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Elward R, Limond J, Chareyron LJ, Ethapemi J, Vargha-Khadem F. Using recognition testing to support semantic learning in developmental amnesia. Neuropsychol Rehabil 2024; 34:1141-1160. [PMID: 37948582 PMCID: PMC11332405 DOI: 10.1080/09602011.2023.2275825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 10/16/2023] [Indexed: 11/12/2023]
Abstract
ABSTRACTPatients with developmental amnesia (DA) have suffered hippocampal damage in infancy and subsequently shown poor episodic memory, but good semantic memory. It is not clear how patients with DA learn semantic information in the presence of episodic amnesia. However, patients with DA show good recognition memory and it is possible that semantic learning may be supported by recognition. Building on previous work, we compared two methods for supporting semantic learning in DA; recognition-learning and recall-learning. In each condition, a patient with DA (aged 8 years) was presented with semantic information in animated videos. After each presentation of a video, learning was supported by an immediate memory test. Two videos were paired with a cued recall test. Another two videos were paired with a multiple-choice test to enable recognition-based learning. The outcome measure was semantic recall performance after a short delay of 30 min and a long delay of one week. Results showed a benefit of recognition-learning compared to recall-learning on cued recall in the patient with DA (76% vs. 35%). This finding indicates that young people with severe hippocampal damage can utilize recognition to support semantic learning. This has implications for the support of school-aged children with episodic memory difficulties.
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Affiliation(s)
- Rachael Elward
- Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Jennifer Limond
- Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Loïc J. Chareyron
- Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Janice Ethapemi
- Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Faraneh Vargha-Khadem
- Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London, UK
- Great Ormond Street Hospital for Children NHS Foundation Trust
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2
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Chareyron LJ, Chong WKK, Banks T, Burgess N, Saunders RC, Vargha-Khadem F. Anatomo-functional changes in neural substrates of cognitive memory in developmental amnesia: Insights from automated and manual MRI examinations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.01.23.525152. [PMID: 36789443 PMCID: PMC9928053 DOI: 10.1101/2023.01.23.525152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Despite bilateral hippocampal damage dating to perinatal or early-childhood period, and severely-impaired episodic memory that unfolds in later childhood, patients with developmental amnesia continue to exhibit well-developed semantic memory across the developmental trajectory. Detailed information on the extent and focality of brain damage in these patients is needed to hypothesize about the neural substrate that supports their remarkable capacity for encoding and retrieval of semantic memory. In particular, we need to assess whether the residual hippocampal tissue is involved in this preservation, or whether the surrounding cortical areas reorganise to rescue aspects of these critical cognitive memory processes after early injury. We used voxel-based morphometry (VBM) analysis, automatic (FreeSurfer) and manual segmentation to characterize structural changes in the brain of an exceptionally large cohort of 23 patients with developmental amnesia in comparison with 32 control subjects. Both the VBM and the FreeSurfer analyses revealed severe structural alterations in the hippocampus and thalamus of patients with developmental amnesia. Milder damage was found in the amygdala, caudate and parahippocampal gyrus. Manual segmentation demonstrated differences in the degree of atrophy of the hippocampal subregions in patients. The level of atrophy in CA-DG subregions and subicular complex was more than 40% while the atrophy of the uncus was moderate (-23%). Anatomo-functional correlations were observed between the volumes of residual hippocampal subregions in patients and selective aspects of their cognitive performance viz, intelligence, working memory, and verbal and visuospatial recall. Our findings suggest that in patients with developmental amnesia, cognitive processing is compromised as a function of the extent of atrophy in hippocampal subregions, such that the greater the damage, the more likely it is that surrounding cortical areas will be recruited to rescue the putative functions of the damaged subregions. Our findings document for the first time not only the extent, but also the limits of circuit reorganization occurring in the young brain after early bilateral hippocampal damage.
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Bevandić J, Chareyron LJ, Bachevalier J, Cacucci F, Genzel L, Newcombe NS, Vargha-Khadem F, Ólafsdóttir HF. Episodic memory development: Bridging animal and human research. Neuron 2024; 112:1060-1080. [PMID: 38359826 PMCID: PMC11129319 DOI: 10.1016/j.neuron.2024.01.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 12/22/2023] [Accepted: 01/19/2024] [Indexed: 02/17/2024]
Abstract
Human episodic memory is not functionally evident until about 2 years of age and continues to develop into the school years. Behavioral studies have elucidated this developmental timeline and its constituent processes. In tandem, lesion and neurophysiological studies in non-human primates and rodents have identified key neural substrates and circuit mechanisms that may underlie episodic memory development. Despite this progress, collaborative efforts between psychologists and neuroscientists remain limited, hindering progress. Here, we seek to bridge human and non-human episodic memory development research by offering a comparative review of studies using humans, non-human primates, and rodents. We highlight critical theoretical and methodological issues that limit cross-fertilization and propose a common research framework, adaptable to different species, that may facilitate cross-species research endeavors.
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Affiliation(s)
- Juraj Bevandić
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands
| | - Loïc J Chareyron
- Cognitive Neuroscience and Neuropsychiatry, Developmental Neurosciences, University College London Great Ormond Street Institute of Child Health, London, UK; Laboratory of Brain and Cognitive Development, Institute of Psychology, University of Lausanne, Lausanne, Switzerland
| | - Jocelyne Bachevalier
- Division of Developmental and Cognitive Neuroscience, Emory National Primate Research Center, Department of Psychology, Emory University, Atlanta, GA, USA.
| | - Francesca Cacucci
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK.
| | - Lisa Genzel
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands.
| | - Nora S Newcombe
- Department of Psychology, Temple University, Philadelphia, PA, USA.
| | - Faraneh Vargha-Khadem
- Cognitive Neuroscience and Neuropsychiatry, Developmental Neurosciences, University College London Great Ormond Street Institute of Child Health, London, UK.
| | - H Freyja Ólafsdóttir
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands.
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Villard J, Chareyron LJ, Piguet O, Lambercy P, Lonchampt G, Lavenex PB, Amaral DG, Lavenex P. Structural plasticity in the entorhinal and perirhinal cortices following hippocampal lesions in rhesus monkeys. Hippocampus 2023; 33:1094-1112. [PMID: 37337377 PMCID: PMC10543642 DOI: 10.1002/hipo.23567] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 05/19/2023] [Accepted: 06/02/2023] [Indexed: 06/21/2023]
Abstract
Immature neurons expressing the Bcl2 protein are present in various regions of the mammalian brain, including the amygdala and the entorhinal and perirhinal cortices. Their functional role is unknown but we have previously shown that neonatal and adult hippocampal lesions increase their differentiation in the monkey amygdala. Here, we assessed whether hippocampal lesions similarly affect immature neurons in the entorhinal and perirhinal cortices. Since Bcl2-positive cells were found mainly in areas Eo, Er, and Elr of the entorhinal cortex and in layer II of the perirhinal cortex, we also used Nissl-stained sections to determine the number and soma size of immature and mature neurons in layer III of area Er and layer II of area 36 of the perirhinal cortex. We found different structural changes in these regions following hippocampal lesions, which were influenced by the time of the lesion. In neonate-lesioned monkeys, the number of immature neurons in the entorhinal and perirhinal cortices was generally higher than in controls. The number of mature neurons was also higher in layer III of area Er of neonate-lesioned monkeys but no differences were found in layer II of area 36. In adult-lesioned monkeys, the number of immature neurons in the entorhinal cortex was lower than in controls but did not differ from controls in the perirhinal cortex. The number of mature neurons in layer III of area Er did not differ from controls, but the number of small, mature neurons in layer II of area 36 was lower than in controls. In sum, hippocampal lesions impacted populations of mature and immature neurons in discrete regions and layers of the entorhinal and perirhinal cortices, which are interconnected with the amygdala and provide major cortical inputs to the hippocampus. These structural changes may contribute to some functional recovery following hippocampal injury in an age-dependent manner.
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Affiliation(s)
- Justine Villard
- Laboratory of Brain and Cognitive Development, Institute of Psychology, University of Lausanne, Switzerland
| | - Loïc J. Chareyron
- Laboratory of Brain and Cognitive Development, Institute of Psychology, University of Lausanne, Switzerland
| | - Olivia Piguet
- Laboratory of Brain and Cognitive Development, Institute of Psychology, University of Lausanne, Switzerland
| | - Pauline Lambercy
- Laboratory of Brain and Cognitive Development, Institute of Psychology, University of Lausanne, Switzerland
| | - Gianni Lonchampt
- Laboratory of Brain and Cognitive Development, Institute of Psychology, University of Lausanne, Switzerland
| | - Pamela Banta Lavenex
- Laboratory of Brain and Cognitive Development, Institute of Psychology, University of Lausanne, Switzerland
- Faculty of Psychology, UniDistance Suisse, Switzerland
| | - David G. Amaral
- MIND Institute and Department of Psychiatry and Behavioral Sciences, University of California at Davis
- California National Primate Research Center, University of California at Davis
| | - Pierre Lavenex
- Laboratory of Brain and Cognitive Development, Institute of Psychology, University of Lausanne, Switzerland
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Leshinskaya A, Nguyen MA, Ranganath C. Integration of event experiences to build relational knowledge in the human brain. Cereb Cortex 2023; 33:9997-10012. [PMID: 37492008 DOI: 10.1093/cercor/bhad260] [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: 04/03/2023] [Revised: 06/22/2023] [Accepted: 06/23/2023] [Indexed: 07/27/2023] Open
Abstract
We investigated how the human brain integrates experiences of specific events to build general knowledge about typical event structure. We examined an episodic memory area important for temporal relations, anterior-lateral entorhinal cortex, and a semantic memory area important for action concepts, middle temporal gyrus, to understand how and when these areas contribute to these processes. Participants underwent functional magnetic resonance imaging while learning and recalling temporal relations among novel events over two sessions 1 week apart. Across distinct contexts, individual temporal relations among events could either be consistent or inconsistent with each other. Within each context, during the recall phase, we measured associative coding as the difference of multivoxel correlations among related vs unrelated pairs of events. Neural regions that form integrative representations should exhibit stronger associative coding in the consistent than the inconsistent contexts. We found evidence of integrative representations that emerged quickly in anterior-lateral entorhinal cortex (at session 1), and only subsequently in middle temporal gyrus, which showed a significant change across sessions. A complementary pattern of findings was seen with signatures during learning. This suggests that integrative representations are established early in anterior-lateral entorhinal cortex and may be a pathway to the later emergence of semantic knowledge in middle temporal gyrus.
