101
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Herweg NA, Kahana MJ. Spatial Representations in the Human Brain. Front Hum Neurosci 2018; 12:297. [PMID: 30104966 PMCID: PMC6078001 DOI: 10.3389/fnhum.2018.00297] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 07/06/2018] [Indexed: 11/13/2022] Open
Abstract
While extensive research on the neurophysiology of spatial memory has been carried out in rodents, memory research in humans had traditionally focused on more abstract, language-based tasks. Recent studies have begun to address this gap using virtual navigation tasks in combination with electrophysiological recordings in humans. These studies suggest that the human medial temporal lobe (MTL) is equipped with a population of place and grid cells similar to that previously observed in the rodent brain. Furthermore, theta oscillations have been linked to spatial navigation and, more specifically, to the encoding and retrieval of spatial information. While some studies suggest a single navigational theta rhythm which is of lower frequency in humans than rodents, other studies advocate for the existence of two functionally distinct delta-theta frequency bands involved in both spatial and episodic memory. Despite the general consensus between rodent and human electrophysiology, behavioral work in humans does not unequivocally support the use of a metric Euclidean map for navigation. Formal models of navigational behavior, which specifically consider the spatial scale of the environment and complementary learning mechanisms, may help to better understand different navigational strategies and their neurophysiological mechanisms. Finally, the functional overlap of spatial and declarative memory in the MTL calls for a unified theory of MTL function. Such a theory will critically rely upon linking task-related phenomena at multiple temporal and spatial scales. Understanding how single cell responses relate to ongoing theta oscillations during both the encoding and retrieval of spatial and non-spatial associations appears to be key toward developing a more mechanistic understanding of memory processes in the MTL.
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Affiliation(s)
- Nora A. Herweg
- Computational Memory Lab, Department of Psychology, University of Pennsylvania, Philadelphia, PA, United States
| | - Michael J. Kahana
- Computational Memory Lab, Department of Psychology, University of Pennsylvania, Philadelphia, PA, United States
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102
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Burke SN, Gaynor LS, Barnes CA, Bauer RM, Bizon JL, Roberson ED, Ryan L. Shared Functions of Perirhinal and Parahippocampal Cortices: Implications for Cognitive Aging. Trends Neurosci 2018; 41:349-359. [PMID: 29555181 PMCID: PMC5970964 DOI: 10.1016/j.tins.2018.03.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Revised: 02/16/2018] [Accepted: 03/01/2018] [Indexed: 01/13/2023]
Abstract
A predominant view of perirhinal cortex (PRC) and postrhinal/parahippocampal cortex (POR/PHC) function contends that these structures are tuned to represent objects and spatial information, respectively. However, known anatomical connectivity, together with recent electrophysiological, neuroimaging, and lesion data, indicate that both brain areas participate in spatial and nonspatial processing. Instead of content-based organization, the PRC and PHC/POR may participate in two computationally distinct cortical-hippocampal networks: one network that is tuned to process coarse information quickly, forming gist-like representations of scenes/environments, and a second network tuned to process information about the specific sensory details that are necessary for discrimination across sensory modalities. The available data suggest that the latter network may be more vulnerable in advanced age.
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Affiliation(s)
- Sara N Burke
- McKnight Brain Institute, Department of Neuroscience, University of Florida, Gainesville, FL, USA; Institute on Aging, University of Florida, Gainesville, FL, USA.
| | - Leslie S Gaynor
- McKnight Brain Institute, Department of Neuroscience, University of Florida, Gainesville, FL, USA; Department of Clinical and Health Psychology, College of Public Health and Health Professions, University of Florida, Gainesville, FL, USA
| | - Carol A Barnes
- Evelyn F. McKnight Brain Institute, University of Arizona, Tucson, AZ, USA; Division of Neural Systems Memory and Aging, University of Arizona, Tucson, AZ, USA; Department of Psychology, University of Arizona, Tucson, AZ, USA; Department of Neurology and Neuroscience, University of Arizona, Tucson, AZ, USA
| | - Russell M Bauer
- Department of Clinical and Health Psychology, College of Public Health and Health Professions, University of Florida, Gainesville, FL, USA
| | - Jennifer L Bizon
- McKnight Brain Institute, Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | - Erik D Roberson
- Evelyn F. McKnight Brain Institute, Alzheimer's Disease Center, Center for Neurodegeneration and Experimental Therapeutics, Departments of Neurology and Neurobiology, University of Alabama at Birmingham, AL, USA
| | - Lee Ryan
- Evelyn F. McKnight Brain Institute, University of Arizona, Tucson, AZ, USA; Department of Psychology, University of Arizona, Tucson, AZ, USA.
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103
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Avery SN, Rogers BP, Heckers S. Hippocampal Network Modularity Is Associated With Relational Memory Dysfunction in Schizophrenia. BIOLOGICAL PSYCHIATRY. COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2018; 3:423-432. [PMID: 29653904 PMCID: PMC5940573 DOI: 10.1016/j.bpsc.2018.02.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 01/12/2018] [Accepted: 02/13/2018] [Indexed: 11/18/2022]
Abstract
BACKGROUND Functional dysconnectivity has been proposed as a major pathophysiological mechanism for cognitive dysfunction in schizophrenia. The hippocampus is a focal point of dysconnectivity in schizophrenia, with decreased hippocampal functional connectivity contributing to the marked memory deficits observed in patients. Normal memory function relies on the interaction of complex corticohippocampal networks. However, only recent technological advances have enabled the large-scale exploration of functional networks with accuracy and precision. METHODS We investigated the modularity of hippocampal resting-state functional networks in a sample of 45 patients with schizophrenia spectrum disorders and 38 healthy control subjects. Modularity was calculated for two distinct functional networks: a core hippocampal-medial temporal lobe cortex network and an extended hippocampal-cortical network. As hippocampal function differs along its longitudinal axis, follow-up analyses examined anterior and posterior networks separately. To explore effects of resting network function on behavior, we tested associations between modularity and relational memory ability. Age, sex, handedness, and parental education were similar between groups. RESULTS Network modularity was lower in schizophrenia patients, especially in the posterior hippocampal network. Schizophrenia patients also showed markedly lower relational memory ability compared with control subjects. We found a distinct brain-behavior relationship in schizophrenia that differed from control subjects by network and anterior/posterior division-while relational memory in control subjects was associated with anterior hippocampal-cortical modularity, schizophrenia patients showed an association with posterior hippocampal-medial temporal lobe cortex network modularity. CONCLUSIONS Our findings support a model of abnormal resting-state corticohippocampal network coherence in schizophrenia, which may contribute to relational memory deficits.
