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Llana T, Garces-Arilla S, Juan MC, Mendez-Lopez M, Mendez M. An immersive virtual reality-based object-location memory task reveals spatial long-term memory alterations in Long-COVID. Behav Brain Res 2024; 471:115127. [PMID: 38936427 DOI: 10.1016/j.bbr.2024.115127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 06/07/2024] [Accepted: 06/19/2024] [Indexed: 06/29/2024]
Abstract
Object-location memory (OLM) is a type of declarative memory for spatial information and consists of the individual's ability to establish accurate associations between objects and their spatial locations. Long-COVID describes the long-term effects of the COVID-19 disease. Long-COVID patients show medial temporal lobe dysfunction and neuropsychological alterations affecting memory. This study aimed to assess OLM in a group of Long-COVID patients, n=66, and a Control group of healthy individuals with similar age and sex composition, n=21, using an immersive virtual reality (iVR)-based OLM task. We also explored associations between the performance in the iVR-based OLM task and general cognitive function (MoCA), and both verbal (VSTM) and visuospatial (SSTM) span. The Long-COVID group showed fewer correct responses, made more task attempts, and invested more time in the iVR-based OLM task than the Control group. Delayed memory was more severely altered than immediate memory in Long-COVID participants. Better MoCA scores of the Long-COVID group were strongly associated with shorter times to complete the immediate recall of the iVR-based OLM task. Besides, the months elapsed since the COVID-19 infection were slightly associated with fewer correct responses in the immediate and 24-hour recalls. These results corroborate previous findings of memory alterations in the Long-COVID syndrome using an iVR-based OLM task, adding new evidence on spatial memory and long-term memory in this population. Implementing spatial iVR tasks to clinical research may improve our understanding of neuropsychological disorders.
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Affiliation(s)
- Tania Llana
- Neuroscience Institute of Principado de Asturias (INEUROPA), Faculty of Psychology, Plaza Feijoo s/n, Oviedo, Asturias 33003, Spain; Department of Psychology, University of Oviedo, Faculty of Psychology, Plaza Feijoo s/n, Oviedo, Asturias 33003, Spain.
| | - Sara Garces-Arilla
- Department of Psychology and Sociology, University of Zaragoza, Pedro Cerbuna 12, Zaragoza, Aragón 50009, Spain.
| | - M-Carmen Juan
- Instituto Universitario de Automática e Informática Industrial, Universitat Politècnica de València, C/Camino de Vera, s/n, Valencia 46022, Spain.
| | - Magdalena Mendez-Lopez
- Department of Psychology and Sociology, University of Zaragoza, Pedro Cerbuna 12, Zaragoza, Aragón 50009, Spain; IIS Aragón, San Juan Bosco, 13, Zaragoza, Aragón 50009, Spain.
| | - Marta Mendez
- Neuroscience Institute of Principado de Asturias (INEUROPA), Faculty of Psychology, Plaza Feijoo s/n, Oviedo, Asturias 33003, Spain; Department of Psychology, University of Oviedo, Faculty of Psychology, Plaza Feijoo s/n, Oviedo, Asturias 33003, Spain; Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Av. del Hospital Universitario, s/n, Oviedo, Asturias 33011, Spain.
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2
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Brown A, Burles F, Iaria G, Einstein G, Moscovitch M. Sex and menstrual cycle influence human spatial navigation strategies and performance. Sci Rep 2023; 13:14953. [PMID: 37696837 PMCID: PMC10495464 DOI: 10.1038/s41598-023-41153-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 08/22/2023] [Indexed: 09/13/2023] Open
Abstract
Which facets of human spatial navigation do sex and menstrual cycle influence? To answer this question, a cross-sectional online study of reproductive age women and men was conducted in which participants were asked to demonstrate and self-report their spatial navigation skills and strategies. Participants self-reported their sex and current menstrual phase [early follicular (EF), late follicular/periovulatory (PO), and mid/late luteal (ML)], and completed a series of questionnaires and tasks measuring self-reported navigation strategy use, topographical memory, cognitive map formation, face recognition, and path integration. We found that sex influenced self-reported use of cognitive map- and scene-based strategies, face recognition, and path integration. Menstrual phase moderated the influence of sex: compared to men, women had better face recognition and worse path integration, but only during the PO phase; PO women were also better at path integration in the presence of a landmark compared to EF + ML women and men. These findings provide evidence that human spatial navigation varies with the menstrual cycle and suggest that sensitivity of the entorhinal cortex and longitudinal axis of the hippocampus to differential hormonal effects may account for this variation.