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Affiliation(s)
- Anna Leshinskaya
- Center for Neuroscience, University of California, Davis, 1544 Newton Court, Davis, CA 95618, USA
| | - Mitchell A Nguyen
- Center for Neuroscience, University of California, Davis, 1544 Newton Court, Davis, CA 95618, USA
| | - Charan Ranganath
- Center for Neuroscience, University of California, Davis, 1544 Newton Court, Davis, CA 95618, USA
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Rouy M, Pereira M, Saliou P, Sanchez R, El Mardi W, Sebban H, Baqué E, Dezier C, Porte P, Micaux J, de Gardelle V, Mamassian P, Moulin CJA, Dondé C, Roux P, Faivre N. Confidence in visual detection, familiarity and recollection judgments is preserved in schizophrenia spectrum disorder. SCHIZOPHRENIA (HEIDELBERG, GERMANY) 2023; 9:55. [PMID: 37679358 PMCID: PMC10485068 DOI: 10.1038/s41537-023-00387-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 08/03/2023] [Indexed: 09/09/2023]
Abstract
An effective way to quantify metacognitive performance is to ask participants to estimate their confidence in the accuracy of their response during a cognitive task. A recent meta-analysis1 raised the issue that most assessments of metacognitive performance in schizophrenia spectrum disorders may be confounded with cognitive deficits, which are known to be present in this population. Therefore, it remains unclear whether the reported metacognitive deficits are metacognitive in nature or rather inherited from cognitive deficits. Arbitrating between these two possibilities requires equating task performance between experimental groups. Here, we aimed to characterize metacognitive performance among individuals with schizophrenia across three tasks (visual detection, familiarity, recollection) using a within-subject design while controlling experimentally for intra-individual task performance and statistically for between-subject task performance. In line with our hypotheses, we found no metacognitive deficit for visual detection and familiarity judgments. While we expected metacognition for recollection to be specifically impaired among individuals with schizophrenia, we found evidence in favor of an absence of a deficit in that domain also. We found no specific metacognitive deficit in schizophrenia spectrum disorder in the visual or memory domain. The clinical relevance of our findings is discussed in light of a hierarchical framework of metacognition.
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Affiliation(s)
- Martin Rouy
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, LPNC, 38000, Grenoble, France.
| | - Michael Pereira
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, LPNC, 38000, Grenoble, France
| | - Pauline Saliou
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, LPNC, 38000, Grenoble, France
| | - Rémi Sanchez
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, LPNC, 38000, Grenoble, France
| | - Wassila El Mardi
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, LPNC, 38000, Grenoble, France
| | - Hanna Sebban
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, LPNC, 38000, Grenoble, France
| | - Eugénie Baqué
- Centre Hospitalier de Versailles, Service Hospitalo-Universitaire de Psychiatrie d'Adultes et d'Addictologie, Le Chesnay; Université Paris-Saclay; Université de Versailles Saint-Quentin-En-Yvelines; DisAP-DevPsy-CESP, INSERM UMR1018, Villejuif, France
| | - Childéric Dezier
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, LPNC, 38000, Grenoble, France
| | - Perrine Porte
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, LPNC, 38000, Grenoble, France
| | - Julia Micaux
- Centre Hospitalier de Versailles, Service Hospitalo-Universitaire de Psychiatrie d'Adultes et d'Addictologie, Le Chesnay; Université Paris-Saclay; Université de Versailles Saint-Quentin-En-Yvelines; DisAP-DevPsy-CESP, INSERM UMR1018, Villejuif, France
| | - Vincent de Gardelle
- Centre d'Économie de la Sorbonne, CNRS and Paris School of Economics, Paris, France
| | - Pascal Mamassian
- Laboratoire des Systèmes Perceptifs, Département d'Études Cognitives, École Normale Supérieure, PSL University, CNRS, Paris, France
| | - Chris J A Moulin
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, LPNC, 38000, Grenoble, France
| | - Clément Dondé
- Univ. Grenoble Alpes, Inserm, U1216, Adult Psychiatry Department CHU Grenoble Alpes, Grenoble Institut Neurosciences, 38000, Grenoble, France
- Adult Psychiatry Department, CH Alpes-Isère, F-38000, Saint-Egrève, France
| | - Paul Roux
- Centre Hospitalier de Versailles, Service Hospitalo-Universitaire de Psychiatrie d'Adultes et d'Addictologie, Le Chesnay; Université Paris-Saclay; Université de Versailles Saint-Quentin-En-Yvelines; DisAP-DevPsy-CESP, INSERM UMR1018, Villejuif, France
| | - Nathan Faivre
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, LPNC, 38000, Grenoble, France
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Hannula DE, Minor GN, Slabbekoorn D. Conscious awareness and memory systems in the brain. WILEY INTERDISCIPLINARY REVIEWS. COGNITIVE SCIENCE 2023; 14:e1648. [PMID: 37012615 DOI: 10.1002/wcs.1648] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 01/06/2023] [Accepted: 03/05/2023] [Indexed: 04/05/2023]
Abstract
The term "memory" typically refers to conscious retrieval of events and experiences from our past, but experience can also change our behaviour without corresponding awareness of the learning process or the associated outcome. Based primarily on early neuropsychological work, theoretical perspectives have distinguished between conscious memory, said to depend critically on structures in the medial temporal lobe (MTL), and a collection of performance-based memories that do not. The most influential of these memory systems perspectives, the declarative memory theory, continues to be a mainstay of scientific work today despite mounting evidence suggesting that contributions of MTL structures go beyond the kinds or types of memory that can be explicitly reported. Consistent with these reports, more recent perspectives have focused increasingly on the processing operations supported by particular brain regions and the qualities or characteristics of resulting representations whether memory is expressed with or without awareness. These alternatives to the standard model generally converge on two key points. First, the hippocampus is critical for relational memory binding and representation even without awareness and, second, there may be little difference between some types of priming and explicit, familiarity-based recognition. Here, we examine the evolution of memory systems perspectives and critically evaluate scientific evidence that has challenged the status quo. Along the way, we highlight some of the challenges that researchers encounter in the context of this work, which can be contentious, and describe innovative methods that have been used to examine unconscious memory in the lab. This article is categorized under: Psychology > Memory Psychology > Theory and Methods Philosophy > Consciousness.
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Borzello M, Ramirez S, Treves A, Lee I, Scharfman H, Stark C, Knierim JJ, Rangel LM. Assessments of dentate gyrus function: discoveries and debates. Nat Rev Neurosci 2023; 24:502-517. [PMID: 37316588 PMCID: PMC10529488 DOI: 10.1038/s41583-023-00710-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/28/2023] [Indexed: 06/16/2023]
Abstract
There has been considerable speculation regarding the function of the dentate gyrus (DG) - a subregion of the mammalian hippocampus - in learning and memory. In this Perspective article, we compare leading theories of DG function. We note that these theories all critically rely on the generation of distinct patterns of activity in the region to signal differences between experiences and to reduce interference between memories. However, these theories are divided by the roles they attribute to the DG during learning and recall and by the contributions they ascribe to specific inputs or cell types within the DG. These differences influence the information that the DG is thought to impart to downstream structures. We work towards a holistic view of the role of DG in learning and memory by first developing three critical questions to foster a dialogue between the leading theories. We then evaluate the extent to which previous studies address our questions, highlight remaining areas of conflict, and suggest future experiments to bridge these theories.
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Affiliation(s)
- Mia Borzello
- Department of Cognitive Science, University of California, San Diego, La Jolla, CA, USA
| | - Steve Ramirez
- Department of Psychological and Brain Sciences, Boston University, Boston, MA, USA
| | | | - Inah Lee
- Department of Brain and Cognitive Sciences, Seoul National University, Seoul, South Korea
| | - Helen Scharfman
- Departments of Child and Adolescent Psychiatry, Neuroscience and Physiology and Psychiatry and the Neuroscience Institute, New York University Langone Health, New York, NY, USA
- The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, USA
| | - Craig Stark
- Department of Neurobiology and Behaviour, University of California, Irvine, Irvine, CA, USA
| | - James J Knierim
- Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD, USA
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA
| | - Lara M Rangel
- Department of Cognitive Science, University of California, San Diego, La Jolla, CA, USA.
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De Marco M, Bocchetta M, Venneri A. Item-Level Scores on the Boston Naming Test as an Independent Predictor of Perirhinal Volume in Individuals with Mild Cognitive Impairment. Brain Sci 2023; 13:806. [PMID: 37239278 PMCID: PMC10216160 DOI: 10.3390/brainsci13050806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 04/17/2023] [Accepted: 05/10/2023] [Indexed: 05/28/2023] Open
Abstract
We explored the methodological value of an item-level scoring procedure applied to the Boston Naming Test (BNT), and the extent to which this scoring approach predicts grey matter (GM) variability in regions that sustain semantic memory. Twenty-seven BNT items administered as part of the Alzheimer's Disease Neuroimaging Initiative were scored according to their "sensorimotor interaction" (SMI) value. Quantitative scores (i.e., the count of correctly named items) and qualitative scores (i.e., the average of SMI scores for correctly named items) were used as independent predictors of neuroanatomical GM maps in two sub-cohorts of 197 healthy adults and 350 mild cognitive impairment (MCI) participants. Quantitative scores predicted clusters of temporal and mediotemporal GM in both sub-cohorts. After accounting for quantitative scores, the qualitative scores predicted mediotemporal GM clusters in the MCI sub-cohort; clusters extended to the anterior parahippocampal gyrus and encompassed the perirhinal cortex. This was confirmed by a significant yet modest association between qualitative scores and region-of-interest-informed perirhinal volumes extracted post hoc. Item-level scoring of BNT performance provides complementary information to standard quantitative scores. The concurrent use of quantitative and qualitative scores may help profile lexical-semantic access more precisely, and might help detect changes in semantic memory that are typical of early-stage Alzheimer's disease.
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Affiliation(s)
- Matteo De Marco
- Centre for Cognitive and Clinical Neuroscience, Division of Psychology, Department of Life Sciences, College of Health, Medicine and Life Sciences, Brunel University London, London UB8 3PH, UK; (M.D.M.); (M.B.)
| | - Martina Bocchetta
- Centre for Cognitive and Clinical Neuroscience, Division of Psychology, Department of Life Sciences, College of Health, Medicine and Life Sciences, Brunel University London, London UB8 3PH, UK; (M.D.M.); (M.B.)
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London WC1E 6BT, UK
| | - Annalena Venneri
- Centre for Cognitive and Clinical Neuroscience, Division of Psychology, Department of Life Sciences, College of Health, Medicine and Life Sciences, Brunel University London, London UB8 3PH, UK; (M.D.M.); (M.B.)
