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Joensen BH, Ashton JE, Berens SC, Gaskell MG, Horner AJ. An Enduring Role for Hippocampal Pattern Completion in Addition to an Emergent Nonhippocampal Contribution to Holistic Episodic Retrieval after a 24 h Delay. J Neurosci 2024; 44:e1740232024. [PMID: 38527810 PMCID: PMC11063816 DOI: 10.1523/jneurosci.1740-23.2024] [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: 09/15/2023] [Revised: 03/05/2024] [Accepted: 03/08/2024] [Indexed: 03/27/2024] Open
Abstract
Episodic memory retrieval is associated with the holistic neocortical reinstatement of all event information, an effect driven by hippocampal pattern completion. However, whether holistic reinstatement occurs, and whether hippocampal pattern completion continues to drive reinstatement, after a period of consolidation is unclear. Theories of systems consolidation predict either a time-variant or time-invariant role of the hippocampus in the holistic retrieval of episodic events. Here, we assessed whether episodic events continue to be reinstated holistically and whether hippocampal pattern completion continues to facilitate holistic reinstatement following a period of consolidation. Female and male human participants learned "events" that comprised multiple overlapping pairs of event elements (e.g., person-location, object-location, location-person). Importantly, encoding occurred either immediately before or 24 h before retrieval. Using fMRI during the retrieval of events, we show evidence for holistic reinstatement, as well as a correlation between reinstatement and hippocampal pattern completion, regardless of whether retrieval occurred immediately or 24 h after encoding. Thus, hippocampal pattern completion continues to contribute to holistic reinstatement after a delay. However, our results also revealed that some holistic reinstatement can occur without evidence for a corresponding signature of hippocampal pattern completion after a delay (but not immediately after encoding). We therefore show that hippocampal pattern completion, in addition to a nonhippocampal process, has a role in holistic reinstatement following a period of consolidation. Our results point to a consolidation process where the hippocampus and neocortex may work in an additive, rather than compensatory, manner to support episodic memory retrieval.
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Affiliation(s)
- Bárður H Joensen
- Department of Psychology, Lund University, Lund 221 00, Sweden
- Department of Psychology, University of York, York YO10 5DD, United Kingdom
| | - Jennifer E Ashton
- Department of Psychology, University of York, York YO10 5DD, United Kingdom
| | - Sam C Berens
- School of Psychology, University of Sussex, Falmer BN1 9QH, United Kingdom
| | - M Gareth Gaskell
- Department of Psychology, University of York, York YO10 5DD, United Kingdom
- York Biomedical Research Institute, University of York, York YO10 5NG, United Kingdom
| | - Aidan J Horner
- Department of Psychology, University of York, York YO10 5DD, United Kingdom
- York Biomedical Research Institute, University of York, York YO10 5NG, United Kingdom
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2
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Nwaubani P, Cercignani M, Colasanti A. In vivo quantitative imaging of hippocampal inflammation in autoimmune neuroinflammatory conditions: a systematic review. Clin Exp Immunol 2022; 210:24-38. [PMID: 35802780 PMCID: PMC9585553 DOI: 10.1093/cei/uxac058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 05/17/2022] [Accepted: 07/04/2022] [Indexed: 01/25/2023] Open
Abstract
The hippocampus is a morphologically complex region of the brain limbic system centrally involved in important cognitive, affective, and behavioural regulatory roles. It has exquisite vulnerability to neuroinflammatory processes, with some of its subregions found to be specific sites of neuroinflammatory pathology in ex-vivo studies. Optimizing neuroimaging correlates of hippocampal neuroinflammation would enable the direct study of functional consequences of hippocampal neuroinflammatory pathology, as well as the definition of therapeutic end-points for treatments targeting neuroinflammation, and their related affective or cognitive sequelae. However, in vivo traditional imaging of the hippocampus and its subregions is fraught with difficulties, due to methodological challenges deriving from its unique anatomical characteristics. The main objective of this review is to provide a current update on the characterization of quantitative neuroimaging correlates of hippocampal neuroinflammation by focusing on three prototypical autoimmune neuro-inflammatory conditions [multiple sclerosis (MS), systemic lupus erythematosus (SLE), and autoimmune encephalitis (AE)]. We focused on studies employing TSPO-targeting positron emission tomography (PET), quantitative magnetic resonance imaging (MRI), and spectroscopy techniques assumed to be sensitive to neuroinflammatory tissue changes. We found 18 eligible studies (14, 2, and 2 studies in MS, AE, and SLE, respectively). Across conditions, the largest effect was seen in TSPO PET and diffusion-weighted MRI studies. No study examined neuroinflammation-related changes at the hippocampal subfield level. Overall, results were largely inconsistent due to heterogeneous imaging methods, small sample sizes, and different population studies. We discuss how these data could inform future study design and conclude by suggesting further methodological directions aimed at improving the precision and sensitivity of neuroimaging techniques to characterize hippocampal neuroinflammatory pathology in the human brain.