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Affiliation(s)
- Alana Brown
- Psychology, University of Toronto, 100 St. George Street, Toronto, ON, M5S 3G3, Canada.
| | - Ford Burles
- Department of Psychology, Hotchkiss Brain Institute, and Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Giuseppe Iaria
- Department of Psychology, Hotchkiss Brain Institute, and Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Gillian Einstein
- Psychology, University of Toronto, 100 St. George Street, Toronto, ON, M5S 3G3, Canada
- Rotman Research Institute, Baycrest Academy of Research and Education, Baycrest Health Sciences, Toronto, ON, M6A 2E1, Canada
- Linköping University, 581 83, Linköping, Sweden
| | - Morris Moscovitch
- Psychology, University of Toronto, 100 St. George Street, Toronto, ON, M5S 3G3, Canada
- Rotman Research Institute, Baycrest Academy of Research and Education, Baycrest Health Sciences, Toronto, ON, M6A 2E1, Canada
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3
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Poos JM, van der Ham IJM, Leeuwis AE, Pijnenburg YAL, van der Flier WM, Postma A. Short Digital Spatial Memory Test Detects Impairment in Alzheimer's Disease and Mild Cognitive Impairment. Brain Sci 2021; 11:1350. [PMID: 34679414 PMCID: PMC8533689 DOI: 10.3390/brainsci11101350] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/05/2021] [Accepted: 10/09/2021] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Impairment in navigation abilities and object location memory are often seen in early-stage Alzheimer's Disease (AD), yet these constructs are not included in standard neuropsychological assessment. We investigated the differential ability of a short digital spatial memory test in mild AD dementia and mild cognitive impairment (MCI). METHODS 21 patients with AD dementia (66.9 ± 6.9; 47% female), 22 patients with MCI (69.6 ± 8.3; 46% female) and 21 patients with subjective cognitive decline (SCD) (62.2 ± 8.9; 48% female) from the Amsterdam Dementia Cohort performed the Object Location Memory Test (OLMT), consisting of a visual perception and memory trial, and the Virtual Tübingen (VT) test, consisting of a scene recognition, route continuation, route ordering and distance comparison task. The correlations with other cognitive domains were examined. RESULTS Patients with mild AD dementia (Z: -2.51 ± 1.15) and MCI (Z: -1.81 ± 0.92) performed worse than participants with SCD (Z: 0.0 ± 1.0) on the OLMT. Scene recognition and route continuation were equally impaired in patients with AD dementia (Z: -1.14 ± 0.73; Z: -1.44 ± 1.13) and MCI (Z: -1.37 ± 1.25; Z: -1.21 ± 1.07). Route ordering was only impaired in patients with MCI (Z: -0.82 ± 0.78). Weak to moderate correlations were found between route continuation and memory (r(64) = 0.40, p < 0.01), and between route ordering and attention (r(64) = 0.33, p < 0.01), but not for the OLMT. CONCLUSION A short digital spatial memory test battery was able to detect object location memory and navigation impairment in patients with mild AD dementia and MCI, highlighting the value of incorporating such a test battery in standard neuropsychological assessment.
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Affiliation(s)
- Jackie M. Poos
- Alzheimer Center Amsterdam, Department of Neurology, Amsterdam Neuroscience, Amsterdam University Medical Center, Vrije Universiteit Amsterdam, 1007 MB Amsterdam, The Netherlands; (A.E.L.); (Y.A.L.P.); (W.M.v.d.F.)
