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1.
AJNR Am J Neuroradiol ; 38(5): 961-965, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-28279988

RESUMEN

BACKGROUND AND PURPOSE: The entorhinal cortex, a critical gateway between the neocortex and hippocampus, is one of the earliest regions affected by Alzheimer disease-associated neurofibrillary tangle pathology. Although our prior work has automatically delineated an MR imaging-based measure of the entorhinal cortex, whether antemortem entorhinal cortex thickness is associated with postmortem tangle burden within the entorhinal cortex is still unknown. Our objective was to evaluate the relationship between antemortem MRI measures of entorhinal cortex thickness and postmortem neuropathological measures. MATERIALS AND METHODS: We evaluated 50 participants from the Rush Memory and Aging Project with antemortem structural T1-weighted MR imaging and postmortem neuropathologic assessments. Here, we focused on thickness within the entorhinal cortex as anatomically defined by our previously developed MR imaging parcellation system (Desikan-Killiany Atlas in FreeSurfer). Using linear regression, we evaluated the association between entorhinal cortex thickness and tangles and amyloid-ß load within the entorhinal cortex and medial temporal and neocortical regions. RESULTS: We found a significant relationship between antemortem entorhinal cortex thickness and entorhinal cortex (P = .006) and medial temporal lobe tangles (P = .002); we found no relationship between entorhinal cortex thickness and entorhinal cortex (P = .09) and medial temporal lobe amyloid-ß (P = .09). We also found a significant association between entorhinal cortex thickness and cortical tangles (P = .003) and amyloid-ß (P = .01). We found no relationship between parahippocampal gyrus thickness and entorhinal cortex (P = .31) and medial temporal lobe tangles (P = .051). CONCLUSIONS: Our findings indicate that entorhinal cortex-associated in vivo cortical thinning may represent a marker of postmortem medial temporal and neocortical Alzheimer disease pathology.


Asunto(s)
Enfermedad de Alzheimer/patología , Amiloide/análisis , Corteza Entorrinal/patología , Ovillos Neurofibrilares/patología , Anciano , Enfermedad de Alzheimer/diagnóstico por imagen , Amiloidosis/patología , Autopsia , Corteza Entorrinal/diagnóstico por imagen , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino
2.
Epidemiol Infect ; 143(3): 573-7, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24892580

RESUMEN

SUMMARY Wild canids are potential hosts for numerous species of Bartonella, yet little research has been done to quantify their infection rates in South America. We sought to investigate Bartonella seroprevalence in captive wild canids from 19 zoos in São Paulo and Mato Grosso states, Brazil. Blood samples were collected from 97 wild canids belonging to four different native species and three European wolves (Canis lupus). Indirect immunofluorescent antibody testing was performed to detect the presence of B. henselae, B. vinsonii subsp. berkhoffii, B. clarridgeiae, and B. rochalimae. Overall, Bartonella antibodies were detected in 11 of the canids, including five (12·8%) of 39 crab-eating foxes (Cerdocyon thous), three (11·1%) of 27 bush dogs (Speothos venaticus), two (8·7%) of 23 maned wolves (Chrysocyon brachyurus) and one (12·5%) of eight hoary foxes (Lycalopex vetulus), with titres ranging from 1:64 to 1:512. Knowing that many species of canids make excellent reservoir hosts for Bartonella, and that there is zoonotic potential for all Bartonella spp. tested for, it will be important to conduct further research in non-captive wild canids to gain an accurate understanding of Bartonella infection in free-ranging wild canids in South America.


Asunto(s)
Animales de Zoológico , Anticuerpos Antibacterianos/sangre , Infecciones por Bartonella/veterinaria , Bartonella/inmunología , Canidae , Animales , Infecciones por Bartonella/epidemiología , Infecciones por Bartonella/microbiología , Brasil/epidemiología , Técnica del Anticuerpo Fluorescente Indirecta , Estudios Seroepidemiológicos
3.
Neuroimage ; 45(1): 237-46, 2009 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-19015038