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Affiliation(s)
- Suzanne N Avery
- Department of Psychiatry, Vanderbilt University Medical Center, Nashville, Tennessee.
| | - Baxter P Rogers
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Stephan Heckers
- Department of Psychiatry, Vanderbilt University Medical Center, Nashville, Tennessee; Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee
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104
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Flexible egocentric and allocentric representations of heading signals in parietal cortex. Proc Natl Acad Sci U S A 2018; 115:E3305-E3312. [PMID: 29555744 DOI: 10.1073/pnas.1715625115] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
By systematically manipulating head position relative to the body and eye position relative to the head, previous studies have shown that vestibular tuning curves of neurons in the ventral intraparietal (VIP) area remain invariant when expressed in body-/world-centered coordinates. However, body orientation relative to the world was not manipulated; thus, an egocentric, body-centered representation could not be distinguished from an allocentric, world-centered reference frame. We manipulated the orientation of the body relative to the world such that we could distinguish whether vestibular heading signals in VIP are organized in body- or world-centered reference frames. We found a hybrid representation, depending on gaze direction. When gaze remained fixed relative to the body, the vestibular heading tuning of VIP neurons shifted systematically with body orientation, indicating an egocentric, body-centered reference frame. In contrast, when gaze remained fixed relative to the world, this representation changed to be intermediate between body- and world-centered. We conclude that the neural representation of heading in posterior parietal cortex is flexible, depending on gaze and possibly attentional demands.
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105
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Fan LY, Lai YM, Chen TF, Hsu YC, Chen PY, Huang KZ, Cheng TW, Tseng WYI, Hua MS, Chen YF, Chiu MJ. Diminution of context association memory structure in subjects with subjective cognitive decline. Hum Brain Mapp 2018. [PMID: 29516634 DOI: 10.1002/hbm.24022] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Alzheimer's disease (AD) progresses insidiously from the preclinical stage to dementia. While people with subjective cognitive decline (SCD) have normal cognitive performance, some may be in the preclinical stage of AD. Neurofibrillary tangles appear first in the transentorhinal cortex, followed by the entorhinal cortex in the clinically silent stage of AD. We expected the earliest changes in subjects with SCD to occur in medial temporal subfields other than the hippocampal proper. These selective structural changes would affect specific memory subcomponents. We used the Family Picture subtest of the Wechsler Memory Scale-III, which was modified to separately compute character, activity, and location subscores for episodic memory subcomponents. We recruited 43 subjects with SCD, 44 subjects with amnesic mild cognitive impairment, and 34 normal controls. MRI was used to assess cortical thickness, subcortical gray matter volume, and fractional anisotropy. The results demonstrated that SCD subjects showed significant cortical atrophy in their bilateral parahippocampus and perirhinal and the left entorhinal cortices but not in their hippocampal regions. SCD subjects also exhibited significantly decreased mean fractional anisotropy in their bilateral uncinate fasciculi. The diminution of cortical thickness over the mesial temporal subfields corresponded to brain areas with early tangle deposition, and early degradation of the uncinate fasciculus was in accordance with the retrogenesis hypothesis. The parahippocampus and perirhinal cortex contribute mainly to context association memory while the entorhinal cortex, along with the uncinate fasciculus, contributes to content-related contextual memory. We proposed that context association and related memory structures are vulnerable in the SCD stage.
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Affiliation(s)
- Ling-Yun Fan
- Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan.,Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ya-Mei Lai
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan.,Center for Clinical Psychology, National Taiwan University Hospital, Taipei, Taiwan
| | - Ta-Fu Chen
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yung-Chin Hsu
- Graduate Institute of Medical Device and Imaging, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Pin-Yu Chen
- Graduate Institute of Medical Device and Imaging, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Kuo-Zhou Huang
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ting-Wen Cheng
- Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan.,Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Wen-Yi Isaac Tseng
- Graduate Institute of Medical Device and Imaging, College of Medicine, National Taiwan University, Taipei, Taiwan.,Department of Medical Imaging, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Mau-Sun Hua
- Department of Psychology, Asia University, Taichung, Taiwan.,Department of Psychology, College of Science, National Taiwan University, Taipei, Taiwan
| | - Ya-Fang Chen
- Department of Medical Imaging, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ming-Jang Chiu
- Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan.,Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan.,Department of Psychology, College of Science, National Taiwan University, Taipei, Taiwan.,Graduate Institute of Biomedical Engineering and Bioinformatics, National Taiwan University, Taipei, Taiwan
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106
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Reagh ZM, Noche JA, Tustison NJ, Delisle D, Murray EA, Yassa MA. Functional Imbalance of Anterolateral Entorhinal Cortex and Hippocampal Dentate/CA3 Underlies Age-Related Object Pattern Separation Deficits. Neuron 2018; 97:1187-1198.e4. [PMID: 29518359 PMCID: PMC5937538 DOI: 10.1016/j.neuron.2018.01.039] [Citation(s) in RCA: 123] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 12/20/2017] [Accepted: 01/19/2018] [Indexed: 02/08/2023]
Abstract
The entorhinal cortex (EC) is among the earliest brain areas to deteriorate in Alzheimer's disease (AD). However, the extent to which functional properties of the EC are altered in the aging brain, even in the absence of clinical symptoms, is not understood. Recent human fMRI studies have identified a functional dissociation within the EC, similar to what is found in rodents. Here, we used high-resolution fMRI to identify a specific hypoactivity in the anterolateral EC (alEC) commensurate with major behavioral deficits on an object pattern separation task in asymptomatic older adults. Only subtle deficits were found in a comparable spatial condition, with no associated differences in posteromedial EC between young and older adults. We additionally linked this condition to dentate/CA3 hyperactivity, and the ratio of activity between the regions was associated with object mnemonic discrimination impairment. These results provide novel evidence of alEC-dentate/CA3 circuit dysfunction in cognitively normal aged humans.
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Affiliation(s)
- Zachariah M Reagh
- Department of Neurology, Center for Neuroscience, University of California Davis, Davis, CA 95616, USA.
| | - Jessica A Noche
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, UC Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, CA 92697, USA
| | - Nicholas J Tustison
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA 22904, USA
| | - Derek Delisle
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, UC Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, CA 92697, USA
| | - Elizabeth A Murray
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, UC Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, CA 92697, USA
| | - Michael A Yassa
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, UC Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, CA 92697, USA.
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107
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Naumann RK, Preston-Ferrer P, Brecht M, Burgalossi A. Structural modularity and grid activity in the medial entorhinal cortex. J Neurophysiol 2018. [PMID: 29513150 DOI: 10.1152/jn.00574.2017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Following the groundbreaking discovery of grid cells, the medial entorhinal cortex (MEC) has become the focus of intense anatomical, physiological, and computational investigations. Whether and how grid activity maps onto cell types and cortical architecture is still an open question. Fundamental similarities in microcircuits, function, and connectivity suggest a homology between rodent MEC and human posteromedial entorhinal cortex. Both are specialized for spatial processing and display similar cellular organization, consisting of layer 2 pyramidal/calbindin cell patches superimposed on scattered stellate neurons. Recent data indicate the existence of a further nonoverlapping modular system (zinc patches) within the superficial MEC layers. Zinc and calbindin patches have been shown to receive largely segregated inputs from the presubiculum and parasubiculum. Grid cells are also clustered in the MEC, and we discuss possible structure-function schemes on how grid activity could map onto cortical patch systems. We hypothesize that in the superficial layers of the MEC, anatomical location can be predictive of function; thus relating functional properties and neuronal morphologies to the cortical modules will be necessary for resolving how grid activity maps onto cortical architecture. Imaging or cell identification approaches in freely moving animals will be required for testing this hypothesis.