- Department of Medicine and Surgery, University of Parma, 43125 Parma, Italy
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How May a Brief Seizure Lead to Prolonged Epileptic Amnesia? Brain Topogr 2023; 36:129-134. [PMID: 36624220 DOI: 10.1007/s10548-022-00930-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 11/27/2022] [Indexed: 01/11/2023]
Abstract
Pure amnestic seizures are defined as self-limited episodes with isolated, anterograde memory loss and have been attributed to bilateral dysfunction of mesial temporal structures. This type of seizure can occur in patients with different forms of temporal lobe epilepsy and has been more recently associated with a late-onset epileptic syndrome, called transient epileptic amnesia (TEA). The mechanisms of such prolonged manifestations are not well known and notably its ictal or post-ictal origin remains poorly understood. We report a case of prolonged anterograde amnesia (lasting several hours) following a brief seizure induced by stimulation of the left entorhinal cortex, recorded during stereo-EEG (SEEG). This episode was associated with prolonged changes in the intracerebral EEG signal complexity (entropy) within bilateral mesial temporal structures, particularly the entorhinal cortices, with a progressive normalization paralleling the clinical recovery. Our case shows that long-lasting (hours) memory impairment may follow brief seizure that led to prolonged electrophysiological signals alterations in bilateral mesial temporal structures.
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11
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Almeida VN, Radanovic M. Semantic processing and neurobiology in Alzheimer's disease and Mild Cognitive Impairment. Neuropsychologia 2022; 174:108337. [DOI: 10.1016/j.neuropsychologia.2022.108337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 07/17/2022] [Accepted: 07/17/2022] [Indexed: 11/28/2022]
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Waisman A, Pavlova M, Noel M, Katz J. Painful Reminders: Involvement of the Autobiographical Memory System in Pediatric Postsurgical Pain and the Transition to Chronicity. Can J Pain 2022; 6:121-141. [PMID: 35692557 PMCID: PMC9176239 DOI: 10.1080/24740527.2022.2058474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Affiliation(s)
- Anna Waisman
- Department of Psychology, York University, Toronto, ON, Canada
| | - Maria Pavlova
- Department of Psychology, University of Calgary, Calgary, AB, Canada
| | - Melanie Noel
- Department of Psychology, University of Calgary, Calgary, AB, Canada
- Alberta Children’s Hospital Research Institute, Calgary, AB, Canada
- Hotchkiss Brain Institute, Calgary, AB, Canada
| | - Joel Katz
- Department of Psychology, York University, Toronto, ON, Canada
- Department of Anesthesia and Pain Management, Toronto General Hospital, Toronto, ON, Canada
- Department of Anesthesiology and Pain Medicine, University of Toronto, ON, Canada
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13
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De Marco M, Venneri A. Serial Recall Order of Category Fluency Words: Exploring Its Neural Underpinnings. Front Psychol 2022; 12:777838. [PMID: 35069359 PMCID: PMC8773965 DOI: 10.3389/fpsyg.2021.777838] [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: 09/15/2021] [Accepted: 12/01/2021] [Indexed: 11/26/2022] Open
Abstract
Background: Although performance on the category fluency test (CFT) is influenced by many cognitive functions (i.e., including language, executive functioning and speed of processing), item-level scoring methods of CFT performance might be a promising way to capture aspects of semantic memory that are less influenced by intervenient abilities. One such approach is based on the calculation of correlation coefficients that quantify the association between item-level features and the serial order with which words are recalled (SRO). Methods: We explored the neural underpinnings of 10 of these correlational indices in a sample of 40 healthy adults who completed a classic 1-min CFT and an MRI protocol inclusive of T1-weighted (analysed with voxel-based morphometry) and resting-state fMRI sequences for the evaluation of the default-mode network (DMN). Two sets of linear models were defined to test the association between neural maps and each correlational index: a first set in which major demographic and clinical descriptors were controlled for and a second set in which, additionally, all other 9 correlational indices were regressed out. Results: In the analysis of the DMN, ‘SRO-frequency’, ‘SRO-dominance’ and ‘SRO-body-object interaction’ correlational indices were all negatively associated with the anterior portion of the right temporoparietal junction. The ‘SRO-frequency’ correlational index was also negatively associated with the right dorsal anterior cingulate and the ‘SRO-dominance’ correlational index with the right lateral prefrontal cortex. From the second set of models, the ‘SRO-typicality’ correlational index was positively associated with the left entorhinal cortex. No association was found in relation to grey matter maps. Conclusion: The ability to retrieve more difficult words during CFT performance as measured by the correlational indices between SRO and item-level descriptors is associated with DMN expression in regions deputed to attentional reorienting and processing of salience of infrequent stimuli and dominance status. Of all item-level features, typicality appears to be that most closely linked with entorhinal functioning and may thus play a relevant role in assessing its value in testing procedures for early detection of subtle cognitive difficulties in people with suspected Alzheimer’s degeneration. Although exploratory, these findings warrant further investigations in larger cohorts.
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Affiliation(s)
- Matteo De Marco
- Department of Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Annalena Venneri
- Department of Life Sciences, Brunel University London, Uxbridge, United Kingdom
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14
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Puteikis K, Wolf P, Mameniškienė R. Accelerated long-term forgetting in adult patients with genetic generalized epilepsy. Epilepsia 2021; 63:474-482. [PMID: 34893974 DOI: 10.1111/epi.17144] [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: 09/14/2021] [Revised: 11/24/2021] [Accepted: 11/29/2021] [Indexed: 10/19/2022]
Abstract
OBJECTIVE Accelerated long-term forgetting (ALF) has been demonstrated among children but not adults with genetic generalized epilepsy (GGE). We investigated (1) how forgetting patterns of verbal and visuospatial material differ between patients with GGE and healthy controls (HCs) and (2) whether ALF is associated with ictal or interictal epileptic activity. METHODS Forty-two patients with GGE (39, 92.9% experiencing seizures) were compared to 57 HCs in word, logical story, and Rey-Osterrieth complex figure recall tasks by testing after intervals of 30 min and 4 weeks. Ambulatory electroencephalography (EEG) was performed before testing to detect generalized epileptic activity, and patients were asked to document the number of seizures during the 4-week interval. RESULTS A two-way repeated measures ANOVA indicated that individuals with GGE have different forgetting patterns in comparison to HCs in tasks of word (delay by group interaction F1.5, 142.5 = 4.5, p = .02, η p 2 = .04) and figure (F2, 194 = 15.9, p < .001, η p 2 = .14) but not story (F1.6 151.1 = .5, p = .58, η p 2 = .005) recall. Last learning trial-adjusted scores of word recall were comparable between HCs and patients with epilepsy (PWEs) at 30 min (p = .21) but not at 4 weeks (p = .006). Individuals with GGE performed worse than HCs in figure recall at 30 min and 4 weeks (p < .001), with lower performance after the 4-week interval present only among seizure-positive and EEG-positive individuals (p < .001) during subgroup analysis. Performance on memory tests was unrelated to overall seizure frequency, the number of antiseizure drugs used, and epilepsy duration. SIGNIFICANCE Our study supports the presence of ALF in a task of word recall among adult patients with GGE. The pattern of forgetting visuospatial information suggests greater forgetting of material before the first delay and ongoing deficits among PWEs with epileptic activity. Future studies should confirm our findings and investigate the functional or pathological mechanisms of memory dysfunction in GGE.
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Affiliation(s)
| | - Peter Wolf
- Center for Neurology, Vilnius University, Vilnius, Lithuania.,Danish Epilepsy Center Filadelfia, Dianalund, Denmark.,Postgraduation Program of Medical Sciences, Santa Catarina Federal University, Florianópolis, Brazil
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15
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Finnie PSB, Komorowski RW, Bear MF. The spatiotemporal organization of experience dictates hippocampal involvement in primary visual cortical plasticity. Curr Biol 2021; 31:3996-4008.e6. [PMID: 34314678 PMCID: PMC8524775 DOI: 10.1016/j.cub.2021.06.079] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/26/2021] [Accepted: 06/25/2021] [Indexed: 11/18/2022]
Abstract
The hippocampus and neocortex are theorized to be crucial partners in the formation of long-term memories. Here, we assess hippocampal involvement in two related forms of experience-dependent plasticity in the primary visual cortex (V1) of mice. Like control animals, those with hippocampal lesions exhibit potentiation of visually evoked potentials after passive daily exposure to a phase-reversing oriented grating stimulus, which is accompanied by long-term habituation of a reflexive behavioral response. Thus, low-level recognition memory is formed independently of the hippocampus. However, response potentiation resulting from daily exposure to a fixed sequence of four oriented gratings is severely impaired in mice with hippocampal damage. A feature of sequence plasticity in V1 of controls, which is absent in lesioned mice, is the generation of predictive responses to an anticipated stimulus element when it is withheld or delayed. Thus, the hippocampus is involved in encoding temporally structured experience, even within the primary sensory cortex.
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Affiliation(s)
- Peter S B Finnie
- Massachusetts Institute of Technology, The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Robert W Komorowski
- Massachusetts Institute of Technology, The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Mark F Bear
- Massachusetts Institute of Technology, The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Avenue, Cambridge, MA 02139, USA.
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16
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Elward RL, Rugg MD, Vargha-Khadem F. When the brain, but not the person, remembers: Cortical reinstatement is modulated by retrieval goal in developmental amnesia. Neuropsychologia 2021; 154:107788. [PMID: 33587931 PMCID: PMC7967023 DOI: 10.1016/j.neuropsychologia.2021.107788] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 01/18/2021] [Accepted: 02/08/2021] [Indexed: 11/16/2022]
Abstract
Developmental amnesia (DA) is associated with early hippocampal damage and subsequent episodic amnesia emerging in childhood alongside age-appropriate development of semantic knowledge. We employed fMRI to assess whether patients with DA show evidence of 'cortical reinstatement', a neural correlate of episodic memory, despite their amnesia. At study, 23 participants (5 patients) were presented with words overlaid on a scene or a scrambled image for later recognition. Scene reinstatement was indexed by scene memory effects (greater activity for previously presented words paired with a scene rather than scrambled images) that overlapped with scene perception effects. Patients with DA demonstrated scene reinstatement effects in the parahippocampal and retrosplenial cortex that were equivalent to those shown by healthy controls. Behaviourally, however, patients with DA showed markedly impaired scene memory. The data indicate that reinstatement can occur despite hippocampal damage, but that cortical reinstatement is insufficient to support accurate memory performance. Furthermore, scene reinstatement effects were diminished during a retrieval task in which scene information was not relevant for accurate responding, indicating that strategic mnemonic processes operate normally in DA. The data suggest that cortical reinstatement of trial-specific contextual information is decoupled from the experience of recollection in the presence of severe hippocampal atrophy.