RESUMEN

Older adults often show bilateral brain activation, compared to unilateral activation in younger adults, when performing tasks in domains of age-associated cognitive impairment, such as episodic and working memory. Less is known about activation associated with performance in cognitive domains that are typically unaffected by healthy aging. We used event-related functional magnetic resonance imaging to examine age-related patterns in brain activation associated with a form of implicit memory, repetition priming, which is typically preserved in healthy aging. Sixteen younger adults and 15 nondemented older adults performed semantic judgments (abstract/concrete) on single words in a study phase. In a test phase, identical judgments were made for repeated and new words. Younger and older adults showed similar response-time benefits (repetition priming) from repeated semantic classification. Repetition priming was associated with repetition-related reductions of prefrontal activation in both groups, but the patterns of activation differed between groups. Both groups showed similar activation reductions in dorsal left inferior prefrontal cortex (LIPFC), but older adults showed less reduction than younger adults in ventral and anterior LIPFC. Activation reductions were exclusively left-lateralized for younger adults, whereas older adults showed additional reductions in multiple regions of right frontal cortices. Right prefrontal activation reductions in older adults correlated with better repetition priming and better performance on independent tests of semantic processing. Thus, reduced asymmetry of prefrontal activation reductions in healthy aging was related to conceptual repetition priming, a form of learning that is spared in aging, and with the sparing of semantic memory.


Asunto(s)
Envejecimiento/fisiología , Encéfalo/fisiología , Cognición/fisiología , Lateralidad Funcional/fisiología , Recuerdo Mental , Corteza Prefrontal/fisiología , Reconocimiento en Psicología , Semántica , Adulto , Anciano , Mapeo Encefálico , Toma de Decisiones/fisiología , Potenciales Evocados/fisiología , Femenino , Humanos , Masculino , Análisis y Desempeño de Tareas
4.
J Neurol Neurosurg Psychiatry ; 75(2): 191-5, 2004 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-14742585

RESUMEN

BACKGROUND: Chronic stress has been associated with impaired episodic memory, but the association of premorbidly experienced distress with memory function in Alzheimer's disease is unknown. OBJECTIVE: To investigate the link between proneness to distress and Alzheimer's disease. METHODS: Participants were 363 persons with clinically diagnosed Alzheimer's disease. At baseline, a knowledgeable informant rated each person's premorbid personality (that is, before dementia onset) along five dimensions, one of which was the tendency to experience psychological distress. Participants underwent structured clinical evaluations at baseline and then annually for up to four years. Each evaluation included 17 cognitive tests from which previously established measures of episodic memory, visuoconstruction, repetition, and naming were derived. RESULTS: In a series of random effects models adjusted for age, sex, and education, premorbid distress proneness was associated with baseline impairment in episodic memory but not with impairment in other cognitive domains, or with change in any cognitive domain. No other trait was related to baseline function or rate of decline in any cognitive domain. CONCLUSIONS: The results suggest that premorbid proneness to experience psychological distress is related to level of impairment in episodic memory in persons with Alzheimer's disease, but neither distress proneness nor other personality traits are related to disease progression.


Asunto(s)
Enfermedad de Alzheimer/psicología , Trastorno Depresivo Mayor/etiología , Trastornos de la Memoria/diagnóstico , Anciano , Trastornos del Conocimiento/diagnóstico , Trastornos del Conocimiento/epidemiología , Trastorno Depresivo Mayor/diagnóstico , Trastorno Depresivo Mayor/epidemiología , Femenino , Estudios de Seguimiento , Humanos , Masculino , Trastornos de la Memoria/epidemiología , Pruebas Neuropsicológicas , Trastornos de la Personalidad/diagnóstico , Trastornos de la Personalidad/epidemiología , Psicometría , Índice de Severidad de la Enfermedad , Factores de Tiempo
5.
J Int Neuropsychol Soc ; 7(7): 785-94, 2001 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11771621

RESUMEN

This study examined the distinction between identification and production processes in repetition priming for 16 patients with Alzheimer's disease (AD) and 16 healthy old control participants (NC). Words were read in three study phases. In three test phases, participants (1) reread studied words, along with unstudied words, in a word-naming task (identification priming); (2) completed 3-letter stems of studied and unstudied words into words in a word-stem completion task (production priming); and (3) answered yes or no to having read studied and unstudied words in a recognition task (explicit memory). Explicit memory and word-stem completion priming were impaired in the AD group compared to the NC group. After correcting for baseline slowing, word-naming priming magnitude did not differ between the groups. The results suggest that the distinction between production and identification processes has promise for explaining the pattern of preservation and failure of repetition priming in AD.