- Department of Neurology, Erasmus MC University Medical Center, 3015 GD Rotterdam, The Netherlands
- Helmholtz Institute, Experimental Psychology, Utrecht University, 3584 CS Utrecht, The Netherlands;
| | - Ineke J. M. van der Ham
- Institute of Psychology, Health, Medical and Neuropsychology, Leiden University, 2300 RB Leiden, The Netherlands;
| | - Anna E. Leeuwis
- Alzheimer Center Amsterdam, Department of Neurology, Amsterdam Neuroscience, Amsterdam University Medical Center, Vrije Universiteit Amsterdam, 1007 MB Amsterdam, The Netherlands; (A.E.L.); (Y.A.L.P.); (W.M.v.d.F.)
| | - Yolande A. L. Pijnenburg
- Alzheimer Center Amsterdam, Department of Neurology, Amsterdam Neuroscience, Amsterdam University Medical Center, Vrije Universiteit Amsterdam, 1007 MB Amsterdam, The Netherlands; (A.E.L.); (Y.A.L.P.); (W.M.v.d.F.)
| | - Wiesje M. van der Flier
- Alzheimer Center Amsterdam, Department of Neurology, Amsterdam Neuroscience, Amsterdam University Medical Center, Vrije Universiteit Amsterdam, 1007 MB Amsterdam, The Netherlands; (A.E.L.); (Y.A.L.P.); (W.M.v.d.F.)
- Department of Epidemiology & Biostatistics, Vrije Universiteit Amsterdam, Amsterdam UMC, 1081 HV Amsterdam, The Netherlands
| | - Albert Postma
- Helmholtz Institute, Experimental Psychology, Utrecht University, 3584 CS Utrecht, The Netherlands;
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Lugtmeijer S, Lammers NA, de Haan EHF, de Leeuw FE, Kessels RPC. Post-Stroke Working Memory Dysfunction: A Meta-Analysis and Systematic Review. Neuropsychol Rev 2020; 31:202-219. [PMID: 33230717 PMCID: PMC7889582 DOI: 10.1007/s11065-020-09462-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 10/07/2020] [Indexed: 12/16/2022]
Abstract
This review investigates the severity and nature of post-stroke working memory deficits with reference to the multi-component model of working memory. We conducted a systematic search in PubMed up to March 2019 with search terms for stroke and memory. Studies on adult stroke patients, that included a control group, and assessed working memory function, were selected. Effect sizes (Hedges' g) were extracted from 50 studies (in total 3,084 stroke patients) based on the sample size, mean and standard deviation of patients and controls. Performance of stroke patients was compared to healthy controls on low-load (i.e. capacity) and high-load (executively demanding) working memory tasks, grouped by modality (verbal, non-verbal). A separate analysis compared patients in the sub-acute and the chronic stage. Longitudinal studies and effects of lesion location were systematically reviewed. Stroke patients demonstrated significant deficits in working memory with a moderate effect size for both low-load (Hedges' g = -.58 [-.82 to -.43]) and high-load (Hedges' g = -.59 [-.73 to -.45]) tasks. The effect sizes were comparable for verbal and non-verbal material. Systematically reviewing the literature showed that working memory deficits remain prominent in the chronic stage of stroke. Lesions in a widespread fronto-parietal network are associated with working memory deficits. Stroke patients show decrements of moderate magnitude in all subsystems of working memory. This review clearly demonstrates the global nature of the impairment in working memory post-stroke.
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Affiliation(s)
- Selma Lugtmeijer
- University of Amsterdam, Amsterdam, the Netherlands. .,Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands.