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Affiliation(s)
- P Nwaubani
- Department of Clinical Neuroscience and Neuroimaging, Brighton and Sussex Medical School, University of Sussex, Falmer, Brighton, UK
| | - M Cercignani
- Cardiff University Brain Research Imaging Centre, Cardiff University, Cardiff, UK
| | - A Colasanti
- Correspondence: Alessandro Colasanti, Department of Clinical Neuroscience and Neuroimaging, Brighton and Sussex Medical School, University of Sussex, Trafford Centre for Medical Research, University of Sussex, Falmer, Brighton, BN1 4RY, UK.
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Lad M, Mullally SL, Houston AL, Kelly T, Griffiths TD. Characterizing memory loss in patients with autoimmune limbic encephalitis hippocampal lesions. Hippocampus 2019; 29:1114-1120. [PMID: 31472008 PMCID: PMC6852518 DOI: 10.1002/hipo.23150] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 08/05/2019] [Accepted: 08/09/2019] [Indexed: 12/29/2022]
Abstract
Since the publication of Scoville and Milner's (1957) seminal paper, the precise functional role played by the hippocampus in support of human memory has been fiercely debated. For instance, the single question of whether the hippocampus plays a time-limited or an indelible role in the recollection of personal memories led to a deep and tenacious schism within the field. Similar polarizations arose between those who debated the precise nature of the role played by the hippocampus in support of semantic relative to episodic memories and in recall/recollection relative to familiarity-based recognition. At the epicenter of these divisions lies conflicting neuropsychological findings. These differences likely arise due to the consistent use of heterogeneous patient populations to adjudicate between these positions. Here we utilized traditional neuropsychological measures in a homogenous patient population with a highly discrete hippocampal lesion (i.e., VGKCC-Ab related autoimmune limbic encephalitis patients). We observed consistent impairment of recent episodic memories, a present but less striking impairment of remote episodic memories, preservation of personal semantic memory, and recall but not recognition memory deficits. We conclude that this increasingly well-characterized patient group may represent an important homogeneous population in which the functional role played by the hippocampus may be more precisely delineated.
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Affiliation(s)
- Meher Lad
- Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUnited Kingdom
| | - Sinéad L. Mullally
- Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUnited Kingdom
| | | | - Tom Kelly
- The Neuropsychology DepartmentRoyal Victoria InfirmaryNewcastle upon TyneUnited Kingdom
| | - Timothy D. Griffiths
- Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUnited Kingdom
- Wellcome Trust Centre for NeuroimagingUniversity College LondonLondonUnited Kingdom
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Migliorati K, Muratori A, Fontanella MM, Panciani PP. Adult bilateral idiopathic occlusion of foramina of Monro: is foraminoplasty really safe and effective? BMJ Case Rep 2018; 2018:bcr-2018-226332. [PMID: 30366894 DOI: 10.1136/bcr-2018-226332] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Idiopathic bilateral occlusion of foramina of Monro is an extremely rare condition in adults and only few cases are reported. Currently, foraminoplasty is indicated as first-line treatment. We reported the case of a 52-year-old woman who presented with headache, instability and urinary incontinence. The imaging demonstrated bilateral occlusion of foramina of Monro and consequent biventricular hydrocephalus. A ventriculo-peritoneal shunt allowed to treat the hydrocephalus, but it was necessary to remove it for the appearance of peritonitis from salpingitis. Since the initial symptomatology reappeared, according to the literature, we performed an endoscopic foraminoplasty with septostomy. The patient immediately developed short-term memory impairment and subsequently we observed the hydrocephalus recurrence. The positioning of a ventriculo-atrial shunt allowed to improve the symptoms, but the memory remained impaired. In case of bilateral true stenosis of foramina of Monro, foraminoplasty may lead to severe memory impairment. Therefore, cerebrospinal fluid shunting should be considered as an effective and safer treatment.