Asunto(s)
Enfermedad de Alzheimer/diagnóstico , Atención , Recuerdo Mental , Práctica Psicológica , Aprendizaje Verbal , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/psicología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Aprendizaje por Asociación de Pares , Reconocimiento Visual de Modelos , Retención en Psicología
6.
Curr Opin Neurobiol ; 9(2): 240-4, 1999 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10322182

RESUMEN

Recent findings have further characterized the neural and psychological bases of long-term memory failure in Alzheimer's disease. Convergent volumetric neuroimaging studies indicate that loss of episodic memory is specifically related to early-stage limbic-diencephalic pathology, and that non-mnemonic impairment is specifically related to later-stage temporal-neocortical pathology. Recent studies of Alzheimer's disease have also reported informative cognitive dissociations in semantic memory and implicit memory.


Asunto(s)
Enfermedad de Alzheimer/psicología , Trastornos de la Memoria/fisiopatología , Envejecimiento/fisiología , Humanos , Semántica
7.
Neuropsychology ; 13(1): 22-30, 1999 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-10067772

RESUMEN

There are many conflicting results concerning the effects of age and Alzheimer's disease (AD) on word-stem completion priming. To examine potential sources of this variability, the authors examined the influences on such priming of age, cognitive status, and encoding in a large sample of young, old, and AD individuals. At study, words were processed aloud by reading, reading and rating likeability, or generating from definition. Old participants had less priming than young participants and more priming than AD patients. For the healthy old participants, priming decreased with advancing age and with cognitive loss following generation only. For AD patients, priming decreased as dementia severity increased; patients with the mildest dementia did not differ from healthy old participants. Thus, age, cognitive status, and encoding differentially influenced the magnitude of priming in healthy aging and AD.


Asunto(s)
Envejecimiento/fisiología , Enfermedad de Alzheimer/complicaciones , Trastornos del Conocimiento/etiología , Estado de Salud , Vocabulario , Adulto , Factores de Edad , Anciano , Trastornos del Conocimiento/diagnóstico , Humanos , Pruebas Neuropsicológicas , Índice de Severidad de la Enfermedad
8.
J Exp Psychol Gen ; 128(4): 479-98, 1999 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-10650584

RESUMEN

Four experiments examined a distinction between kinds of repetition priming which involve either the identification of the form or meaning of a stimulus or the production of a response on the basis of a cue. Patients with Alzheimer's disease had intact priming on picture-naming and category-exemplar identification tasks and impaired priming on word-stem completion and category-exemplar production tasks. Division of study-phase attention in healthy participants reduced priming on word-stem completion and category-exemplar production tasks but not on picture-naming and category-exemplar identification tasks. The parallel dissociations in normal and abnormal memory cannot be explained by implicit-explicit or perceptual-conceptual distinctions but are explained by an identification-production distinction. There may be separable cognitive and neural bases for implicit modulation of identification and production forms of knowledge.


Asunto(s)
Enfermedad de Alzheimer/psicología , Atención , Señales (Psicología) , Memoria , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Casos y Controles , Femenino , Humanos , Masculino , Recuerdo Mental , Persona de Mediana Edad , Reconocimiento Visual de Modelos , Pruebas de Asociación de Palabras
9.
J Int Neuropsychol Soc ; 5(7): 659-67, 1999 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-10645707

RESUMEN

Impairments to either perceptual or word-retrieval processes have been hypothesized to explain confrontation naming impairments in patients with Alzheimer's disease (AD). This study measured the effects of structural similarity, which affects perceptual processing, and name frequency, which affects word retrieval, on naming latency and accuracy in 16 AD patients and 16 age-matched controls. AD patients named pictures more slowly and made more errors than control participants. Their naming accuracy was disproportionately affected by name frequency, but not by structural similarity. The findings indicate that the processing of structural properties of objects is unaffected in early-stage AD, and suggest that word-retrieval impairments underlie the naming deficit in AD.