| | | | | | - Frank-Erik de Leeuw
- Radboud University Medical Center, Department of Neurology, Nijmegen, the Netherlands
| | - Roy P C Kessels
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands.,Department of Medical Psychology, Radboud University Medical Center, Nijmegen, the Netherlands
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Cohen-Dallal H, Soroker N, Pertzov Y. Working Memory in Unilateral Spatial Neglect: Evidence for Impaired Binding of Object Identity and Object Location. J Cogn Neurosci 2020; 33:46-62. [PMID: 32985947 DOI: 10.1162/jocn_a_01631] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Working memory (WM) is known to be impaired in patients with stroke experiencing unilateral spatial neglect (USN). Here, we examined in a systematic manner three WM components: memory of object identity, memory of object location, and binding between object identity and location. Moreover, we used two different retention intervals to isolate maintenance from other mnemonic and perceptual processes. Fourteen USN first-event stroke patients with right-hemisphere damage were tested in two different WM experiments using long and short retention intervals and an analog response scale. Patients exhibited more identification errors for items displayed on the contralesional side. Localization errors were also more prominent in the contralesional side, especially after a long retention interval. These localization errors were often a result of swap errors, that is, erroneous localizations of correctly identified contralesional objects in correctly memorized locations of ipsilesional objects. We conclude that a key WM deficit in USN is a lateralized impairment in binding between the identity of an object and its spatial tag.
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Affiliation(s)
| | - Nachum Soroker
- Loewenstein Hospital, Raanana, Israel.,Tel-Aviv University
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6
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Tambini A, Nee DE, D’Esposito M. Hippocampal-targeted Theta-burst Stimulation Enhances Associative Memory Formation. J Cogn Neurosci 2018; 30:1452-1472. [PMID: 29916791 PMCID: PMC7467684 DOI: 10.1162/jocn_a_01300] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The hippocampus plays a critical role in episodic memory, among other cognitive functions. However, few tools exist to causally manipulate hippocampal function in healthy human participants. Recent work has targeted hippocampal-cortical networks by performing TMS to a region interconnected with the hippocampus, posterior inferior parietal cortex (pIPC). Such hippocampal-targeted TMS enhances associative memory and influences hippocampal functional connectivity. However, it is currently unknown which stages of mnemonic processing (encoding or retrieval) are affected by hippocampal-targeted TMS. Here, we examined whether hippocampal-targeted TMS influences the initial encoding of associations (vs. items) into memory. To selectively influence encoding and not retrieval, we performed continuous theta-burst TMS before participants encoded object-location associations and assessed memory after the direct effect of stimulation dissipated. Relative to control TMS and baseline memory, pIPC TMS enhanced associative memory success and confidence. Item memory was unaffected, demonstrating a selective influence on associative versus item memory. The strength of hippocampal-pIPC functional connectivity predicted TMS-related memory benefits, which was mediated by parahippocampal and retrosplenial cortices. Our findings indicate that hippocampal-targeted TMS can specifically modulate the encoding of new associations into memory without directly influencing retrieval processes and suggest that the ability to influence associative memory may be related to the fidelity of hippocampal TMS targeting. These results support the notion that pIPC TMS may serve as a potential tool for manipulating hippocampal function in healthy participants. Nonetheless, future work combining hippocampal-targeted continuous theta-burst TMS with neuroimaging is needed to better understand the neural basis of TMS-induced memory changes.
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Affiliation(s)
| | - Derek Evan Nee
- University of California, Berkeley
- Florida State University
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7
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Sharma G, Kaushal Y, Chandra S, Singh V, Mittal AP, Dutt V. Influence of Landmarks on Wayfinding and Brain Connectivity in Immersive Virtual Reality Environment. Front Psychol 2017; 8:1220. [PMID: 28775698 PMCID: PMC5517459 DOI: 10.3389/fpsyg.2017.01220] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 07/04/2017] [Indexed: 01/17/2023] Open
Abstract
Spatial navigation is influenced by landmarks, which are prominent visual features in the environment. Although previous research has focused on finding advantages of landmarks on wayfinding via experimentation; however, less attention has been given to identifying the key attributes of landmarks that facilitate wayfinding, including the study of neural correlates (involving electroencephalogram, EEG analyses). In this paper, we combine behavioral measures, virtual environment, and EEG signal-processing to provide a holistic investigation about the influence of landmarks on performance during navigation in a maze-like environment. In an experiment, participants were randomly divided into two conditions, Landmark-enriched (LM+; N = 17) and Landmark-devoid (LM-; N = 18), and asked to navigate from an initial location to a goal location in a maze. In the LM+ condition, there were landmarks placed at certain locations, which participants could use for wayfinding in the maze. However, in the LM- condition, such landmarks were not present. Beyond behavioral analyses of data, analyses were carried out of the EEG data collected using a 64-channel device. Results revealed that participants took less time and committed fewer errors in navigating the maze in the LM+ condition compared to the LM- condition. EEG analyses of the data revealed that the left-hemispheric activation was more prominent in the LM+ condition compared to the LM- condition. The event-related desynchronization/synchronization (ERD/ERS) of the theta frequency band, revealed activation in the left posterior inferior and superior regions in the LM+ condition compared to the LM- condition, suggesting an occurrence of an object-location binding in the LM+ condition along with spatial transformation between representations. Moreover, directed transfer function method, which measures information flow between two regions, showed a higher number of active channels in the LM- condition compared to the LM+ condition, exhibiting additional wiring cost associated with the cognitive demands when no landmark was available. These findings reveal pivotal role of the left-hemispheric region (especially, parietal cortex), which indicates the integration of available sensory cues and current memory requirements to encode contextual information of landmarks. Overall, this research helps to understand the role of brain regions and processes that are utilized when people use landmarks in navigating maze-like environments.