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Affiliation(s)
- Karol Migliorati
- Department of Neurosurgery, Medical and Surgical Specialties, Radiological Sciences, and Public Health, University of Brescia, Brescia, Italy
| | - Andrea Muratori
- Department of Neurosurgery, Medical and Surgical Specialties, Radiological Sciences, and Public Health, University of Brescia, Brescia, Italy
| | - Marco Maria Fontanella
- Department of Neurosurgery, Medical and Surgical Specialties, Radiological Sciences, and Public Health, University of Brescia, Brescia, Italy
| | - Pier Paolo Panciani
- Department of Neurosurgery, Spedali Civili University Hospital of Brescia, Brecia, Italy
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5
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Salvalaggio A, Cagnin A, Nardetto L, Manara R, Briani C. Acute amnestic syndrome in isolated bilateral fornix stroke. Eur J Neurol 2018; 25:787-789. [PMID: 29427459 DOI: 10.1111/ene.13592] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 01/08/2018] [Indexed: 11/30/2022]
Abstract
BACKGROUND AND PURPOSE Acute onset of amnestic syndrome may represent a challenging diagnostic issue. In addition to non-vascular etiology, thalamic strokes or infarction involving several temporal lobe structures have been reported. METHODS We describe three patients in whom an isolated bilateral anterior fornix infarction presented with an acute amnestic syndrome. Clinical presentation, differential diagnosis and magnetic resonance images are discussed for each patient and vascular anatomy of the involved brain regions is also considered. RESULTS Bilateral anterior columns of the fornix showed cytotoxic edema and bilateral narrowing of anterior cerebral artery was demonstrated. CONCLUSIONS We suggest that bilateral fornix infarction should always be considered in the diagnostic work-up of an amnestic syndrome with acute onset.
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Affiliation(s)
- A Salvalaggio
- Department of Neurosciences (DNS), University of Padova, Padova
| | - A Cagnin
- Department of Neurosciences (DNS), University of Padova, Padova.,IRCCS San Camillo Hospital, Venice
| | | | - R Manara
- Neuroradiology. Sezione di Neuroscienze, University of Salerno, Salerno, Italy
| | - C Briani
- Department of Neurosciences (DNS), University of Padova, Padova
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Nikolakaros G, Ilonen T, Kurki T, Paju J, Papageorgiou SG, Vataja R. Non-alcoholic Korsakoff syndrome in psychiatric patients with a history of undiagnosed Wernicke's encephalopathy. J Neurol Sci 2016; 370:296-302. [PMID: 27772780 DOI: 10.1016/j.jns.2016.09.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 08/30/2016] [Accepted: 09/14/2016] [Indexed: 12/12/2022]
Abstract
Wernicke's encephalopathy is often undiagnosed, particularly in non-alcoholics. There are very few reports of non-alcoholic patients diagnosed with Korsakoff syndrome in the absence of a prior diagnosis of Wernicke's encephalopathy and no studies of diffusion tensor imaging in non-alcoholic Korsakoff syndrome. We report on three non-alcoholic psychiatric patients (all women) with long-term non-progressive memory impairment that developed after malnutrition accompanied by at least one of the three Wernicke's encephalopathy manifestations: ocular abnormalities, ataxia or unsteadiness, and an altered mental state or mild memory impairment. In neuropsychological examination, all patients had memory impairment, including intrusions. One patient had mild cerebellar vermis atrophy in MRI taken after the second episode of Wernicke's encephalopathy. The same patient had mild hypometabolism in the lateral cortex of the temporal lobes. Another patient had mild symmetrical atrophy and hypometabolism of the superior frontal lobes. Two patients were examined with diffusion tensor imaging. Reduced fractional anisotropy values were found in the corona radiata in two patients, and the uncinate fasciculus and the inferior longitudinal fasciculus in one patient. Our results suggest that non-alcoholic Korsakoff syndrome is underdiagnosed. Psychiatric patients with long-term memory impairment may have Korsakoff syndrome and, therefore, they should be evaluated for a history of previously undiagnosed Wernicke's encephalopathy.
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Affiliation(s)
- Georgios Nikolakaros
- "Specialists in Psychiatry" Medical Center, Yliopistonkatu 33C28, 20100 Turku, Finland; Satakunta Hospital District, Psychiatric Care Division, General Psychiatry Outpatient Clinic, Sairaalantie 3, 28500 Pori, Finland.
| | - Tuula Ilonen
- Department of Psychiatry, University of Turku, Kunnallissairaalantie 20, rak. 9, 20700 Turku, Finland.
| | - Timo Kurki
- Terveystalo Pulssi Medical Center, Humalistonkatu 9-11, 20100 Turku, Finland; Department of Radiology, University of Turku, Kiinamyllynkatu 4-8, 20520, Turku, Finland.
| | - Janina Paju
- Department of Psychiatry, University of Turku, Kunnallissairaalantie 20, rak. 9, 20700 Turku, Finland.
| | - Sokratis G Papageorgiou
- Cognitive Disorders/Dementia Unit, 2nd University Department of Neurology, Medical School, National and Kapodistrian University of Athens, University General Hospital "ATTIKON", Rimini street, 12462 Athens, Greece.
| | - Risto Vataja
- Division of Neuropsychiatry, Helsinki University Hospital, PL 100, 00029 HUS, Helsinki, Finland.
