Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 19 de 19
Filtrar
1.
Sleep Health ; 10(2): 229-236, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38233280

RESUMO

STUDY OBJECTIVES: Although sleep affects a range of waking behaviors, the majority of studies have focused on sleep loss with relatively little attention on sustained periods of adequate sleep. The goal of this study was to use an experimental design to examine the effect of both of these sleep patterns on cognitive performance in healthy adults. METHODS: This study used a randomized crossover design. Participants who regularly slept 7-9 hours/night completed two 6-week intervention conditions, adequate sleep (maintenance of habitual bed/wake times) and insufficient sleep (reduction in sleep of 1.5 hours relative to adequate sleep), separated by a 2-6weeks (median=43days) washout period. Cognitive functioning was evaluated at baseline and endpoint of each intervention using the NIH Toolbox Cognition Battery. General linear models contrasted scores following each condition to the baseline of the first condition; the baseline of the second condition was included to evaluate practice effects. RESULTS: Sixty-five participants (age 35.9 ± 4.9years, 89% women, 52% non-White race/ethnicity) completed study procedures. There was improvement in performance on the List Sorting Working Memory task after the adequate sleep condition that exceeded practice effects. Cognitive performance after insufficient sleep did not reach the level expected with practice and did not differ from baseline. A similar pattern was found on the Flanker Inhibitory Control and Attention task. CONCLUSIONS: These findings contribute to our understanding of the complex interplay between sleep and cognition and demonstrate that consistent, stable sleep of at least 7 hours/night improves working memory and response inhibition in healthy adults. CLINICAL TRIAL REGISTRATION: The manuscript reports on data from two clinical trials: Impact of Sleep Restriction on Performance in Adults (URL: https://clinicaltrials.gov/ct2/show/NCT02960776, ID Number: NCT02960776) and Impact of Sleep Restriction in Women (URL: https://clinicaltrials.gov/ct2/show/NCT02835261, ID Number: NCT02835261).


Assuntos
Cognição , Estudos Cross-Over , Sono , Humanos , Feminino , Masculino , Adulto , Privação do Sono/psicologia
2.
Am J Clin Nutr ; 119(3): 692-701, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38244989

RESUMO

BACKGROUND: Longer effects of multivitamin-mineral (MVM) supplementation on late-life cognitive function remain untested using in-person, detailed neuropsychological assessments. Furthermore, insufficient evidence exists for healthcare providers to recommend daily MVM supplements to prevent cognitive decline. OBJECTIVES: This study aimed to test MVM effects on cognitive change using in-person, detailed neuropsychological assessments and conduct a meta-analysis within COSMOS (COcoa Supplement and Multivitamin Outcomes Study) cognitive substudies for a robust evaluation of MVM effects on cognition. METHODS: COSMOS is a 2 × 2 factorial trial of cocoa extract (500 mg flavanols/d) and/or a daily MVM supplement for cardiovascular disease and cancer prevention among 21,442 United States adults aged ≥60 y. There were 573 participants in the clinic subcohort of COSMOS (that is, COSMOS-Clinic) who completed all cognitive tests administered at baseline. For the meta-analysis, we included nonoverlapping participants across 3 COSMOS cognitive substudies: COSMOS-Clinic (n = 573); COSMOS-Mind (n = 2158); COSMOS-Web (n = 2472). RESULTS: In COSMOS-Clinic, we observed a modest benefit of MVM compared with placebo on global cognition over 2 y {mean difference [95% confidence interval (CI)] = 0.06 SD units (SU) (-0.003, 0.13)}, with a significantly more favorable change in episodic memory [mean difference (95% CI) = 0.12 SU (0.002, 0.23)] but not in executive function or attention [mean difference (95% CI) = 0.04 SU (-0.04, 0.11)]. The meta-analysis of COSMOS substudies showed clear evidence of MVM benefits on global cognition [mean difference (95% CI) = 0.07 SU (0.03, 0.11); P = 0.0009] and episodic memory [mean difference (95% CI) = 0.06 SU (0.03, 0.10); P = 0.0007]; the magnitude of effect on global cognition was equivalent to reducing cognitive aging by 2 y. CONCLUSIONS: In COSMOS-Clinic, daily MVM supplementation leads to a significantly more favorable 2-y change in episodic memory. The meta-analysis within COSMOS cognitive substudies indicates that daily MVM significantly benefits both global cognition and episodic memory. These findings within the COSMOS trial support the benefits of a daily MVM in preventing cognitive decline among older adults. This trial was registered at COSMOS-clinicaltrials.gov as NCT02422745, at COSMOS-Mind-clinicaltrials.gov as NCT03035201, and at COSMOS-Web-clinicaltrials.gov as NCT04582617.


