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Kunz L, Staresina BP, Reinacher PC, Brandt A, Guth TA, Schulze-Bonhage A, Jacobs J. Ripple-locked coactivity of stimulus-specific neurons and human associative memory. Nat Neurosci 2024; 27:587-599. [PMID: 38366143 PMCID: PMC10917673 DOI: 10.1038/s41593-023-01550-x] [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: 12/09/2022] [Accepted: 12/11/2023] [Indexed: 02/18/2024]
Abstract
Associative memory enables the encoding and retrieval of relations between different stimuli. To better understand its neural basis, we investigated whether associative memory involves temporally correlated spiking of medial temporal lobe (MTL) neurons that exhibit stimulus-specific tuning. Using single-neuron recordings from patients with epilepsy performing an associative object-location memory task, we identified the object-specific and place-specific neurons that represented the separate elements of each memory. When patients encoded and retrieved particular memories, the relevant object-specific and place-specific neurons activated together during hippocampal ripples. This ripple-locked coactivity of stimulus-specific neurons emerged over time as the patients' associative learning progressed. Between encoding and retrieval, the ripple-locked timing of coactivity shifted, suggesting flexibility in the interaction between MTL neurons and hippocampal ripples according to behavioral demands. Our results are consistent with a cellular account of associative memory, in which hippocampal ripples coordinate the activity of specialized cellular populations to facilitate links between stimuli.
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Affiliation(s)
- Lukas Kunz
- Department of Epileptology, University Hospital Bonn, Bonn, Germany.
- Epilepsy Center, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
| | - Bernhard P Staresina
- Department of Experimental Psychology, University of Oxford, Oxford, UK
- Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford, UK
| | - Peter C Reinacher
- Department of Stereotactic and Functional Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Fraunhofer Institute for Laser Technology, Aachen, Germany
| | - Armin Brandt
- Epilepsy Center, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Tim A Guth
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
- Epilepsy Center, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Andreas Schulze-Bonhage
- Epilepsy Center, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Joshua Jacobs
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
- Department of Neurological Surgery, Columbia University Medical Center, New York, NY, USA
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2
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Weizenbaum EL, Soberanes D, Hsieh S, Molinare CP, Buckley RF, Betensky RA, Properzi MJ, Marshall GA, Rentz DM, Johnson KA, Sperling RA, Amariglio RE, Papp KV. Capturing learning curves with the multiday Boston Remote Assessment of Neurocognitive Health (BRANCH): Feasibility, reliability, and validity. Neuropsychology 2024; 38:198-210. [PMID: 37971862 PMCID: PMC10841660 DOI: 10.1037/neu0000933] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023] Open
Abstract
OBJECTIVE Unsupervised remote digital cognitive assessment makes frequent testing feasible and allows for measurement of learning over repeated evaluations on participants' own devices. This provides the opportunity to derive individual multiday learning curve scores over short intervals. Here, we report feasibility, reliability, and validity, of a 7-day cognitive battery from the Boston Remote Assessment for Neurocognitive Health (Multiday BRANCH), an unsupervised web-based assessment. METHOD Multiday BRANCH was administered remotely to 181 cognitively unimpaired older adults using their own electronic devices. For 7 consecutive days, participants completed three tests with associative memory components (Face-Name, Groceries-Prices, Digit Signs), using the same stimuli, to capture multiday learning curves for each test. We assessed the feasibility of capturing learning curves across the 7 days. Additionally, we examined the reliability and associations of learning curves with demographics, and traditional cognitive and subjective report measures. RESULTS Multiday BRANCH was feasible with 96% of participants completing all study assessments; there were no differences dependent on type of device used (t = 0.71, p = .48) or time of day completed (t = -0.08, p = .94). Psychometric properties of the learning curves were sound including good test-retest reliability of individuals' curves (intraclass correlation = 0.94). Learning curves were positively correlated with in-person cognitive tests and subjective report of cognitive complaints. CONCLUSIONS Multiday BRANCH is a feasible, reliable, and valid cognitive measure that may be useful for identifying subtle changes in learning and memory processes in older adults. In the future, we will determine whether Multiday BRANCH is predictive of the presence of preclinical Alzheimer's disease. (PsycInfo Database Record (c) 2024 APA, all rights reserved).
