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Fromm AE, Grittner U, Brodt S, Flöel A, Antonenko D. No Object-Location Memory Improvement through Focal Transcranial Direct Current Stimulation over the Right Temporoparietal Cortex. Life (Basel) 2024; 14:539. [PMID: 38792561 PMCID: PMC11122124 DOI: 10.3390/life14050539] [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: 02/18/2024] [Revised: 04/14/2024] [Accepted: 04/17/2024] [Indexed: 05/26/2024] Open
Abstract
Remembering objects and their associated location (object-location memory; OLM), is a fundamental cognitive function, mediated by cortical and subcortical brain regions. Previously, the combination of OLM training and transcranial direct current stimulation (tDCS) suggested beneficial effects, but the evidence remains heterogeneous. Here, we applied focal tDCS over the right temporoparietal cortex in 52 participants during a two-day OLM training, with anodal tDCS (2 mA, 20 min) or sham (40 s) on the first day. The focal stimulation did not enhance OLM performance on either training day (stimulation effect: -0.09, 95%CI: [-0.19; 0.02], p = 0.08). Higher electric field magnitudes in the target region were not associated with individual performance benefits. Participants with content-related learning strategies showed slightly superior performance compared to participants with position-related strategies. Additionally, training gains were associated with individual verbal learning skills. Consequently, the lack of behavioral benefits through focal tDCS might be due to the involvement of different cognitive processes and brain regions, reflected by participant's learning strategies. Future studies should evaluate whether other brain regions or memory-relevant networks may be involved in the modulation of object-location associations, investigating other target regions, and further exploring individualized stimulation parameters.
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Affiliation(s)
- Anna Elisabeth Fromm
- Department of Neurology, Universitätsmedizin Greifswald, Ferdinand-Sauerbruch-Straße, 17475 Greifswald, Germany
| | - Ulrike Grittner
- Berlin Institute of Health (BIH), 10178 Berlin, Germany
- Institute of Biometry and Clinical Epidemiology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany
| | - Svenja Brodt
- Max Planck Institute for Biological Cybernetics, 72076 Tübingen, Germany
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, 72076 Tübingen, Germany
| | - Agnes Flöel
- Department of Neurology, Universitätsmedizin Greifswald, Ferdinand-Sauerbruch-Straße, 17475 Greifswald, Germany
- German Centre for Neurodegenerative Diseases (DZNE) Standort Greifswald, 17489 Greifswald, Germany
| | - Daria Antonenko
- Department of Neurology, Universitätsmedizin Greifswald, Ferdinand-Sauerbruch-Straße, 17475 Greifswald, Germany
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Thams F, Külzow N, Flöel A, Antonenko D. Modulation of network centrality and gray matter microstructure using multi-session brain stimulation and memory training. Hum Brain Mapp 2022; 43:3416-3426. [PMID: 35373873 PMCID: PMC9248322 DOI: 10.1002/hbm.25857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 02/15/2022] [Accepted: 03/24/2022] [Indexed: 11/07/2022] Open
Abstract
Neural mechanisms of behavioral improvement induced by repeated transcranial direct current stimulation (tDCS) combined with cognitive training are yet unclear. Previously, we reported behavioral effects of a 3-day visuospatial memory training with concurrent anodal tDCS over the right temporoparietal cortex in older adults. To investigate intervention-induced neural alterations we here used functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) datasets available from 35 participants of this previous study, acquired before and after the intervention. To delineate changes in whole-brain functional network architecture, we employed eigenvector centrality mapping. Gray matter alterations were analyzed using DTI-derived mean diffusivity (MD). Network centrality in the bilateral posterior temporooccipital cortex was reduced after anodal compared to sham stimulation. This focal effect is indicative of decreased functional connectivity of the brain region underneath the anodal electrode and its left-hemispheric homolog with other "relevant" (i.e., highly connected) brain regions, thereby providing evidence for reorganizational processes within the brain's network architecture. Examining local MD changes in these clusters, an interaction between stimulation condition and training success indicated a decrease of MD in the right (stimulated) temporooccipital cluster in individuals who showed superior behavioral training benefits. Using a data-driven whole-brain network approach, we provide evidence for targeted neuromodulatory effects of a combined tDCS-and-training intervention. We show for the first time that gray matter alterations of microstructure (assessed by DTI-derived MD) may be involved in tDCS-enhanced cognitive training. Increased knowledge on how combined interventions modulate neural networks in older adults, will help the development of specific therapeutic interventions against age-associated cognitive decline.