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7
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Jeltsch-David H, Muller S. Neuropsychiatric systemic lupus erythematosus and cognitive dysfunction: the MRL-lpr mouse strain as a model. Autoimmun Rev 2014; 13:963-73. [PMID: 25183233 DOI: 10.1016/j.autrev.2014.08.015] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 07/10/2014] [Indexed: 12/19/2022]
Abstract
Mouse models of autoimmunity, such as (NZB×NZW)F1, MRL/MpJ-Fas(lpr) (MRL-lpr) and BXSB mice, spontaneously develop systemic lupus erythematosus (SLE)-like syndromes with heterogeneity and complexity that characterize human SLE. Despite their inherent limitations, such models have highly contributed to our current understanding of the pathogenesis of SLE as they provide powerful tools to approach the human disease at the genetic, cellular, molecular and environmental levels. They also allow novel treatment strategies to be evaluated in a complex integrated system, a favorable context knowing that very few murine models that adequately mimic human autoimmune diseases exist. As we move forward with more efficient medications to treat lupus patients, certain forms of the disease that requires to be better understood at the mechanistic level emerge. This is the case of neuropsychiatric (NP) events that affect 50-60% at SLE onset or within the first year after SLE diagnosis. Intense research performed at deciphering NP features in lupus mouse models has been undertaken. It is central to develop the first lead molecules aimed at specifically treating NPSLE. Here we discuss how mouse models, and most particularly MRL-lpr female mice, can be used for studying the pathogenesis of NPSLE in an animal setting, what are the NP symptoms that develop, and how they compare with human SLE, and, with a critical view, what are the neurobehavioral tests that are pertinent for evaluating the degree of altered functions and the progresses resulting from potentially active therapeutics.
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Affiliation(s)
- Hélène Jeltsch-David
- CNRS, Immunopathologie et chimie thérapeutique/Laboratory of excellence Medalis, Institut de Biologie Moléculaire et Cellulaire, 67000 Strasbourg, France.
| | - Sylviane Muller
- CNRS, Immunopathologie et chimie thérapeutique/Laboratory of excellence Medalis, Institut de Biologie Moléculaire et Cellulaire, 67000 Strasbourg, France.
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8
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Grilli MD, Verfaellie M. Personal semantic memory: Insights from neuropsychological research on amnesia. Neuropsychologia 2014; 61:56-64. [DOI: 10.1016/j.neuropsychologia.2014.06.012] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 05/14/2014] [Accepted: 06/09/2014] [Indexed: 11/27/2022]
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9
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Li Q, Lu Q, Lu H, Tian S, Lu Q. Systemic autoimmunity in TAM triple knockout mice causes inflammatory brain damage and cell death. PLoS One 2013; 8:e64812. [PMID: 23840307 PMCID: PMC3688737 DOI: 10.1371/journal.pone.0064812] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 04/18/2013] [Indexed: 12/14/2022] Open
Abstract
The Tyro3, Axl and Mertk (TAM) triply knockout (TKO) mice exhibit systemic autoimmune diseases, with characteristics of increased proinflammatory cytokine production, autoantibody deposition and autoreactive lymphocyte infiltration into a variety of tissues. Here we show that TKO mice produce high level of serum TNF-α and specific autoantibodies deposited onto brain blood vessels. The brain-blood barrier (BBB) in mutant brains exhibited increased permeability for Evans blue and fluorescent-dextran, suggesting a breakdown of the BBB in the mutant brains. Impaired BBB integrity facilitated autoreactive T cells infiltrating into all regions of the mutant brains. Brain autoimmune disorder caused accumulation of the ubiquitin-reactive aggregates in the mutant hippocampus, and early formation of autofluorescent lipofuscins in the neurons throughout the entire brains. Chronic neuroinflammation caused damage of the hippocampal mossy fibers and neuronal apoptotic death. This study shows that chronic systemic inflammation and autoimmune disorders in the TKO mice cause neuronal damage and death.