Assuntos
Cacau , Disfunção Cognitiva , Humanos , Idoso , Vitaminas/farmacologia , Vitaminas/uso terapêutico , Suplementos Nutricionais , Cognição , Disfunção Cognitiva/prevenção & controle , Minerais/farmacologia , Método Duplo-Cego , Ensaios Clínicos Controlados Aleatórios como Assunto
3.
Am J Clin Nutr ; 118(1): 273-282, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37244291

RESUMO

BACKGROUND: Maintenance of cognitive abilities is of critical importance to older adults, yet few effective strategies to slow cognitive decline currently exist. Multivitamin supplementation is used to promote general health; it is unclear whether it favorably affects cognition in older age. OBJECTIVES: To examine the effect of daily multivitamin/multimineral supplementation on memory in older adults. METHODS: The COcoa Supplement and Multivitamin Outcomes Study Web (COSMOS-Web) ancillary study (NCT04582617) included 3562 older adults. Participants were randomly assigned to a daily multivitamin supplement (Centrum Silver) or placebo and evaluated annually with an Internet-based battery of neuropsychological tests for 3 y. The prespecified primary outcome measure was change in episodic memory, operationally defined as immediate recall performance on the ModRey test, after 1 y of intervention. Secondary outcome measures included changes in episodic memory over 3 y of follow-up and changes in performance on neuropsychological tasks of novel object recognition and executive function over 3 y. RESULTS: Compared with placebo, participants randomly assigned to multivitamin supplementation had significantly better ModRey immediate recall at 1 y, the primary endpoint (t(5889) = 2.25, P = 0.025), as well as across the 3 y of follow-up on average (t(5889) = 2.54, P = 0.011). Multivitamin supplementation had no significant effects on secondary outcomes. Based on cross-sectional analysis of the association between age and performance on the ModRey, we estimated that the effect of the multivitamin intervention improved memory performance above placebo by the equivalent of 3.1 y of age-related memory change. CONCLUSIONS: Daily multivitamin supplementation, compared with placebo, improves memory in older adults. Multivitamin supplementation holds promise as a safe and accessible approach to maintaining cognitive health in older age. This trial was registered at clinicaltrials.gov as NCT04582617.


Assuntos
Suplementos Nutricionais , Vitaminas , Humanos , Idoso , Estudos Transversais , Método Duplo-Cego , Vitaminas/farmacologia , Vitaminas/uso terapêutico , Cognição
4.
Proc Natl Acad Sci U S A ; 120(23): e2216932120, 2023 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-37252983

RESUMO

Dietary flavanols are food constituents found in certain fruits and vegetables that have been linked to cognitive aging. Previous studies suggested that consumption of dietary flavanols might specifically be associated with the hippocampal-dependent memory component of cognitive aging and that memory benefits of a flavanol intervention might depend on habitual diet quality. Here, we tested these hypotheses in the context of a large-scale study of 3,562 older adults, who were randomly assigned to a 3-y intervention of cocoa extract (500 mg of cocoa flavanols per day) or a placebo [(COcoa Supplement and Multivitamin Outcomes Study) COSMOS-Web, NCT04582617]. Using the alternative Healthy Eating Index in all participants and a urine-based biomarker of flavanol intake in a subset of participants [n = 1,361], we show that habitual flavanol consumption and diet quality at baseline are positively and selectively correlated with hippocampal-dependent memory. While the prespecified primary end point testing for an intervention-related improvement in memory in all participants after 1 y was not statistically significant, the flavanol intervention restored memory among participants in lower tertiles of habitual diet quality or habitual flavanol consumption. Increases in the flavanol biomarker over the course of the trial were associated with improving memory. Collectively, our results allow dietary flavanols to be considered in the context of a depletion-repletion paradigm and suggest that low flavanol consumption can act as a driver of the hippocampal-dependent component of cognitive aging.