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Affiliation(s)
- Emma L Weizenbaum
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School
| | - Daniel Soberanes
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School
| | - Stephanie Hsieh
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School
| | - Cassidy P Molinare
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School
| | - Rachel F Buckley
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School
| | - Rebecca A Betensky
- Department of Biostatistics, School of Global Public Health, New York University
| | - Michael J Properzi
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School
| | - Gad A Marshall
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School
| | - Dorene M Rentz
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School
| | - Keith A Johnson
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School
| | - Reisa A Sperling
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School
| | - Rebecca E Amariglio
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School
| | - Kathryn V Papp
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School
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Bastin C, Delhaye E. Targeting the function of the transentorhinal cortex to identify early cognitive markers of Alzheimer's disease. COGNITIVE, AFFECTIVE & BEHAVIORAL NEUROSCIENCE 2023:10.3758/s13415-023-01093-5. [PMID: 37024735 DOI: 10.3758/s13415-023-01093-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/19/2023] [Indexed: 04/08/2023]
Abstract
Initial neuropathology of early Alzheimer's disease accumulates in the transentorhinal cortex. We review empirical data suggesting that tasks assessing cognitive functions supported by the transenthorinal cortex are impaired as early as the preclinical stages of Alzheimer's disease. These tasks span across various domains, including episodic memory, semantic memory, language, and perception. We propose that all tasks sensitive to Alzheimer-related transentorhinal neuropathology commonly rely on representations of entities supporting the processing and discrimination of items having perceptually and conceptually overlapping features. In the future, we suggest a screening tool that is sensitive and specific to very early Alzheimer's disease to probe memory and perceptual discrimination of highly similar entities.
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Affiliation(s)
- Christine Bastin
- GIGA-Cyclotron Research Centre-In Vivo Imaging, University of Liège, Allée du 6 Août, B30, 4000, Liège, Belgium.
| | - Emma Delhaye
- GIGA-Cyclotron Research Centre-In Vivo Imaging, University of Liège, Allée du 6 Août, B30, 4000, Liège, Belgium
- CICPSI, Faculdade de Psicologia, Universidade de Lisboa, Lisbon, Portugal
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Pavon MV, Navakkode S, Wong LW, Sajikumar S. Inhibition of Nogo-A rescues synaptic plasticity and associativity in APP/PS1 animal model of Alzheimer's disease. Semin Cell Dev Biol 2023; 139:111-120. [PMID: 35431138 DOI: 10.1016/j.semcdb.2022.04.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 03/30/2022] [Accepted: 04/06/2022] [Indexed: 12/31/2022]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by memory loss and cognitive decline. Synaptic impairment is one of the first events to occur in the progression of this disease. Synaptic plasticity and cellular association of various plastic events have been shown to be affected in AD models. Nogo-A, a well-known axonal growth inhibitor with a recently discovered role as a plasticity suppressor, and its main receptor Nogo-66 receptor 1 (NGR1) have been found to be overexpressed in the hippocampus of Alzheimer's patients. However, the role of Nogo-A and its receptor in the pathology of AD is still widely unknown. In this work we set out to investigate whether Nogo-A is working as a plasticity suppressor in AD. Our results show that inhibition of the Nogo-A pathway via the Nogo-R antibody in an Alzheimer's mouse model, APP/PS1, leads to the restoration of both synaptic plasticity and associativity in a protein synthesis and NMDR-dependent manner. We also show that inhibition of the p75NTR pathway, which is strongly associated with NGR1, restores synaptic plasticity as well. Mechanistically, we propose that the restoration of synaptic plasticity in APP/PS1 via inhibition of the Nogo-A pathway is due to the modulation of the RhoA-ROCK2 pathway and increase in plasticity related proteins. Our study identifies Nogo-A as a plasticity suppressor in AD models hence targeting Nogo-A could be a promising strategy to understanding AD pathology.
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Affiliation(s)
- Maria Vazquez Pavon
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore; Life Sciences Institute, Neurobiology Programme, National University of Singapore, Singapore 117456, Singapore
| | - Sheeja Navakkode
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore
| | - Lik-Wei Wong
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore; Life Sciences Institute, Neurobiology Programme, National University of Singapore, Singapore 117456, Singapore
| | - Sreedharan Sajikumar
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore; Life Sciences Institute, Neurobiology Programme, National University of Singapore, Singapore 117456, Singapore; Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117456, Singapore.
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Nie A, Jiang G. Does stimulus emotionality influence associative memory? Insights from directed forgetting. CURRENT PSYCHOLOGY 2021. [DOI: 10.1007/s12144-019-00449-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Flores Vazquez JF, Rubiño J, Contreras López JJ, Siquier A, Cruz Contreras C, Sosa-Ortiz AL, Enriquez Geppert S, Andrés P. Worse associative memory recall in healthy older adults compared to young ones, a face-name study in Spain and Mexico. J Clin Exp Neuropsychol 2021; 43:558-567. [PMID: 34538200 DOI: 10.1080/13803395.2021.1962252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
INTRODUCTION The Face Name Associative Memory Exam (FNAME) is sensitive to associative memory changes early in the Alzheimer's disease spectrum, but little is known about how healthy aging affects FNAME performance. We aimed to assess aging effects on an extended version of the test, which captures further associative memory abilities beyond the recall and recognition domains measured in the original version. METHOD We adapted FNAME versions in Spain and Mexico, adding new subtests (Spontaneous Name Recall, Face-Name Matching). We compared the performance of 21 young adults (YA) and 27 older adults (OA) in Spain, and 34 YA and 36 OA in Mexico. Recall was analyzed using a mixed-model ANOVA including subtest scores as dependent variables, age group as a fixed-factor independent variable, and recall subtest as a three-level repeated-measure independent variable. The rest of the associative memory domains were analyzed through t-tests comparing the performance of YA and OA. RESULTS In Spain, we found significant effects for age group and recall subtest, with large effect sizes. The recognition subtests (Face Recognition, Name Recognition) displayed ceiling effects in both groups. The new subtests displayed medium-to-large effect sizes when comparing age groups. In Mexico, these results were replicated, additionally controlling for education. In both studies, recall performance improved after repeated exposures and it was sustained after 30 minutes in YA and OA. CONCLUSIONS We document, in two different countries, a clear aging pattern on the extended FNAME: regardless of education, OA remember fewer stimuli than YA through recall subtests. The new subtests provide evidence on associative memory changes in aging beyond recall.