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Affiliation(s)
- Robert K Naumann
- Bernstein Center for Computational Neuroscience, Humboldt University of Berlin , Berlin , Germany.,Max-Planck-Institute for Brain Research, Frankfurt am Main , Germany.,Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen University Town, Nanshan District, Shenzhen , China
| | | | - Michael Brecht
- Bernstein Center for Computational Neuroscience, Humboldt University of Berlin , Berlin , Germany.,German Center for Neurodegenerative Diseases , Berlin , Germany
| | - Andrea Burgalossi
- Werner-Reichardt Centre for Integrative Neuroscience , Tübingen , Germany
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108
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Chen J, Shu H, Wang Z, Liu D, Shi Y, Xu L, Zhang Z. Protective effect of APOE epsilon 2 on intrinsic functional connectivity of the entorhinal cortex is associated with better episodic memory in elderly individuals with risk factors for Alzheimer's disease. Oncotarget 2018; 7:58789-58801. [PMID: 27542235 PMCID: PMC5312276 DOI: 10.18632/oncotarget.11289] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 07/11/2016] [Indexed: 01/23/2023] Open
Abstract
The apolipoprotein E (APOE) ε4 allele associates with accelerating the conversion from amnestic mild cognitive impairment (aMCI) to Alzheimer's disease (AD), whereas the protectiveAPOEε2 allele appears to be against the disease. Moreover, entorhinal cortex (ERC) is one of the earliest brain regions of AD pathology that disrupts the formation of episodic memory. To investigate the effects of APOE ε2 and ε4alleles on functional connectivity (FC) of ERC and cognition in aMCI. Methods The FC analyses of ERC were performed in 83 aMCI (9 ε2-carrier, 44 ε3ε3, and 30 ε4-carrier) and 88 healthy controls (HC, 15 ε2-carrier, 40 ε3ε3, and 33 ε4-carrier). Multiple linear regression model was performed between the altered ERC connectivities and cognition. In the ERC network, aMCI with ε4-carriers showed decreased FC in the bilateral middle temporal gyrus (MTG), right precuneus, and right precentral gyrus (PreCG), while ε2-carriers showed increased FC in these regions (except the right PreCG) compared to HC. The altered FC between ERC and right MTG correlated with episodic memory performance in aMCI carried ε2 and ε4 alleles. These results suggest that the effects ofAPOEon the ERC network are closely linked to the role of this gene on AD risk, which aMCI with ε4-carriers can accelerate the pathological progression of network-based mechanisms while ε2-carriers may play a protective role in contributing to a compensatory mechanism. It further suggests that APOE can appear to directly affect the ERC-MTG neural pathway associated with the impairment of episodic memory in aMCI.
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Affiliation(s)
- Jiu Chen
- Department of Neurology, Affiliated ZhongDa Hospital, Medical School, Southeast University, Nanjing, Jiangsu, China
| | - Hao Shu
- Department of Neurology, Affiliated ZhongDa Hospital, Medical School, Southeast University, Nanjing, Jiangsu, China
| | - Zan Wang
- Department of Neurology, Affiliated ZhongDa Hospital, Medical School, Southeast University, Nanjing, Jiangsu, China
| | - Duan Liu
- Department of Neurology, Affiliated ZhongDa Hospital, Medical School, Southeast University, Nanjing, Jiangsu, China
| | - Yongmei Shi
- Department of Neurology, Affiliated ZhongDa Hospital, Medical School, Southeast University, Nanjing, Jiangsu, China
| | - Lin Xu
- Key Laboratory of Animal Models and Human Disease Mechanisms, Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming, Yunnan, China
| | - Zhijun Zhang
- Department of Neurology, Affiliated ZhongDa Hospital, Medical School, Southeast University, Nanjing, Jiangsu, China.,Department of Psychology, Xinxiang Medical University, Xinxiang, Henan, China
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109
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Goh JOS, Hung HY, Su YS. A conceptual consideration of the free energy principle in cognitive maps: How cognitive maps help reduce surprise. PSYCHOLOGY OF LEARNING AND MOTIVATION 2018. [DOI: 10.1016/bs.plm.2018.09.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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110
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Collin SHP, Milivojevic B, Doeller CF. Hippocampal hierarchical networks for space, time, and memory. Curr Opin Behav Sci 2017. [DOI: 10.1016/j.cobeha.2017.06.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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111
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Ku SP, Nakamura NH, Maingret N, Mahnke L, Yoshida M, Sauvage MM. Regional Specific Evidence for Memory-Load Dependent Activity in the Dorsal Subiculum and the Lateral Entorhinal Cortex. Front Syst Neurosci 2017; 11:51. [PMID: 28790897 PMCID: PMC5524887 DOI: 10.3389/fnsys.2017.00051] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 07/03/2017] [Indexed: 11/13/2022] Open
Abstract
The subiculum and the lateral entorhinal cortex (LEC) are the main output areas of the hippocampus which contribute to spatial and non-spatial memory. The proximal part of the subiculum (bordering CA1) receives heavy projections from the perirhinal cortex and the distal part of CA1 (bordering the subiculum), both known for their ties to object recognition memory. However, the extent to which the proximal subiculum contributes to non-spatial memory is still unclear. Comparatively, the involvement of the LEC in non-spatial information processing is quite well known. However, very few studies have investigated its role within the frame of memory function. Thus, it is not known whether its contribution depends on memory load. In addition, the deep layers of the EC have been shown to be predictive of subsequent memory performance, but not its superficial layers. Hence, here we tested the extent to which the proximal part of the subiculum and the superficial and deep layers of the LEC contribute to non-spatial memory, and whether this contribution depends on the memory load of the task. To do so, we imaged brain activity at cellular resolution in these areas in rats performing a delayed nonmatch to sample task based on odors with two different memory loads (5 or 10 odors). This imaging technique is based on the detection of the RNA of the immediate-early gene Arc, which is especially tied to synaptic plasticity and behavioral demands, and is commonly used to map activity in the medial temporal lobe. We report for the first time that the proximal part of the subiculum is recruited in a memory-load dependent manner and the deep layers of the LEC engaged under high memory load conditions during the retrieval of non-spatial memory, thus shedding light on the specific networks contributing to non-spatial memory retrieval.