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Affiliation(s)
- Greeshma Sharma
- Department of Biomedical Engineering, Institute of Nuclear Medicine and Allied SciencesNew Delhi, India
| | | | - Sushil Chandra
- Department of Biomedical Engineering, Institute of Nuclear Medicine and Allied SciencesNew Delhi, India
| | | | - Alok P Mittal
- Netaji Subhas Institute of TechnologyNew Delhi, India.,All India Council for Technical EducationNew Delhi, India
| | - Varun Dutt
- School of Computing and Electrical Engineering and School of Humanities and Social Sciences, Indian Institute of Technology MandiMandi, India
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8
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Zimmermann K, Eschen A. Brain regions involved in subprocesses of small-space episodic object-location memory: a systematic review of lesion and functional neuroimaging studies. Memory 2016; 25:487-519. [DOI: 10.1080/09658211.2016.1188965] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Kathrin Zimmermann
- International Normal Aging and Plasticity Center (INAPIC), University of Zurich, Zurich, Switzerland
- Department of Gerontopsychology, University of Zurich, Zurich, Switzerland
- University Research Priority Program “Dynamics of Healthy Aging”, University of Zurich, Zurich, Switzerland
| | - Anne Eschen
- International Normal Aging and Plasticity Center (INAPIC), University of Zurich, Zurich, Switzerland
- University Research Priority Program “Dynamics of Healthy Aging”, University of Zurich, Zurich, Switzerland
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9
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Abstract
There is no research on the assessment or treatment of help-seeking behaviours for individuals with traumatic brain injury (TBI). This paper describes the development of a protocol, NICE (Noticing you have a problem, Identifying the information you need for help, Compensatory strategies, Evaluating progress) to train help-seeking for adults with TBI when lost. Theoretical and treatment components from three empirically validated interventions that target social problem-solving and communication skills were adapted to develop NICE: the Group Interactive Structured Treatment for Social Competence (GIST), the Problem Solving Group Protocol (PSG) and Interpersonal Recall (IPR). Preliminary pilot data evaluating the efficacy are presented for three adult persons with TBI. All three participants improved on the Executive Function Route Finding Task (EFRT) and help-seeking behaviours when wayfinding. Help-seeking is a constitutive factor in the wayfinding process capable of improvement. Preliminary evidence supports further investigation of this group intervention.
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10
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Parietal and frontal contributions to episodic encoding of location. Behav Brain Res 2013; 243:16-20. [PMID: 23295390 DOI: 10.1016/j.bbr.2012.12.048] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Revised: 12/21/2012] [Accepted: 12/27/2012] [Indexed: 11/23/2022]
Abstract
Specific contributions of frontal and parietal regions to visuospatial encoding and attention remain controversial. This study used fMRI to examine associative encoding of sequentially-presented spatial cues and object stimuli. The cue preceded the centrally-displayed object by a jittered-delay-interval to better isolate attempt and success in episodically integrating pure location information with separately presented objects. Superior parietal response was modulated by attempted location binding, while superior/middle frontal response was predictive of successful location binding.
