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Hall S. Is the Papez circuit the location of the elusive episodic memory engram? IBRO Neurosci Rep 2024; 16:249-259. [PMID: 38370006 PMCID: PMC10869290 DOI: 10.1016/j.ibneur.2024.01.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 01/31/2024] [Indexed: 02/20/2024] Open
Abstract
All of the brain structures and white matter that make up Papez' circuit, as well as the circuit as a whole, are implicated in the literature in episodic memory formation and recall. This paper shows that Papez' circuit has the detailed structure and connectivity that is evidently required to support the episodic memory engram, and that identifying Papez' circuit as the location of the engram answers a number of long-standing questions regarding the role of medial temporal lobe structures in episodic memory. The paper then shows that the process by which the episodic memory engram may be formed is a network-wide Hebbian potentiation termed "racetrack potentiation", whose frequency corresponds to that observed in vivo in humans for memory functions. Further, by considering the microcircuits observed in the medial temporal lobe structures forming Papez' circuit, the paper establishes the neural mechanisms behind the required functions of sensory information storage and recall, pattern completion, pattern separation, and memory consolidation. The paper shows that Papez' circuit has the necessary connectivity to gather the various elements of an episodic memory occurring within Pöppel's experienced time or "quantum of experience". Finally, the paper shows how the memory engram located in Papez' circuit might be central to the formation of a duplicate engram in the cortex enabling consolidation and long-term storage of episodic memories.
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Affiliation(s)
- Steven Hall
- Department of Psychology, University of Bolton, Deane Road, Bolton BL3 5AB, UK
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2
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Hadler MD, Alle H, Geiger JRP. Parvalbumin interneuron cell-to-network plasticity: mechanisms and therapeutic avenues. Trends Pharmacol Sci 2024:S0165-6147(24)00068-3. [PMID: 38763836 DOI: 10.1016/j.tips.2024.04.003] [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: 03/31/2024] [Revised: 04/16/2024] [Accepted: 04/16/2024] [Indexed: 05/21/2024]
Abstract
Alzheimer's disease (AD) and schizophrenia (SCZ) represent two major neuropathological conditions with a high disease burden. Despite their distinct etiologies, patients suffering from AD or SCZ share a common burden of disrupted memory functions unattended by current therapies. Recent preclinical analyses highlight cell-type-specific contributions of parvalbumin interneurons (PVIs), particularly the plasticity of their cellular excitability, towards intact neuronal network function (cell-to-network plasticity) and memory performance. Here we argue that deficits of PVI cell-to-network plasticity may underlie memory deficits in AD and SCZ, and we explore two therapeutic avenues: the targeting of PVI-specific neuromodulation, including by neuropeptides, and the recruitment of network synchrony in the gamma frequency range (40 Hz) by external stimulation. We finally propose that these approaches be merged under consideration of recent insights into human brain physiology.
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Affiliation(s)
- Michael D Hadler
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany; Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
| | - Henrik Alle
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany; Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Jörg R P Geiger
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany; Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
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Rajagopal L, Huang M, Mahjour S, Ryan C, Elzokaky A, Svensson KA, Meltzer HY. The dopamine D1 receptor positive allosteric modulator, DETQ, improves cognition and social interaction in aged mice and enhances cortical and hippocampal acetylcholine efflux. Behav Brain Res 2024; 459:114766. [PMID: 38048913 DOI: 10.1016/j.bbr.2023.114766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 11/06/2023] [Accepted: 11/15/2023] [Indexed: 12/06/2023]
Abstract
Dopamine (DA) D1 and D2 receptors (Rs) are critical for cognitive functioning. D1 positive allosteric modulators (D1PAMs) activate D1Rs without desensitization or an inverted U-shaped dose response curve. DETQ, [2-(2,6-dichlorophenyl)-1-((1S,3R)-3-(hydroxymethyl)-5-(2-hydroxypropan-2-yl)-1-methyl-3,4-dihydroisoquinolin-2(1H)-yl)ethan-1-one] is highly selective for the human D1Rs as shown in humanized D1R knock-in (hD1Ki) mice. Here, we have ascertained the efficacy of DETQ in aged [13-23-month-old (mo)] hD1Ki mice and their corresponding age-matched wild-type (WT; C57BL/6NTac) controls. We found that in aged mice, DETQ, given acutely, subchronically, and chronically, rescued both novel object recognition memory and social behaviors, using novel object recognition (NOR) and social interaction (SI) tasks, respectively without any adverse effect on body weight or mortality. We have also shown, using in vivo microdialysis, a significant decrease in basal DA and norepinephrine, increase in glutamate (Glu) and gamma-amino butyric acid (GABA) efflux with no significant changes in acetylcholine (ACh) levels in aged vs young mice. In young and aged hD1Ki mice, DETQ, acutely and subchronically increased ACh in the medial prefrontal cortex and hippocampal regions in aged hD1Ki mice without affecting Glu. These results suggest that the D1PAM mechanism is of interest as potential treatment for cognitive and social behavioral deficits in neuropsychiatric disorders including but not restricted to neurodegenerative disorders, such as Parkinson's disease.
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Affiliation(s)
- Lakshmi Rajagopal
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Mei Huang
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Sanaz Mahjour
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Chelsea Ryan
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Ahmad Elzokaky
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Kjell A Svensson
- Neuroscience Discovery, Eli Lilly & Company, Indianapolis, IN, USA
| | - H Y Meltzer
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL 60611, USA.
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Rai AR, Joy T, Poojari M, Pai MM, Massand A, Murlimanju BV. Role of Acorus calamus in preventing depression, anxiety, and oxidative stress in long-term socially isolated rats. Vet World 2023; 16:1755-1764. [PMID: 37766700 PMCID: PMC10521175 DOI: 10.14202/vetworld.2023.1755-1764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 07/22/2023] [Indexed: 09/29/2023] Open
Abstract
Background and Aim Social isolation stress (SIS) and individual housing have been shown to cause abnormal cognitive insufficiencies, altered anxiety levels, and signs of psychiatric diseases. Acorus calamus (AC), commonly known as Sweet Flag, has been widely used in India to treat neurological, metabolic, and respiratory disorders, indicating its potential therapeutic value. This study aimed to determine the antidepressant and antioxidative effects of AC on rats subjected to long-term, social isolation-induced stress. Materials and Methods This study involved 2-month-old male rats (24) weighing approximately 180-200 g bred in-house. The rats were divided into four groups (n = 6): Group 1 received saline, Group 2 received SIS, Group 3 received only 50 mg/kg AC, and Group 4 received 50 mg/kg AC and SIS for 6 weeks. After this, behavioral, biochemical, and neuronal assays were conducted. Results Behavioral experiments showed significantly higher activity levels (p < 0.001) in AC-treated rats than in the SIS group. In addition, rats subjected to SIS with AC treatment exhibited enhanced total antioxidants, superoxide dismutase, and neuronal assays compared to rats subjected to SIS alone. Conclusion Acorus calamus treatment improved the antidepressant and antioxidant potential against SIS in rat brain tissue. Moreover, we proved that AC can effectively reverse the neurotoxicity induced by SIS in animal models. As we battle against the coronavirus disease 2019 pandemic and social isolation, AC could be considered a supplementary treatment to alleviate depressive-like symptoms in our present-day lifestyle.