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Affiliation(s)
- Juan Francisco Flores Vazquez
- Department of Clinical and Developmental Neuropsychology, University of Groningen, Groningen, The Netherlands.,Department of Biomedical Sciences of Cells & Systems, Section of Cognitive Neuropsychiatry, University of Groningen, Groningen, The Netherlands.,Dementia Laboratory, National Institute of Neurology and Neurosurgery, Mexico City, Mexico
| | - José Rubiño
- Department of Psychology and Research Institute of Health Sciences (IUNICS), University of the Balearic Islands, Palma, Spain
| | | | - Antonia Siquier
- Department of Psychology and Research Institute of Health Sciences (IUNICS), University of the Balearic Islands, Palma, Spain
| | - Cecilia Cruz Contreras
- Department of Clinical and Developmental Neuropsychology, University of Groningen, Groningen, The Netherlands.,Dementia Laboratory, National Institute of Neurology and Neurosurgery, Mexico City, Mexico
| | - Ana Luisa Sosa-Ortiz
- Dementia Laboratory, National Institute of Neurology and Neurosurgery, Mexico City, Mexico
| | - Stefanie Enriquez Geppert
- Department of Clinical and Developmental Neuropsychology, University of Groningen, Groningen, The Netherlands.,Department of Biomedical Sciences of Cells & Systems, Section of Cognitive Neuropsychiatry, University of Groningen, Groningen, The Netherlands
| | - Pilar Andrés
- Department of Psychology and Research Institute of Health Sciences (IUNICS), University of the Balearic Islands, Palma, Spain
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Zhang J, Zhang Y, Pan Y, Xu Y, Xue Y. The neural foundation of associative memory: a dynamic functional connectivity study for right-handed young adults. Exp Brain Res 2021; 239:3527-3536. [PMID: 34537860 DOI: 10.1007/s00221-021-06222-5] [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: 04/10/2021] [Accepted: 09/12/2021] [Indexed: 11/30/2022]
Abstract
The medial temporal lobe (MTL) is the core neural construction related to associative memory. This study sought to explore the dynamic functional connectivity (dFC) between the subdivisions of MTL and other regions in the whole brain. Additionally, it sought to determine relationships between connectivity stability and associative memory function, to elucidate the neural foundation of associative memory from the perspectives of dFC. A Wechsler Memory Scale China revised edition (WMS-RC) measurement and a resting-state functional magnetic resonance imaging were conducted to clarify adults' function of associative memory and dFC patterns in subdivisions of the MTL. A multiple regression analysis was carried out to analyze the relationships described above. The results demonstrated that (i) connectivity in the left brain included the anterior hippocampus (aHIP) and right fusiform (Fusiform_R), middle hippocampus (mHIP) and right inferior parietal lobule (IPL_R), posterior hippocampus (pHIP) and left inferior parietal lobule (IPL_L), perirhinal cortex (PRC) and left supramarginal gyrus (SMG_L), entorhinal cortex (ERC) and [left middle temporal gyrus (MTG_L), left superior parietal lobule (SPL_L), right fusiform (Fusiform_R)], anterior parahippocampal cortex (aPHC) and right precentral gyrus (PCG_R); (ii) connectivity in the right brain included the aHIP and right supramarginal gyrus (SMG_R), mHIP and left paracentral lobule (PCL_L), pHIP and left superior occipital gyrus (SOG_L), PRC and left middle occipital gyrus (MOG_L), ERC and right middle occipital gyrus (MOG_R); (iii) for most connectivity patterns, the more stable the dFC, the better are the associative memory functions. This study elucidates the neural foundations of associative memory in terms of dFC patterns.
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Affiliation(s)
- Jian Zhang
- School of Psychology, Guizhou Normal University, Guiyang, People's Republic of China
| | - Yujia Zhang
- Department of Community Prevention, Tianjin Anding Hospital, Tianjin, People's Republic of China
| | - Yun Pan
- School of Psychology, Guizhou Normal University, Guiyang, People's Republic of China
| | - Yong Xu
- Department of Psychiatry, First Hospital/First Clinical Medical College of Shanxi Medical University, 85 Jiefang South Road, Taiyuan, 030001, People's Republic of China. .,MDT Center for Cognitive Impairment and Sleep Disorders, First Hospital of Shanxi Medical University, Taiyuan, People's Republic of China.
| | - Yunzhen Xue
- Department of Humanities and Social Science, Shanxi Medical University, 56 Xinjian South Road, Taiyuan, 030001, People's Republic of China.
