disrupt acquisition of this physical skill. Therefore, physical skill training that does not depend on the hippocampus can effectively increase the number of surviving cells in the adult hippocampus, the vast majority of which become mature neurons.
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Affiliation(s)
- Daniel M. Curlik
- Department of Psychology and Center for Collaborative Neuroscience, Rutgers University, Piscataway, New Jersey, United States of America
| | - Lisa Y. Maeng
- Department of Psychology and Center for Collaborative Neuroscience, Rutgers University, Piscataway, New Jersey, United States of America
| | - Prateek R. Agarwal
- Department of Psychology and Center for Collaborative Neuroscience, Rutgers University, Piscataway, New Jersey, United States of America
| | - Tracey J. Shors
- Department of Psychology and Center for Collaborative Neuroscience, Rutgers University, Piscataway, New Jersey, United States of America
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Anand KS, Dhikav V. Hippocampus in health and disease: An overview. Ann Indian Acad Neurol 2013; 15:239-46. [PMID: 23349586 PMCID: PMC3548359 DOI: 10.4103/0972-2327.104323] [Citation(s) in RCA: 248] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 04/29/2012] [Accepted: 06/20/2012] [Indexed: 12/20/2022] Open
Abstract
Hippocampus is a complex brain structure embedded deep into temporal lobe. It has a major role in learning and memory. It is a plastic and vulnerable structure that gets damaged by a variety of stimuli. Studies have shown that it also gets affected in a variety of neurological and psychiatric disorders. In last decade or so, lot has been learnt about conditions that affect hippocampus and produce changes ranging from molecules to morphology. Progresses in radiological delineation, electrophysiology, and histochemical characterization have made it possible to study this archicerebral structure in greater detail. Present paper attempts to give an overview of hippocampus, both in health and diseases.
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Affiliation(s)
- Kuljeet Singh Anand
- Department of Neurology, Dr. Ram Manohar Lohia, PGIMER- Guru Gobind Singh Indraprasth University, New Delhi, India
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Nokia MS, Anderson ML, Shors TJ. Chemotherapy disrupts learning, neurogenesis and theta activity in the adult brain. Eur J Neurosci 2012; 36:3521-30. [PMID: 23039863 DOI: 10.1111/ejn.12007] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Revised: 07/26/2012] [Accepted: 08/30/2012] [Indexed: 12/24/2022]
Abstract
Chemotherapy, especially if prolonged, disrupts attention, working memory and speed of processing in humans. Most cancer drugs that cross the blood-brain barrier also decrease adult neurogenesis. Because new neurons are generated in the hippocampus, this decrease may contribute to the deficits in working memory and related thought processes. The neurophysiological mechanisms that underlie these deficits are generally unknown. A possible mediator is hippocampal oscillatory activity within the theta range (3-12 Hz). Theta activity predicts and promotes efficient learning in healthy animals and humans. Here, we hypothesised that chemotherapy disrupts learning via decreases in hippocampal adult neurogenesis and theta activity. Temozolomide was administered to adult male Sprague-Dawley rats in a cyclic manner for several weeks. Treatment was followed by training with different types of eyeblink classical conditioning, a form of associative learning. Chemotherapy reduced both neurogenesis and endogenous theta activity, as well as disrupted learning and related theta-band responses to the conditioned stimulus. The detrimental effects of temozolomide only occurred after several weeks of treatment, and only on a task that requires the association of events across a temporal gap and not during training with temporally overlapping stimuli. Chemotherapy did not disrupt the memory for previously learned associations, a memory independent of (new neurons in) the hippocampus. In conclusion, prolonged systemic chemotherapy is associated with a decrease in hippocampal adult neurogenesis and theta activity that may explain the selective deficits in processes of learning that describe the 'chemobrain'.
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Affiliation(s)
- Miriam S Nokia
- Department of Psychology, University of Jyvaskyla, PO Box 35, 40014 Jyvaskyla, Finland.
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35
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Training your brain: Do mental and physical (MAP) training enhance cognition through the process of neurogenesis in the hippocampus? Neuropharmacology 2012; 64:506-14. [PMID: 22898496 DOI: 10.1016/j.neuropharm.2012.07.027] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 07/11/2012] [Accepted: 07/13/2012] [Indexed: 10/28/2022]
Abstract
New neurons are produced each day in the hippocampus through the process of neurogenesis. Both mental and physical training can modify this process by increasing the number of new cells that mature into functional neurons in the adult brain. However, the mechanisms whereby these increases occur are not necessarily the same. Physical activity, especially aerobic exercise greatly increases the number of new neurons that are produced in the hippocampal formation. In contrast, mental training via skill learning increases the numbers that survive, particularly when the training goals are challenging. Both manipulations can increase cognitive performance in the future, some of which are reportedly mediated by the presence of new neurons in the adult hippocampus. Based on these data, we suggest that a combination of mental and physical training, referred to here as MAP training, is more beneficial for neuronal recruitment and overall mental health than either activity alone. This article is part of a Special Issue entitled 'Cognitive Enhancers'.
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