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Affiliation(s)
- Ashwin Rohan Rai
- Department of Anatomy, Kasturba Medical College, Mangalore, Manipal Academy of Higher Education, Manipal, India
| | - Teresa Joy
- Department of Anatomy, American University of Antigua College of Medicine, University Park, Jabberwock Beach Road, Coolidge, St. John’s, Antigua, West Indies
| | - Meghana Poojari
- Department of Anatomy, Basaveshwara Medical College and Hospital, Chitradurga, India
| | - Mangala M. Pai
- Department of Anatomy, Kasturba Medical College, Mangalore, Manipal Academy of Higher Education, Manipal, India
| | - Amit Massand
- Department of Anatomy, Kasturba Medical College, Mangalore, Manipal Academy of Higher Education, Manipal, India
| | - B. V. Murlimanju
- Department of Anatomy, Kasturba Medical College, Mangalore, Manipal Academy of Higher Education, Manipal, India
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Sridhar S, Khamaj A, Asthana MK. Cognitive neuroscience perspective on memory: overview and summary. Front Hum Neurosci 2023; 17:1217093. [PMID: 37565054 PMCID: PMC10410470 DOI: 10.3389/fnhum.2023.1217093] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 07/10/2023] [Indexed: 08/12/2023] Open
Abstract
This paper explores memory from a cognitive neuroscience perspective and examines associated neural mechanisms. It examines the different types of memory: working, declarative, and non-declarative, and the brain regions involved in each type. The paper highlights the role of different brain regions, such as the prefrontal cortex in working memory and the hippocampus in declarative memory. The paper also examines the mechanisms that underlie the formation and consolidation of memory, including the importance of sleep in the consolidation of memory and the role of the hippocampus in linking new memories to existing cognitive schemata. The paper highlights two types of memory consolidation processes: cellular consolidation and system consolidation. Cellular consolidation is the process of stabilizing information by strengthening synaptic connections. System consolidation models suggest that memories are initially stored in the hippocampus and are gradually consolidated into the neocortex over time. The consolidation process involves a hippocampal-neocortical binding process incorporating newly acquired information into existing cognitive schemata. The paper highlights the role of the medial temporal lobe and its involvement in autobiographical memory. Further, the paper discusses the relationship between episodic and semantic memory and the role of the hippocampus. Finally, the paper underscores the need for further research into the neurobiological mechanisms underlying non-declarative memory, particularly conditioning. Overall, the paper provides a comprehensive overview from a cognitive neuroscience perspective of the different processes involved in memory consolidation of different types of memory.
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Affiliation(s)
- Sruthi Sridhar
- Department of Psychology, Mount Allison University, Sackville, NB, Canada
| | - Abdulrahman Khamaj
- Department of Industrial Engineering, College of Engineering, Jazan University, Jazan, Saudi Arabia
| | - Manish Kumar Asthana
- Department of Humanities and Social Sciences, Indian Institute of Technology Roorkee, Roorkee, India
- Department of Design, Indian Institute of Technology Roorkee, Roorkee, India
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Eo SJ, Leem YH. Effects of exercise intensity on the reactive astrocyte polarization in the medial prefrontal cortex. Phys Act Nutr 2023; 27:19-24. [PMID: 37583068 PMCID: PMC10440185 DOI: 10.20463/pan.2023.0014] [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: 06/06/2023] [Revised: 06/26/2023] [Accepted: 06/29/2023] [Indexed: 08/17/2023] Open
Abstract
PURPOSE Physical exercise contributes to neuroplasticity by promoting cognitive functions, such as learning and memory. The astrocytic phenotype is closely associated with synaptic plasticity. This study aimed to determine whether astrocyte polarization and synaptic alterations in the medial prefrontal cortex (mPFC) are affected differently by high- and moderate-intensity exercise. METHODS Mice were subjected to moderate-(MIE) and high-intensity treadmill running (HIE). Memory capacity was assessed using the novel object recognition and modified Y-maze tests. For immunohistochemistry, c-Fos-positive cells were counted in the mPFC. Using western blot analysis, astrocyte phenotype markers were quantified in whole-cell lysates, and synaptic molecules were determined in the synaptosomal fraction. RESULTS Exercise lengthened the approach time to novel objects regardless of intensity in the NOR test, whereas MIE only improved spatial memory. Exercise induced c-Fos expression in the anterior cingulate cortex (ACC) and c-Fos-positive cells were higher in MIE than in HIE in the ACC area. In the prelimbic/infralimbic cortex region, the number of c-Fos-positive cells were enhanced in MIE and decreased in HIE mice. The A1 astrocyte marker (C3) was increased in HIE mice, while the A2 astrocyte markers were enhanced in exercised mice, regardless of the intensity. In the synaptosomal fraction, synaptic proteins were elevated by exercise regardless of intensity. CONCLUSION These results suggest that exercise intensity affects neuronal plasticity by modulating the reactive state of astrocytes in the mPFC.
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Affiliation(s)
- Su-Ju Eo
- Department of Beauty Health Design, Open Cyber University of Korea, Seoul, Republic of Korea
| | - Yea-Hyun Leem
- Department of Molecular Medicine and Inflammation-Cancer Microenvironment Research Center, School of Medicine, Ewha Womans University, Seoul, Republic of Korea
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Delgado-Sallent C, Gener T, Nebot P, López-Cabezón C, Puig MV. Neural substrates of cognitive impairment in a NMDAR hypofunction mouse model of schizophrenia and partial rescue by risperidone. Front Cell Neurosci 2023; 17:1152248. [PMID: 37066076 PMCID: PMC10104169 DOI: 10.3389/fncel.2023.1152248] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 03/10/2023] [Indexed: 04/03/2023] Open
Abstract
N-methyl D-aspartate receptor (NMDAR) hypofunction is a pathophysiological mechanism relevant for schizophrenia. Acute administration of the NMDAR antagonist phencyclidine (PCP) induces psychosis in patients and animals while subchronic PCP (sPCP) produces cognitive dysfunction for weeks. We investigated the neural correlates of memory and auditory impairments in mice treated with sPCP and the rescuing abilities of the atypical antipsychotic drug risperidone administered daily for two weeks. We recorded neural activities in the medial prefrontal cortex (mPFC) and the dorsal hippocampus (dHPC) during memory acquisition, short-term, and long-term memory in the novel object recognition test and during auditory processing and mismatch negativity (MMN) and examined the effects of sPCP and sPCP followed by risperidone. We found that the information about the familiar object and its short-term storage were associated with mPFC→dHPC high gamma connectivity (phase slope index) whereas long-term memory retrieval depended on dHPC→mPFC theta connectivity. sPCP impaired short-term and long-term memories, which were associated with increased theta power in the mPFC, decreased gamma power and theta-gamma coupling in the dHPC, and disrupted mPFC-dHPC connectivity. Risperidone rescued the memory deficits and partly restored hippocampal desynchronization but did not ameliorate mPFC and circuit connectivity alterations. sPCP also impaired auditory processing and its neural correlates (evoked potentials and MMN) in the mPFC, which were also partly rescued by risperidone. Our study suggests that the mPFC and the dHPC disconnect during NMDAR hypofunction, possibly underlying cognitive impairment in schizophrenia, and that risperidone targets this circuit to ameliorate cognitive abilities in patients.