Assuntos
Cacau , Dieta , Humanos , Idoso , Suplementos Nutricionais , Polifenóis , Biomarcadores , Método Duplo-Cego
5.
Sci Rep ; 11(1): 3837, 2021 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-33589674

RESUMO

With the world's population aging, age-related memory decline is an impending cognitive epidemic. Assessing the impact of diet on cognitive aging, we conducted a controlled, randomized, parallel-arm dietary intervention with 211 healthy adults (50-75 years) investigating effects of either a placebo or 260, 510 and 770 mg/day of cocoa flavanols for 12-weeks followed by 8-weeks washout. The primary outcome was a newly-developed object-recognition task localized to the hippocampus' dentate gyrus. Secondary outcomes included a hippocampal-dependent list-learning task and a prefrontal cortex-dependent list-sorting task. The alternative Healthy Eating Index and a biomarker of flavanol intake (gVLM) were measured. In an MRI substudy, hippocampal cerebral blood volume was mapped. Object-recognition and list-sorting performance did not correlate with baseline diet quality and did not improve after flavanol intake. However, the hippocampal-dependent list-learning performance was directly associated with baseline diet quality and improved after flavanol intake, particularly in participants in the bottom tertile of baseline diet quality. In the imaging substudy, a region-of-interest analysis was negative but a voxel-based-analysis suggested that dietary flavanols target the dentate gyrus. While replication is needed, these findings suggest that diet in general, and dietary flavanols in particular, may be associated with memory function of the aging hippocampus and normal cognitive decline.


Assuntos
Envelhecimento Cognitivo , Dieta , Suplementos Nutricionais , Flavonóis/administração & dosagem , Idoso , Envelhecimento/psicologia , Encéfalo/diagnóstico por imagem , Encéfalo/fisiopatologia , Cognição , Feminino , Voluntários Saudáveis , Humanos , Aprendizagem , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Estado Nutricional , Desempenho Físico Funcional , Vigilância em Saúde Pública , Ensaios Clínicos Controlados Aleatórios como Assunto
6.
Neurobiol Aging ; 98: 134-145, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33278686

RESUMO

The entorhinal cortex is subdivided into anterolateral entorhinal cortex (alERC) and posteromedial entorhinal cortex (pmERC) subregions, which are theorized to support distinct cognitive roles. This distinction is particularly important as the alERC is one of the earliest cortical regions affected by Alzheimer's pathology and related neurodegeneration. The relative associations of alERC/pmERC with neuropsychological test performance have not been examined. We examined how alERC/pmERC volumes differentially relate to performance on 1) the Modified Rey Auditory Learning Test (ModRey), a verbal memory test designed to assess normal/preclinical populations, 2) the Montreal Cognitive Assessment (MoCA), and 3) the National Alzheimer's Coordinating Center neuropsychological battery. We also examined whether alERC/pmERC volumes correlate with Alzheimer's disease cerebrospinal fluid (CSF) biomarkers. In 65 cognitively healthy (CDR = 0) older adults, alERC, but not pmERC, volume was associated with ModRey memory retention. Only alERC volume differentiated between participants who scored above and below the MoCA cutoff score for impairment. Evaluating the MoCA subdomains revealed that alERC was particularly associated with verbal recall. On the National Alzheimer's Coordinating Center battery, both alERC and pmERC volumes were associated with Craft story recall and Benson figure copy, but only alERC volume was associated with Craft story retention and semantic fluency. Neither alERC nor pmERC volume correlated with CSF levels of amyloid or tau, and regression analyses showed that alERC volume and CSF amyloid levels were independently associated with ModRey retention performance. Taken together, these results suggest that the alERC is important for memory performance and that alERC volume differences are related to a pattern of neuropsychological test performance (i.e., impairments in episodic memory and semantic fluency) typically seen in clinical Alzheimer's disease.


Assuntos
Envelhecimento/patologia , Envelhecimento/psicologia , Córtex Entorrinal/patologia , Retenção Psicológica , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/patologia , Biomarcadores , Córtex Entorrinal/fisiologia , Feminino , Humanos , Masculino , Testes Neuropsicológicos , Tamanho do Órgão
7.
Neurobiol Aging ; 84: 90-97, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31520793

RESUMO

Alzheimer's disease is defined by abnormal levels of amyloid and tau biomarkers. Even cognitively normal older adults with clinically relevant amyloid and tau levels perform worse on memory tests. However, it is unclear if the relationship between biomarker level and memory extends below clinical thresholds. We hypothesized that even subclinical biomarker levels are associated with memory when measured with neuropsychological tests designed to detect dysfunction in preclinical disease states. In a group of cognitively normal, "biomarker-negative" older men and women, we investigated the relationship between cerebrospinal fluid biomarker levels and memory measured with the ModRey, a list-learning task designed to assess memory in preclinical and cognitively normal adults. Cerebrospinal amyloid levels were associated with ModRey memory retention, the proportion of information retained after a delay period. When older adults with mild impairment were included, cerebrospinal fluid tau levels were also associated with ModRey retention. The association of amyloid and tau levels with memory was independent of each other. These results suggest cognitive changes associated with Alzheimer's disease pathology might occur earlier than currently thought.