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Affiliation(s)
- Rachael L Elward
- UCL Great Ormond Street Institute for Child Health, London, UK; London South Bank University, London, UK
| | - Michael D Rugg
- Center for Vital Longevity and School of Behavioral and Brain Sciences, University of Texas at Dallas, USA; School of Psychology, University of East Anglia, UK
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17
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Vargha-Khadem F, Cacucci F. A brief history of developmental amnesia. Neuropsychologia 2020; 150:107689. [PMID: 33253689 DOI: 10.1016/j.neuropsychologia.2020.107689] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 11/17/2020] [Indexed: 10/22/2022]
Affiliation(s)
- Faraneh Vargha-Khadem
- Centre for Developmental Cognitive Neuroscience, UCL Great Ormond Street Institute of Child Health, London, UK; Great Ormond Street Hospital for Children National Health Service Foundation Trust, London, UK.
| | - Francesca Cacucci
- Centre for Developmental Cognitive Neuroscience, UCL Great Ormond Street Institute of Child Health, London, UK; Dept. of Neuroscience, Physiology and Pharmacology, UCL, London, UK
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18
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Wicks RT, Witcher MR, Couture DE, Laxton AW, Popli G, Whitlow CT, Fetterhoff D, Dakos AS, Roeder BM, Deadwyler SA, Hampson RE. Hippocampal CA1 and CA3 neural recording in the human brain: validation of depth electrode placement through high-resolution imaging and electrophysiology. Neurosurg Focus 2020; 49:E5. [PMID: 32610296 DOI: 10.3171/2020.4.focus20164] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 04/16/2020] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Intracranial human brain recordings typically utilize recording systems that do not distinguish individual neuron action potentials. In such cases, individual neurons are not identified by location within functional circuits. In this paper, verified localization of singly recorded hippocampal neurons within the CA3 and CA1 cell fields is demonstrated. METHODS Macro-micro depth electrodes were implanted in 23 human patients undergoing invasive monitoring for identification of epileptic seizure foci. Individual neurons were isolated and identified via extracellular action potential waveforms recorded via macro-micro depth electrodes localized within the hippocampus. A morphometric survey was performed using 3T MRI scans of hippocampi from the 23 implanted patients, as well as 46 normal (i.e., nonepileptic) patients and 26 patients with a history of epilepsy but no history of depth electrode placement, which provided average dimensions of the hippocampus along typical implantation tracks. Localization within CA3 and CA1 cell fields was tentatively assigned on the basis of recording electrode site, stereotactic positioning of the depth electrode in comparison with the morphometric survey, and postsurgical MRI. Cells were selected as candidate CA3 and CA1 principal neurons on the basis of waveform and firing rate characteristics and confirmed within the CA3-to-CA1 neural projection pathways via measures of functional connectivity. RESULTS Cross-correlation analysis confirmed that nearly 80% of putative CA3-to-CA1 cell pairs exhibited positive correlations compatible with feed-forward connection between the cells, while only 2.6% exhibited feedback (inverse) connectivity. Even though synchronous and long-latency correlations were excluded, feed-forward correlation between CA3-CA1 pairs was identified in 1071 (26%) of 4070 total pairs, which favorably compares to reports of 20%-25% feed-forward CA3-CA1 correlation noted in published animal studies. CONCLUSIONS This study demonstrates the ability to record neurons in vivo from specified regions and subfields of the human brain. As brain-machine interface and neural prosthetic research continues to expand, it is necessary to be able to identify recording and stimulation sites within neural circuits of interest.
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Affiliation(s)
| | | | | | | | | | | | - Dustin Fetterhoff
- 6Program in Neuroscience, Wake Forest Baptist Medical Center, Winston-Salem, North Carolina
| | - Alexander S Dakos
- 6Program in Neuroscience, Wake Forest Baptist Medical Center, Winston-Salem, North Carolina
| | - Brent M Roeder
- 6Program in Neuroscience, Wake Forest Baptist Medical Center, Winston-Salem, North Carolina
| | - Sam A Deadwyler
- 5Physiology and Pharmacology, and.,6Program in Neuroscience, Wake Forest Baptist Medical Center, Winston-Salem, North Carolina
| | - Robert E Hampson
- 2Neurology.,5Physiology and Pharmacology, and.,6Program in Neuroscience, Wake Forest Baptist Medical Center, Winston-Salem, North Carolina
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19
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LeDoux JE, Michel M, Lau H. A little history goes a long way toward understanding why we study consciousness the way we do today. Proc Natl Acad Sci U S A 2020; 117:6976-6984. [PMID: 32170012 PMCID: PMC7132279 DOI: 10.1073/pnas.1921623117] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Consciousness is currently a thriving area of research in psychology and neuroscience. While this is often attributed to events that took place in the early 1990s, consciousness studies today are a continuation of research that started in the late 19th century and that continued throughout the 20th century. From the beginning, the effort built on studies of animals to reveal basic principles of brain organization and function, and of human patients to gain clues about consciousness itself. Particularly important and our focus here is research in the 1950s, 1960s, and 1970s involving three groups of patients-amnesia, split brain, and blindsight. Across all three groups, a similar pattern of results was found-the patients could respond appropriately to stimuli that they denied seeing (or in the case of amnesiacs, having seen before). These studies paved the way for the current wave of research on consciousness. The field is, in fact, still grappling with the implications of the findings showing that the ability to consciously know and report the identity of a visual stimulus can be dissociated in the brain from the mechanisms that underlie the ability to behave in a meaningful way to the same stimulus.
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Affiliation(s)
- Joseph E LeDoux
- Center for Neural Science, New York University, New York, NY 10003;
- Department of Psychology, New York University, New York, NY 10003
- Department of Psychiatry, New York University Langone Medical School, New York, NY 10003
- Department of Child and Adolescent Psychiatry, New York University Langone Medical School, New York, NY 10003
- Emotional Brain Institute, Nathan Kline Institute, Orangeburg, NY 10962
| | - Matthias Michel
- Consciousness, Cognition & Computation Group, Université Libre de Bruxelles, B1050 Bruxelles, Belgium
- Center for Mind, Brain and Consciousness, New York University, New York, NY 10003
| | - Hakwan Lau
- Department of Psychology, University of California, Los Angeles, CA 90095
- Brain Research Institute, University of California, Los Angeles, CA 90095
- Department of Psychology, University of Hong Kong, Hong Kong
- State Key Laboratory of Brain and Cognitive Sciences, University of Hong Kong, Hong Kong
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20
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Abstract
I present the case for viewing human memory as a set of dynamic processes rather than as structural entities or memory stores. This perspective stems largely from the construct of levels of processing, reflecting work I published with Robert Lockhart and with Endel Tulving. I describe the personal and professional contexts in which these and other ideas evolved, and I discuss criticisms of the ideas and our responses to critics. I also show how later versions of a processing approach to memory may fit with current findings and theories in memory research. In related work I have been involved in studies of cognitive aging, and I describe some theoretical and empirical points deriving from this aspect of my research efforts. Finally, I deal briefly with some experiments and reflections on divided attention, consolidation, and bilingualism and touch upon the neural bases of a processing approach.
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Affiliation(s)
- Fergus I.M. Craik
- Rotman Research Institute at Baycrest, Toronto, Ontario M6A 2E1, Canada
- Department of Psychology, University of Toronto, Toronto, Ontario M5S 3G3, Canada
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21
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The Counteracting Effects of Exercise on High-Fat Diet-Induced Memory Impairment: A Systematic Review. Brain Sci 2019; 9:brainsci9060145. [PMID: 31226771 PMCID: PMC6627483 DOI: 10.3390/brainsci9060145] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 06/17/2019] [Accepted: 06/18/2019] [Indexed: 12/15/2022] Open
Abstract
The objective of the present review was to evaluate whether exercise can counteract a potential high-fat diet-induced memory impairment effect. The evaluated databases included: Google Scholar, Sports Discus, Embase/PubMed, Web of Science, and PsychInfo. Studies were included if: (1) an experimental/intervention study was conducted, (2) the experiment/intervention included both a high-fat diet and exercise group, and evaluated whether exercise could counteract the negative effects of a high-fat diet on memory, and (3) evaluated memory function (any type) as the outcome measure. In total, 17 articles met the inclusionary criteria. All 17 studies (conducted in rodents) demonstrated that the high-fat diet protocol impaired memory function and all 17 studies demonstrated a counteracting effect with chronic exercise engagement. Mechanisms of these robust effects are discussed herein.
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22
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Annink KV, de Vries LS, Groenendaal F, van den Heuvel MP, van Haren NEM, Swaab H, van Handel M, Jongmans MJ, Benders MJ, van der Aa NE. The long-term effect of perinatal asphyxia on hippocampal volumes. Pediatr Res 2019; 85:43-49. [PMID: 30254237 DOI: 10.1038/s41390-018-0115-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 06/20/2018] [Accepted: 06/22/2018] [Indexed: 01/25/2023]
Abstract
BACKGROUND Hypoxic-ischemic encephalopathy (HIE) in term-born infants can lead to memory problems. The hippocampus is important for long-term episodic memory. The primary aim was to investigate the effect of HIE on hippocampal volumes in 9- to 10-year-old children. The secondary aim was to investigate the association between hippocampal volumes and previously found impaired memory and cognitive functions in the current cohort. METHODS In total 26 children with mild HIE, 26 with moderate HIE, and 37 controls were included. The intelligence quotient (IQ) and memory were tested. A 3D-volumetric MRI was obtained. Brain segmentation was performed for hippocampal volumes and intracranial volume. The differences in hippocampal volumes, memory, and IQ between the groups were determined. Multivariable linear regression analyses were performed, including hippocampal volume as a percentage of intracranial volume as a dependent variable. RESULTS Smaller hippocampal volumes were found in moderate HIE (p < 0.001), with a trend toward smaller volumes in mild HIE, compared to controls. In multivariable linear regression analysis, hippocampal volume as a percentage of intracranial volume was significantly associated with long-term visuospatial memory. CONCLUSION Children with moderate HIE had smaller hippocampal volumes than controls, with a trend toward smaller volumes following mild HIE. Reduced hippocampal volumes were associated with poorer long-term visuospatial memory.