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Affiliation(s)
- Friederike Thams
- Department of Neurology, Universitätsmedizin Greifswald, Greifswald, Germany
| | - Nadine Külzow
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Neurocure Cluster of Excellence, Berlin, Germany.,Neurological Rehabilitation Clinic, Kliniken Beelitz GmbH, Beelitz, Germany
| | - Agnes Flöel
- Department of Neurology, Universitätsmedizin Greifswald, Greifswald, Germany.,German Centre for Neurodegenerative Diseases (DZNE) Standort Greifswald, Greifswald, Germany
| | - Daria Antonenko
- Department of Neurology, Universitätsmedizin Greifswald, Greifswald, Germany
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Bernstein LJ, Edelstein K, Sharma A, Alain C. Chemo-brain: An activation likelihood estimation meta-analysis of functional magnetic resonance imaging studies. Neurosci Biobehav Rev 2021; 130:314-325. [PMID: 34454915 DOI: 10.1016/j.neubiorev.2021.08.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 07/24/2021] [Accepted: 08/23/2021] [Indexed: 11/17/2022]
Abstract
Adults with non-central nervous system (CNS) cancers frequently report problems in attention, memory and executive function during or after chemotherapy, referred to as cancer-related cognitive dysfunction (CRCD). Despite numerous studies investigating CRCD, there is no consensus regarding the brain areas implicated. We sought to determine if there are brain areas that consistently show either hyper- or hypo-activation in people treated with chemotherapy for non-CNS cancer (Chemo+). Using activation likelihood estimation on brain coordinates from 14 fMRI studies yielding 25 contrasts from 375 Chemo+ and 429 chemotherapy-naive controls while they performed cognitive tasks, the meta-analysis yielded two significant clusters which are part of the frontoparietal attention network, both showing lower activation in Chemo+. One cluster peaked in the left superior parietal cortex, extending into precuneus, inferior parietal lobule, and angular gyrus. The other peaked in the right superior prefrontal areas, extending into inferior prefrontal cortex. We propose that these observed lower activations reflect a dysfunction in mobilizing and/or sustaining attention due to depletion of cognitive resources. This could explain higher level of mental fatigue reported by Chemo+ and why cancer survivors report problems in a wide variety of cognitive domains.
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Affiliation(s)
- Lori J Bernstein
- Department of Supportive Care, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Canada.
| | - Kim Edelstein
- Department of Supportive Care, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Canada
| | - Alisha Sharma
- Department of Supportive Care, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Claude Alain
- Rotman Research Institute, Baycrest Health Centre, Canada; Department of Psychology, University of Toronto, Canada
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de Sousa AVC, Grittner U, Rujescu D, Külzow N, Flöel A. Impact of 3-Day Combined Anodal Transcranial Direct Current Stimulation-Visuospatial Training on Object-Location Memory in Healthy Older Adults and Patients with Mild Cognitive Impairment. J Alzheimers Dis 2020; 75:223-244. [PMID: 32280093 PMCID: PMC7306891 DOI: 10.3233/jad-191234] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/21/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND Associative object-location memory (OLM) is known to decline even in normal aging, and this process is accelerated in patients with mild cognitive impairment (MCI). Given the lack of curative treatment for Alzheimer's disease, activating cognitive resources during its preclinical phase might prevent progression to dementia. OBJECTIVE To evaluate the effects of anodal transcranial direct current stimulation (atDCS) combined with an associative episodic memory training on OLM in MCI patients and in healthy elderly (HE). METHODS In a single-blind cross-over design, 16 MCI patients and 32 HE underwent a 3-day visuospatial OLM training paired with either 20 min or 30 s (sham) atDCS (1 mA, right temporoparietal cortex). Effects on immediate (training success) and long-term memory (1-month) were investigated by conducting Mixed Model analyses. In addition, the impact of combined intervention on within-session (online) and on between-session (offline) performance were explored. RESULTS OLM training+atDCS enhanced training success only in MCI patients, but not HE (difference n.s.). Relative performance gain was similar in MCI patients compared to HE under atDCS. No beneficial effect was found after 1-month. Exploratory analyses suggested a positive impact on online, but a negative effect on offline performance in MCI patients. In both groups, exploratory post-hoc analyses indicated an association between initially low-performers and greater benefit from atDCS. CONCLUSION Cognitive training in MCI may be enhanced by atDCS, but further delineation of the impact of current brain state, as well as temporal characteristics of multi-session atDCS-training application, may be needed to induce longer-lasting effects.