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FKBP52 overexpression accelerates hippocampal-dependent memory impairments in a tau transgenic mouse model. NPJ Aging Mech Dis 2021; 7:9. [PMID: 33941782 PMCID: PMC8093247 DOI: 10.1038/s41514-021-00062-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 02/17/2021] [Indexed: 01/31/2023] Open
Abstract
Abnormal accumulation of hyperphosphorylated tau induces pathogenesis in neurodegenerative diseases, like Alzheimer's disease. Molecular chaperones with peptidyl-prolyl cis/trans isomerase (PPIase) activity are known to regulate these processes. Previously, in vitro studies have shown that the 52 kDa FK506-binding protein (FKBP52) interacts with tau inducing its oligomerization and fibril formation to promote toxicity. Thus, we hypothesized that increased expression of FKBP52 in the brains of tau transgenic mice would alter tau phosphorylation and neurofibrillary tangle formation ultimately leading to memory impairments. To test this, tau transgenic (rTg4510) and wild-type mice received bilateral hippocampal injections of virus overexpressing FKBP52 or GFP control. We examined hippocampal-dependent memory, synaptic plasticity, tau phosphorylation status, and neuronal health. This work revealed that rTg4510 mice overexpressing FKBP52 had impaired spatial learning, accompanied by long-term potentiation deficits and hippocampal neuronal loss, which was associated with a modest increase in total caspase 12. Together with previous studies, our findings suggest that FKBP52 may sensitize neurons to tau-mediated dysfunction via activation of a caspase-dependent pathway, contributing to memory and learning impairments.
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Gellersen HM, Coughlan G, Hornberger M, Simons JS. Memory precision of object-location binding is unimpaired in APOE ε4-carriers with spatial navigation deficits. Brain Commun 2021; 3:fcab087. [PMID: 33987536 PMCID: PMC8108563 DOI: 10.1093/braincomms/fcab087] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 03/09/2021] [Accepted: 03/29/2021] [Indexed: 12/19/2022] Open
Abstract
Research suggests that tests of memory fidelity, feature binding and spatial navigation are promising for early detection of subtle behavioural changes related to Alzheimer's disease. In the absence of longitudinal data, one way of testing the early detection potential of cognitive tasks is through the comparison of individuals at different genetic risk for Alzheimer's dementia. Most studies have done so using samples aged 70 years or older. Here, we tested whether memory fidelity of long-term object-location binding may be a sensitive marker even among cognitively healthy individuals in their mid-60s by comparing participants at low and higher risk based on presence of the ε4-allele of the apolipoprotein gene (n = 26 ε3ε3, n = 20 ε3ε4 carriers). We used a continuous report paradigm in a visual memory task that required participants to recreate the spatial position of objects in a scene. We employed mixture modelling to estimate the two distinct memory processes that underpin the trial-by-trial variation in localization errors: retrieval success which indexes the proportion of trials where participants recalled any information about an object's position and the precision with which participants retrieved this information. Prior work has shown that these memory paradigms that separate retrieval success from precision are capable of detecting subtle differences in mnemonic fidelity even when retrieval success could not. Nonetheless, Bayesian analyses found good evidence that ε3ε4 carriers did not remember fewer object locations [F(1, 42) = 0.450, P = 0.506, BF01 = 3.02], nor was their precision for the spatial position of objects reduced compared to ε3ε3 carriers [F(1, 42) = 0.12, P = 0.726, BF01 = 3.19]. Because the participants in the sample presented here were a subset of a study on apolipoprotein ε4-carrier status and spatial navigation in the Sea Hero Quest game [Coughlan et al., 2019. PNAS, 116(9)], we obtained these data to contrast genetic effects on the two tasks within the same sample (n = 33). Despite the smaller sample size, wayfinding deficits among ε3ε4 carriers could be replicated [F(1, 33) = 5.60, P = 0.024, BF10 = 3.44]. Object-location memory metrics and spatial navigation scores were not correlated (all r < 0.25, P > 0.1, 0 < BF10 < 3). These findings show spared object-location binding in the presence of a detrimental apolipoprotein ε4 effect on spatial navigation. This suggests that the sensitivity of memory fidelity and binding tasks may not extend to individuals with one ε4-allele in their early to mid-60s. The results provide further support to prior proposals that spatial navigation may be a sensitive marker for the earliest cognitive changes in Alzheimer's disease, even before episodic memory.