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Affiliation(s)
- Cristina Delgado-Sallent
- Hospital del Mar Medical Research Institute (IMIM), Barcelona Biomedical Research Park, Barcelona, Spain
| | - Thomas Gener
- Hospital del Mar Medical Research Institute (IMIM), Barcelona Biomedical Research Park, Barcelona, Spain
- Catalan Institute of Nanoscience and Nanotechnology, CSIC and BIST, Barcelona, Spain
- Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Pau Nebot
- Hospital del Mar Medical Research Institute (IMIM), Barcelona Biomedical Research Park, Barcelona, Spain
| | - Cristina López-Cabezón
- Catalan Institute of Nanoscience and Nanotechnology, CSIC and BIST, Barcelona, Spain
- Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - M. Victoria Puig
- Hospital del Mar Medical Research Institute (IMIM), Barcelona Biomedical Research Park, Barcelona, Spain
- Catalan Institute of Nanoscience and Nanotechnology, CSIC and BIST, Barcelona, Spain
- Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain
- *Correspondence: M. Victoria Puig,
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Liampas I, Folia V, Ntanasi E, Yannakoulia M, Sakka P, Hadjigeorgiou G, Scarmeas N, Dardiotis E, Kosmidis MH. Longitudinal episodic memory trajectories in older adults with normal cognition. Clin Neuropsychol 2023; 37:304-321. [PMID: 35400289 DOI: 10.1080/13854046.2022.2059011] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
OBJECTIVE To determine the longitudinal trajectories and normative standards of episodic memory in older adults. METHODS Participants were drawn from the cognitively normal(CN) subgroup of the population-based HELIAD cohort, a fairly representative cohort of the older Greek population. Verbal and non-verbal memory were assessed using the Greek Verbal Learning Test and Medical College of Georgia-Complex Figure Test. Baseline and longitudinal associations of memory performance with age, sex and formal education were explored with linear regression analysis and generalized estimated equations. RESULTS A total of 1607 predominantly female (60%) individuals (73.82 ± 5.43 years), with a mean educational attainment of 8.17(±4.86) years were CN at baseline. Baseline analysis revealed a continuum of memory decline with aging and lower educational attainment. Women performed better in composite and verbal memory measures, while men performed better in non-verbal memory tasks. A subgroup of 761 participants with available assessments after 3.07(±0.82) years remained CN at follow-up. Composite memory scores yearly diminished by an additional 0.007 of a SD for each additional year of age at baseline. Regarding verbal learning, immediate free verbal recall, delayed free verbal recall and delayed cued verbal recall, an additional yearly decrease of 0.107, 0.043, 0.036 and 0.026 words were respectively recorded at follow-up, for each additional year of age at baseline. Women underwent steeper yearly decreases of 0.227 words in delayed cued verbal recall. No significant longitudinal associations emerged for immediate non-verbal memory, delayed non-verbal memory and immediate cued verbal recall. CONCLUSIONS In the present study, aging (but not educational attainment) was consistently associated with steeper verbal memory decline. Supplemental data for this article is available online at https://doi.org/10.1080/13854046.2022.2059011 .
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Affiliation(s)
- Ioannis Liampas
- Department of Neurology, University Hospital of Larissa, School of Medicine, University of Thessaly, Larissa, Greece
| | - Vasiliki Folia
- Lab of Cognitive Neuroscience, School of Psychology, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Eva Ntanasi
- Department of Nutrition and Dietetics, Harokopio University, Athens, Greece.,1st Department of Neurology, Aiginition Hospital, National and Kapodistrian University of Athens Medical School, Athens, Greece
| | - Mary Yannakoulia
- Department of Nutrition and Dietetics, Harokopio University, Athens, Greece
| | - Paraskevi Sakka
- Athens Association of Alzheimer's Disease and Related Disorders, Marousi, Greece
| | - Georgios Hadjigeorgiou
- Department of Neurology, University Hospital of Larissa, School of Medicine, University of Thessaly, Larissa, Greece.,Department of Neurology, Medical School, University of Cyprus, Nicosia, Cyprus
| | - Nikolaos Scarmeas
- 1st Department of Neurology, Aiginition Hospital, National and Kapodistrian University of Athens Medical School, Athens, Greece.,Taub Institute for Research in Alzheimer's Disease and the Aging Brain, the Gertrude H. Sergievsky Center, Department of Neurology, Columbia University, New York, NY, USA
| | - Efthimios Dardiotis
- Department of Neurology, University Hospital of Larissa, School of Medicine, University of Thessaly, Larissa, Greece
| | - Mary H Kosmidis
- Lab of Cognitive Neuroscience, School of Psychology, Aristotle University of Thessaloniki, Thessaloniki, Greece
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Abstract
A schema refers to a structured body of prior knowledge that captures common patterns across related experiences. Schemas have been studied separately in the realms of episodic memory and spatial navigation across different species and have been grounded in theories of memory consolidation, but there has been little attempt to integrate our understanding across domains, particularly in humans. We propose that experiences during navigation with many similarly structured environments give rise to the formation of spatial schemas (for example, the expected layout of modern cities) that share properties with but are distinct from cognitive maps (for example, the memory of a modern city) and event schemas (such as expected events in a modern city) at both cognitive and neural levels. We describe earlier theoretical frameworks and empirical findings relevant to spatial schemas, along with more targeted investigations of spatial schemas in human and non-human animals. Consideration of architecture and urban analytics, including the influence of scale and regionalization, on different properties of spatial schemas may provide a powerful approach to advance our understanding of spatial schemas.