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Affiliation(s)
- Angelica Vieira Cavalcanti de Sousa
- Charité – Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Neurocure Cluster of Excellence, Berlin, Germany
| | - Ulrike Grittner
- Charité – Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Center for Stroke Research, Berlin, Germany
- Charité – Universitätsmedizin Berlin, Institute of Biometry and Clinical Epidemiology, Berlin, Germany
| | - Dan Rujescu
- Department of Psychiatry, Psychotherapy and Psychosomatic, Martin-Luther-University Halle-Wittenberg, Germany
| | - Nadine Külzow
- Charité – Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Neurocure Cluster of Excellence, Berlin, Germany
- Kliniken Beelitz GmbH, Neurological Rehabilitation Clinic, Beelitz-Heilstätten, Germany
| | - Agnes Flöel
- Charité – Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Neurocure Cluster of Excellence, Berlin, Germany
- Charité – Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Center for Stroke Research, Berlin, Germany
- University Medicine Greifswald, Department of Neurology, Greifswald, Germany
- German Centre for Neurodegenerative Diseases (DZNE), Greifswald, Germany
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5
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Yaple ZA, Stevens WD, Arsalidou M. Meta-analyses of the n-back working memory task: fMRI evidence of age-related changes in prefrontal cortex involvement across the adult lifespan. Neuroimage 2019; 196:16-31. [DOI: 10.1016/j.neuroimage.2019.03.074] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 03/20/2019] [Accepted: 03/30/2019] [Indexed: 10/27/2022] Open
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Simon SS, Hampstead BM, Nucci MP, Duran FLS, Fonseca LM, Martin MDGM, Ávila R, Porto FHG, Brucki SMD, Martins CB, Tascone LS, Amaro E, Busatto GF, Bottino CMC. Training gains and transfer effects after mnemonic strategy training in mild cognitive impairment: A fMRI study. Int J Psychophysiol 2019; 154:15-26. [PMID: 30936043 DOI: 10.1016/j.ijpsycho.2019.03.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 03/21/2019] [Accepted: 03/28/2019] [Indexed: 12/14/2022]
Abstract
Prior work has revealed that mnemonic strategy training (MST) can enhance memory for specific content and engages regions in the frontoparietal cognitive control network. Evidence of transfer to novel content is less clear. Here, we provide secondary analysis of functional magnetic resonance imaging (fMRI) data acquired during a randomized controlled trial that compared MST to an active education control condition in patients with amnestic mild cognitive impairment (a-MCI). In the trial, thirty participants with a-MCI were randomized to the education program (EP) or MST, where they learned to apply the technique to face-name associations during four intervening hour long training sessions. Participants underwent pre- and post-training fMRI scans, during which they encoded both the trained (i.e., those used during the four training sessions) and untrained ('novel') face-name associations. The primary cognitive outcome measures revealed significantly improved memory for both trained and novel stimuli - effects supporting near transfer of MST. Relative to pre-training, there were significant and highly similar increases in activation for both trained and novel stimuli, especially in regions associated with the frontoparietal cognitive control network bilaterally, but also in temporal areas related to social cognition and emotional processing. Critically, this pattern of activation was notably different from the EP group. Thus, the changes in activation were consistent with the strategies trained and, combined with the cognitively-based near transfer effects, suggest that MST focused on face-name association enhances performance by engaging cognitive control and social/emotional processing. Finally, our data indicated that our MST is a relevant and efficient intervention to a-MCI.
