1,125 research outputs found

    What memory binding functions is the hippocampus responsible for?

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    The role of the hippocampus in binding information in working memory (WM) is little understood. When complex experiences comprise associations between different pieces of information such as objects and locations (relational binding), the function of the hippocampus is required to hold them in WM (Mitchell et al., 2000; 2006; Piekema, 2006). However, recent evidence suggests that if the to-be-associated information leads to the formation of integrated objects such as coloured shapes (conjunctive binding), the hippocampus is less involved in holding temporary representations of these complex events in WM (Baddeley et al., 2010; Piekema, 2006). We investigated the relational and conjunctive binding hypotheses of the hippocampal functions in a patient with right hippocampal damage. The patient and controls were asked to study visual arrays of stimuli which consisted of shape-colour relations (shape-colour pairs) or shape-colour conjunctions (coloured shapes). After the study array, they were presented with a new screen consisting of one set of shapes (line drawings) and one set of colours. They were asked to reconstruct the bindings by selecting the shapes and their corresponding colours. As compared to healthy controls, the patient was impaired in holding relations of shapes and colours in WM whereas he could retain the conjunctions similarly to controls. These results lend support to the role of the hippocampus in supporting memory for inter-item associations but not memory for conjunctions of features which define objects' identity

    Short-term memory binding in mild cognitive impairment

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    We showed that short-term memory (STM) binding is sensitive to sporadic and familial Alzheimer's disease (AD) but is not affected by healthy ageing, chronic depression in the elderly or other forms of dementia. STM binding deficits were also observed in individuals with a genetic susceptibility for AD in the preclinical stages. Hence, we aim to investigate longitudinally individuals with Mild Cognitive Impairment (MCI) using STM binding tasks. Here we report on preliminary cross-sectional results. A comprehensive neuropsychological test battery and a visual STM task were given to 21 MCI patients and 20 controls. The STM task required participants to recognise changes across two consecutive arrays presenting either single features (colour or shape) or feature bindings. The MCI group performed significantly poorer than controls on standard tests of memory, attention and on the binding condition of the STM task, but not on single feature conditions. Performance on the binding task and on standard memory tests did not correlate. Eight MCI patients clearly performed outwith the range of normality in the binding task. However, they did not significantly differ from the other 13 MCI patients in disease severity or demographic and neuropsychological variables. Six patients with binding impairments showed a multiple domain profile whereas ten patients with a preserved binding function showed an amnesic profile [Chi-square = 5.45, p = 0.020]. These results suggest that (1) the binding task is assessing a function different from other memory tests and that (2) STM binding may be differentially impaired in MCI subgroups

    A novel peripheral biomarker for mild cognitive impairment and Alzheimer's disease

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    Background: Recent evidence suggests that oculomotor behaviours linked to cognitive performance can be a biomarker of Alzheimer’s disease (AD). Short-Term Memory Binding (STMB) declines in patients with AD dementia and in those at risk of dementia. STMB relies on brain regions relevant to visual processing which are known to support oculomotor behaviours. A combined analysis of oculomotor responses during STMB can enhance the sensitivity of the assessment of patients with AD or at risk of AD such as those with Mild Cognitive Impairment (MCI). We investigated this hypothesis. Methods: Using eye-tracking technologies, we measured pupil dilation, fixation, and exploratory eye movement behaviours in patients with AD, MCI and in healthy controls while they performed the STMBT. The STMBT assesses the ability to temporarily hold bicoloured objects whose colours had to be remembered either as individual features (baseline) or integrated within unified representations (binding). Results: Experiment 1 involved 18 healthy older adults and 18 patients with AD dementia. We observed (1) altered pupil dilation linked to poor STMB performance in AD patients. Experiment 2 involved 42 healthy older adults and 63 patients with MCI. Impaired fixation and exploratory eye movement behaviours accompanied poor STMB abilities in MCI patients. Conclusion: Taken together, the results above suggest that eye-tracking measures combined with cognitive markers for AD (STMBT) can (1) enrich the clinical phenotype of this type of dementia, (2) unveil novel features of AD dementia unknown to date, and (2) provide more sensitive tools which can detect and trace aspects of such phenotype in people at risk, thus helping to ascertain the presence of the prodromal stages of the disease