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Affiliation(s)
- Helena M Gellersen
- Department of Psychology, University of Cambridge, Cambridge CB2 3EB, UK
| | - Gillian Coughlan
- Rotman Research Institute, Baycrest Hospital, Toronto, ON M6A 1W1, Canada
| | | | - Jon S Simons
- Department of Psychology, University of Cambridge, Cambridge CB2 3EB, UK
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Baby N, Alagappan N, Dheen ST, Sajikumar S. MicroRNA-134-5p inhibition rescues long-term plasticity and synaptic tagging/capture in an Aβ(1-42)-induced model of Alzheimer's disease. Aging Cell 2020; 19:e13046. [PMID: 31625272 PMCID: PMC6974725 DOI: 10.1111/acel.13046] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 07/31/2019] [Accepted: 08/28/2019] [Indexed: 12/21/2022] Open
Abstract
Progressive memory loss is one of the most common characteristics of Alzheimer's disease (AD), which has been shown to be caused by several factors including accumulation of amyloid β peptide (Aβ) plaques and neurofibrillary tangles. Synaptic plasticity and associative plasticity, the cellular basis of memory, are impaired in AD. Recent studies suggest a functional relevance of microRNAs (miRNAs) in regulating plasticity changes in AD, as their differential expressions were reported in many AD brain regions. However, the specific role of these miRNAs in AD has not been elucidated. We have reported earlier that late long-term potentiation (late LTP) and its associative mechanisms such as synaptic tagging and capture (STC) were impaired in Aβ (1-42)-induced AD condition. This study demonstrates that expression of miR-134-5p, a brain-specific miRNA is upregulated in Aβ (1-42)-treated AD hippocampus. Interestingly, the loss of function of miR-134-5p restored late LTP and STC in AD. In AD brains, inhibition of miR-134-5p elevated the expression of plasticity-related proteins (PRPs), cAMP-response-element binding protein (CREB-1) and brain-derived neurotrophic factor (BDNF), which are otherwise downregulated in AD condition. The results provide the first evidence that the miR-134-mediated post-transcriptional regulation of CREB-1 and BDNF is an important molecular mechanism underlying the plasticity deficit in AD; thus demonstrating the critical role of miR-134-5p as a potential therapeutic target for restoring plasticity in AD condition.
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Affiliation(s)
- Nimmi Baby
- Department of PhysiologyYong Loo Lin School of MedicineNational University Health SystemNational University of SingaporeSingapore
- Centre for Life SciencesLife Sciences Institute, Neurobiology ProgrammeNational University of SingaporeSingapore
| | - Nithyakalyani Alagappan
- Department of PhysiologyYong Loo Lin School of MedicineNational University Health SystemNational University of SingaporeSingapore
- Centre for Life SciencesLife Sciences Institute, Neurobiology ProgrammeNational University of SingaporeSingapore
| | - Shaikali Thameem Dheen
- Department of AnatomyYong Loo Lin School of MedicineNational University Health SystemNational University of SingaporeSingapore
| | - Sreedharan Sajikumar
- Department of PhysiologyYong Loo Lin School of MedicineNational University Health SystemNational University of SingaporeSingapore
- Centre for Life SciencesLife Sciences Institute, Neurobiology ProgrammeNational University of SingaporeSingapore
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Furlano JA, Nagamatsu LS. Feasibility of a 6-month pilot randomised controlled trial of resistance training on cognition and brain health in Canadian older adults at-risk for diabetes: study protocol. BMJ Open 2019; 9:e032047. [PMID: 31585978 PMCID: PMC6797349 DOI: 10.1136/bmjopen-2019-032047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
INTRODUCTION Type 2 diabetes (T2D) is associated with cognitive deficits and increased risk of dementia, and thus individuals at high risk for T2D (ie, those who are overweight or prediabetic) are also at greater risk for cognitive decline. Aerobic exercise is known to preserve and improve cognitive function, but the effects of resistance training (RT) are much less known in older adults. Moreover, research on the effects of RT on cognition and brain health (structure and function) in older adults at-risk for diabetes is limited. To address this question, a 6-month RT intervention is needed. Importantly, before conducting a full-scale randomised controlled trial (RCT), we are conducting a feasibility pilot study to assess potential recruitment rates, adherence and retention in this specific population. METHODS AND ANALYSIS We are conducting a 6-month, thrice-weekly RT RCT. Participants (aged 60-80; sedentary; fasting plasma glucose of 6.1-7.0 mmol/L or body mass index ≥25) are randomised into one of two groups: (1) RT or (2) balance and tone (control). Based on other exercise trials using a similar population, we will consider our trial feasible if we have adherence and retention at 70%. Recruitment rate will be measured as time it takes to enrol 20 participants. To assess behavioural and MRI data, we will report descriptive statistics and estimation using a 95% CI. ETHICS AND DISSEMINATION Our study has received ethics approval from the Health Sciences Research Ethics Board at Western University. As this is a small pilot study, data will only be made available to other researchers on request. Results from this study will be disseminated via academic publication. TRIAL REGISTRATION NUMBER NCT03254381.