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Desaunay P, Guillery B, Moussaoui E, Eustache F, Bowler DM, Guénolé F. Brain correlates of declarative memory atypicalities in autism: a systematic review of functional neuroimaging findings. Mol Autism 2023; 14:2. [PMID: 36627713 PMCID: PMC9832704 DOI: 10.1186/s13229-022-00525-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 11/29/2022] [Indexed: 01/11/2023] Open
Abstract
The long-described atypicalities of memory functioning experienced by people with autism have major implications for daily living, academic learning, as well as cognitive remediation. Though behavioral studies have identified a robust profile of memory strengths and weaknesses in autism spectrum disorder (ASD), few works have attempted to establish a synthesis concerning their neural bases. In this systematic review of functional neuroimaging studies, we highlight functional brain asymmetries in three anatomical planes during memory processing between individuals with ASD and typical development. These asymmetries consist of greater activity of the left hemisphere than the right in ASD participants, of posterior brain regions-including hippocampus-rather than anterior ones, and presumably of the ventral (occipito-temporal) streams rather than the dorsal (occipito-parietal) ones. These functional alterations may be linked to atypical memory processes in ASD, including the pre-eminence of verbal over spatial information, impaired active maintenance in working memory, and preserved relational memory despite poor context processing in episodic memory.
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Affiliation(s)
- Pierre Desaunay
- grid.411149.80000 0004 0472 0160Service de Psychiatrie de l’Enfant et de l’Adolescent, CHU de Caen Normandie, 27 rue des compagnons, 14000 Caen, France ,grid.412043.00000 0001 2186 4076EPHE, INSERM, U1077, Pôle des Formations et de Recherche en Santé, CHU de Caen Normandie, GIP Cyceron, Neuropsychologie et Imagerie de la Mémoire Humaine, Normandie Univ, UNICAEN, PSL Research University, 2 rue des Rochambelles, 14032 Caen Cedex CS, France
| | - Bérengère Guillery
- grid.412043.00000 0001 2186 4076EPHE, INSERM, U1077, Pôle des Formations et de Recherche en Santé, CHU de Caen Normandie, GIP Cyceron, Neuropsychologie et Imagerie de la Mémoire Humaine, Normandie Univ, UNICAEN, PSL Research University, 2 rue des Rochambelles, 14032 Caen Cedex CS, France
| | - Edgar Moussaoui
- grid.411149.80000 0004 0472 0160Service de Psychiatrie de l’Enfant et de l’Adolescent, CHU de Caen Normandie, 27 rue des compagnons, 14000 Caen, France
| | - Francis Eustache
- grid.412043.00000 0001 2186 4076EPHE, INSERM, U1077, Pôle des Formations et de Recherche en Santé, CHU de Caen Normandie, GIP Cyceron, Neuropsychologie et Imagerie de la Mémoire Humaine, Normandie Univ, UNICAEN, PSL Research University, 2 rue des Rochambelles, 14032 Caen Cedex CS, France
| | - Dermot M. Bowler
- grid.28577.3f0000 0004 1936 8497Autism Research Group, City University of London, DG04 Rhind Building, Northampton Square, EC1V 0HB London, UK
| | - Fabian Guénolé
- grid.411149.80000 0004 0472 0160Service de Psychiatrie de l’Enfant et de l’Adolescent, CHU de Caen Normandie, 27 rue des compagnons, 14000 Caen, France ,grid.412043.00000 0001 2186 4076EPHE, INSERM, U1077, Pôle des Formations et de Recherche en Santé, CHU de Caen Normandie, GIP Cyceron, Neuropsychologie et Imagerie de la Mémoire Humaine, Normandie Univ, UNICAEN, PSL Research University, 2 rue des Rochambelles, 14032 Caen Cedex CS, France ,grid.412043.00000 0001 2186 4076Faculté de Médecine, Pôle des Formation et de Recherche en Santé, Université de Caen Normandie, 2 rue des Rochambelles, 14032 Caen cedex CS, France
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Audrain S, Gilmore AW, Wilson JM, Schacter DL, Martin A. A Role for the Anterior Hippocampus in Autobiographical Memory Construction Regardless of Temporal Distance. J Neurosci 2022; 42:6445-6452. [PMID: 35851328 PMCID: PMC9398537 DOI: 10.1523/jneurosci.0832-22.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 06/02/2022] [Accepted: 06/30/2022] [Indexed: 11/21/2022] Open
Abstract
Mounting evidence suggests distinct functional contributions of the anterior and posterior hippocampus to autobiographical memory retrieval, but how these subregions function under different retrieval demands as memories age is not yet understood. Specifically, autobiographical memory retrieval is not a homogeneous process; rather, it is thought to consist of the following multiple stages: an early stage of memory construction and a later stage of detailed elaboration, which may differently engage the hippocampus over time. In the present study, we analyzed data from 40 participants (23 female/17 male) who constructed and overtly elaborated on recent and remote memories in response to picture cues in the fMRI scanner. We previously reported a temporal gradient in the posterior hippocampus during the elaboration period of autobiographical retrieval, with posterior hippocampal activation observed for recent but not remote time points. Here, we consider the previously unanalyzed construction stage of retrieval, where participants searched for and selected a memory. We found no evidence of a temporal gradient during memory construction, instead observing strong anterior hippocampus activity regardless of memory remoteness. Our findings suggest a unique contribution of the anterior hippocampus to the construction process of autobiographical retrieval over time. These findings highlight that retrieval processes, which have yet to be integrated with current models of systems consolidation, offer novel insights into hippocampal subregion function over time.SIGNIFICANCE STATEMENT Hippocampal contributions to autobiographical memory retrieval may depend on several distinct factors including memory age and the retrieval process engaged. We previously found that the contribution of the posterior hippocampus to detailed elaborative retrieval diminishes as memories age, with no reliable activation of the anterior hippocampus over time. Here, we report that consideration of the earlier "construction" period of retrieval, where participants search for and retrieve general aspects of the memory, yielded significant anterior hippocampus activation regardless of memory age. These results provide evidence for a unique contribution of the anterior hippocampus to the constructive process of autobiographical retrieval over time and suggest that component processes of retrieval should be integrated into models of systems consolidation.