    Is it time to change the way we detect Alzheimer’s disease and monitor its progression? Towards affordable and theory-driven approaches from cognitive neurosciences

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    A large proportion of people suffering from Alzheimer’s disease (AD) worldwide are not receiving a timely diagnosis. The tools currently used to detect AD and monitor its progression are not sensitive to the preclinical stages and lack specificity for correctdiagnosis. Available biomarkers show acceptable levels of sensitivity but remain littlespecific and not accessible to everyone. We embrace the view that enhancing cognitive assessment of AD should be a research priority. This Perspective paper focuses on issues which, to our view, have been preventing cognitive tests from meeting outstanding needs in the early of detection, monitoring, and treatment development of AD dementia.We first outline the limitations of current diagnostic procedures both theoretically and practically. We then provide a rationale for theory-driven cognitive approaches which would allow mapping assessment tools to specific neuropathological stages of the neurodegenerative course of AD. Finally, we propose research strategies that would help test a hypothesis which, though launched five years ago, remains untested.That is: “Which memory system is impaired first in Alzheimer’s disease?

    Vídeo autobiográfico: una memoria cultural en constante hibridación: Caso: Estudiantes indígenas pertenecientes al Cabildo Indígena Universitario de la Universidad Tecnológica de Pereira, durante el año 2018

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    El presente documento expone la investigación realizada durante el primer semestre académico del año 2017, hasta el segundo semestre del año lectivo 2018, denominado “Reconstrucción de memoria cultural mediante la producción del vídeo autobiográfico en estudiantes pertenecientes al Cabildo Indígena Universitario de la Universidad Tecnológica de Pereira, durante el año 2018”. Este trabajo se encuentra en el marco de la Educomunicación, realizando una mediación entre la comunicación, la educación y por supuesto la cultura. Donde se realizó un arduo trabajo de campo para identificar los rasgos de memoria cultural que conservaban los estudiantes indígenas de la Universidad Tecnológica de Pereira, en el entorno educativo y social. Mediante la construcción del vídeo autobiográfico como herramienta, se les permitió a los estudiantes indígenas, contar y narrar su ser, expresando costumbres, vivencias y aspectos de su cultura, para de esta forma reconstruir y reconocer su memoria. Así, la acción de contar, re vivir y plasmar hechos vividos mediante la narración audiovisual, permitió al individuo realizar un proceso de reconocimiento en el cual se generó una auto observación y por ende una construcción propia de sí mismo. El proceso generado en el presente trabajo investigativo, posibilitó la reflexión sobre las trasformaciones que evidencia y experimenta un individuo al cambiar de entornos, ambientes y relaciones, dejando de lado de forma indirecta, su cultura. Por lo tanto, el desarrollo de esta investigación nos dio pie para exponer enfoques teóricos que consolidaron la metodología y buscaron el objetivo general de este trabajo de grado: generar la producción de video autobiográfico como posible posibilitadora de la reconstrucción de memoria cultural; y los objetivos específicos: Recopilar información de la historia personal de cada uno de los estudiantes, Crear videos autobiográficos e Interpretar cómo el proceso de creación del video autobiográfico, que contribuyen a lograr la reconstrucción de memoria cultural en los estudiantes pertenecientes al Cabildo Indígena Universitario de la Universidad Tecnológica de Pereira (CIU-UTP)

    determinación de la cinemática de objetos móviles bajo condiciones controladas mediante imágenes afectadas por desenfoque de movimiento lineal

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    A través de los años el hombre ha presentado un cambio radical en su nivel de vida; los conocimientos que él ha logrado acumular y aplicar en su trabajo ha sido para su beneficio, que ha cambiado radicalmente su modo de vivir, a medida que pasa el tiempo nos damos cuenta que cada vez es más y más importante el uso de la tecnología en nuestras vidas, vemos como poco a poco las cosas y sobre todo los aparatos tecnológicos han venido cambiando y modificando fuertemente. En el procesamiento digital de imágenes deben tomarse en cuenta varios aspectos como la percepción psicovisual del ser humano. Éste es un factor importante, porque independientemente del tratamiento que se le aplique a una imagen, el observador será quien, según su percepción, decidirá si dicha imagen le agrada o no
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