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MESH Headings
- Animals
- Apoptosis
- Autoantibodies/blood
- Autoimmune Diseases/genetics
- Autoimmune Diseases/immunology
- Autoimmune Diseases/pathology
- Blood-Brain Barrier/metabolism
- Brain Damage, Chronic/genetics
- Brain Damage, Chronic/immunology
- Brain Damage, Chronic/pathology
- CA3 Region, Hippocampal/blood supply
- CA3 Region, Hippocampal/immunology
- CA3 Region, Hippocampal/pathology
- Capillary Permeability/immunology
- Cells, Cultured
- Cytokines/metabolism
- Dentate Gyrus/blood supply
- Dentate Gyrus/immunology
- Dentate Gyrus/pathology
- Endothelial Cells/immunology
- Endothelial Cells/metabolism
- Female
- Gene Knockdown Techniques
- Inclusion Bodies/metabolism
- Inflammation Mediators/metabolism
- Lipopolysaccharides/pharmacology
- Mice
- Mice, 129 Strain
- Mice, Inbred C57BL
- Mice, Knockout
- Microvessels/immunology
- Microvessels/metabolism
- Neurons/physiology
- Proto-Oncogene Proteins/genetics
- Receptor Protein-Tyrosine Kinases/genetics
- T-Lymphocytes/immunology
- Tumor Necrosis Factor-alpha/blood
- Ubiquitinated Proteins/metabolism
- c-Mer Tyrosine Kinase
- Axl Receptor Tyrosine Kinase
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Affiliation(s)
- Qiutang Li
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, Kentucky, United States of America
- The James Graham Brown Cancer Center, University of Louisville, Louisville, Kentucky, United States of America
| | - Qingjun Lu
- School of Basic Medicine and Beijing Tong-Ren Hospital, Beijing Ophthalmology and Visual Science Key Laboratory, Capital Medical University, Beijing, China
| | - Huayi Lu
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, Kentucky, United States of America
| | - Shifu Tian
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, Kentucky, United States of America
| | - Qingxian Lu
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, Kentucky, United States of America
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky, United States of America
- The James Graham Brown Cancer Center, University of Louisville, Louisville, Kentucky, United States of America
- * E-mail:
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10
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Meier B, Rey-Mermet A, Woodward TS, Müri R, Gutbrod K. Episodic context binding in task switching: Evidence from amnesia. Neuropsychologia 2013; 51:886-92. [DOI: 10.1016/j.neuropsychologia.2013.01.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 01/18/2013] [Accepted: 01/20/2013] [Indexed: 11/29/2022]
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Abstract
Work with patient H.M., beginning in the 1950s, established key principles about the organization of memory that inspired decades of experimental work. Since H.M., the study of human memory and its disorders has continued to yield new insights and to improve understanding of the structure and organization of memory. Here we review this work with emphasis on the neuroanatomy of medial temporal lobe and diencephalic structures important for memory, multiple memory systems, visual perception, immediate memory, memory consolidation, the locus of long-term memory storage, the concepts of recollection and familiarity, and the question of how different medial temporal lobe structures may contribute differently to memory functions.
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Affiliation(s)
- Larry R Squire
- Veterans Affairs Healthcare System, San Diego, California 92161, USA.
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12
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Abstract
With time and experience, memories undergo a process of reorganization that involves different neuronal networks, known as systems consolidation. The traditional view, as articulated in standard consolidation theory (SCT), is that (episodic and semantic) memories initially depend on the hippocampus, but eventually become consolidated in their original forms in other brain regions. In this study, we review the main principles of SCT and report evidence from the neuropsychological literature that would not be predicted by this theory. By comparison, the evidence supports an alternative account, the transformation hypothesis, whose central premise is that changes in neural representation in systems consolidation are accompanied by corresponding changes in the nature of the memory. According to this view, hippocampally dependent, episodic, or context-specific memories transform into semantic or gist-like versions that are represented in extra-hippocampal structures. To the extent that episodic memories are retained, they will continue to require the hippocampus, but the hippocampus is not needed for the retrieval of semantic memories. The transformation hypothesis emphasizes the dynamic nature of memory, as well as the underlying functional and neural interactions that must be taken into account in a comprehensive theory of memory.
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13
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Abnormal Cortical Network Activation in Human Amnesia: A High-resolution Evoked Potential Study. Brain Topogr 2009; 23:72-81. [DOI: 10.1007/s10548-009-0124-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Accepted: 11/23/2009] [Indexed: 11/25/2022]
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14
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Lah S, Miller L. Effects of Temporal Lobe Lesions on Retrograde Memory: A Critical Review. Neuropsychol Rev 2008; 18:24-52. [PMID: 18392939 DOI: 10.1007/s11065-008-9053-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2007] [Accepted: 11/26/2007] [Indexed: 10/22/2022]
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15
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Squire LR, Bayley PJ. The neuroscience of remote memory. Curr Opin Neurobiol 2007; 17:185-96. [PMID: 17336513 PMCID: PMC2277361 DOI: 10.1016/j.conb.2007.02.006] [Citation(s) in RCA: 231] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2006] [Accepted: 02/21/2007] [Indexed: 01/30/2023]
Abstract
Recently, there has been renewed interest in the organization and neurobiology of remote memory, and the pace of work in this area has accelerated. Yet the recent literature does not suggest that a consensus is developing, and there is disagreement about both facts and their interpretation. This article undertakes a comprehensive review of the three kinds of evidence that have been most prominent in recent discussion: studies of retrograde amnesia in memory-impaired patients who have well-characterized lesions, neuroimaging of healthy volunteers, and work with experimental animals including lesion studies, imaging and mouse genetics. The available evidence tells a coherent story and leads to some straightforward conclusions about the neuroscience of remote memory.