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Delhaye E, Mechanic-Hamilton D, Saad L, Das SR, Wisse LEM, Yushkevich PA, Wolk DA, Bastin C. Associative memory for conceptually unitized word pairs in mild cognitive impairment is related to the volume of the perirhinal cortex. Hippocampus 2019; 29:630-638. [PMID: 30588714 PMCID: PMC6565465 DOI: 10.1002/hipo.23063] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 11/23/2018] [Accepted: 11/30/2018] [Indexed: 11/06/2022]
Abstract
Unitization, that is, the encoding of an association as one integrated entity, has been shown to improve associative memory in populations presenting with associative memory deficit due to hippocampal dysfunction, such as amnesic patients with focal hippocampal lesions and healthy older adults. One reason for this benefit is that encoding of unitized associations would rely on the perirhinal cortex (PrC) and thus minimize the need for hippocampal recruitment. Mild cognitive impairment (MCI) is accompanied by a deficit in associative memory. However, unitization has never been studied to explore the potential benefit in associative memory in MCI, maybe because MCI is characterized by PrC pathology. However, the PrC may potentially still function sufficiently to allow for the successful adoption of unitization. In this study, we aimed at assessing whether unitization could attenuate MCI patients' associative memory deficit, and whether the ability to remember unitized associations would be modulated by the integrity of the PrC in MCI patients. Unitization was manipulated at a conceptual level, by encouraging participants to encode unrelated word pairs as new compound words. Participants also underwent a structural MRI exam, and measures of PrC were extracted (Brodmann Areas [BA] 35 and 36). Results showed that, contrary to healthy controls, MCI patients did not benefit from unitization. Moreover, their memory performance for unitized associations was related to the measure of PrC integrity (BA35), while it was not the case in controls. This finding thus suggests that unitization does not help to attenuate the associative deficit in MCI patients, and brings support to the literature linking unitization to the PrC function.
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Affiliation(s)
- Emma Delhaye
- GIGA-CRC In-Vivo Imaging, Liege University, Liège, Belgium
- PsyNCog, Faculty of Psychology, Liege, Belgium
| | - Dawn Mechanic-Hamilton
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Penn Memory Center, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Laura Saad
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Penn Memory Center, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Sandhitsu R. Das
- Penn Image Computing and Science Laboratory, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Laura E. M. Wisse
- Penn Memory Center, University of Pennsylvania, Philadelphia, Pennsylvania
- Penn Image Computing and Science Laboratory, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Paul A. Yushkevich
- Penn Image Computing and Science Laboratory, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - David A. Wolk
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Penn Memory Center, University of Pennsylvania, Philadelphia, Pennsylvania
- Penn Image Computing and Science Laboratory, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Christine Bastin
- GIGA-CRC In-Vivo Imaging, Liege University, Liège, Belgium
- PsyNCog, Faculty of Psychology, Liege, Belgium
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Novelty processing and memory impairment in Alzheimer's disease: A review. Neurosci Biobehav Rev 2019; 100:237-249. [DOI: 10.1016/j.neubiorev.2019.02.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 12/24/2018] [Accepted: 02/28/2019] [Indexed: 01/09/2023]
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Do Alzheimer's Disease Patients Benefit From Prior-Knowledge in Associative Recognition Memory? J Int Neuropsychol Soc 2019; 25:443-452. [PMID: 30696494 DOI: 10.1017/s1355617718001212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVES Although the influence of prior knowledge on associative memory in healthy aging has received great attention, it has never been studied in Alzheimer's disease (AD). This study aimed at assessing whether AD patients could benefit from prior knowledge in associative memory and whether such benefit would be related to the integrity of their semantic memory. METHODS Twenty-one AD patients and 21 healthy older adults took part in an associative memory task using semantically related and unrelated word pairs and were also submitted to an evaluation of their semantic memory. RESULTS While participants of both groups benefited from semantic relatedness in associative discrimination, related pairs recognition was significantly predicted by semantic memory integrity in healthy older adults only. CONCLUSIONS We suggest that patients benefitted from semantic knowledge to improve their performance in the associative memory task, but that such performance is not related to semantic knowledge integrity evaluation measures because the two tasks differ in the way semantic information is accessed: in an automatic manner for the associative memory task, with automatic processes thought to be relatively preserved in AD, and in a controlled manner for the semantic knowledge evaluation, with controlled processes thought to be impaired in AD. (JINS, 2019, 25, 443-452).