Assuntos
Proteínas Amiloidogênicas/líquido cefalorraquidiano , Envelhecimento Saudável/fisiologia , Memória , Retenção Psicológica , Biomarcadores/líquido cefalorraquidiano , Feminino , Humanos , Masculino , Proteínas tau/líquido cefalorraquidiano
8.
J Cogn Neurosci ; 31(5): 711-729, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30822207

RESUMO

The lateral portion of the entorhinal cortex is one of the first brain regions affected by tau pathology, an important biomarker for Alzheimer disease. Improving our understanding of this region's cognitive role may help identify better cognitive tests for early detection of Alzheimer disease. Based on its functional connections, we tested the idea that the human anterolateral entorhinal cortex (alERC) may play a role in integrating spatial information into object representations. We recently demonstrated that the volume of the alERC was related to processing the spatial relationships of the features within an object [Yeung, L. K., Olsen, R. K., Bild-Enkin, H. E. P., D'Angelo, M. C., Kacollja, A., McQuiggan, D. A., et al. Anterolateral entorhinal cortex volume predicted by altered intra-item configural processing. Journal of Neuroscience, 37, 5527-5538, 2017]. In this study, we investigated whether the human alERC might also play a role in processing the spatial relationships between an object and its environment using an eye-tracking task that assessed visual fixations to a critical object within a scene. Guided by rodent work, we measured both object-in-place memory, the association of an object with a given context [Wilson, D. I., Langston, R. F., Schlesiger, M. I., Wagner, M., Watanabe, S., & Ainge, J. A. Lateral entorhinal cortex is critical for novel object-context recognition. Hippocampus, 23, 352-366, 2013], and object-trace memory, the memory for the former location of objects [Tsao, A., Moser, M. B., & Moser, E. I. Traces of experience in the lateral entorhinal cortex. Current Biology, 23, 399-405, 2013]. In a group of older adults with varying stages of brain atrophy and cognitive decline, we found that the volume of the alERC and the volume of the parahippocampal cortex selectively predicted object-in-place memory, but not object-trace memory. These results provide support for the notion that the alERC may integrate spatial information into object representations.


Assuntos
Córtex Entorrinal/fisiologia , Percepção de Forma/fisiologia , Giro Para-Hipocampal/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Processamento Espacial/fisiologia , Idoso , Idoso de 80 Anos ou mais , Córtex Entorrinal/anatomia & histologia , Movimentos Oculares , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Memória , Pessoa de Meia-Idade , Tamanho do Órgão , Giro Para-Hipocampal/anatomia & histologia
9.
Assessment ; 26(6): 1154-1161, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-28799411

RESUMO

List learning tests are used in practice for diagnosis and in research to characterize episodic memory, but often suffer from ceiling effects in unimpaired individuals. We developed the Modified Rey Auditory Verbal Learning Test, or ModRey, an episodic memory test for use in normal and preclinical populations. We administered the ModRey to 230 healthy adults and to 86 of the same individuals 102 days later and examined psychometric properties and effects of demographic factors. Primary measures were normally distributed without evidence of ceiling effect. Differences between alternate forms were of very small magnitude and not significant. Test-retest reliability was good. Higher participant age and lower participant education was associated with poorer performance across most outcome measures. We conclude that the ModRey is appropriate for episodic memory characterization in normal populations and could be used as an outcome measure in studies involving preclinical populations.