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Affiliation(s)
- Larry R Squire
- Veterans Affairs Medical Center 116A, 3550 La Jolla Village Drive, San Diego, CA 92161, USA.
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16
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Alexander JJ, Quigg RJ. Systemic lupus erythematosus and the brain: what mice are telling us. Neurochem Int 2006; 50:5-11. [PMID: 16989923 DOI: 10.1016/j.neuint.2006.08.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2006] [Revised: 07/26/2006] [Accepted: 08/22/2006] [Indexed: 01/18/2023]
Abstract
Neuropsychiatric symptoms occur in systemic lupus erythematosus (SLE), a complex, autoimmune disease of unknown origin. Although several pathogenic mechanisms have been suggested to play a significant role in the etiology of the disease, the exact underlying mechanisms still remain elusive. Several inbred strains of mice are used as models to study SLE, which exhibit a diversity of central nervous system (CNS) manifestations similar to that observed in patients. This review will attempt to give a brief overview of the CNS alterations observed in these models, including biochemical, structural and behavioral changes.
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Affiliation(s)
- Jessy J Alexander
- Department of Medicine, University of Chicago, 5841 South Maryland Avenue, MC5100, Chicago, IL 60637, United States.
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17
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Rekkas PV, Constable RT. Evidence that autobiographic memory retrieval does not become independent of the hippocampus: an fMRI study contrasting very recent with remote events. J Cogn Neurosci 2006; 17:1950-61. [PMID: 16475281 DOI: 10.1162/089892905775008652] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Traditional consolidation theory, which seeks to explain how new memories are incorporated into the preexisting neural architecture, stipulates that the hippocampus plays a time-limited role in this process. However, although there is abundant research showing that the hippocampus is necessary for the initial (encoding) phase, there is very little experimental evidence with human subjects proving that the structure ceases to play a role in the retrieval of episodic items from memory stores. To test this hypothesis, we investigated recall activation associated with recent memories (2.5 days) versus remote memories (mean of 8 years) using functional magnetic resonance imaging. In accordance with the multiple memory trace theory, recall of consolidated autobiographic information, represented by the remote condition, was not independent of the hippocampus. Both types of memory retrieval produced significant activation in parahippocampal, prefrontal, and midtemporal gyri, the parietal-temporal junction, and a medial region of cortex spanning the posterior cingulate and precuneus gyri. However, where recent events activated bilateral regions of the caudate nucleus, remote events yielded significantly greater activation within the hippocampus proper. The results challenge traditional consolidation theory, which would predict greater hippocampal activity for recent events. Furthermore, they highlight the interplay between multiple memory systems in the brain. We argue that our particular question format, which encouraged depth of recall and did not require a prescan interview, as well as our delineation of the recent and remote time periods, were the determining factors for the observed pattern of hippocampal activation.
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Affiliation(s)
- P V Rekkas
- Department of Diagnostic Radiology, Yale University School of Medicine, TAC MRRC N127, P.O. Box 208042, New Haven, CT 06520-8042, USA.
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18
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Steinvorth S, Levine B, Corkin S. Medial temporal lobe structures are needed to re-experience remote autobiographical memories: evidence from H.M. and W.R. Neuropsychologia 2005; 43:479-96. [PMID: 15716139 DOI: 10.1016/j.neuropsychologia.2005.01.001] [Citation(s) in RCA: 164] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2004] [Revised: 12/28/2004] [Accepted: 01/07/2005] [Indexed: 12/26/2022]
Abstract
The nature and extent of retrograde amnesia in patients with medial temporal lobe (MTL) lesions is currently under debate. While some investigators propose a temporally limited role for the MTL in episodic and semantic memory, others claim that MTL structures are needed for episodic memories of one's entire lifetime, and that only semantic memory becomes independent of the MTL. To address this issue, we tested two amnesic patients, H.M. and W.R., with bilateral MTL lesions on a series of remote memory tests that together distinguished episodic memory from semantic memory performance. Notably, we used a new method to assess autobiographical memory that measured the degree of re-experiencing of personal happenings from the past. Both patients showed relatively spared semantic memory, but severe impairment on measures of autobiographical memory, with no temporal gradient. Our data support the view that MTL structures play a significant role in recalling specific personal episodes, not only from the recent past but from the distant past as well.
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Affiliation(s)
- Sarah Steinvorth
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, NE20-392, Cambridge, MA 02139, USA.