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Bjekić J, Čolić MV, Živanović M, Milanović SD, Filipović SR. Transcranial direct current stimulation (tDCS) over parietal cortex improves associative memory. Neurobiol Learn Mem 2019; 157:114-120. [DOI: 10.1016/j.nlm.2018.12.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 10/09/2018] [Accepted: 12/12/2018] [Indexed: 10/27/2022]
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Delhaye E, Bahri MA, Salmon E, Bastin C. Impaired perceptual integration and memory for unitized representations are associated with perirhinal cortex atrophy in Alzheimer's disease. Neurobiol Aging 2018; 73:135-144. [PMID: 30342274 DOI: 10.1016/j.neurobiolaging.2018.09.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 09/12/2018] [Accepted: 09/15/2018] [Indexed: 11/27/2022]
Abstract
Unitization, the capacity to encode associations as one integrated entity, can enhance associative memory in populations with an associative memory deficit by promoting familiarity-based associative recognition. Patients with Alzheimer's disease (AD) are typically impaired in associative memory compared with healthy controls but do not benefit from unitization strategies. Using fragmented pictures of objects, this study aimed at assessing which of the cognitive processes that compose unitization is actually affected in AD: the retrieval of unitized representations itself, or some earlier stages of processing, such as the integration process at a perceptual or conceptual stage of representation. We also intended to relate patients' object unitization capacity to the integrity of their perirhinal cortex (PrC), as the PrC is thought to underlie unitization and is also one of the first affected regions in AD. We evaluated perceptual integration capacity and subsequent memory for those items that have supposedly been unitized in 23 mild AD patients and 20 controls. We systematically manipulated the level of perceptual integration during encoding by presenting object pictures that were either left intact, separated into 2 fragments, or separated into 4 fragments. Subjects were instructed to unitize the fragments into a single representation. Success of integration was assessed by a question requiring the identification of the object. Participants also underwent a structural magnetic resonance imaging examination, and measures of PrC, posterior cingulate cortex volume and thickness, and hippocampal volume, were extracted. The results showed that patients' perceptual integration performance decreased with the increased fragmentation level and that their memory for unitized representations was impaired whatever the demands in terms of perceptual integration at encoding. Both perceptual integration and memory for unitized representations were related to the integrity of the PrC, and memory for unitized representations was also related to the volume of the hippocampus. We argue that, globally, this supports representational theories of memory that hold that the role of the PrC is not only perceptual nor mnemonic but instead underlies complex object representation.
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Affiliation(s)
- Emma Delhaye
- GIGA-CRC In-Vivo Imaging, University in Liège, Liège, Belgium; PsyNCog, Faculty of Psychology, University in Liège, Liège, Belgium.
| | | | - Eric Salmon
- GIGA-CRC In-Vivo Imaging, University in Liège, Liège, Belgium; PsyNCog, Faculty of Psychology, University in Liège, Liège, Belgium; Memory Clinic, CHU Liege, University in Liège, Liège, Belgium
| | - Christine Bastin
- GIGA-CRC In-Vivo Imaging, University in Liège, Liège, Belgium; PsyNCog, Faculty of Psychology, University in Liège, Liège, Belgium
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Kapogiannis D, El Haj M. Beneficial Effect of Minimal Interference on Item Memory But Not on Source Memory in Alzheimer's Disease. Curr Alzheimer Res 2018; 15:1070-1076. [PMID: 29992879 PMCID: PMC6162162 DOI: 10.2174/1567205015666180711105242] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 05/23/2018] [Accepted: 07/06/2018] [Indexed: 11/22/2022]
Abstract
OBJECTIVES Research suggests beneficial effects of minimal interference on item memory in mild Alzheimer's disease (AD). We conducted a study to test whether these beneficial effects extend to source memory, i.e., the ability to remember the episodic context in which an information was previously acquired. METHOD Twenty-six mild AD participants and 28 controls manipulated six objects or watched the experimenter manipulating six other objects. After immediate item recall ("what were the items?") and source recall ("by whom the items were previously manipulated?"), an interference or a minimal interference condition was administrated. In the interference condition, participants were assessed with neuropsychological tests for 10 min. In the minimal interference condition, they rested alone in a dark and quiet room for 10 minutes. Both interference and minimal interference conditions were followed by the delayed recall, on which participants were asked to remember the previously-presented objects and their source. RESULTS Higher item memory was observed following minimal interference than following interference in AD participants (p < .01) and controls (p < .01). Also, AD participants demonstrated higher item memory on immediate recall than following interference (p < .001) or minimal interference (p < .001); controls also demonstrated higher item memory on immediate recall than following interference (p < .001) or minimal interference (p < .001). Considering source memory, similar source memory was observed following interference and minimal interference in AD participants (p > .1) and controls (p > .1). Also, AD participants demonstrated higher source memory on immediate recall than following interference (p < .001) or minimal interference (p < .001); controls also demonstrated higher source memory on immediate recall than following interference (p < .001) or minimal interference (p < .001). CONCLUSION Failures of hippocampus-dependent associative or consolidation processes in AD may preclude benefits of minimal interference for source memory. Nevertheless, AD patients may show some capacity to retain simple material, should the material presentation be followed by short delays that are free of further stimuli.