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Affiliation(s)
- Shih-Pi Ku
- Department of Functional Architecture of Memory, Leibniz-Institute for NeurobiologyMagdeburg, Germany
| | - Nozomu H Nakamura
- Department of Physiology, Hyogo College of MedicineNishinomiya, Japan.,Mercator Research Group, Functional Architecture of Memory Unit, Ruhr-UniversityBochum, Germany
| | - Nicolas Maingret
- Mercator Research Group, Functional Architecture of Memory Unit, Ruhr-UniversityBochum, Germany
| | - Liv Mahnke
- Department of Functional Architecture of Memory, Leibniz-Institute for NeurobiologyMagdeburg, Germany.,Mercator Research Group, Functional Architecture of Memory Unit, Ruhr-UniversityBochum, Germany.,Faculty of Natural Science, Otto von Guericke UniversityMagdeburg, Germany
| | - Motoharu Yoshida
- Department of Functional Architecture of Memory, Leibniz-Institute for NeurobiologyMagdeburg, Germany.,German Center for Neurodegenerative Diseases (DZNE), Cognitive Neurophysiology LaboratoryMagdeburg, Germany
| | - Magdalena M Sauvage
- Department of Functional Architecture of Memory, Leibniz-Institute for NeurobiologyMagdeburg, Germany.,Mercator Research Group, Functional Architecture of Memory Unit, Ruhr-UniversityBochum, Germany.,Medical Faculty, Department of Functional Neuroplasticity, Otto von Guericke UniversityMagdeburg, Germany.,Center for Behavioral Brain Sciences, Otto von Guericke UniversityMagdeburg, Germany
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112
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Marquand AF, Haak KV, Beckmann CF. Functional corticostriatal connection topographies predict goal directed behaviour in humans. Nat Hum Behav 2017; 1:0146. [PMID: 28804783 PMCID: PMC5549843 DOI: 10.1038/s41562-017-0146] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Anatomical tracing studies in non-human primates have suggested that corticostriatal connectivity is topographically organized: nearby locations in striatum are connected with nearby locations in cortex. The topographic organization of corticostriatal connectivity is thought to underpin many goal-directed behaviours, but these topographies have not been completely characterised in humans and their relationship to uniquely human behaviours remains to be fully determined. Instead, the dominant approach employs parcellations that cannot model the continuous nature of the topography, nor accommodate overlapping cortical projections in the striatum. Here, we employ a different approach to studying human corticostriatal circuitry: we estimate smoothly-varying and spatially overlapping 'connection topographies' from resting state fMRI. These correspond exceptionally well with and extend the topographies predicted from primate tracing studies. We show that striatal topography is preserved in regions not previously known to have topographic connections with the striatum and that many goal-directed behaviours can be mapped precisely onto individual variations in the spatial layout of striatal connectivity.
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Affiliation(s)
- Andre F Marquand
- Radboud University Medical Centre, Kapittelweg 29, 6525 EN, Nijmegen, the Netherlands.,Donders Centre for Cognitive Neuroimaging, Donders Institute for Brain, Cognition and Behaviour, Kapittelweg 29, 6525 EN, Nijmegen, the Netherlands.,Department of Neuroimaging, Centre for Neuroimaging Sciences, Institute of Psychiatry, King's College London, De Crespigny Park, London SE5 8AF, United Kingdom
| | - Koen V Haak
- Radboud University Medical Centre, Kapittelweg 29, 6525 EN, Nijmegen, the Netherlands.,Donders Centre for Cognitive Neuroimaging, Donders Institute for Brain, Cognition and Behaviour, Kapittelweg 29, 6525 EN, Nijmegen, the Netherlands
| | - Christian F Beckmann
- Radboud University Medical Centre, Kapittelweg 29, 6525 EN, Nijmegen, the Netherlands.,Donders Centre for Cognitive Neuroimaging, Donders Institute for Brain, Cognition and Behaviour, Kapittelweg 29, 6525 EN, Nijmegen, the Netherlands.,Oxford Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB), University of Oxford, Oxford OX3 9DU, United Kingdom
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113
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van Oort ESB, Mennes M, Navarro Schröder T, Kumar VJ, Zaragoza Jimenez NI, Grodd W, Doeller CF, Beckmann CF. Functional parcellation using time courses of instantaneous connectivity. Neuroimage 2017; 170:31-40. [PMID: 28716715 DOI: 10.1016/j.neuroimage.2017.07.027] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Revised: 07/12/2017] [Accepted: 07/13/2017] [Indexed: 02/03/2023] Open
Abstract
Functional neuroimaging studies have led to understanding the brain as a collection of spatially segregated functional networks. It is thought that each of these networks is in turn composed of a set of distinct sub-regions that together support each network's function. Considering the sub-regions to be an essential part of the brain's functional architecture, several strategies have been put forward that aim at identifying the functional sub-units of the brain by means of functional parcellations. Current parcellation strategies typically employ a bottom-up strategy, creating a parcellation by clustering smaller units. We propose a novel top-down parcellation strategy, using time courses of instantaneous connectivity to subdivide an initial region of interest into sub-regions. We use split-half reproducibility to choose the optimal number of sub-regions. We apply our Instantaneous Connectivity Parcellation (ICP) strategy on high-quality resting-state FMRI data, and demonstrate the ability to generate parcellations for thalamus, entorhinal cortex, motor cortex, and subcortex including brainstem and striatum. We evaluate the subdivisions against available cytoarchitecture maps to show that our parcellation strategy recovers biologically valid subdivisions that adhere to known cytoarchitectural features.
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Affiliation(s)
- Erik S B van Oort
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands.
| | - Maarten Mennes
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Tobias Navarro Schröder
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands; Kavli Institute for Systems Neuroscience and Centre for the Biology of Memory, Norwegian University of Science and Technology, NTNU, 7491 Trondheim, Norway
| | - Vinod J Kumar
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Nestor I Zaragoza Jimenez
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands; Max Planck Institute for Human Cognitive and Brain Sciences, Department of Neuropsychology, Leipzig, Germany
| | - Wolfgang Grodd
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Christian F Doeller
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands; Kavli Institute for Systems Neuroscience and Centre for the Biology of Memory, Norwegian University of Science and Technology, NTNU, 7491 Trondheim, Norway
| | - Christian F Beckmann
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands; Radboud University Medical Centre, Department of Cognitive Neuroscience, Nijmegen, The Netherlands; Oxford Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB), University of Oxford, Oxford, OX3 9DU, United Kingdom
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114
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Witter MP, Doan TP, Jacobsen B, Nilssen ES, Ohara S. Architecture of the Entorhinal Cortex A Review of Entorhinal Anatomy in Rodents with Some Comparative Notes. Front Syst Neurosci 2017; 11:46. [PMID: 28701931 PMCID: PMC5488372 DOI: 10.3389/fnsys.2017.00046] [Citation(s) in RCA: 197] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 06/07/2017] [Indexed: 12/18/2022] Open
Abstract
The entorhinal cortex (EC) is the major input and output structure of the hippocampal formation, forming the nodal point in cortico-hippocampal circuits. Different division schemes including two or many more subdivisions have been proposed, but here we will argue that subdividing EC into two components, the lateral EC (LEC) and medial EC (MEC) might suffice to describe the functional architecture of EC. This subdivision then leads to an anatomical interpretation of the different phenotypes of LEC and MEC. First, we will briefly summarize the cytoarchitectonic differences and differences in hippocampal projection patterns on which the subdivision between LEC and MEC traditionally is based and provide a short comparative perspective. Second, we focus on main differences in cortical connectivity, leading to the conclusion that the apparent differences may well correlate with the functional differences. Cortical connectivity of MEC is features interactions with areas such as the presubiculum, parasubiculum, retrosplenial cortex (RSC) and postrhinal cortex, all areas that are considered to belong to the "spatial processing domain" of the cortex. In contrast, LEC is strongly connected with olfactory areas, insular, medial- and orbitofrontal areas and perirhinal cortex. These areas are likely more involved in processing of object information, attention and motivation. Third, we will compare the intrinsic networks involving principal- and inter-neurons in LEC and MEC. Together, these observations suggest that the different phenotypes of both EC subdivisions likely depend on the combination of intrinsic organization and specific sets of inputs. We further suggest a reappraisal of the notion of EC as a layered input-output structure for the hippocampal formation.