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Tomita M, Khan RL, Blehm BH, Santoro TJ. The potential pathogenetic link between peripheral immune activation and the central innate immune response in neuropsychiatric systemic lupus erythematosus. Med Hypotheses 2004; 62:325-35. [PMID: 14975498 DOI: 10.1016/j.mehy.2003.10.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2003] [Accepted: 10/26/2003] [Indexed: 10/26/2022]
Abstract
Systemic lupus erythematosus (SLE) is an autoimmune disease of unknown etiology. Neuropsychiatric disturbances unexplained by drugs or by other untoward manifestations of disease are present in up to one-half of SLE patients and have profound economic and social impact. In patients with neuropsychiatric SLE, structural lesions have been identified in the hippocampus and proinflammatory cytokines have been detected in the cerebrospinal fluid. Similarly, murine models of lupus, such as MRL-lpr/lpr mice display behavioral disturbances which map to the hippocampus and exhibit overexpression of proinflammatory cytokine genes in hippocampal homogenates. Neuropsychiatric SLE typically occurs in the presence of serologically and clinically active lupus. In animal models of SLE, such as MRL-lpr/lpr, NZB, BXSB, and [NZB x NZW]F(1), uncontrolled autoreactivity in the periphery is accompanied by behavioral disturbances that are chronic and progressive. These observations suggest the hypothesis that central nervous system disease in SLE is driven by cross-talk between the peripheral immune system and the brain's innate immune system, which results in the inexorable activation of astrocytes, microglia, and/or neurons within the hippocampus. This leads to overproduction of brain cytokines, which induce the synthesis of pro-oxidant molecules, such as eicosanoids and reactive oxygen species, with resultant tissue injury. The cascade becomes self-perpetuating and eventuates in neuronal death, which is followed by impaired cognition. A better understanding of the molecular events that operate in the pathogenesis of neuropsychiatric SLE may provide the basis for a more rational therapeutic approach to this incompletely understood disease.
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Affiliation(s)
- Michiyo Tomita
- Department of Internal Medicine, University of North Dakota School of Medicine, 1919 North Elm Street, Fargo, ND 58102, USA.
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Ballok DA, Woulfe J, Sur M, Cyr M, Sakic B. Hippocampal damage in mouse and human forms of systemic autoimmune disease. Hippocampus 2004; 14:649-61. [PMID: 15301441 PMCID: PMC1764443 DOI: 10.1002/hipo.10205] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Systemic lupus erythematosus (SLE) is frequently accompanied by neuropsychiatric (NP) and cognitive deficits of unknown etiology. By using autoimmune MRL-lpr mice as an animal model of NP-SLE, we examine the relationship between autoimmunity, hippocampal damage, and behavioral dysfunction. Fluoro Jade B (FJB) staining and anti-ubiquitin (anti-Ub) immunocytochemistry were used to assess neuronal damage in young (asymptomatic) and aged (diseased) mice, while spontaneous alternation behavior (SAB) was used to estimate the severity of hippocampal dysfunction. The causal relationship between autoimmunity and neuropathology was tested by prolonged administration of the immunosuppressive drug cyclophosphamide (CY). In comparison to congenic MRL +/+ controls, SAB acquisition rates and performance in the "reversal" trial were impaired in diseased MRL-lpr mice, suggesting limited use of the spatial learning strategy. FJB-positive neurons and anti-Ub particles were frequent in the CA3 region. Conversely, CY treatment attenuated the SAB deficit and overall FJB staining. Similarly to mouse brain, the hippocampus from a patient who died from NP-SLE showed reduced neuronal density in the CA3 region and dentate gyrus, as well as increased FJB positivity in these regions. Gliosis and neuronal loss were observed in the gray matter, and T lymphocytes and stromal calcifications were common in the choroid plexus. Taken together, these results suggest that systemic autoimmunity induces significant hippocampal damage, which may underlie affective and cognitive deficits in NP-SLE.
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Affiliation(s)
- David A. Ballok
- Department of Psychiatry and Behavioral Neurosciences, Hamilton, Ontario, Canada
| | | | - Monalisa Sur
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Michael Cyr
- Pathology and Laboratory Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Boris Sakic
- Department of Psychiatry and Behavioral Neurosciences, Hamilton, Ontario, Canada
- Brain-Body Institute, St. Joseph’s Healthcare, Hamilton, Ontario, Canada
- *Correspondence to: Boris Sakic, Department of Psychiatry and Behavioral Neurosciences, HSC Rm 4N81, McMaster University, 1200 Main Street West, Hamilton, Ontario, Canada L8N 3Z5. E-mail:
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Bayley PJ, Hopkins RO, Squire LR. Successful recollection of remote autobiographical memories by amnesic patients with medial temporal lobe lesions. Neuron 2003; 38:135-44. [PMID: 12691671 DOI: 10.1016/s0896-6273(03)00156-9] [Citation(s) in RCA: 139] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Current views about the organization of human memory make strikingly different predictions about the integrity of remote autobiographical memory following damage to the medial temporal lobe. We have carried out a detailed analysis of narrative content in memory-impaired patients for whom neuropsychological and neuroanatomical information is available. All eight patients were able to recall detailed memories from their early lives. The recollections of the patients and the recollections of 25 matched controls contained the same number of details (+/-5%) and were also similar by several other measures. The results support the view that autobiographical memories eventually become independent of the medial temporal lobe as time passes after learning. A number of other considerations suggest that the neocortex ultimately supports the capacity for recollecting remote autobiographical memory.