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Affiliation(s)
- Sam Audrain
- Section on Cognitive Neuropsychology, Laboratory of Brain and Cognition, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892
| | - Adrian W Gilmore
- Section on Cognitive Neuropsychology, Laboratory of Brain and Cognition, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892
| | - Jenna M Wilson
- Section on Cognitive Neuropsychology, Laboratory of Brain and Cognition, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892
| | - Daniel L Schacter
- Department of Psychology, Harvard University, Cambridge, Massachusetts 02138
| | - Alex Martin
- Section on Cognitive Neuropsychology, Laboratory of Brain and Cognition, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892
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12
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Yu X, Jembere F, Takehara-Nishiuchi K. Prefrontal projections to the nucleus reuniens signal behavioral relevance of stimuli during associative learning. Sci Rep 2022; 12:11995. [PMID: 35835794 PMCID: PMC9283438 DOI: 10.1038/s41598-022-15886-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 06/30/2022] [Indexed: 12/04/2022] Open
Abstract
The nucleus reuniens (RE) is necessary for memories dependent on the interaction between the medial prefrontal cortex (mPFC) and hippocampus (HPC). One example is trace eyeblink conditioning, in which the mPFC exhibits differential activity to neutral conditioned stimuli (CS) depending on their contingency with an aversive unconditioned stimulus (US). To test if this relevancy signal is routed to the RE, we photometrically recorded mPFC axon terminals within the RE and tracked their changes with learning. As a comparison, we measured prefrontal terminal activity in the mediodorsal thalamus (MD), which lacks connectivity with the HPC. In naïve male rats, prefrontal terminals within the RE were not strongly activated by tone or light. As the rats associated one of the stimuli (CS+) with the US, terminals gradually increased their response to the CS+ but not the other stimulus (CS-). In contrast, stimulus-evoked responses of prefrontal terminals within the MD were strong even before conditioning. They also became augmented only to the CS+ in the first conditioning session; however, the degree of activity differentiation did not improve with learning. These findings suggest that associative learning selectively increased mPFC output to the RE, signaling the behavioral relevance of sensory stimuli.
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Affiliation(s)
- Xiaotian Yu
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada.,Collaborative Program in Neuroscience, University of Toronto, Toronto, Canada
| | - Fasika Jembere
- Human Biology Program, University of Toronto, Toronto, Canada
| | - Kaori Takehara-Nishiuchi
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada. .,Department of Psychology, University of Toronto, Toronto, Canada. .,Collaborative Program in Neuroscience, University of Toronto, Toronto, Canada.
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13
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Lin C, Oh MM, Disterhoft JF. Aging-Related Alterations to Persistent Firing in the Lateral Entorhinal Cortex Contribute to Deficits in Temporal Associative Memory. Front Aging Neurosci 2022; 14:838513. [PMID: 35360205 PMCID: PMC8963507 DOI: 10.3389/fnagi.2022.838513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 02/07/2022] [Indexed: 11/13/2022] Open
Abstract
With aging comes a myriad of different disorders, and cognitive decline is one of them. Studies have consistently shown a decline amongst aged subjects in their ability to acquire and maintain temporal associative memory. Defined as the memory of the association between two objects that are separated in time, temporal associative memory is dependent on neocortical structures such as the prefrontal cortex and temporal lobe structures. For this memory to be acquired, a mental trace of the first stimulus is necessary to bridge the temporal gap so the two stimuli can be properly associated. Persistent firing, the ability of the neuron to continue to fire action potentials even after the termination of a triggering stimulus, is one mechanism that is posited to support this mental trace. A recent study demonstrated a decline in persistent firing ability in pyramidal neurons of layer III of the lateral entorhinal cortex with aging, contributing to learning impairments in temporal associative memory acquisition. In this work, we explore the potential ways persistent firing in lateral entorhinal cortex (LEC) III supports temporal associative memory, and how aging may disrupt this mechanism within the temporal lobe system, resulting in impairment in this crucial behavior.
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14
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Pershina EV, Kulagina TP, Savina TA, Aripovsky AV, Levin SG, Arkhipov VI. Changes in the level of fatty acids in the brain of rats during memory acquisition. Behav Brain Res 2022; 417:113599. [PMID: 34563602 DOI: 10.1016/j.bbr.2021.113599] [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: 03/10/2021] [Revised: 09/20/2021] [Accepted: 09/22/2021] [Indexed: 11/29/2022]
Abstract
Memory acquisition is accompanied by many cellular and molecular processes, and it is not always clear what role they play. Fatty acids (FAs) are known to be important for cognitive functions, but the details of their involvement in memory processes remain unknown. We investigated FAs in the prefrontal cortex and hippocampus of rats trained to perform a task with food reinforcement. The learning consisted of two training sessions, each of which included 10 trials. The results showed that such training altered individual FAs in the brains. The most significant changes were in the prefrontal cortex, where an increase in the level of many FAs occurred, especially after the second training session: palmitic (16:0), stearic (18:0), docosahexaenoic (22:6, n-3), arachidonic (22:4, n-6), docosapentaenoic (22:5, n-6) acids. Changes in the fatty acid level after training in rats were detected only in the left hippocampus, where the levels of palmitic, docosapentaenoic, and docosahexaenoic acids changed. The changes in the right hippocampus were not significant. In both the prefrontal cortex and the left hippocampus, 72 h after training, all FAs returned to control levels. We believe that the main role of a reversible increase in FA levels during memory acquisition is to support and protect cellular processes involved in memory acquisition. Consolidation of memory traces, which occurs mainly in the neocortex, requires protection from external influences, to which FAs makes a significant contribution. They are able to improve neuronal plasticity, enhance local blood flow, improve mitochondrial processes, and suppress pro-inflammatory signals.
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Affiliation(s)
- Ekaterina V Pershina
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region 142290 Russia.
| | - Tatyana P Kulagina
- Institute of Cell Biophysics of Russian Academy of Sciences, PSCBR RAS, Pushchino, Moscow Region 142290, Russia
| | - Tatyana A Savina
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region 142290 Russia
| | | | - Sergey G Levin
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region 142290 Russia
| | - Vladimir I Arkhipov
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region 142290 Russia
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15
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Gómez-A A, Dannenhoffer CA, Elton A, Lee SH, Ban W, Shih YYI, Boettiger CA, Robinson DL. Altered Cortico-Subcortical Network After Adolescent Alcohol Exposure Mediates Behavioral Deficits in Flexible Decision-Making. Front Pharmacol 2021; 12:778884. [PMID: 34912227 PMCID: PMC8666507 DOI: 10.3389/fphar.2021.778884] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 11/03/2021] [Indexed: 12/24/2022] Open
Abstract
Behavioral flexibility, the ability to modify behavior according to changing conditions, is essential to optimize decision-making. Deficits in behavioral flexibility that persist into adulthood are one consequence of adolescent alcohol exposure, and another is decreased functional connectivity in brain structures involved in decision-making; however, a link between these two outcomes has not been established. We assessed effects of adolescent alcohol and sex on both Pavlovian and instrumental behaviors and resting-state functional connectivity MRI in adult animals to determine associations between behavioral flexibility and resting-state functional connectivity. Alcohol exposure impaired attentional set reversals and decreased functional connectivity among cortical and subcortical regions-of-interest that underlie flexible behavior. Moreover, mediation analyses indicated that adolescent alcohol-induced reductions in functional connectivity within a subnetwork of affected brain regions statistically mediated errors committed during reversal learning. These results provide a novel link between persistent reductions in brain functional connectivity and deficits in behavioral flexibility resulting from adolescent alcohol exposure.