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Affiliation(s)
- Menno P. Witter
- Functional Neuroanatomy, KavlI Institute for Systems Neuroscience, Center for Computational Neuroscience, Egil and Pauline Braathen and Fred Kavli Center for Cortical Microcircuits, NTNU Norwegian University of Science and TechnologyTrondheim, Norway
| | - Thanh P. Doan
- Functional Neuroanatomy, KavlI Institute for Systems Neuroscience, Center for Computational Neuroscience, Egil and Pauline Braathen and Fred Kavli Center for Cortical Microcircuits, NTNU Norwegian University of Science and TechnologyTrondheim, Norway
| | - Bente Jacobsen
- Functional Neuroanatomy, KavlI Institute for Systems Neuroscience, Center for Computational Neuroscience, Egil and Pauline Braathen and Fred Kavli Center for Cortical Microcircuits, NTNU Norwegian University of Science and TechnologyTrondheim, Norway
| | - Eirik S. Nilssen
- Functional Neuroanatomy, KavlI Institute for Systems Neuroscience, Center for Computational Neuroscience, Egil and Pauline Braathen and Fred Kavli Center for Cortical Microcircuits, NTNU Norwegian University of Science and TechnologyTrondheim, Norway
| | - Shinya Ohara
- Division of Systems Neuroscience, Tohoku University Graduate School of Life ScienceSendai, Japan
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115
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Anterolateral Entorhinal Cortex Volume Predicted by Altered Intra-Item Configural Processing. J Neurosci 2017; 37:5527-5538. [PMID: 28473640 DOI: 10.1523/jneurosci.3664-16.2017] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 04/20/2017] [Accepted: 04/25/2017] [Indexed: 01/03/2023] Open
Abstract
Recent functional imaging studies have proposed that the human entorhinal cortex (ERC) is subdivided into functionally distinct anterolateral (alERC) and posteromedial (pmERC) subregions. The alERC overlaps with regions that are affected earliest by Alzheimer's disease pathology, yet its cognitive function remains poorly understood. Previous human fMRI studies have focused on its role in object memory, but rodent studies on the putatively homologous lateral entorhinal cortex suggest that it also plays an important role in representing spatial properties of objects. To investigate the cognitive effects of human alERC volume differences, we developed an eye-tracking-based task to evaluate intra-item configural processing (i.e., processing the arrangement of an object's features) and used manual segmentation based on a recently developed protocol to delineate the alERC/pmERC and other medial temporal lobe (MTL) subregions. In a group of older adult men and women at varying stages of brain atrophy and cognitive decline, we found that intra-item configural processing, regardless of an object's novelty, was strongly predicted by alERC volume, but not by the volume of any other MTL subregion. These results provide the first evidence that the human alERC plays a role in supporting a distinct aspect of object processing, namely attending to the arrangement of an object's component features.SIGNIFICANCE STATEMENT Alzheimer's disease pathology appears earliest in brain regions that overlap with the anterolateral entorhinal cortex (alERC). However, the cognitive role of the alERC is poorly understood. Previous human studies treat the alERC as an extension of the neighboring perirhinal cortex, supporting object memory. Animal studies suggest that the alERC may support the spatial properties of objects. In a group of older adult humans at the earliest stages of cognitive decline, we show here that alERC volume selectively predicted configural processing (attention to the spatial arrangement of an object's parts). This is the first study to demonstrate a cognitive role related to alERC volume in humans. This task can be adapted to serve as an early detection method for Alzheimer's disease pathology.
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116
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Abstract
As the world's population continues to age, an understanding of the aging brain becomes increasingly crucial. This review focuses on several recent ideas and findings in the study of neurocognitive aging, specifically focusing on episodic memory, and discusses how they can be considered and used to guide us moving forward. Topics include dysfunction in neural circuits, the roles of neurogenesis and inhibitory signaling, vulnerability in the entorhinal cortex, individual differences, and comorbidities. These avenues of study provide a brief overview of promising themes in the field and together provide a snapshot of what we believe will be important emerging topics in selective vulnerabilities in the aging brain.
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Affiliation(s)
- Zachariah Reagh
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, USA
| | - Michael Yassa
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, USA
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117
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Bejanin A, Desgranges B, La Joie R, Landeau B, Perrotin A, Mézenge F, Belliard S, de La Sayette V, Eustache F, Chételat G. Distinct white matter injury associated with medial temporal lobe atrophy in Alzheimer's versus semantic dementia. Hum Brain Mapp 2017; 38:1791-1800. [PMID: 27981671 PMCID: PMC6866822 DOI: 10.1002/hbm.23482] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 11/15/2016] [Accepted: 11/21/2016] [Indexed: 01/31/2023] Open
Abstract
This study aims at further understanding the distinct vulnerability of brain networks in Alzheimer's disease (AD) versus semantic dementia (SD) investigating the white matter injury associated with medial temporal lobe (MTL) atrophy in both conditions. Twenty-six AD patients, twenty-one SD patients, and thirty-nine controls underwent a high-resolution T1-MRI scan allowing to obtain maps of grey matter volume and white matter density. A statistical conjunction approach was used to identify MTL regions showing grey matter atrophy in both patient groups. The relationship between this common grey matter atrophy and white matter density maps was then assessed within each patient group. Patterns of grey matter atrophy were distinct in AD and SD but included a common region in the MTL, encompassing the hippocampus and amygdala. This common atrophy was associated with alterations in different white matter areas in AD versus SD, mainly including the cingulum and corpus callosum in AD, while restricted to the temporal lobe - essentially the uncinate and inferior longitudinal fasciculi - in SD. Complementary analyses revealed that these relationships remained significant when controlling for global atrophy or disease severity. Overall, this study provides the first evidence that atrophy of the same MTL region is related to damage in distinct white matter fibers in AD and SD. These different patterns emphasize the vulnerability of distinct brain networks related to the MTL in these two disorders, which might underlie the discrepancy in their symptoms. These results further suggest differences between AD and SD in the neuropathological processes occurring in the MTL. Hum Brain Mapp 38:1791-1800, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Alexandre Bejanin
- U1077, InsermCaenFrance
- UMR‐S1077, Université de Caen ‐ NormandieCaenFrance
- UMR‐S1077, Ecole Pratique des Hautes EtudesCaenFrance
- U1077, CHU de CaenCaenFrance
| | - Béatrice Desgranges
- U1077, InsermCaenFrance
- UMR‐S1077, Université de Caen ‐ NormandieCaenFrance
- UMR‐S1077, Ecole Pratique des Hautes EtudesCaenFrance
- U1077, CHU de CaenCaenFrance
| | - Renaud La Joie
- U1077, InsermCaenFrance
- UMR‐S1077, Université de Caen ‐ NormandieCaenFrance
- UMR‐S1077, Ecole Pratique des Hautes EtudesCaenFrance
- U1077, CHU de CaenCaenFrance
| | - Brigitte Landeau
- U1077, InsermCaenFrance
- UMR‐S1077, Université de Caen ‐ NormandieCaenFrance
- UMR‐S1077, Ecole Pratique des Hautes EtudesCaenFrance
- U1077, CHU de CaenCaenFrance
| | - Audrey Perrotin
- U1077, InsermCaenFrance
- UMR‐S1077, Université de Caen ‐ NormandieCaenFrance
- UMR‐S1077, Ecole Pratique des Hautes EtudesCaenFrance
- U1077, CHU de CaenCaenFrance
| | - Florence Mézenge