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Affiliation(s)
- Peter J Bayley
- University of California, San Diego, La Jolla, California 92093, USA
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Tomita M, Holman BJ, Santoro TJ. Aberrant cytokine gene expression in the hippocampus in murine systemic lupus erythematosus. Neurosci Lett 2001; 302:129-32. [PMID: 11290404 DOI: 10.1016/s0304-3940(01)01679-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cytokines are important mediators of immune regulation and have been implicated in the pathogenesis of the neurological disturbances, which occur in up to sixty percent of patients with systemic lupus erythematosus (SLE). SLE is an autoimmune disease characterized by the presence of autoantibodies against nuclear antigens, including native DNA. Cytokines are thought to drive autoantibody production in lupus. Certain of the derangements in memory and learning described in human and experimental SLE map to the hippocampus. The current study examines the expression of cytokine genes in the hippocampus in lupus, using MRL-lpr/lpr mice as the experimental model. These mice spontaneously develop a SLE-like illness accompanied by disturbances in spatial learning. Our results suggest a potential role for proinflammatory cytokines in the cognitive aberrations observed in lupus.
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Affiliation(s)
- M Tomita
- Department of Medicine, Medical College of Ohio, Toledo, OH 43614, USA
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Abstract
The role of the hippocampus in retrograde amnesia remains controversial and poorly understood. Two cases are reported of discrete bilateral hippocampal damage, one of which was a rare case of limbic encephalitis secondary to the human herpes virus 6. Detailed memory testing showed marked anterograde memory impairment, but only mild, temporally-limited retrograde amnesia that covered a period of several years in both autobiographical and factual knowledge domains. The absence of extensive retrograde amnesia in these two cases points to a time-limited role for the hippocampus in the retrieval of retrograde memories, and suggests that entorhinal, perirhinal, parahippocampal, or neocortical areas of the temporal lobe may be more critical than the hippocampus proper for long-term retrograde memory functioning. Our findings offer general support to theories of memory consolidation that propose a gradual transfer of memory from hippocampal to neocortical dependency.
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Affiliation(s)
- N Kapur
- Wessex Neurological Centre, Southampton General Hospital, England.
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Moscovitch M, Nadel L. Consolidation and the hippocampal complex revisited: in defense of the multiple-trace model. Curr Opin Neurobiol 1998; 8:297-300. [PMID: 9635217 DOI: 10.1016/s0959-4388(98)80155-4] [Citation(s) in RCA: 146] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- M Moscovitch
- Department of Psychology, University of Toronto, Mississauga, Ontario, Canada.
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Schnider A, Gutbrod K, Hess CW, Schroth G. Memory without context: amnesia with confabulations after infarction of the right capsular genu. J Neurol Neurosurg Psychiatry 1996; 61:186-93. [PMID: 8708688 PMCID: PMC1073994 DOI: 10.1136/jnnp.61.2.186] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVE To explore the mechanism of an amnesia marked by confabulations and lack of insight in a patient with an infarct of the right inferior capsular genu. The confabulations could mostly be traced back to earlier events, indicating that the memory disorder ensued from an inability to store the temporal and spatial context of information acquisition rather than a failure to store new information. METHODS To test the patient's ability to store the context of information acquisition, two experiments were composed in which she was asked to decide when or where she had learned the words from two word lists presented at different points in time or in different rooms. To test her ability to store new information, two continuous recognition tests with novel non-words and nonsense designs were used. Recognition of these stimuli was assumed to be independent of the context of acquisition because the patient could not have an a priori sense of familiarity with them. RESULTS The patient performed at chance in the experiments probing knowledge of the context of information acquisition, although she recognised the presented words almost as well as the controls. By contrast, her performance was normal in the recognition tests with non-words and nonsense designs. CONCLUSION These findings indicate that the patient's amnesia was based on an inability to store the context of information acquisition rather than the information itself. Based on an analysis of her lesion, which disconnected the thalamus from the orbitofrontal cortex and the amygdala, and considering the similarities between her disorder, Wernicke-Korsakoff syndrome, and the amnesia after orbitofrontal lesions, it is proposed that contextual amnesia results from interruption of the loop connecting the amygdala, the dorsomedial nucleus, and the orbitofrontal cortex.
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Affiliation(s)
- A Schnider
- Department of Neurology, University Hospital, Bern, Switzerland
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