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Affiliation(s)
- Alexander Gómez-A
- Bowles Center for Alcohol Studies, University of North Carolina, Chapel Hill, NC, United States
| | - Carol A. Dannenhoffer
- Bowles Center for Alcohol Studies, University of North Carolina, Chapel Hill, NC, United States
| | - Amanda Elton
- Department of Psychology and Neuroscience, University of North Carolina, Chapel Hill, NC, United States
- Biomedical Research Imaging Center, University of North Carolina, Chapel Hill, NC, United States
| | - Sung-Ho Lee
- Biomedical Research Imaging Center, University of North Carolina, Chapel Hill, NC, United States
- Department of Neurology, University of North Carolina, Chapel Hill, NC, United States
| | - Woomi Ban
- Biomedical Research Imaging Center, University of North Carolina, Chapel Hill, NC, United States
| | - Yen-Yu Ian Shih
- Bowles Center for Alcohol Studies, University of North Carolina, Chapel Hill, NC, United States
- Biomedical Research Imaging Center, University of North Carolina, Chapel Hill, NC, United States
- Department of Neurology, University of North Carolina, Chapel Hill, NC, United States
- Neuroscience Curriculum, University of North Carolina, Chapel Hill, NC, United States
| | - Charlotte A. Boettiger
- Bowles Center for Alcohol Studies, University of North Carolina, Chapel Hill, NC, United States
- Department of Psychology and Neuroscience, University of North Carolina, Chapel Hill, NC, United States
- Biomedical Research Imaging Center, University of North Carolina, Chapel Hill, NC, United States
- Neuroscience Curriculum, University of North Carolina, Chapel Hill, NC, United States
| | - Donita L. Robinson
- Bowles Center for Alcohol Studies, University of North Carolina, Chapel Hill, NC, United States
- Neuroscience Curriculum, University of North Carolina, Chapel Hill, NC, United States
- Department of Psychiatry, University of North Carolina, Chapel Hill, NC, United States
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16
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Shan X, Contreras MP, Mendez M, Born J, Inostroza M. Unfolding of spatial representation at systems level in infant rats. Hippocampus 2021; 32:121-133. [PMID: 34786798 DOI: 10.1002/hipo.23392] [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: 12/17/2020] [Revised: 10/25/2021] [Accepted: 11/01/2021] [Indexed: 11/10/2022]
Abstract
Spatial representations enable navigation from early life on. However, the brain regions essential to form spatial representations, like the hippocampus, are considered functionally immature before weaning. Here, we examined the formation of representations of space in rat pups on postnatal day (PD) 16, using a simple habituation paradigm where the pups were exposed to an arena on three occasions, separated by ~140 min. Whereas on the first two occasions the arena was the same, on the third "test" occasion either proximal cues (Prox group), or distal cues (Dist group), or proximal and distal cues (Prox-Dist group), or no cues (No-change group) were rearranged. Locomotion (distance traveled) was used as behavioral measure of habituation, and c-Fos expression to measure regional brain activity at test. Locomotion generally decreased across the first two occasions. At test, it reached a minimum in the No-change group, indicating familiarity with the spatial conditions. By contrast, the Prox-Dist group displayed a significant increase in locomotion which was less robust in the Prox group and absent in the Dist group, a pattern suggesting that the pups relied more on proximal than distal cues during spatial exploration. c-Fos activity in the No-change group was significantly suppressed in the hippocampus (CA1, CA3, dentate gyrus) but simultaneously enhanced in the prelimbic area (PL) of the medial prefrontal cortex, compared with untreated Home-cage controls, pointing to a possible involvement of the PL in regulating locomotion in familiar spaces. By contrast, in both Prox-Dist and Prox groups c-Fos activity was enhanced in hippocampal CA1 and CA3 regions, suggesting these regions might be particularly involved in regulating exploration of spatial novelty. Our findings show that functional representations of space at a systems level are formed already in pre-weanling rats.
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Affiliation(s)
- Xia Shan
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.,Graduate School of Neural & Behavioral Science, International Max Planck Research School, Tübingen, Germany
| | - María P Contreras
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.,Graduate School of Neural & Behavioral Science, International Max Planck Research School, Tübingen, Germany
| | - Marta Mendez
- Laboratory of Neuroscience, Department of Psychology, Instituto de Neurociencias del Principado de Asturias (INEUROPA), University of Oviedo, Plaza Feijoo, Oviedo, Spain
| | - Jan Born
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.,German Center for Diabetes Research (DZD), Institute for Diabetes Research & Metabolic Diseases of the Helmholtz Center Munich at the University Tübingen (IDM), Tübingen, Germany.,Werner Reichert Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Marion Inostroza
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
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17
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Goto A, Bota A, Miya K, Wang J, Tsukamoto S, Jiang X, Hirai D, Murayama M, Matsuda T, McHugh TJ, Nagai T, Hayashi Y. Stepwise synaptic plasticity events drive the early phase of memory consolidation. Science 2021; 374:857-863. [PMID: 34762472 DOI: 10.1126/science.abj9195] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Akihiro Goto
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan.,RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Ayaka Bota
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan.,RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.,Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
| | - Ken Miya
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.,Department of Molecular Neurobiology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan.,Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Jingbo Wang
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan
| | - Suzune Tsukamoto
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan
| | - Xinzhi Jiang
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan
| | - Daichi Hirai
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Masanori Murayama
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.,RIKEN Center for Brain Science, Wako, Saitama 351-0198, Japan
| | - Tomoki Matsuda
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Thomas J McHugh
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.,RIKEN Center for Brain Science, Wako, Saitama 351-0198, Japan
| | - Takeharu Nagai
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Yasunori Hayashi
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan.,RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.,Brain and Body System Science Institute, Saitama University, Saitama 338-8570, Japan
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18
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Fama R, Le Berre AP, Sassoon SA, Zahr NM, Pohl KM, Pfefferbaum A, Sullivan EV. Memory impairment in alcohol use disorder is associated with regional frontal brain volumes. Drug Alcohol Depend 2021; 228:109058. [PMID: 34610518 PMCID: PMC8595873 DOI: 10.1016/j.drugalcdep.2021.109058] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 08/03/2021] [Accepted: 09/13/2021] [Indexed: 01/31/2023]
Abstract
BACKGROUND Episodic memory deficits occur in alcohol use disorder (AUD), but their anatomical substrates remain in question. Although persistent memory impairment is classically associated with limbic circuitry disruption, learning and retrieval of new information also relies on frontal systems. Despite AUD vulnerability of frontal lobe integrity, relations between frontal regions and memory processes have been under-appreciated. METHODS Participants included 91 AUD (49 with a drug diagnosis history) and 36 controls. Verbal and visual episodic memory scores were age- and education-corrected. Structural magnetic resonance imaging (MRI) data yielded regional frontal lobe (precentral, superior, orbital, middle, inferior, supplemental motor, and medial) and total hippocampal volumes. RESULTS AUD were impaired on all memory scores and had smaller precentral frontal and hippocampal volumes than controls. Orbital, superior, and inferior frontal volumes and lifetime alcohol consumption were independent predictors of episodic memory in AUD. Selectivity was established with a double dissociation, where orbital frontal volume predicted verbal but not visual memory, whereas inferior frontal volumes predicted visual but not verbal memory. Further, superior frontal volumes predicted verbal memory in AUD alone, whereas orbital frontal volumes predicted verbal memory in AUD+drug abuse history. CONCLUSIONS Selective relations among frontal subregions and episodic memory processes highlight the relevance of extra-limbic regions in mnemonic processes in AUD. Memory deficits resulting from frontal dysfunction, unlike the episodic memory impairment associated with limbic dysfunction, may be more amenable to recovery with cessation or reduction of alcohol misuse and may partially explain the heterogeneity in episodic memory abilities in AUD.