Asunto(s)
Enfermedad de Alzheimer , Trastornos de la Memoria/diagnóstico , Semántica , Percepción Visual/fisiología , Vocabulario , Anciano , Enfermedad de Alzheimer/diagnóstico , Humanos , Índice de Severidad de la Enfermedad
10.
Cortex ; 34(4): 493-511, 1998 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-9800086

RESUMEN

The present study examined whether the same brain region mediates visual-perceptual repetition priming and a familiarity component of visual recognition memory. In two experiments, familiarity-based recognition was measured in an individual (M.S.) with impaired visual repetition priming due to a lesion of right occipital cortex. In both experiments, M.S. demonstrated intact recognition familiarity despite his visual nondeclarative memory impairment. These results converge with other behavioral results to indicate that recognition familiarity does not depend on the same memory system that mediates perceptual priming.


Asunto(s)
Trastornos Disociativos/fisiopatología , Memoria/fisiología , Pruebas Neuropsicológicas , Reconocimiento Visual de Modelos/fisiología , Percepción Visual/fisiología , Adulto , Trastornos Disociativos/psicología , Lateralidad Funcional , Humanos , Masculino , Trastornos de la Memoria/etiología , Trastornos de la Memoria/fisiopatología , Trastornos de la Memoria/psicología , Lóbulo Occipital/anatomía & histología , Lóbulo Occipital/patología , Lóbulo Occipital/fisiología , Estimulación Luminosa , Factores de Tiempo , Corteza Visual/fisiología , Vías Visuales/fisiología , Pruebas de Asociación de Palabras
11.
J Int Neuropsychol Soc ; 4(5): 435-46, 1998 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-9745233

RESUMEN

Priming for line drawings of real and nonreal objects was examined in an object decision task for 16 patients with Alzheimer's disease (AD) and 16 normal elderly control (NC) participants. In two study phases, participants decided if objects were real or nonreal. In an implicit test phase, real/nonreal decisions were made for studied and unstudied objects, and priming was measured as the difference in decision speed or accuracy between studied and unstudied objects. In an explicit test phase, yes/no recognition was measured for real and nonreal objects. AD patients had impaired explicit memory for real and nonreal objects and intact repetition priming for real objects. By the latency measure, both AD and NC groups showed priming for nonreal objects but in opposite ways. Classification decisions about studied relative to nonstudied nonreal objects were slower for the AD patients, whereas such decisions were faster for the NC participants. Classification decisions of both groups were less accurate for repeated nonreal objects. These results support the claim that AD patients with mild cognitive impairment show normal perceptual priming. The AD inhibition for studied nonreal objects is discussed in terms of the decision conflict that occurs when recollection of source is not available to counter the influence of familiarity.


Asunto(s)
Enfermedad de Alzheimer/psicología , Toma de Decisiones/fisiología , Percepción Visual/fisiología , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Memoria/fisiología , Persona de Mediana Edad , Desempeño Psicomotor/fisiología , Tiempo de Reacción/fisiología
12.
Neuropsychology ; 12(3): 340-52, 1998 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-9673992

RESUMEN

Picture-naming priming was examined across different study-test transformations to explore the nature of memory representations of objects supporting implicit memory processes in patients with Alzheimer's disease (AD). Although severely impaired in explicit memory for pictures and words, AD patients demonstrated normal priming across perceptual transformations in picture orientation (Experiment 1) and picture size (Experiment 2) and across symbolic transformations from words to pictures (Experiment 3). In addition, the priming across alterations in picture size was invariant. This demonstrates that AD patients have preserved implicit memory for high-level, abstract representations of objects.


Asunto(s)
Enfermedad de Alzheimer/fisiopatología , Trastornos de la Memoria/fisiopatología , Reconocimiento Visual de Modelos/fisiología , Transferencia de Experiencia en Psicología/fisiología , Conducta Verbal/fisiología , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/complicaciones , Análisis de Varianza , Anomia/fisiopatología , Formación de Concepto/fisiología , Señales (Psicología) , Femenino , Humanos , Masculino , Trastornos de la Memoria/etiología , Persona de Mediana Edad , Orientación/fisiología , Tiempo de Reacción , Lectura , Percepción del Tamaño/fisiología , Vocabulario
13.
Psychol Aging ; 13(1): 88-119, 1998 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-9533193