Assuntos
Doença de Alzheimer/diagnóstico , Diagnóstico Precoce , Memória Episódica , Testes Neuropsicológicos , Adulto , Fatores Etários , Escolaridade , Feminino , Humanos , Masculino , Psicometria , Reprodutibilidade dos Testes
10.
Front Psychol ; 9: 2668, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30713514

RESUMO

Face processing in autism spectrum disorder (ASD) is thought to be atypical, but it is unclear whether differences in visual conjunctive processing are specific to faces. To address this, we adapted a previously established eye-tracking paradigm which modulates the need for conjunctive processing by varying the degree of feature ambiguity in faces and objects. Typically-developed (TD) participants showed a canonical pattern of conjunctive processing: High-ambiguity objects were processed more conjunctively than low-ambiguity objects, and faces were processed in an equally conjunctive manner regardless of ambiguity level. In contrast, autistic individuals did not show differences in conjunctive processing based on stimulus category, providing evidence that atypical visual conjunctive processing in ASD is the result of a domain general lack of perceptual specialization.

11.
Neurobiol Aging ; 57: 195-205, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28578804

RESUMO

We investigated whether older adults without subjective memory complaints, but who present with cognitive decline in the laboratory, demonstrate atrophy in medial temporal lobe (MTL) subregions associated with Alzheimer's disease. Forty community-dwelling older adults were categorized based on Montreal Cognitive Assessment (MoCA) performance. Total gray/white matter, cerebrospinal fluid, and white matter hyperintensity load were quantified from whole-brain T1-weighted and fluid-attenuated inversion recovery magnetic resonance imaging scans, whereas hippocampal subfields and MTL cortical subregion volumes (CA1, dentate gyrus/CA2/3, subiculum, anterolateral and posteromedial entorhinal, perirhinal, and parahippocampal cortices) were quantified using high-resolution T2-weighted scans. Cognitive status was evaluated using standard neuropsychological assessments. No significant differences were found in the whole-brain measures. However, MTL volumetry revealed that anterolateral entorhinal cortex (alERC) volume-the same region in which Alzheimer's pathology originates-was strongly associated with MoCA performance. This is the first study to demonstrate that alERC volume is related to cognitive decline in undiagnosed community-dwelling older adults.


Assuntos
Envelhecimento/patologia , Envelhecimento/psicologia , Cognição/fisiologia , Disfunção Cognitiva/etiologia , Disfunção Cognitiva/patologia , Córtex Entorrinal/patologia , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/etiologia , Doença de Alzheimer/patologia , Disfunção Cognitiva/diagnóstico , Imagem de Difusão por Ressonância Magnética , Córtex Entorrinal/diagnóstico por imagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão
12.
J Neurosci ; 37(22): 5527-5538, 2017 05 31.
Artigo em Inglês | MEDLINE | ID: mdl-28473640

RESUMO

Recent functional imaging studies have proposed that the human entorhinal cortex (ERC) is subdivided into functionally distinct anterolateral (alERC) and posteromedial (pmERC) subregions. The alERC overlaps with regions that are affected earliest by Alzheimer's disease pathology, yet its cognitive function remains poorly understood. Previous human fMRI studies have focused on its role in object memory, but rodent studies on the putatively homologous lateral entorhinal cortex suggest that it also plays an important role in representing spatial properties of objects. To investigate the cognitive effects of human alERC volume differences, we developed an eye-tracking-based task to evaluate intra-item configural processing (i.e., processing the arrangement of an object's features) and used manual segmentation based on a recently developed protocol to delineate the alERC/pmERC and other medial temporal lobe (MTL) subregions. In a group of older adult men and women at varying stages of brain atrophy and cognitive decline, we found that intra-item configural processing, regardless of an object's novelty, was strongly predicted by alERC volume, but not by the volume of any other MTL subregion. These results provide the first evidence that the human alERC plays a role in supporting a distinct aspect of object processing, namely attending to the arrangement of an object's component features.SIGNIFICANCE STATEMENT Alzheimer's disease pathology appears earliest in brain regions that overlap with the anterolateral entorhinal cortex (alERC). However, the cognitive role of the alERC is poorly understood. Previous human studies treat the alERC as an extension of the neighboring perirhinal cortex, supporting object memory. Animal studies suggest that the alERC may support the spatial properties of objects. In a group of older adult humans at the earliest stages of cognitive decline, we show here that alERC volume selectively predicted configural processing (attention to the spatial arrangement of an object's parts). This is the first study to demonstrate a cognitive role related to alERC volume in humans. This task can be adapted to serve as an early detection method for Alzheimer's disease pathology.