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Affiliation(s)
- Kim V Annink
- Department of Neonatology, Brain Center Rudolf Magnus, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Linda S de Vries
- Department of Neonatology, Brain Center Rudolf Magnus, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Floris Groenendaal
- Department of Neonatology, Brain Center Rudolf Magnus, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Martijn P van den Heuvel
- Connectome Lab, Department of Complex Traits Genetics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.,Department of Clinical Genetics, VU Medical Center, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Neeltje E M van Haren
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Hanna Swaab
- Department of Clinical Child and Adolescent studies, University Leiden, Leiden, The Netherlands
| | - Mariëlle van Handel
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Marian J Jongmans
- Department of Neonatology, Brain Center Rudolf Magnus, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands.,Department of Education & Pedagogy, Utrecht University, Utrecht, The Netherlands
| | - Manon J Benders
- Department of Neonatology, Brain Center Rudolf Magnus, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Niek E van der Aa
- Department of Neonatology, Brain Center Rudolf Magnus, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands.
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23
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Y-Shaped Maze to Test Spontaneous Object Recognition and Temporal Order Memory After Traumatic Brain Injury. Methods Mol Biol 2019; 2011:383-392. [PMID: 31273711 DOI: 10.1007/978-1-4939-9554-7_22] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Traumatic brain injury (TBI) is one of the most frequent causes of brain damage. Cognitive deficits have been reported in the literature after mild-to-severe TBI affecting memory, language, executive functions, attention, and information processing speed. In this chapter, we describe a method to characterize cognitive impairment in rats following TBI of various intensities. The focus will be on spontaneous object recognition and temporal order memory in rats. These tests are performed in a Y-shaped maze. We have previously identified using this method persistent spontaneous object recognition and temporal order memory deficits following mild-to-moderate TBI in the animals up to 35-day postinjury.
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24
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Lah S, Gott C, Epps A, Parry L. Imagining the Future in Children with Severe Traumatic Brain Injury. J Neurotrauma 2018; 35:2036-2043. [DOI: 10.1089/neu.2017.5250] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Affiliation(s)
- Suncica Lah
- School of Psychology, The University of Sydney, Sydney, New South Wales, Australia
- ARC Center of Excellence in Cognition and its Disorders, Sydney, New South Wales, Australia
| | - Chloe Gott
- School of Psychology, The University of Sydney, Sydney, New South Wales, Australia
| | - Adrienne Epps
- Brain Injury Rehabilitation Program, Rehab2Kids, Sydney Children's Hospital, Randwick, Randwick, New South Wales, Australia
| | - Louise Parry
- Brain Injury Rehabilitation Program, Rehab2Kids, Sydney Children's Hospital, Randwick, Randwick, New South Wales, Australia
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25
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Reagh ZM, Ranganath C. What does the functional organization of cortico-hippocampal networks tell us about the functional organization of memory? Neurosci Lett 2018; 680:69-76. [PMID: 29704572 PMCID: PMC6467646 DOI: 10.1016/j.neulet.2018.04.050] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Revised: 04/23/2018] [Accepted: 04/24/2018] [Indexed: 12/12/2022]
Abstract
Historically, research on the cognitive processes that support human memory proceeded, to a large extent, independently of research on the neural basis of memory. Accumulating evidence from neuroimaging, however, has enabled the field to develop a broader and more integrative perspective. Here, we briefly outline how advances in cognitive neuroscience can potentially shed light on concepts and controversies in human memory research. We argue that research on the functional properties of cortico-hippocampal networks informs us about how memories might be organized in the brain, which, in turn, helps to reconcile seemingly disparate perspectives in cognitive psychology. Finally, we discuss several open questions and directions for future research.
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Affiliation(s)
- Zachariah M Reagh
- Center for Neuroscience, United States; Department of Neurology, University of California, Davis, United States.
| | - Charan Ranganath
- Center for Neuroscience, United States; Memory and Plasticity (MAP) Program, United States; Department of Psychology, University of California, Davis, United States.
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26
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Venneri A, Jahn-Carta C, de Marco M, Quaranta D, Marra C. Diagnostic and prognostic role of semantic processing in preclinical Alzheimer's disease. Biomark Med 2018; 12:637-651. [PMID: 29896968 DOI: 10.2217/bmm-2017-0324] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Relatively spared during most of the timeline of normal aging, semantic memory shows a subtle yet measurable decline even during the pre-clinical stage of Alzheimer's disease. This decline is thought to reflect early neurofibrillary changes and impairment is detectable using tests of language relying on lexical-semantic abilities. A promising approach is the characterization of semantic parameters such as typicality and age of acquisition of words, and propositional density from verbal output. Seminal research like the Nun Study or the analysis of the linguistic decline of famous writers and politicians later diagnosed with Alzheimer's disease supports the early diagnostic value of semantic processing and semantic memory. Moreover, measures of these skills may play an important role for the prognosis of patients with mild cognitive impairment.
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Affiliation(s)
- Annalena Venneri
- Department of Neuroscience, University of Sheffield, Sheffield, UK
| | | | - Matteo de Marco
- Department of Neuroscience, University of Sheffield, Sheffield, UK
| | - Davide Quaranta
- Neurology Unit, Fondazione Policlinico Universitario 'A Gemelli', Rome, Italy
| | - Camillo Marra
- Institute of Neurology, Università Cattolica del Sacro Cuore, Rome; Memory Clinic, Fondazione Policlinico Universitario 'A Gemelli', Rome, Italy
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27
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Grot S, Leclerc ME, Luck D. Examining the neural correlates of active and passive forms of verbal-spatial binding in working memory. Biol Psychol 2018; 136:67-75. [PMID: 29802860 DOI: 10.1016/j.biopsycho.2018.05.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 03/15/2018] [Accepted: 05/17/2018] [Indexed: 11/29/2022]
Abstract
We designed an fMRI study to pinpoint the neural correlates of active and passive binding in working memory. Participants were instructed to memorize three words and three spatial locations. In the passive binding condition, words and spatial locations were directly presented as bound. Conversely, in the active binding condition, words and spatial locations were presented as separated, and participants were directed to intentionally create associations between them. Our results showed that participants performed better on passive binding relative to active binding. FMRI analysis revealed that both binding conditions induced greater activity within the hippocampus. Additionally, our analyses divulged regions specifically engaged in passive and active binding. Altogether, these data allow us to propose the hippocampus as a central candidate for working memory binding. When needed, a frontal-parietal network can contribute to the rearrangement of information. These findings may inform theories of working memory binding.
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Affiliation(s)
- Stéphanie Grot
- Centre de recherche, Institut universitaire en santé mentale de Montréal, Montreal, Canada; Department of Psychiatry, Faculty of Medicine, Université de Montréal, Montreal, Canada
| | - Marie-Eve Leclerc
- Centre de recherche, Institut universitaire en santé mentale de Montréal, Montreal, Canada; Department of Psychiatry, Faculty of Medicine, Université de Montréal, Montreal, Canada
| | - David Luck
- Centre de recherche, Institut universitaire en santé mentale de Montréal, Montreal, Canada; Department of Psychiatry, Faculty of Medicine, Université de Montréal, Montreal, Canada.
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28
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Elward RL, Vargha-Khadem F. Semantic memory in developmental amnesia. Neurosci Lett 2018; 680:23-30. [PMID: 29715544 PMCID: PMC6086936 DOI: 10.1016/j.neulet.2018.04.040] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 04/07/2018] [Accepted: 04/21/2018] [Indexed: 11/23/2022]
Abstract
Profile of patients with developmental amnesia and dissociations in cognitive memory. Variables affecting semantic learning in developmental amnesia. Differences between adult-onset versus early-onset amnesia.
Patients with developmental amnesia resulting from bilateral hippocampal atrophy associated with neonatal hypoxia-ischaemia typically show relatively preserved semantic memory and factual knowledge about the natural world despite severe impairments in episodic memory. Understanding the neural and mnemonic processes that enable this context-free semantic knowledge to be acquired throughout development without the support of the contextualised episodic memory system is a serious challenge. This review describes the clinical presentation of patients with developmental amnesia, contrasts its features with those reported for adult-onset hippocampal amnesia, and analyses the effects of variables that influence the learning of new semantic information.
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Affiliation(s)
- Rachael L Elward
- Cognitive Neuroscience & Neuropsychiatry Section, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, United Kingdom
| | - Faraneh Vargha-Khadem
- Cognitive Neuroscience & Neuropsychiatry Section, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, United Kingdom.
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Lee ACH, Barense MD, Graham KS. The Contribution of the Human Medial Temporal Lobe to Perception: Bridging the Gap between Animal and Human Studies. ACTA ACUST UNITED AC 2018; 58:300-25. [PMID: 16194971 DOI: 10.1080/02724990444000168] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The medial temporal lobe (MTL) has been considered traditionally to subserve declarative memory processes only. Recent studies in nonhuman primates suggest, however, that the MTL may also be critical to higher order perceptual processes, with the hippocampus and perirhinal cortex being involved in scene and object perception, respectively. The current article reviews the human neuropsychological literature to determine whether there is any evidence to suggest that these same views may apply to the human MTL. Although the majority of existing studies report intact perception following MTL damage in human amnesics, there have been recent studies that suggest that when scene and object perception are assessed systematically, signifi-cant impairments in perception become apparent. These findings have important implications for current mnemonic theories of human MTL function and our understanding of human amnesia as a result of MTL lesions.
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Affiliation(s)
- Andy C H Lee
- MRC Cognition and Brain Sciences Unit, Cambridge, UK.
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Characterization of a Factual Knowledge–Associated Brain Memory Area by Functional Magnetic Resonance Imaging and Implementation in Tumor and Epilepsy Brain Surgery. World Neurosurg 2017; 107:291-301. [DOI: 10.1016/j.wneu.2017.07.176] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 07/26/2017] [Accepted: 07/29/2017] [Indexed: 11/19/2022]
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31
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Abstract
Debate about the function of the hippocampus often pits theories advocating for spatial mapping against those that argue for a central role in memory. This review addresses whether research in the monkey supports the view that processing spatial information is fundamental to the function of the hippocampus. In support of spatial processing theories, neurons in the monkey hippocampal formation have striking spatial tuning, and an intact hippocampus is necessary to effectively utilize allocentric spatial relationships. However, the hippocampus also supports non-spatial processes, as its neurons acutely respond to distinct task events and hippocampal damage disrupts both expedient task acquisition and the monitoring of ongoing events in non-spatial paradigms. The features that are shared between spatial and non-spatial hippocampal-dependent tasks point toward a common mechanism underlying hippocampal function that is independent of processing spatial information. We suggest that spatial information is only one facet of immediate experience represented by the hippocampus. The current data support the idea that the hippocampus tracks many aspects of ongoing experience and the primary role of the hippocampus may be in linking experienced events into unitary episodes.