RESUMEN

On repetition priming tasks, memory is measured indirectly as a change in performance due to recent experience. It is often functionally and neurally dissociated from performance on explicit memory tasks, which directly measure conscious recall or recognition of recent events. Repetition priming has therefore been extensively studied in normal aging and Alzheimer's disease, which feature mild to severe changes in explicit memory. Initial studies indicated that repetition priming was immune to the effects of aging and greatly reduced in Alzheimer's disease (AD). As more studies have been performed, however, these initial conclusions appear less clear than before and, in the case of AD, actually misleading. The purpose of this article is to provide a comprehensive review of this rapidly expanding literature, articulate the issues that are critical to interpreting the empirical results, and discuss what new conclusions are suggested by the overall pattern of findings.


Asunto(s)
Envejecimiento/psicología , Enfermedad de Alzheimer/psicología , Recuerdo Mental , Anciano , Cognición , Señales (Psicología) , Femenino , Humanos , Masculino , Procesos Mentales , Persona de Mediana Edad , Lectura , Retención en Psicología
14.
Brain Cogn ; 35(1): 42-57, 1997 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-9339301

RESUMEN

Patient M.S., who underwent right-occipital lobe resection to treat intractable epilepsy, has intact recall and recognition memory for words, but impaired repetition priming in word identification and visual stem-completion tasks. This mirror dissociation to amnesia suggests that explicit recognition and visuoperceptual repetition priming are mediated by distinct neural systems. In prior studies, however, M.S.' recognition memory was tested only with tasks that drew upon his intact verbal knowledge. The present study examined M.S.' recognition memory for nonverbal perceptual information, namely, the modality and font of word presentation and line patterns. M.S.' recognition memory was intact, providing further evidence that perceptual explicit and implicit memory processes are subserved by functionally and neurally independent memory systems.


Asunto(s)
Trastornos de la Memoria/diagnóstico , Trastornos de la Percepción/diagnóstico , Adulto , Epilepsia/cirugía , Humanos , Masculino , Pruebas Neuropsicológicas , Lóbulo Occipital/cirugía , Reconocimiento Visual de Modelos
15.
Neuropsychology ; 11(1): 59-69, 1997 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-9055270

RESUMEN

To examine the status of conceptual memory processes in amnesia, a conceptual memory task with implicit or explicit task instructions was given to amnesic and control groups. After studying a list of category exemplars, participants saw category labels and were asked to generate as many exemplars as possible (an implicit memory task) or to generate exemplars that had been in the prior study list (an explicit memory task). After incidental deep or shallow encoding of exemplars, amnesic patients showed normal implicit memory performance (priming), a normal levels-of-processing effect on priming, and impaired explicit memory performance. After intentional encoding of exemplars, amnesic patients showed impaired implicit and explicit memory performance. Results suggest that although amnesic patients can show impairments on implicit and explicit conceptual memory tasks, their deficit does not generalize to all conceptual memory tasks.


Asunto(s)
Amnesia/fisiopatología , Memoria/fisiología , Recuerdo Mental/fisiología , Vías Nerviosas/fisiología , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad
16.
Neuropsychologia ; 35(1): 25-35, 1997 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-8981374

RESUMEN

This study examined whether the frequently reported word-stem completion priming deficit of Alzheimer's disease (AD) patients could be characterized as either a semantic encoding deficit or a conceptual priming deficit. AD patients and normal elderly control subjects studied words in two conditions: (1) reading visually presented words aloud, which maximizes perceptual encoding of seen words, and (2) generating words aloud from definitions, which maximizes conceptual encoding of words not seen but retrieved on the basis of semantic context. Recognition accuracy was greater for words that were generated at study, and word-stem completion priming was greater for words that were read at study. For the AD patients, recognition accuracy was impaired and word-stem completion priming was intact for words encoded in both conditions. The findings are discussed in terms of discrepant results about word-stem completion priming in AD.


Asunto(s)
Enfermedad de Alzheimer/psicología , Memoria/fisiología , Percepción/fisiología , Anciano , Cognición/fisiología , Señales (Psicología) , Humanos , Memoria a Corto Plazo/fisiología , Recuerdo Mental/fisiología , Aprendizaje Verbal
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