- U1077, InsermCaenFrance
- UMR‐S1077, Université de Caen ‐ NormandieCaenFrance
- UMR‐S1077, Ecole Pratique des Hautes EtudesCaenFrance
- U1077, CHU de CaenCaenFrance
| | - Serge Belliard
- U1077, InsermCaenFrance
- UMR‐S1077, Université de Caen ‐ NormandieCaenFrance
- UMR‐S1077, Ecole Pratique des Hautes EtudesCaenFrance
- Service de NeurologieCHU PontchaillouRennesFrance
| | - Vincent de La Sayette
- U1077, InsermCaenFrance
- UMR‐S1077, Université de Caen ‐ NormandieCaenFrance
- UMR‐S1077, Ecole Pratique des Hautes EtudesCaenFrance
- U1077, CHU de CaenCaenFrance
- Service de NeurologieCHU de CaenCaenFrance
| | - Francis Eustache
- U1077, InsermCaenFrance
- UMR‐S1077, Université de Caen ‐ NormandieCaenFrance
- UMR‐S1077, Ecole Pratique des Hautes EtudesCaenFrance
- U1077, CHU de CaenCaenFrance
| | - Gaël Chételat
- U1077, InsermCaenFrance
- UMR‐S1077, Université de Caen ‐ NormandieCaenFrance
- UMR‐S1077, Ecole Pratique des Hautes EtudesCaenFrance
- U1077, CHU de CaenCaenFrance
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118
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Bergmann E, Zur G, Bershadsky G, Kahn I. The Organization of Mouse and Human Cortico-Hippocampal Networks Estimated by Intrinsic Functional Connectivity. Cereb Cortex 2016; 26:4497-4512. [PMID: 27797832 PMCID: PMC5193145 DOI: 10.1093/cercor/bhw327] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 09/12/2016] [Indexed: 12/11/2022] Open
Abstract
While the hippocampal memory system has been relatively conserved across mammals, the cerebral cortex has undergone massive expansion. A central question in brain evolution is how cortical development affected the nature of cortical inputs to the hippocampus. To address this question, we compared cortico-hippocampal connectivity using intrinsic functional connectivity MRI (fcMRI) in awake mice and humans. We found that fcMRI recapitulates anatomical connectivity, demonstrating sensory mapping within the mouse parahippocampal region. Moreover, we identified a similar topographical modality-specific organization along the longitudinal axis of the mouse hippocampus, indicating that sensory information arriving at the hippocampus is only partly integrated. Finally, comparing cortico-hippocampal connectivity across species, we discovered preferential hippocampal connectivity of sensory cortical networks in mice compared with preferential connectivity of association cortical networks in humans. Supporting this observation in humans but not in mice, sensory and association cortical networks are connected to spatially distinct subregions within the parahippocampal region. Collectively, these findings indicate that sensory cortical networks are coupled to the mouse but not the human hippocampal memory system, suggesting that the emergence of expanded and new association areas in humans resulted in the rerouting of cortical information flow and dissociation of primary sensory cortices from the hippocampus.
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Affiliation(s)
- Eyal Bergmann
- Department of Neuroscience, Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa 31096, Israel
| | - Gil Zur
- Department of Neuroscience, Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa 31096, Israel
| | - Guy Bershadsky
- Department of Neuroscience, Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa 31096, Israel
| | - Itamar Kahn
- Department of Neuroscience, Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa 31096, Israel
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119
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Bellmund JL, Deuker L, Navarro Schröder T, Doeller CF. Grid-cell representations in mental simulation. eLife 2016; 5. [PMID: 27572056 PMCID: PMC5005038 DOI: 10.7554/elife.17089] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 07/27/2016] [Indexed: 01/10/2023] Open
Abstract
Anticipating the future is a key motif of the brain, possibly supported by mental simulation of upcoming events. Rodent single-cell recordings suggest the ability of spatially tuned cells to represent subsequent locations. Grid-like representations have been observed in the human entorhinal cortex during virtual and imagined navigation. However, hitherto it remains unknown if grid-like representations contribute to mental simulation in the absence of imagined movement. Participants imagined directions between building locations in a large-scale virtual-reality city while undergoing fMRI without re-exposure to the environment. Using multi-voxel pattern analysis, we provide evidence for representations of absolute imagined direction at a resolution of 30° in the parahippocampal gyrus, consistent with the head-direction system. Furthermore, we capitalize on the six-fold rotational symmetry of grid-cell firing to demonstrate a 60° periodic pattern-similarity structure in the entorhinal cortex. Our findings imply a role of the entorhinal grid-system in mental simulation and future thinking beyond spatial navigation. DOI:http://dx.doi.org/10.7554/eLife.17089.001 Recordings of brain activity in moving rats have found neurons that fire when the rat is at specific locations. These neurons are known as grid cells because their activity produces a grid-like pattern. A separate group of neurons, called head direction cells, represents the rat’s facing direction. Functional magnetic resonance imaging (fMRI) studies that have tracked brain activity in humans as they navigate virtual environments have found similar grid-like and direction-related responses. A recent study showed grid-like responses even if the people being studied just imagined moving around an arena while lying still. Theoretical work suggests that spatially tuned cells might generally be important for our ability to imagine and simulate future events. However, it is not clear whether these location- and direction-responsive cells are active when people do not visualize themselves moving. Bellmund et al. used fMRI to track brain activity in volunteers as they imagined different views in a virtual reality city. Before the fMRI experiment, the volunteers completed extensive training where they learned the layout of the city and the names of its buildings. Then, during the fMRI experiment, the volunteers had to imagine themselves standing in front of certain buildings and facing different directions. Crucially, they did not imagine themselves moving between these buildings. By using representational similarity analysis, which compares patterns of brain activity, Bellmund et al. could distinguish between the directions the volunteers were imagining. Activity patterns in the parahippocampal gyrus (a brain region known to be important for navigation) were more similar when participants were imagining similar directions. The fMRI results also show grid-like responses in a brain area called entorhinal cortex, which is known to contain grid cells. While participants were imagining, this region exhibited activity patterns with a six-fold symmetry, as Bellmund et al. predicted from the characteristic firing patterns of grid cells. The findings presented by Bellmund et al. provide evidence that suggests that grid cells are involved in planning how to navigate, and so support previous theoretical assumptions. The computations of these cells might contribute to other kinds of thinking too, such as remembering the past or imagining future events. DOI:http://dx.doi.org/10.7554/eLife.17089.002
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Affiliation(s)
- Jacob Ls Bellmund
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands.,Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Trondheim, Norway
| | - Lorena Deuker
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands.,Department of Neuropsychology, Institute of Cognitive Neuroscience, Ruhr University Bochum, Bochum, Germany
| | - Tobias Navarro Schröder
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands.,Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Trondheim, Norway
| | - Christian F Doeller
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands.,Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Trondheim, Norway
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120