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Affiliation(s)
- Rosemary Fama
- Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 401 Quarry Rd, Stanford, CA 94305, USA; Center for Health Sciences, Bioscience Division, SRI International, 333 Ravenswood Ave, Menlo Park, CA 94025, USA.
| | - Anne-Pascale Le Berre
- Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 401 Quarry Rd, Stanford, CA 94305, USA
| | - Stephanie A Sassoon
- Center for Health Sciences, Bioscience Division, SRI International, 333 Ravenswood Ave, Menlo Park, CA 94025, USA
| | - Natalie M Zahr
- Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 401 Quarry Rd, Stanford, CA 94305, USA; Center for Health Sciences, Bioscience Division, SRI International, 333 Ravenswood Ave, Menlo Park, CA 94025, USA
| | - Kilian M Pohl
- Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 401 Quarry Rd, Stanford, CA 94305, USA; Center for Health Sciences, Bioscience Division, SRI International, 333 Ravenswood Ave, Menlo Park, CA 94025, USA
| | - Adolf Pfefferbaum
- Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 401 Quarry Rd, Stanford, CA 94305, USA; Center for Health Sciences, Bioscience Division, SRI International, 333 Ravenswood Ave, Menlo Park, CA 94025, USA
| | - Edith V Sullivan
- Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 401 Quarry Rd, Stanford, CA 94305, USA
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19
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Examining the transition of novel information toward familiarity. Neuropsychologia 2021; 161:107993. [PMID: 34411595 DOI: 10.1016/j.neuropsychologia.2021.107993] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 08/14/2021] [Accepted: 08/15/2021] [Indexed: 11/23/2022]
Abstract
Throughout their lives, humans encounter multiple instances of new information that can be inconsistent with prior knowledge (novel). Over time, the once-novel information becomes integrated into their established knowledge base, shifting from novelty to familiarity. In this study, we investigated the processes by which the first steps of this transition take place. We hypothesized that the neural representations of initially novel items gradually change over the course of repeated presentations, expressing a shift toward familiarity. We further assumed that this shift could be traced by examining neural patterns using fMRI. In two experiments, while being scanned, participants read noun-adjective word pairs that were either consistent or inconsistent with their prior knowledge. Stimuli were repeated 3-6 times within the scans. Employing mass univariate and multivariate similarity analyses, we showed that the neural representations associated with the initial presentation of familiar versus novel objects differed in lateral frontal and temporal regions, the medial prefrontal cortex, and the medial temporal lobe. Importantly, the neural representations of novel stimuli gradually changed throughout repetitions until they became indistinguishable from their respective familiar items. We interpret these findings as indicating that an early phase of familiarization can be completed within a few repetitions. This initial familiarization can then serve as the prerequisite to the integration of novel items into existing knowledge. Future empirical and theoretical works can build on the current findings to develop a comprehensive model of the transition from novelty to familiarity.
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20
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Yu XT, Yu J, Choi A, Takehara-Nishiuchi K. Lateral entorhinal cortex supports the development of prefrontal network activity that bridges temporally discontiguous stimuli. Hippocampus 2021; 31:1285-1299. [PMID: 34606152 DOI: 10.1002/hipo.23389] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 09/14/2021] [Accepted: 09/16/2021] [Indexed: 01/16/2023]
Abstract
The lateral entorhinal cortex (LEC) is an essential component of the brain circuitry supporting long-term memory by serving as an interface between the hippocampus and neocortex. Dysfunction of the LEC affects sensory coding in the hippocampus, leading to a view that the LEC provides the hippocampus with highly processed sensory information. It remains unclear, however, how the LEC modulates neural processing in the neocortical regions. To address this point, we pharmacologically inactivated the LEC of male rats during a temporal associative learning task and examined its impact on local network activity in one of the LEC's efferent targets, the prelimbic region of the medial prefrontal cortex (mPFC). Rats were exposed to two neutral stimuli, one of which was paired with an aversive eyelid shock over a short temporal delay. The LEC inhibition reduced the expression of anticipatory blinking responses to the reinforced stimuli without increasing responses to nonreinforced stimuli. In control rats, both the reinforced and nonreinforced stimuli evoked a short-lived, wide-band increase in the prelimbic network activity. With learning, the initial increase of gamma-band activity started to extend into the interval between the reinforced neutral stimulus and the eyelid shock. LEC inhibition attenuated the learning-induced sustained activity, without affecting the initial transient activity. These results suggest that the integrity of LEC is necessary for the formation of temporal stimulus associations and its neural correlates in the mPFC. Given the minimal effects on the innate network responses to sensory stimuli, the LEC appears not to be the main source of sensory inputs to the mPFC; rather it may provide a framework that shapes the mPFC network response to behaviorally relevant cues.