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32
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Familiarity and recollection vs representational models of medial temporal lobe structures: A single-case study. Neuropsychologia 2017; 104:76-91. [DOI: 10.1016/j.neuropsychologia.2017.07.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 07/26/2017] [Accepted: 07/27/2017] [Indexed: 11/20/2022]
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Huffman DJ, Stark CEL. The influence of low-level stimulus features on the representation of contexts, items, and their mnemonic associations. Neuroimage 2017; 155:513-529. [PMID: 28400264 PMCID: PMC5511560 DOI: 10.1016/j.neuroimage.2017.04.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 03/31/2017] [Accepted: 04/07/2017] [Indexed: 11/17/2022] Open
Abstract
Since the earliest attempts to characterize the "receptive fields" of neurons, a central aim of many neuroscience experiments is to elucidate the information that is represented in various regions of the brain. Recent studies suggest that, in the service of memory, information is represented in the medial temporal lobe in a conjunctive or associative form with the contextual aspects of the experience being the primary factor or highest level of the conjunctive hierarchy. A critical question is whether the information that has been observed in these studies reflects notions such as a cognitive representation of context or whether the information reflects the low-level sensory differences between stimuli. We performed two functional magnetic resonance imaging experiments to address this question and we found that associative representations observed between context and item (and order) in the human brain can be highly influenced by low-level sensory differences between stimuli. Our results place clear constraints on the experimental design of studies that aim to investigate the representation of contexts and items during performance of associative memory tasks. Moreover, our results raise interesting theoretical questions regarding the disambiguation of memory-related representations from processing-related representations.
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Affiliation(s)
- Derek J Huffman
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, University of California, Irvine, United States
| | - Craig E L Stark
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, University of California, Irvine, United States.
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Curot J, Busigny T, Valton L, Denuelle M, Vignal JP, Maillard L, Chauvel P, Pariente J, Trebuchon A, Bartolomei F, Barbeau EJ. Memory scrutinized through electrical brain stimulation: A review of 80 years of experiential phenomena. Neurosci Biobehav Rev 2017; 78:161-177. [PMID: 28445741 DOI: 10.1016/j.neubiorev.2017.04.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 03/16/2017] [Accepted: 04/19/2017] [Indexed: 11/17/2022]
Abstract
Electrical brain stimulations (EBS) sometimes induce reminiscences, but it is largely unknown what type of memories they can trigger. We reviewed 80 years of literature on reminiscences induced by EBS and added our own database. We classified them according to modern conceptions of memory. We observed a surprisingly large variety of reminiscences covering all aspects of declarative memory. However, most were poorly detailed and only a few were episodic. This result does not support theories of a highly stable and detailed memory, as initially postulated, and still widely believed as true by the general public. Moreover, memory networks could only be activated by some of their nodes: 94.1% of EBS were temporal, although the parietal and frontal lobes, also involved in memory networks, were stimulated. The qualitative nature of memories largely depended on the site of stimulation: EBS to rhinal cortex mostly induced personal semantic reminiscences, while only hippocampal EBS induced episodic memories. This result supports the view that EBS can activate memory in predictable ways in humans.
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Affiliation(s)
- Jonathan Curot
- Department of Cognitive Neurology, Epileptology and Movement Disorders, Toulouse University Hospital, France; CerCo, CNRS, UMR5549, Toulouse Mind and Brain Institute, France.
| | - Thomas Busigny
- Department of Cognitive Neurology, Epileptology and Movement Disorders, Toulouse University Hospital, France
| | - Luc Valton
- Department of Cognitive Neurology, Epileptology and Movement Disorders, Toulouse University Hospital, France; CerCo, CNRS, UMR5549, Toulouse Mind and Brain Institute, France
| | - Marie Denuelle
- Department of Cognitive Neurology, Epileptology and Movement Disorders, Toulouse University Hospital, France
| | | | - Louis Maillard
- Department of Neurology, Nancy University Hospital, France; University of Nancy, France
| | - Patrick Chauvel
- INSERM, U751, Marseille, France; Faculty of Medicine, Aix-Marseille University, France
| | - Jérémie Pariente
- Department of Cognitive Neurology, Epileptology and Movement Disorders, Toulouse University Hospital, France; INSERM, U1214, TONIC, Toulouse Mind and Brain Institute, France
| | - Agnès Trebuchon
- INSERM, U751, Marseille, France; Faculty of Medicine, Aix-Marseille University, France; Department of Clinical Neurophysiology, Marseille University Hospital, France
| | - Fabrice Bartolomei
- INSERM, U751, Marseille, France; Faculty of Medicine, Aix-Marseille University, France; Department of Clinical Neurophysiology, Marseille University Hospital, France
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Alluri V, Toiviainen P, Burunat I, Kliuchko M, Vuust P, Brattico E. Connectivity patterns during music listening: Evidence for action-based processing in musicians. Hum Brain Mapp 2017; 38:2955-2970. [PMID: 28349620 DOI: 10.1002/hbm.23565] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 02/23/2017] [Accepted: 03/02/2017] [Indexed: 12/13/2022] Open
Abstract
Musical expertise is visible both in the morphology and functionality of the brain. Recent research indicates that functional integration between multi-sensory, somato-motor, default-mode (DMN), and salience (SN) networks of the brain differentiates musicians from non-musicians during resting state. Here, we aimed at determining whether brain networks differentially exchange information in musicians as opposed to non-musicians during naturalistic music listening. Whole-brain graph-theory analyses were performed on participants' fMRI responses. Group-level differences revealed that musicians' primary hubs comprised cerebral and cerebellar sensorimotor regions whereas non-musicians' dominant hubs encompassed DMN-related regions. Community structure analyses of the key hubs revealed greater integration of motor and somatosensory homunculi representing the upper limbs and torso in musicians. Furthermore, musicians who started training at an earlier age exhibited greater centrality in the auditory cortex, and areas related to top-down processes, attention, emotion, somatosensory processing, and non-verbal processing of speech. We here reveal how brain networks organize themselves in a naturalistic music listening situation wherein musicians automatically engage neural networks that are action-based while non-musicians use those that are perception-based to process an incoming auditory stream. Hum Brain Mapp 38:2955-2970, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Vinoo Alluri
- Department of Music, University of Jyväskylä, Jyväskylä, Finland
| | - Petri Toiviainen
- Department of Music, University of Jyväskylä, Jyväskylä, Finland
| | - Iballa Burunat
- Department of Music, University of Jyväskylä, Jyväskylä, Finland
| | - Marina Kliuchko
- Cognitive Brain Research Unit, Institute of Behavioural Sciences, University of Helsinki, Helsinki, Finland
| | - Peter Vuust
- Center for Music in the Brain (MIB), Department of Clinical Medicine, Aarhus University & Royal Academy of Music Aarhus/Aalborg, Denmark
| | - Elvira Brattico
- Center for Music in the Brain (MIB), Department of Clinical Medicine, Aarhus University & Royal Academy of Music Aarhus/Aalborg, Denmark.,Advanced Magnetic Imaging (AMI) Centre, Aalto University School of Science, Espoo, Finland
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36
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Three-dimensional probability maps of the rhinal and the collateral sulci in the human brain. Brain Struct Funct 2016; 221:4235-4255. [DOI: 10.1007/s00429-016-1189-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 01/12/2016] [Indexed: 10/21/2022]
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Abstract
This human neuroimaging review aims to determine the degree to which visual memory evokes activity in neural regions that have been associated with visual perception. A visual perception framework is proposed to identify cortical regions associated with modality-specific processing (i.e., visual, auditory, motor, or olfactory), visual domain-specific processing (i.e., “what” versus “where,” or face versus visual context), and visual feature-specific processing (i.e., color, motion, or spatial location). Independent assessments of visual item memory studies and visual working memory studies revealed activity in the appropriate cortical regions associated with each of the three levels of visual perception processing. These results provide compelling evidence that visual memory and visual perception are associated with common neural substrates. Furthermore, as with visual perception, they support the view that visual memory is a constructive process, in which features or components from disparate cortical regions bind together to form a coherent whole.
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Affiliation(s)
- Scott D Slotnick
- Department of Psychology, Boston College, Chestnut Hill, MA 02467, USA.
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38
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The dynamics of memory retrieval in hierarchical networks. J Comput Neurosci 2016; 40:247-68. [DOI: 10.1007/s10827-016-0595-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 12/07/2015] [Accepted: 02/08/2016] [Indexed: 01/30/2023]
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39
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Dégeilh F, Eustache F, Guillery-Girard B. [Cognitive and brain development of memory from infancy to early adulthood]. Biol Aujourdhui 2016; 209:249-260. [PMID: 26820831 DOI: 10.1051/jbio/2015026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2015] [Indexed: 06/05/2023]
Abstract
Cognitive and brain development are closely linked from infancy to adulthood. The purpose of this article is to review the current state of knowledge on behavioral and brain substrates of memory development. First, we will review cognitive development of different memory systems, from procedural to autobiographical memory. We will discuss how the development of other cognitive functions (language, attention, executive functions and metamemory) participates in memory development. Second, we will describe how structural and functional changes in two core brain regions of memory, i.e. the hippocampus and the prefrontal cortex, impact the protracted development of memory throughout childhood.
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Affiliation(s)
- Fanny Dégeilh
- Inserm, U1077, Caen, France - Université de Caen Normandie, UMR-S1077, Caen, France - École Pratique des Hautes Etudes, UMR-S1077, Caen, France - Centre Hospitalier Universitaire, U1077, Caen, France
| | - Francis Eustache
- Inserm, U1077, Caen, France - Université de Caen Normandie, UMR-S1077, Caen, France - École Pratique des Hautes Etudes, UMR-S1077, Caen, France - Centre Hospitalier Universitaire, U1077, Caen, France
| | - Bérengère Guillery-Girard
- Inserm, U1077, Caen, France - Université de Caen Normandie, UMR-S1077, Caen, France - École Pratique des Hautes Etudes, UMR-S1077, Caen, France - Centre Hospitalier Universitaire, U1077, Caen, France
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Hippocampal Volume Reduction in Humans Predicts Impaired Allocentric Spatial Memory in Virtual-Reality Navigation. J Neurosci 2016; 35:14123-31. [PMID: 26490854 DOI: 10.1523/jneurosci.0801-15.2015] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
UNLABELLED The extent to which navigational spatial memory depends on hippocampal integrity in humans is not well documented. We investigated allocentric spatial recall using a virtual environment in a group of patients with severe hippocampal damage (SHD), a group of patients with "moderate" hippocampal damage (MHD), and a normal control group. Through four learning blocks with feedback, participants learned the target locations of four different objects in a circular arena. Distal cues were present throughout the experiment to provide orientation. A circular boundary as well as an intra-arena landmark provided spatial reference frames. During a subsequent test phase, recall of all four objects was tested with only the boundary or the landmark being present. Patients with SHD were impaired in both phases of this task. Across groups, performance on both types of spatial recall was highly correlated with memory quotient (MQ), but not with intelligence quotient (IQ), age, or sex. However, both measures of spatial recall separated experimental groups beyond what would be expected based on MQ, a widely used measure of general memory function. Boundary-based and landmark-based spatial recall were both strongly related to bilateral hippocampal volumes, but not to volumes of the thalamus, putamen, pallidum, nucleus accumbens, or caudate nucleus. The results show that boundary-based and landmark-based allocentric spatial recall are similarly impaired in patients with SHD, that both types of recall are impaired beyond that predicted by MQ, and that recall deficits are best explained by a reduction in bilateral hippocampal volumes. SIGNIFICANCE STATEMENT In humans, bilateral hippocampal atrophy can lead to profound impairments in episodic memory. Across species, perhaps the most well-established contribution of the hippocampus to memory is not to episodic memory generally but to allocentric spatial memory. However, the extent to which navigational spatial memory depends on hippocampal integrity in humans is not well documented. We investigated spatial recall using a virtual environment in two groups of patients with hippocampal damage (moderate/severe) and a normal control group. The results showed that patients with severe hippocampal damage are impaired in learning and recalling allocentric spatial information. Furthermore, hippocampal volume reduction impaired allocentric navigation beyond what can be predicted by memory quotient as a widely used measure of general memory function.