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Functional connectivity of the left and right hippocampi: Evidence for functional lateralization along the long-axis using meta-analytic approaches and ultra-high field functional neuroimaging. Neuroimage 2016; 135:64-78. [DOI: 10.1016/j.neuroimage.2016.04.022] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 01/31/2016] [Accepted: 04/09/2016] [Indexed: 12/17/2022] Open
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121
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Backus AR, Bosch SE, Ekman M, Grabovetsky AV, Doeller CF. Mnemonic convergence in the human hippocampus. Nat Commun 2016; 7:11991. [PMID: 27325442 PMCID: PMC4919533 DOI: 10.1038/ncomms11991] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 05/19/2016] [Indexed: 11/21/2022] Open
Abstract
The ability to form associations between a multitude of events is the hallmark of episodic memory. Computational models have espoused the importance of the hippocampus as convergence zone, binding different aspects of an episode into a coherent representation, by integrating information from multiple brain regions. However, evidence for this long-held hypothesis is limited, since previous work has largely focused on representational and network properties of the hippocampus in isolation. Here we identify the hippocampus as mnemonic convergence zone, using a combination of multivariate pattern and graph-theoretical network analyses of functional magnetic resonance imaging data from humans performing an associative memory task. We observe overlap of conjunctive coding and hub-like network attributes in the hippocampus. These results provide evidence for mnemonic convergence in the hippocampus, underlying the integration of distributed information into episodic memory representations. The ability to form associations between events is the hallmark of episodic memory and is thought to involve the hippocampus. Here the authors use a combination of multivariate pattern and graph theoretical network analyses of functional imaging data in humans, and show conjunctive coding and hub-like network attributes in the hippocampus.
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Affiliation(s)
- Alexander R Backus
- Radboud University, Donders Institute for Brain, Cognition and Behaviour, Nijmegen 6525 EN, The Netherlands
| | - Sander E Bosch
- Radboud University, Donders Institute for Brain, Cognition and Behaviour, Nijmegen 6525 EN, The Netherlands
| | - Matthias Ekman
- Radboud University, Donders Institute for Brain, Cognition and Behaviour, Nijmegen 6525 EN, The Netherlands
| | | | - Christian F Doeller
- Radboud University, Donders Institute for Brain, Cognition and Behaviour, Nijmegen 6525 EN, The Netherlands
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122
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Zhuo J, Fan L, Liu Y, Zhang Y, Yu C, Jiang T. Connectivity Profiles Reveal a Transition Subarea in the Parahippocampal Region That Integrates the Anterior Temporal-Posterior Medial Systems. J Neurosci 2016; 36:2782-95. [PMID: 26937015 PMCID: PMC6604873 DOI: 10.1523/jneurosci.1975-15.2016] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 01/25/2016] [Accepted: 01/30/2016] [Indexed: 11/21/2022] Open
Abstract
Traditional anatomical studies of the parahippocampal region (PHR) defined the lateral portion into two subregions, the perirhinal (PRC) and parahippocampal (PHC) cortices. Based on this organization, several models suggested that the PRC and the PHC play different roles in memory through connections with different memory-related brain networks. To identify the key components of the human PHR, we used a well accepted connection-based parcellation method on two independent datasets. Our parcellation divided the PRC and PHC into three subregions, specifically, the rostral PRC, caudal PRC (PRCc), and PHC. The connectivity profile for each subregion showed that the rostral PRC was connected to the anterior temporal (AT) system and the PHC was connected to the posterior medial (PM) system. The transition area (PRCc) integrated the AT-PM systems. These results suggest that the lateral PHR not only contains functionally segregated subregions, but also contains a functionally integrated subregion. SIGNIFICANCE STATEMENT We redefined the cartography of the human parahippocampal region (PHR) and identified a transition subarea based on distinct anatomical and functional connectivity profiles. This well defined anatomical organization of the PHR is necessary for expanding our understanding and studying the functional relevance of its subregions in recognition memory. We found that the transition subregion [caudal perirhinal cortex (PRCc)] is a functionally integrated subregion that integrates the anterior temporal (AT)-posterior medial (PM) systems. In addition, we found that the core components of the AT and PM systems connect with the PHR in the rostral PRC and parahippocampal cortex (PHC), respectively, rather than connecting with the traditional, larger, and thus less concise PRC and PHC areas. This may lead to new insights into the human memory system and related neurodegenerative diseases.
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Affiliation(s)
- Junjie Zhuo
- Key Laboratory for NeuroInformation of the Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 625014, Peoples' Republic of China
| | - Lingzhong Fan
- Brainnetome Center, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, Peoples' Republic of China, National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, Peoples' Republic of China
| | - Yong Liu
- Brainnetome Center, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, Peoples' Republic of China, National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, Peoples' Republic of China
| | - Yuanchao Zhang
- Key Laboratory for NeuroInformation of the Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 625014, Peoples' Republic of China
| | - Chunshui Yu
- Department of Radiology, Tianjin Medical University General Hospital, Tianjin, 300052, Peoples' Republic of China
| | - Tianzi Jiang
- Key Laboratory for NeuroInformation of the Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 625014, Peoples' Republic of China, Brainnetome Center, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, Peoples' Republic of China, National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, Peoples' Republic of China, Center for Excellence in Brain Science and Intelligence Technology, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, Peoples' Republic of China, The Queensland Brain Institute, University of Queensland, Brisbane, Queensland 4072, Australia, and
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123
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Duzel E, van Praag H, Sendtner M. Can physical exercise in old age improve memory and hippocampal function? Brain 2016; 139:662-73. [PMID: 26912638 PMCID: PMC4766381 DOI: 10.1093/brain/awv407] [Citation(s) in RCA: 196] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 12/19/2015] [Accepted: 12/21/2015] [Indexed: 01/19/2023] Open
Abstract
Physical exercise can convey a protective effect against cognitive decline in ageing and Alzheimer's disease. While the long-term health-promoting and protective effects of exercise are encouraging, it's potential to induce neuronal and vascular plasticity in the ageing brain is still poorly understood. It remains unclear whether exercise slows the trajectory of normal ageing by modifying vascular and metabolic risk factors and/or consistently boosts brain function by inducing structural and neurochemical changes in the hippocampus and related medial temporal lobe circuitry-brain areas that are important for learning and memory. Hence, it remains to be established to what extent exercise interventions in old age can improve brain plasticity above and beyond preservation of function. Existing data suggest that exercise trials aiming for improvement and preservation may require different outcome measures and that the balance between the two may depend on exercise intensity and duration, the presence of preclinical Alzheimer's disease pathology, vascular and metabolic risk factors and genetic variability.