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11
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Duffin JT, Collins DR, Coughlan T, O'Neill D, Roche RAP, Commins S. Subtle memory and attentional deficits revealed in an Irish stroke patient sample using domain-specific cognitive tasks. J Clin Exp Neuropsychol 2012; 34:864-75. [PMID: 22643030 DOI: 10.1080/13803395.2012.690368] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Stroke disrupts motor, sensory, and cognitive systems in survivors. Unlike in physical impairments, assessment of cognitive function is often inadequate, as no standardized procedure to monitor cognitive recovery post stroke exists. We evaluated a number of novel task-orientated tools designed to assess subtle cognitive deficits (including memory, attention, and executive functioning) in a sample of stroke patients. Although unimpaired on MMSE (Mini-Mental State Examination)-based indices of cognition, memory, and intelligence, stroke survivors were significantly impaired on tasks testing visual attention, spatial/relational processing, and associative memory. We recommend a standardized multidomain cognitive assessment and propose that cognitive deficits post stroke require in-depth assessment to inform patient-orientated rehabilitation.
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Affiliation(s)
- Joseph T Duffin
- Department of Psychology, National University of Ireland Maynooth, Maynooth, Ireland
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12
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Kesner RP. Parietal lesions produce illusory conjunction errors in rats. Front Integr Neurosci 2012; 6:22. [PMID: 22615689 PMCID: PMC3351790 DOI: 10.3389/fnint.2012.00022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 05/03/2012] [Indexed: 11/17/2022] Open
Abstract
When several different objects are presented, visual objects are perceived correctly only if their features are identified and then bound together. Illusory-conjunction errors result when an object is correctly identified but is combined incorrectly. The parietal cortex (PC) has been shown repeatedly to play an important role in feature binding. The present study builds on a series of recent studies that have made use of visual search paradigms to elucidate the neural system involved in feature binding. This experiment attempts to define the role the PC plays in binding the properties of a visual object that varies on the features of color and size in rats. Rats with PC lesions or control surgery were exposed to three blocks of 20 trials administered over a 1-week period, with each block containing 10-one feature and 10-two feature trials. The target object consisted of one color object (e.g., black and white) and one size object (e.g., short and tall). Of the 10 one feature trials, five of the trials were tailored specifically for size discrimination and five for color discrimination. In the two-feature condition, the animal was required to locate the targeted object among four objects with two objects differing in size and two objects differing in color. The results showed that the PC lesioned compared to control rats had difficulty in learning the one and two features components of the task and the rats also performed more poorly on the one vs. two feature components of the task. Based on a subsequent error analysis for color and size, the results showed a significant increase in illusory conjunction errors for the PC lesioned rats relative to controls for color and relative to color discrimination, suggesting that the PC may support feature binding as it relates to color. There was an increase in illusory conjunctions errors for both the PC lesioned and control animals for size, but this appeared to be due to highly variable performance with size discrimination. Overall these results suggest that the PC rats display performance errors that appear to be consistent with the notion of illusory conjunction errors.
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Affiliation(s)
- Raymond P Kesner
- Department of Psychology, University of Utah, Salt Lake City UT, USA
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13
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Abstract
The division of cortical visual processing into distinct dorsal and ventral streams is a key framework that has guided visual neuroscience. The characterization of the ventral stream as a 'What' pathway is relatively uncontroversial, but the nature of dorsal stream processing is less clear. Originally proposed as mediating spatial perception ('Where'), more recent accounts suggest it primarily serves non-conscious visually guided action ('How'). Here, we identify three pathways emerging from the dorsal stream that consist of projections to the prefrontal and premotor cortices, and a major projection to the medial temporal lobe that courses both directly and indirectly through the posterior cingulate and retrosplenial cortices. These three pathways support both conscious and non-conscious visuospatial processing, including spatial working memory, visually guided action and navigation, respectively.
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