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Affiliation(s)
- Dimitrios Kapogiannis
- Laboratory of Neurosciences, National Institute on Aging, Baltimore, MD, United States
| | - Mohamad El Haj
- Laboratoire de Psychologie des Pays de la Loire (EA 4638), Université de Nantes, Nantes, France
- Department of Geriatrics, Tourcoing Hospital, Tourcoing, France
- Institut Universitaire de France, France
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Sharma M, Dierkes T, Sajikumar S. Epigenetic regulation by G9a/GLP complex ameliorates amyloid-beta 1-42 induced deficits in long-term plasticity and synaptic tagging/capture in hippocampal pyramidal neurons. Aging Cell 2017; 16:1062-1072. [PMID: 28665013 PMCID: PMC5595698 DOI: 10.1111/acel.12634] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/27/2017] [Indexed: 12/11/2022] Open
Abstract
Altered epigenetic mechanisms are implicated in the cognitive decline associated with neurodegenerative diseases such as in Alzheimer's disease (AD). AD is the most prevalent form of dementia worldwide; amyloid plaques and neurofibrillary tangles are the histopathological hallmarks of AD. We have recently reported that the inhibition of G9a/GLP complex promotes long-term potentiation (LTP) and its associative mechanisms such as synaptic tagging and capture (STC). However, the role of this complex in plasticity impairments remains elusive. Here, we investigated the involvement of G9a/GLP complex in alleviating the effects of soluble Amyloid-β 1-42 oligomers (oAβ) on neuronal plasticity and associativity in the CA1 region of acute hippocampal slices from 5- to 7-week-old male Wistar rats. Our findings demonstrate that the regulation of G9a/GLP complex by inhibiting its catalytic activity reverses the amyloid-β oligomer-induced deficits in late-LTP and STC. This is achieved by releasing the transcription repression of the brain-derived neurotrophic factor (Bdnf) gene. The catalytic inhibition of G9a/GLP complex leads to the upregulation of Bdnf expression in the slices treated with oAβ. This further ensures the availability of BDNF that subsequently binds its receptor tyrosine kinase B (TrkB) and maintains the late-LTP. Furthermore, the capture of BDNF by weakly activated synapses re-establishes STC. Our findings regarding the reinstatement of functional plasticity and associativity in AD-like conditions provide the first evidence for the role of G9a/GLP complex in AD. We propose G9a/GLP complex as the possible target for preventing oAβ-induced plasticity deficits in hippocampal neurons.
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Affiliation(s)
- Mahima Sharma
- Department of Physiology; Yong Loo Lin School of Medicine; National University of Singapore; Block MD9, 2 Medical Drive Singapore 117 597 Singapore
- Neurobiology/Aging Program; Life Sciences Institute (LSI); National University of Singapore; #04-44, 28 Medical Drive Singapore 117 456 Singapore
| | - Tobias Dierkes
- Department of Physiology; Yong Loo Lin School of Medicine; National University of Singapore; Block MD9, 2 Medical Drive Singapore 117 597 Singapore
- Institute of Innate Immunity; Biomedical Centre; University hospital Bonn; Sigmund-Freud-Str. 25 Bonn 53127 Germany
- Division of Cellular Neurobiology; Zoological Institute; Technical University Braunschweig; Braunschweig Germany
| | - Sreedharan Sajikumar
- Department of Physiology; Yong Loo Lin School of Medicine; National University of Singapore; Block MD9, 2 Medical Drive Singapore 117 597 Singapore
- Neurobiology/Aging Program; Life Sciences Institute (LSI); National University of Singapore; #04-44, 28 Medical Drive Singapore 117 456 Singapore
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Das SR, Mancuso L, Olson IR, Arnold SE, Wolk DA. Short-Term Memory Depends on Dissociable Medial Temporal Lobe Regions in Amnestic Mild Cognitive Impairment. Cereb Cortex 2016; 26:2006-17. [PMID: 25725042 PMCID: PMC4830285 DOI: 10.1093/cercor/bhv022] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Short-term memory (STM) has generally been thought to be independent of the medial temporal lobe (MTL) in contrast to long-term memory (LTM). Prodromal Alzheimer's disease (AD) is a condition in which the MTL is a major early focus of pathology and LTM is thought disproportionately affected relative to STM. However, recent studies have suggested a role for the MTL in STM, particularly hippocampus, when binding of different elements is required. Other work has suggested involvement of extrahippocampal MTL structures, particularly in STM tasks that involve item-level memory. We examined STM for individual objects, locations, and object-location conjunctions in amnestic mild cognitive impairment (MCI), often associated with prodromal AD. Relative to age-matched, cognitively normal controls, MCI patients not only displayed impairment on object-location conjunctions but were similarly impaired for non-bound objects and locations. Moreover, across all participants, these conditions displayed dissociable correlations of cortical thinning along the long axis of the MTL and associated cortical nodes of anterior and posterior MTL networks. These findings support the role of the MTL in visual STM tasks and the division of labor of MTL in support of different types of memory representations, overlapping with findings in LTM.
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Affiliation(s)
- Sandhitsu R. Das
- Department of Radiology
- Penn Image Computing and Science Laboratory
| | | | - Ingrid R. Olson
- Department of Psychology, Temple University, Philadelphia, PA, USA
| | - Steven E. Arnold
- Department of Neurology
- Penn Memory Center
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA, USA
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