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Affiliation(s)
- Emrah Duzel
- 1 Institute of Cognitive Neurology and Dementia Research, Otto-von-Guericke University Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany 2 German Center for Neurodegenerative Diseases (DZNE), Leipziger Str. 44, 39120 Magdeburg, Germany 3 Institute of Cognitive Neuroscience, University College London, 17 Queen Square, London, UK
| | - Henriette van Praag
- 4 Neuroplasticity and Behavior Unit, Laboratory of Neurosciences, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Michael Sendtner
- 5 Institute of Clinical Neurobiology, University of Würzburg, Versbacher Str. 5, 97078 Würzburg, Germany
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124
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Wang SF, Ritchey M, Libby LA, Ranganath C. Functional connectivity based parcellation of the human medial temporal lobe. Neurobiol Learn Mem 2016; 134 Pt A:123-134. [PMID: 26805590 DOI: 10.1016/j.nlm.2016.01.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 12/23/2015] [Accepted: 01/12/2016] [Indexed: 10/22/2022]
Abstract
Regional differences in large-scale connectivity have been proposed to underlie functional specialization along the anterior-posterior axis of the medial temporal lobe (MTL), including the hippocampus (HC) and the parahippocampal gyrus (PHG). However, it is unknown whether functional connectivity (FC) can be used reliably to parcellate the human MTL. The current study aimed to differentiate subregions of the HC and the PHG based on patterns of whole-brain intrinsic FC. FC maps were calculated for each slice along the longitudinal axis of the PHG and the HC. A hierarchical clustering algorithm was then applied to these data in order to group slices according to the similarity of their connectivity patterns. Surprisingly, three discrete clusters were identified in the PHG. Two clusters corresponded to the parahippocampal cortex (PHC) and the perirhinal cortex (PRC), and these regions showed preferential connectivity with previously described posterior-medial and anterior-temporal networks, respectively. The third cluster corresponded to an anterior PRC region previously described as area 36d, and this region exhibited preferential connectivity with auditory cortical areas and with a network involved in visceral processing. The three PHG clusters showed different profiles of activation during a memory-encoding task, demonstrating that the FC-based parcellation identified functionally dissociable sub-regions of the PHG. In the hippocampus, no sub-regions were identified via the parcellation procedure. These results indicate that connectivity-based methods can be used to parcellate functional regions within the MTL, and they suggest that studies of memory and high-level cognition need to differentiate between PHC, posterior PRC, and anterior PRC.
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Affiliation(s)
- Shao-Fang Wang
- Center for Neuroscience, University of California, Davis, CA 95618, USA.
| | - Maureen Ritchey
- Center for Neuroscience, University of California, Davis, CA 95618, USA
| | - Laura A Libby
- Center for Neuroscience, University of California, Davis, CA 95618, USA
| | - Charan Ranganath
- Center for Neuroscience, University of California, Davis, CA 95618, USA; Department of Psychology, University of California, Davis, CA 95616, USA
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Schultz H, Sommer T, Peters J. The Role of the Human Entorhinal Cortex in a Representational Account of Memory. Front Hum Neurosci 2015; 9:628. [PMID: 26635581 PMCID: PMC4653609 DOI: 10.3389/fnhum.2015.00628] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 11/02/2015] [Indexed: 01/08/2023] Open
Abstract
Connectivity studies in animals form the basis for a representational view of medial temporal lobe (MTL) subregions. In this view, distinct subfields of the entorhinal cortex (EC) relay object-related and spatial information from the perirhinal and parahippocampal cortices (PRC, PHC) to the hippocampus (HC). Relatively recent advances in functional magnetic resonance imaging (fMRI) methodology allow examining properties of human EC subregions directly. Antero-lateral and posterior-medial EC subfields show remarkable consistency to their putative rodent and nonhuman primate homologs with regard to intra- and extra-MTL functional connectivity. Accordingly, there is now evidence for a dissociation of object-related vs. spatial processing in human EC subfields. Here, variance in localization may be integrated in the antero-lateral vs. posterior-medial distinction, but may additionally reflect process differences. Functional results in rodents further suggest material-specific representations may be more integrated in EC compared to PRC/PHC. In humans, however, evidence for such a dissociation between EC and PRC/PHC is lacking. Future research may elucidate on the unique contributions of human EC to memory, especially in light of its high degree of intrinsic and extrinsic connectivity. A thorough characterization of EC subfield function may not only advance our understanding of human memory, but also have important clinical implications.
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Affiliation(s)
- Heidrun Schultz
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf Hamburg, Germany ; Department of Education and Psychology, Freie Universität Berlin Berlin, Germany
| | - Tobias Sommer
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf Hamburg, Germany
| | - Jan Peters
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf Hamburg, Germany
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Maass A, Berron D, Libby LA, Ranganath C, Düzel E. Functional subregions of the human entorhinal cortex. eLife 2015; 4. [PMID: 26052749 PMCID: PMC4458841 DOI: 10.7554/elife.06426] [Citation(s) in RCA: 156] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 05/06/2015] [Indexed: 11/13/2022] Open
Abstract
The entorhinal cortex (EC) is the primary site of interactions between the neocortex and hippocampus. Studies in rodents and nonhuman primates suggest that EC can be divided into subregions that connect differentially with perirhinal cortex (PRC) vs parahippocampal cortex (PHC) and with hippocampal subfields along the proximo-distal axis. Here, we used high-resolution functional magnetic resonance imaging at 7 Tesla to identify functional subdivisions of the human EC. In two independent datasets, PRC showed preferential intrinsic functional connectivity with anterior-lateral EC and PHC with posterior-medial EC. These EC subregions, in turn, exhibited differential connectivity with proximal and distal subiculum. In contrast, connectivity of PRC and PHC with subiculum followed not only a proximal-distal but also an anterior-posterior gradient. Our data provide the first evidence that the human EC can be divided into functional subdivisions whose functional connectivity closely parallels the known anatomical connectivity patterns of the rodent and nonhuman primate EC.
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Affiliation(s)
- Anne Maass
- Institute of Cognitive Neurology and Dementia Research, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
| | - David Berron
- Institute of Cognitive Neurology and Dementia Research, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
| | - Laura A Libby
- Center for Neuroscience, University of California at Davis, Davis, United States
| | - Charan Ranganath
- Department of Psychology, University of California at Davis, Davis, United States
| | - Emrah Düzel
- German Center for Neurodegenerative Diseases, Magdeburg, Germany
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127
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Ritchey M, Libby LA, Ranganath C. Cortico-hippocampal systems involved in memory and cognition. PROGRESS IN BRAIN RESEARCH 2015; 219:45-64. [DOI: 10.1016/bs.pbr.2015.04.001] [Citation(s) in RCA: 157] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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