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Numan R. A Prefrontal-Hippocampal Comparator for Goal-Directed Behavior: The Intentional Self and Episodic Memory. Front Behav Neurosci 2015; 9:323. [PMID: 26635567 PMCID: PMC4658443 DOI: 10.3389/fnbeh.2015.00323] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 11/11/2015] [Indexed: 01/02/2023] Open
Abstract
The hypothesis of this article is that the interactions between the prefrontal cortex and the hippocampus play a critical role in the modulation of goal-directed self-action and the strengthening of episodic memories. We describe various theories that model a comparator function for the hippocampus, and then elaborate the empirical evidence that supports these theories. One theory which describes a prefrontal-hippocampal comparator for voluntary action is emphasized. Action plans are essential for successful goal-directed behavior, and are elaborated by the prefrontal cortex. When an action plan is initiated, the prefrontal cortex transmits an efference copy (or corollary discharge) to the hippocampus where it is stored as a working memory for the action plan (which includes the expected outcomes of the action plan). The hippocampus then serves as a response intention-response outcome working memory comparator. Hippocampal comparator function is enabled by the hippocampal theta rhythm allowing the hippocampus to compare expected action outcomes to actual action outcomes. If the expected and actual outcomes match, the hippocampus transmits a signal to prefrontal cortex which strengthens or consolidates the action plan. If a mismatch occurs, the hippocampus transmits an error signal to the prefrontal cortex which facilitates a reformulation of the action plan, fostering behavioral flexibility and memory updating. The corollary discharge provides the self-referential component to the episodic memory, affording the personal and subjective experience of what behavior was carried out, when it was carried out, and in what context (where) it occurred. Such a perspective can be applied to episodic memory in humans, and episodic-like memory in non-human animal species.
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Affiliation(s)
- Robert Numan
- Psychology Department, Santa Clara University Santa Clara, CA, USA
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Opris I, Santos LM, Gerhardt GA, Song D, Berger TW, Hampson RE, Deadwyler SA. Distributed encoding of spatial and object categories in primate hippocampal microcircuits. Front Neurosci 2015; 9:317. [PMID: 26500473 PMCID: PMC4594006 DOI: 10.3389/fnins.2015.00317] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 08/24/2015] [Indexed: 11/16/2022] Open
Abstract
The primate hippocampus plays critical roles in the encoding, representation, categorization and retrieval of cognitive information. Such cognitive abilities may use the transformational input-output properties of hippocampal laminar microcircuitry to generate spatial representations and to categorize features of objects, images, and their numeric characteristics. Four nonhuman primates were trained in a delayed-match-to-sample (DMS) task while multi-neuron activity was simultaneously recorded from the CA1 and CA3 hippocampal cell fields. The results show differential encoding of spatial location and categorization of images presented as relevant stimuli in the task. Individual hippocampal cells encoded visual stimuli only on specific types of trials in which retention of either, the Sample image, or the spatial position of the Sample image indicated at the beginning of the trial, was required. Consistent with such encoding, it was shown that patterned microstimulation applied during Sample image presentation facilitated selection of either Sample image spatial locations or types of images, during the Match phase of the task. These findings support the existence of specific codes for spatial and numeric object representations in primate hippocampus which can be applied on differentially signaled trials. Moreover, the transformational properties of hippocampal microcircuitry, together with the patterned microstimulation are supporting the practical importance of this approach for cognitive enhancement and rehabilitation, needed for memory neuroprosthetics.
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Affiliation(s)
- Ioan Opris
- Department of Physiology and Pharmacology, Wake Forest University School of MedicineWinston-Salem, NC, USA
| | - Lucas M. Santos
- Department of Physiology and Pharmacology, Wake Forest University School of MedicineWinston-Salem, NC, USA
| | - Greg A. Gerhardt
- Department of Anatomy and Neurobiology, University of KentuckyLexington, KY, USA
| | - Dong Song
- Department of Biomedical Engineering, University of Southern CaliforniaLos Angeles, CA, USA
| | - Theodore W. Berger
- Department of Biomedical Engineering, University of Southern CaliforniaLos Angeles, CA, USA
| | - Robert E. Hampson
- Department of Physiology and Pharmacology, Wake Forest University School of MedicineWinston-Salem, NC, USA
| | - Sam A. Deadwyler
- Department of Physiology and Pharmacology, Wake Forest University School of MedicineWinston-Salem, NC, USA
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Neurons in the Primate Medial Basal Forebrain Signal Combined Information about Reward Uncertainty, Value, and Punishment Anticipation. J Neurosci 2015; 35:7443-59. [PMID: 25972172 DOI: 10.1523/jneurosci.0051-15.2015] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
It has been suggested that the basal forebrain (BF) exerts strong influences on the formation of memory and behavior. However, what information is used for the memory-behavior formation is unclear. We found that a population of neurons in the medial BF (medial septum and diagonal band of Broca) of macaque monkeys encodes a unique combination of information: reward uncertainty, expected reward value, anticipation of punishment, and unexpected reward and punishment. The results were obtained while the monkeys were expecting (often with uncertainty) a rewarding or punishing outcome during a Pavlovian procedure, or unexpectedly received an outcome outside the procedure. In vivo anterograde tracing using manganese-enhanced MRI suggested that the major recipient of these signals is the intermediate hippocampal formation. Based on these findings, we hypothesize that the medial BF identifies various contexts and outcomes that are critical for memory processing in the hippocampal formation.
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Didic M, Felician O, Gour N, Bernard R, Pécheux C, Mundler O, Ceccaldi M, Guedj E. Rhinal hypometabolism on FDG PET in healthy APO-E4 carriers: impact on memory function and metabolic networks. Eur J Nucl Med Mol Imaging 2015; 42:1512-21. [PMID: 25900275 DOI: 10.1007/s00259-015-3057-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 03/31/2015] [Indexed: 01/01/2023]
Abstract
PURPOSE The ε4 allele of the apolipoprotein E (APO-E4) gene, a genetic risk factor for Alzheimer's disease (AD), also modulates brain metabolism and function in healthy subjects. The aim of the present study was to explore cerebral metabolism using FDG PET in healthy APO-E4 carriers by comparing cognitively normal APO-E4 carriers to noncarriers and to assess if patterns of metabolism are correlated with performance on cognitive tasks. Moreover, metabolic connectivity patterns were established in order to assess if the organization of neural networks is influenced by genetic factors. METHODS Whole-brain PET statistical analysis was performed at voxel-level using SPM8 with a threshold of p < 0.005, corrected for volume, with age, gender and level of education as nuisance variables. Significant hypometabolism between APO-E4 carriers (n = 11) and noncarriers (n = 30) was first determined. Mean metabolic values with clinical/neuropsychological data were extracted at the individual level, and correlations were searched using Spearman's rank test in the whole group. To evaluate metabolic connectivity from metabolic cluster(s) previously identified in the intergroup comparison, voxel-wise interregional correlation analysis (IRCA) was performed between groups of subjects. RESULTS APO-E4 carriers had reduced metabolism within the left anterior medial temporal lobe (MTL), where neuropathological changes first appear in AD, including the entorhinal and perirhinal cortices. A correlation between metabolism in this area and performance on the DMS48 (delayed matching to sample-48 items) was found, in line with converging evidence involving the perirhinal cortex in object-based memory. Finally, a voxel-wise IRCA revealed stronger metabolic connectivity of the MTL cluster with neocortical frontoparietal regions in carriers than in noncarriers, suggesting compensatory metabolic networks. CONCLUSION Exploring cerebral metabolism using FDG PET can contribute to a better understanding of the influence of genetic factors on cerebral metabolism at both the local and network levels leading to phenotypical variations of the healthy brain and selective vulnerability.
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Affiliation(s)
- Mira Didic
- Service de Neurologie and Neuropsychologie, Pôle de Neurosciences Cliniques, Centre Hospitalo-Universitaire de la Timone, AP-HM, Marseille, France,
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Moving beyond standard procedures to assess spontaneous recognition memory. Neurosci Biobehav Rev 2015; 53:37-51. [PMID: 25842032 DOI: 10.1016/j.neubiorev.2015.03.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 03/19/2015] [Accepted: 03/25/2015] [Indexed: 11/23/2022]
Abstract
This review will consider how spontaneous tasks have been applied alongside neuroscientific techniques to test complex forms of recognition memory for objects and their environmental features, e.g. the spatial location of an object or the context in which it is presented. We discuss studies that investigate the roles of the perirhinal cortex and the hippocampus in recognition memory using standard testing paradigms, and consider how these findings contribute to the ongoing debate about whether recognition memory is a single unitary process or multiple processes that can be dissociated anatomically and functionally. Due to the wide use of spontaneous tasks, the need for improved procedures that reduce animal use is acknowledged, with multiple trial paradigms discussed as a novel way of reducing variability and animal numbers in these tasks. The importance of improving translation of animal models to humans is highlighted, with emphasis on a shift away from relying on the phenomenological experience of human subjects.