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Affiliation(s)
- Xiaotian Tag Yu
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
| | - Jessica Yu
- Human Biology Program, University of Toronto, Toronto, Canada
| | - Allison Choi
- Human Biology Program, University of Toronto, Toronto, Canada
| | - Kaori Takehara-Nishiuchi
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada.,Department of Psychology, University of Toronto, Toronto, Canada.,Collaborative Program in Neuroscience, University of Toronto, Toronto, Canada
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21
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Guo J, Shubeck K, Hu X. Relationship Between Item and Source Memory: Explanation of Connection-Strength Model. Front Psychol 2021; 12:691577. [PMID: 34659007 PMCID: PMC8511408 DOI: 10.3389/fpsyg.2021.691577] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 08/11/2021] [Indexed: 11/24/2022] Open
Abstract
The controversy in the relationship between item memory and source memory is a focus of episodic memory. Some studies show the trade-off between item memory and source memory, some show the consistency between them, and others show the independence between them. This review attempts to point out the connection-strength model, implying the different types and strengths of the important role of the item-source connections in the relationship between item memory and source memory, which is based on the same essence in the unified framework. The logic of the model is that when item memory and source memory share the same or relevant connection between item and source, they positively connect, or they are independently or negatively connected. This review integrates empirical evidence from the domains of cognition, cognitive neuroscience, and mathematical modeling to validate our hypothesis.
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Affiliation(s)
- Junjun Guo
- School of Psychology, Central China Normal University, Wuhan, China
| | - Keith Shubeck
- Department of Psychology, The University of Memphis, Memphis, TN, United States
- Institute for Intelligent Systems, The University of Memphis, Memphis, TN, United States
| | - Xiangen Hu
- School of Psychology, Central China Normal University, Wuhan, China
- Department of Psychology, The University of Memphis, Memphis, TN, United States
- Institute for Intelligent Systems, The University of Memphis, Memphis, TN, United States
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22
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de Sousa AF, Chowdhury A, Silva AJ. Dimensions and mechanisms of memory organization. Neuron 2021; 109:2649-2662. [PMID: 34242564 PMCID: PMC8416710 DOI: 10.1016/j.neuron.2021.06.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 04/17/2021] [Accepted: 06/11/2021] [Indexed: 12/31/2022]
Abstract
Memory formation is dynamic in nature, and acquisition of new information is often influenced by previous experiences. Memories sharing certain attributes are known to interact so that retrieval of one increases the likelihood of retrieving the other, raising the possibility that related memories are organized into associative mnemonic structures of interconnected representations. Although the formation and retrieval of single memories have been studied extensively, very little is known about the brain mechanisms that organize and link related memories. Here we review studies that suggest the existence of mnemonic structures in humans and animal models. These studies suggest three main dimensions of experience that can serve to organize related memories: time, space, and perceptual/conceptual similarities. We propose potential molecular, cellular, and systems mechanisms that might support organization of memories according to these dimensions.
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Affiliation(s)
- André F de Sousa
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences, and Psychology, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Ananya Chowdhury
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences, and Psychology, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Alcino J Silva
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences, and Psychology, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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23
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Gilboa A, Moscovitch M. No consolidation without representation: Correspondence between neural and psychological representations in recent and remote memory. Neuron 2021; 109:2239-2255. [PMID: 34015252 DOI: 10.1016/j.neuron.2021.04.025] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 03/24/2021] [Accepted: 04/26/2021] [Indexed: 10/21/2022]
Abstract
Memory systems consolidation is often conceived as the linear, time-dependent, neurobiological shift of memory from hippocampal-cortical to cortico-cortical dependency. We argue that contrary to this unidirectional view of memory reorganization, information about events may be retained in multiple forms (e.g., event-specific sensory-near episodic memory, event-specific gist information, event-general schematic information, or abstract semantic memory). These representations can all form at the time of the event and may continue to coexist for long durations. Their relative strength, composition, and dominance of expression change with time and experience, with task demands, and through their dynamic interaction with one another. These different psychological mnemonic representations depend on distinct functional and structural neurobiological substrates such that there is a neural-psychological representation correspondence (NPRC) among them. We discuss how the dynamics of psychological memory representations are reflected in multiple levels of neurobiological markers and their interactions. By this view, there are only variations of synaptic consolidation and memory dynamics without assuming a distinct systems consolidation process.
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Affiliation(s)
- Asaf Gilboa
- Rotman Research Institute, Baycrest Health Sciences, 3560 Bathurst Street, Toronto, ON M6A 2E1, Canada; Department of Psychology, University of Toronto, 100 St. George Street, Toronto, ON M5S 3G3, Canada.
| | - Morris Moscovitch
- Rotman Research Institute, Baycrest Health Sciences, 3560 Bathurst Street, Toronto, ON M6A 2E1, Canada; Department of Psychology, University of Toronto, 100 St. George Street, Toronto, ON M5S 3G3, Canada.
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Prefrontal Neural Ensembles Develop Selective Code for Stimulus Associations within Minutes of Novel Experiences. J Neurosci 2020; 40:8355-8366. [PMID: 32989098 DOI: 10.1523/jneurosci.1503-20.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 08/25/2020] [Accepted: 09/20/2020] [Indexed: 12/14/2022] Open
Abstract
Prevailing theories posit that the hippocampus rapidly learns stimulus conjunctions during novel experiences, whereas the neocortex learns slowly through subsequent, off-line interaction with the hippocampus. Parallel evidence, however, shows that the medial prefrontal cortex (mPFC; a critical node of the neocortical network supporting long-term memory storage) undergoes rapid modifications of gene expression, synaptic structure, and physiology at the time of encoding. These observations, along with impaired learning with disrupted mPFC, suggest that mPFC neurons may exhibit rapid neural plasticity during novel experiences; however, direct empirical evidence is lacking. We extracellularly recorded action potentials of cells in the prelimbic region of the mPFC, while male rats received a sequence of stimulus presentations for the first time in life. Moment-to-moment tracking of neural ensemble firing patterns revealed that the prelimbic network activity exhibited an abrupt transition within 1 min after the first encounter of an aversive but not neutral stimulus. This network-level change was driven by ∼15% of neurons that immediately elevated their spontaneous firing rates (FRs) and developed firing responses to a neutral stimulus preceding the aversive stimulus within a few instances of their pairings. When a new sensory stimulus was paired with the same aversive stimulus, about half of these neurons generalized firing responses to the new stimulus association. Thus, prelimbic neurons are capable of rapidly forming ensemble codes for novel stimulus associations within minutes. This circuit property may enable the mPFC to rapidly detect and selectively encode the central content of novel experiences.SIGNIFICANCE STATEMENT During a new experience, a region of the brain, called the hippocampus, rapidly forms its memory and later instructs another region, called the neocortex, that stores its content. Consistent with this dominant view, cells in the neocortex gradually strengthen the selectivity for the memory content over weeks after novel experiences. However, we still do not know precisely when these cells begin to develop the selectivity. We found that neocortical cells were capable of forming the selectivity for ongoing events within a few minutes of new experiences. This finding provides support for an alternative view that the neocortex works with, but not follows, the hippocampus to form new memories.
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