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Affiliation(s)
- Sharon S Simon
- Old Age Research Group (PROTER), Department and Institute of Psychiatry, Faculty of Medicine, University of São Paulo, São Paulo, Brazil.
| | - Benjamin M Hampstead
- Division of Neuropsychology, Department of Psychiatry, University of Michigan, Ann Arbor, MI, USA; VA Ann Arbor Healthcare System, Ann Arbor, MI, USA
| | - Mariana P Nucci
- Neuroimagem funcional (NIF) - Laboratory of Medical Investigations on Magnetic Resonance Imaging (LIM-44), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, Brazil
| | - Fábio L S Duran
- Laboratory of Psychiatric Neuroimaging (LIM-21), Department and Institute of Psychiatry, Faculty of Medicine, University of São Paulo, São Paulo, Brazil
| | - Luciana M Fonseca
- Old Age Research Group (PROTER), Department and Institute of Psychiatry, Faculty of Medicine, University of São Paulo, São Paulo, Brazil
| | - Maria da Graça M Martin
- Neuroimagem funcional (NIF) - Laboratory of Medical Investigations on Magnetic Resonance Imaging (LIM-44), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, Brazil
| | - Renata Ávila
- Old Age Research Group (PROTER), Department and Institute of Psychiatry, Faculty of Medicine, University of São Paulo, São Paulo, Brazil
| | - Fábio H G Porto
- Old Age Research Group (PROTER), Department and Institute of Psychiatry, Faculty of Medicine, University of São Paulo, São Paulo, Brazil
| | - Sônia M D Brucki
- Department of Neurology, Faculty of Medicine, University of São Paulo, São Paulo, Brazil
| | - Camila B Martins
- Department of Preventive Medicine, Paulista School of Medicine, Federal University of São Paulo, São Paulo, Brazil
| | - Lyssandra S Tascone
- Old Age Research Group (PROTER), Department and Institute of Psychiatry, Faculty of Medicine, University of São Paulo, São Paulo, Brazil; Laboratory of Psychiatric Neuroimaging (LIM-21), Department and Institute of Psychiatry, Faculty of Medicine, University of São Paulo, São Paulo, Brazil
| | - Edson Amaro
- Neuroimagem funcional (NIF) - Laboratory of Medical Investigations on Magnetic Resonance Imaging (LIM-44), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, Brazil
| | - Geraldo F Busatto
- Laboratory of Psychiatric Neuroimaging (LIM-21), Department and Institute of Psychiatry, Faculty of Medicine, University of São Paulo, São Paulo, Brazil
| | - Cássio M C Bottino
- Old Age Research Group (PROTER), Department and Institute of Psychiatry, Faculty of Medicine, University of São Paulo, São Paulo, Brazil
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Brodt S, Gais S, Beck J, Erb M, Scheffler K, Schönauer M. Fast track to the neocortex: A memory engram in the posterior parietal cortex. Science 2018; 362:1045-1048. [PMID: 30498125 DOI: 10.1126/science.aau2528] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 10/10/2018] [Indexed: 12/11/2022]
Abstract
Models of systems memory consolidation postulate a fast-learning hippocampal store and a slowly developing, stable neocortical store. Accordingly, early neocortical contributions to memory are deemed to reflect a hippocampus-driven online reinstatement of encoding activity. In contrast, we found that learning rapidly engenders an enduring memory engram in the human posterior parietal cortex. We assessed microstructural plasticity via diffusion-weighted magnetic resonance imaging as well as functional brain activity in an object–location learning task. We detected neocortical plasticity as early as 1 hour after learning and found that it was learning specific, enabled correct recall, and overlapped with memory-related functional activity. These microstructural changes persisted over 12 hours. Our results suggest that new traces can be rapidly encoded into the parietal cortex, challenging views of a slow-learning neocortex.