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46
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Fast, but not slow, familiarity is preserved in patients with amnestic mild cognitive impairment. Cortex 2015; 65:36-49. [DOI: 10.1016/j.cortex.2014.10.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Revised: 06/23/2014] [Accepted: 10/30/2014] [Indexed: 11/20/2022]
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Languille S, Liévin-Bazin A, Picq JL, Louis C, Dix S, De Barry J, Blin O, Richardson J, Bordet R, Schenker E, Djelti F, Aujard F. Deficits of psychomotor and mnesic functions across aging in mouse lemur primates. Front Behav Neurosci 2015; 8:446. [PMID: 25620921 PMCID: PMC4288241 DOI: 10.3389/fnbeh.2014.00446] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 12/10/2014] [Indexed: 11/23/2022] Open
Abstract
Owing to a similar cerebral neuro-anatomy, non-human primates are viewed as the most valid models for understanding cognitive deficits. This study evaluated psychomotor and mnesic functions of 41 young to old mouse lemurs (Microcebus murinus). Psychomotor capacities and anxiety-related behaviors decreased abruptly from middle to late adulthood. However, mnesic functions were not affected in the same way with increasing age. While results of the spontaneous alternation task point to a progressive and widespread age-related decline of spatial working memory, both spatial reference and novel object recognition (NOR) memory tasks did not reveal any tendency due to large inter-individual variability in the middle-aged and old animals. Indeed, some of the aged animals performed as well as younger ones, whereas some others had bad performances in the Barnes maze and in the object recognition test. Hierarchical cluster analysis revealed that declarative-like memory was strongly impaired only in 7 out of 25 middle-aged/old animals. These results suggest that this analysis allows to distinguish elder populations of good and bad performers in this non-human primate model and to closely compare this to human aging.
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Affiliation(s)
- Solène Languille
- UMR 7179, Centre National de la Recherche Scientifique, Muséum National d'Histoire Naturelle France Brunoy, France
| | - Agatha Liévin-Bazin
- UMR 7179, Centre National de la Recherche Scientifique, Muséum National d'Histoire Naturelle France Brunoy, France
| | - Jean-Luc Picq
- UMR 7179, Centre National de la Recherche Scientifique, Muséum National d'Histoire Naturelle France Brunoy, France ; Laboratoire de Psychopathologie et de Neuropsychologie, EA 2027, Université Paris 8 St-Denis, France
| | - Caroline Louis
- Institut de Recherches Servier Croissy-sur-Seine, France
| | | | - Jean De Barry
- INCI UPR3212 CNRS et Innovative Health Diagnostics Strasbourg, France
| | - Olivier Blin
- Centre de Pharmacologie Clinique et d'Evaluations Thérapeutiques-CIC, Timone CNRS-INT-Aix Marseille Université Marseille, France
| | - Jill Richardson
- GlaxoSmithKline, R&D China U.K. Group Stevenage Stevenage, UK
| | - Régis Bordet
- Département de Pharmacologie Médicale, EA 1046, Université Lille Nord de France, UDSL, Faculté de Médecine CHU, Lille, France
| | | | - Fathia Djelti
- UMR 7179, Centre National de la Recherche Scientifique, Muséum National d'Histoire Naturelle France Brunoy, France
| | - Fabienne Aujard
- UMR 7179, Centre National de la Recherche Scientifique, Muséum National d'Histoire Naturelle France Brunoy, France
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Skirrow C, Cross JH, Harrison S, Cormack F, Harkness W, Coleman R, Meierotto E, Gaiottino J, Vargha-Khadem F, Baldeweg T. Temporal lobe surgery in childhood and neuroanatomical predictors of long-term declarative memory outcome. ACTA ACUST UNITED AC 2014; 138:80-93. [PMID: 25392199 PMCID: PMC4285190 DOI: 10.1093/brain/awu313] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
See Berg (doi:10.1093/brain/awu320) for a scientific commentary on this article. In a long-term follow-up study of children who underwent temporal lobe surgery for treatment of epilepsy, Skirrow et al. identify no significant pre-to-post-surgery memory losses, but instead robust improvements in memory functions supported by the unoperated temporal lobe. The integrity of remaining temporal lobe structures places constraints on long-term memory outcomes. The temporal lobes play a prominent role in declarative memory function, including episodic memory (memory for events) and semantic memory (memory for facts and concepts). Surgical resection for medication-resistant and well-localized temporal lobe epilepsy has good prognosis for seizure freedom, but is linked to memory difficulties in adults, especially when the removal is on the left side. Children may benefit most from surgery, because brain plasticity may facilitate post-surgical reorganization, and seizure cessation may promote cognitive development. However, the long-term impact of this intervention in children is not known. We examined memory function in 53 children (25 males, 28 females) who were evaluated for epilepsy surgery: 42 underwent unilateral temporal lobe resections (25 left, 17 right, mean age at surgery 13.8 years), 11 were treated only pharmacologically. Average follow-up was 9 years (range 5–15). Post-surgical change in visual and verbal episodic memory, and semantic memory at follow-up were examined. Pre- and post-surgical T1-weighted MRI brain scans were analysed to extract hippocampal and resection volumes, and evaluate post-surgical temporal lobe integrity. Language lateralization indices were derived from functional magnetic resonance imaging. There were no significant pre- to postoperative decrements in memory associated with surgery. In contrast, gains in verbal episodic memory were seen after right temporal lobe surgery, and visual episodic memory improved after left temporal lobe surgery, indicating a functional release in the unoperated temporal lobe after seizure reduction or cessation. Pre- to post-surgical change in memory function was not associated with any indices of brain structure derived from MRI. However, better verbal memory at follow-up was linked to greater post-surgical residual hippocampal volumes, most robustly in left surgical participants. Better semantic memory at follow-up was associated with smaller resection volumes and greater temporal pole integrity after left temporal surgery. Results were independent of post-surgical intellectual function and language lateralization. Our findings indicate post-surgical, hemisphere-dependent material-specific improvement in memory functions in the intact temporal lobe. However, outcome was linked to the anatomical integrity of the temporal lobe memory system, indicating that compensatory mechanisms are constrained by the amount of tissue which remains in the operated temporal lobe. Careful tailoring of resections for children undergoing epilepsy surgery may enhance long-term memory outcome.
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Affiliation(s)
- Caroline Skirrow
- 1 Cognitive Neuroscience and Neuropsychiatry Section, Developmental Neurosciences Programme, Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK 2 Great Ormond Street Hospital NHS Trust, Great Ormond Street, WC1N 3JH, UK
| | - J Helen Cross
- 2 Great Ormond Street Hospital NHS Trust, Great Ormond Street, WC1N 3JH, UK 3 Clinical Neurosciences Section, Developmental Neurosciences Programme, Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK
| | - Sue Harrison
- 1 Cognitive Neuroscience and Neuropsychiatry Section, Developmental Neurosciences Programme, Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK 2 Great Ormond Street Hospital NHS Trust, Great Ormond Street, WC1N 3JH, UK
| | - Francesca Cormack
- 4 Cognition and Brain Sciences Unit, 15 Chaucer Road, Cambridge, CB2 7EF, UK
| | - William Harkness
- 2 Great Ormond Street Hospital NHS Trust, Great Ormond Street, WC1N 3JH, UK
| | - Rosie Coleman
- 1 Cognitive Neuroscience and Neuropsychiatry Section, Developmental Neurosciences Programme, Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK 2 Great Ormond Street Hospital NHS Trust, Great Ormond Street, WC1N 3JH, UK
| | - Ellen Meierotto
- 1 Cognitive Neuroscience and Neuropsychiatry Section, Developmental Neurosciences Programme, Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK 5 Abteilung für Psychiatrie und Psychotherapie, Universitätsklinik Freiburg, Hugstetter Strasse 55, 29106 Freiburg, Germany
| | - Johanna Gaiottino
- 1 Cognitive Neuroscience and Neuropsychiatry Section, Developmental Neurosciences Programme, Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK
| | - Faraneh Vargha-Khadem
- 1 Cognitive Neuroscience and Neuropsychiatry Section, Developmental Neurosciences Programme, Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK 2 Great Ormond Street Hospital NHS Trust, Great Ormond Street, WC1N 3JH, UK
| | - Torsten Baldeweg
- 1 Cognitive Neuroscience and Neuropsychiatry Section, Developmental Neurosciences Programme, Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK 2 Great Ormond Street Hospital NHS Trust, Great Ormond Street, WC1N 3JH, UK
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Krugel LK, Ehlen F, Tiedt HO, Kühn AA, Klostermann F. Differential impact of thalamic versus subthalamic deep brain stimulation on lexical processing. Neuropsychologia 2014; 63:175-84. [DOI: 10.1016/j.neuropsychologia.2014.08.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 08/26/2014] [Accepted: 08/27/2014] [Indexed: 01/01/2023]
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Barkur RR, Bairy LK. Histological study on hippocampus, amygdala and cerebellum following low lead exposure during prenatal and postnatal brain development in rats. Toxicol Ind Health 2014; 32:1052-63. [PMID: 25147304 DOI: 10.1177/0748233714545624] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Neuropsychological studies in children who are exposed to lead during their early brain development have shown to develop behavioural and cognitive deficit. The aim of the present study was to assess the cellular damage in hippocampus, amygdala and cerebellum of rat pups exposed to lead during different periods of early brain development. Five groups of rat pups were investigated. (a) Control group (n = 8) (mothers of these rats were given normal drinking water throughout gestation and lactation), (b) pregestation lead-exposed group (n = 8) (mothers of these rats were exposed to 0.2% lead acetate in the drinking water for one month before conception), (c) gestation lead-exposed group (n = 8) (exposed to 0.2% lead acetate in the drinking water through the mother throughout gestation [gestation day 01 to day 21]), (d) lactation lead-exposed group (n = 8) (exposed to 0.2% lead acetate in the drinking water through the mother throughout lactation [postnatal day 01 to day 21]) and (e) gestation and lactation lead-exposed group (n = 8) (exposed to 0.2% lead acetate throughout gestation and lactation). On postnatal day 30, rat pups of all the groups were killed. Numbers of surviving neurons in the hippocampus, amygdala and cerebellum regions were counted using cresyl violet staining technique. Histological data indicate that lead exposure caused significant damage to neurons of hippocampus, amygdala and cerebellum regions in all lead-exposed groups except lactation lead-exposed group. The extent of damage to neurons of hippocampus, amygdala and cerebellum regions in lactation lead-exposed group was comparable to gestation and lactation groups even though the duration of lead exposure was much less in lactation lead-exposed group. To conclude, the postnatal period of brain development seems to be more vulnerable to lead neurotoxicity compared to prenatal period of brain development.
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Affiliation(s)
- Rajashekar Rao Barkur
- Department of Biochemistry, Melaka Manipal Medical College, Manipal University, Manipal, India
| | - Laxminarayana K Bairy
- Department of Pharmacology, Kasturba Medical College, Manipal University, Manipal, India
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