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Affiliation(s)
- S. Brodt
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
- Max-Planck-Institute for Biological Cybernetics, Tübingen, Germany
| | - S. Gais
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - J. Beck
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - M. Erb
- Max-Planck-Institute for Biological Cybernetics, Tübingen, Germany
- Biomedical Magnetic Resonance, Universitätsklinikum Tübingen, Tübingen, Germany
| | - K. Scheffler
- Max-Planck-Institute for Biological Cybernetics, Tübingen, Germany
- Biomedical Magnetic Resonance, Universitätsklinikum Tübingen, Tübingen, Germany
| | - M. Schönauer
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
- Max-Planck-Institute for Biological Cybernetics, Tübingen, Germany
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
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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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Hampstead BM, Towler S, Stringer AY, Sathian K. Continuous measurement of object location memory is sensitive to effects of age and mild cognitive impairment and related to medial temporal lobe volume. ALZHEIMER'S & DEMENTIA: DIAGNOSIS, ASSESSMENT & DISEASE MONITORING 2017; 10:76-85. [PMID: 29255787 PMCID: PMC5724745 DOI: 10.1016/j.dadm.2017.10.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Introduction We present findings of a novel and ecologically relevant associative memory test, the Object Location Touchscreen Test (OLTT), which was posited as sensitive to early medial temporal lobe compromise associated with mild cognitive impairment (MCI). Methods A total of 114 participants, including healthy young and older controls and patients with MCI, completed the OLTT and standard neuropsychological testing. The OLTT required participants to recall the location of objects under free and cued recall conditions, with accuracy evaluated using distance measures (i.e., a continuous error score), and a standard recognition format. Correlations between performance and volumetric data were evaluated from a subset of 77 participants. Results Significant age effects were dwarfed by MCI effects across all test conditions. OLTT Cued Recall was strongly and specifically related to the volume of disease-relevant medial temporal lobe regions, generally more than traditional memory tests. Discussion The OLTT may be sensitive to early structural compromise in regions affected by Alzheimer's disease. Evaluated age and mild cognitive impairment effects using ecologically relevant object location (OL) task. Performance evaluated using both continuous and dichotomous measures of accuracy. Greater decline in OL memory with mild cognitive impairment than with “healthy” aging. Performance, especially continuous measure, reflected medial temporal integrity. Novel OL memory task may be sensitive to early structural compromise.
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Affiliation(s)
- Benjamin M Hampstead
- Mental Health Service, VA Ann Arbor Healthcare System, Ann Arbor, MI, USA.,Department of Psychiatry, Neuropsychology Program, University of Michigan, Ann Arbor, MI, USA.,Department of Neurology, Michigan Alzheimer's Disease Core Center, University of Michigan, Ann Arbor, MI, USA.,Rehabilitation R&D Center for Visual and Neurocognitive Rehabilitation, Atlanta VAMC, Decatur, GA, USA.,Department of Rehabilitation Medicine, Emory University, Atlanta, GA, USA
| | - Stephen Towler
- Rehabilitation R&D Center for Visual and Neurocognitive Rehabilitation, Atlanta VAMC, Decatur, GA, USA
| | - Anthony Y Stringer
- Department of Rehabilitation Medicine, Emory University, Atlanta, GA, USA.,Department of Psychology, Emory University, Atlanta, GA, USA
| | - Krishnankutty Sathian
- Rehabilitation R&D Center for Visual and Neurocognitive Rehabilitation, Atlanta VAMC, Decatur, GA, USA.,Department of Rehabilitation Medicine, Emory University, Atlanta, GA, USA.,Department of Neurology, Emory University, Atlanta, GA, USA.,Department of Psychology, Emory University, Atlanta, GA, USA
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10
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Classification of somatosensory cortex activities using fNIRS. Behav Brain Res 2017; 333:225-234. [PMID: 28668280 DOI: 10.1016/j.bbr.2017.06.034] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 06/10/2017] [Accepted: 06/20/2017] [Indexed: 01/08/2023]
Abstract
The ability of the somatosensory cortex in differentiating various tactile sensations is very important for a person to perceive the surrounding environment. In this study, we utilize a lab-made multi-channel functional near-infrared spectroscopy (fNIRS) to discriminate the hemodynamic responses (HRs) of four different tactile stimulations (handshake, ball grasp, poking, and cold temperature) applied to the right hand of eight healthy male subjects. The activated brain areas per stimulation are identified with the t-values between the measured data and the desired hemodynamic response function. Linear discriminant analysis is utilized to classify the acquired data into four classes based on three features (mean, peak value, and skewness) of the associated oxy-hemoglobin (HbO) signals. The HRs evoked by the handshake and poking stimulations showed higher peak values in HbO than the ball grasp and cold temperature stimulations. For comparison purposes, additional two-class classifications of poking vs. temperature and handshake vs. ball grasp were performed. The attained classification accuracies were higher than the corresponding chance levels. Our results indicate that fNIRS can be used as an objective measure discriminating different tactile stimulations from the somatosensory cortex of human brain.
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