Assuntos
Cognição , Disfunção Cognitiva/fisiopatologia , Córtex Entorrinal/fisiopatologia , Percepção de Forma , Rede Nervosa/fisiopatologia , Reconhecimento Visual de Modelos , Idoso , Idoso de 80 Anos ou mais , Atrofia/patologia , Disfunção Cognitiva/patologia , Córtex Entorrinal/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Rede Nervosa/patologia , Tamanho do Órgão/fisiologia
13.
Nat Neurosci ; 17(12): 1798-803, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25344629

RESUMO

The dentate gyrus (DG) is a region in the hippocampal formation whose function declines in association with human aging and is therefore considered to be a possible source of age-related memory decline. Causal evidence is needed, however, to show that DG-associated memory decline in otherwise healthy elders can be improved by interventions that enhance DG function. We addressed this issue by first using a high-resolution variant of functional magnetic resonance imaging (fMRI) to map the precise site of age-related DG dysfunction and to develop a cognitive task whose function localized to this anatomical site. Then, in a controlled randomized trial, we applied these tools to study healthy 50-69-year-old subjects who consumed either a high or low cocoa flavanol-containing diet for 3 months. A high-flavanol intervention was found to enhance DG function, as measured by fMRI and by cognitive testing. Our findings establish that DG dysfunction is a driver of age-related cognitive decline and suggest non-pharmacological means for its amelioration.


Assuntos
Cacau , Cognição/fisiologia , Giro Denteado/fisiologia , Dieta/métodos , Flavanonas/administração & dosagem , Estimulação Acústica/métodos , Idoso , Teste de Esforço/métodos , Teste de Esforço/psicologia , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Fatores de Tempo
14.
J Exp Psychol Gen ; 142(4): 1384-97, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23937183

RESUMO

A fundamental assumption underlying most current theories of amnesia is that memory impairments arise because previously studied information either is lost rapidly or is made inaccessible (i.e., the old information appears to be new). Recent studies in rodents have challenged this view, suggesting instead that under conditions of high interference, recognition memory impairments following medial temporal lobe damage arise because novel information appears as though it has been previously seen. Here, we developed a new object recognition memory paradigm that distinguished whether object recognition memory impairments were driven by previously viewed objects being treated as if they were novel or by novel objects falsely recognized as though they were previously seen. In this indirect, eyetracking-based passive viewing task, older adults at risk for mild cognitive impairment showed false recognition to high-interference novel items (with a significant degree of feature overlap with previously studied items) but normal novelty responses to low-interference novel items (with a lower degree of feature overlap). The indirect nature of the task minimized the effects of response bias and other memory-based decision processes, suggesting that these factors cannot solely account for false recognition. These findings support the counterintuitive notion that recognition memory impairments in this memory-impaired population are not characterized by forgetting but rather are driven by the failure to differentiate perceptually similar objects, leading to the false recognition of novel objects as having been seen before.


Assuntos
Disfunção Cognitiva/psicologia , Reconhecimento Psicológico/fisiologia , Percepção Visual/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino
15.
Neuron ; 75(1): 157-67, 2012 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-22794269

RESUMO

Memory and perception have long been considered separate cognitive processes, and amnesia resulting from medial temporal lobe (MTL) damage is thought to reflect damage to a dedicated memory system. Recent work has questioned these views, suggesting that amnesia can result from impoverished perceptual representations in the MTL, causing an increased susceptibility to interference. Using a perceptual matching task for which fMRI implicated a specific MTL structure, the perirhinal cortex, we show that amnesics with MTL damage including the perirhinal cortex, but not those with damage limited to the hippocampus, were vulnerable to object-based perceptual interference. Importantly, when we controlled such interference, their performance recovered to normal levels. These findings challenge prevailing conceptions of amnesia, suggesting that effects of damage to specific MTL regions are better understood not in terms of damage to a dedicated declarative memory system, but in terms of impoverished representations of the stimuli those regions maintain.


Assuntos
Amnésia/fisiopatologia , Memória/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Estimulação Luminosa/métodos , Desempenho Psicomotor/fisiologia , Percepção Visual/fisiologia , Adolescente , Adulto , Amnésia/psicologia , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Adulto Jovem
16.
Front Hum Neurosci ; 6: 91, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22529794

RESUMO

In this review, we will discuss the idea that the hippocampus may be involved in both memory and perception, contrary to theories that posit functional and neuroanatomical segregation of these processes. This suggestion is based on a number of recent neuropsychological and functional neuroimaging studies that have demonstrated that the hippocampus is involved in the visual discrimination of complex spatial scene stimuli. We argue that these findings cannot be explained by long-term memory or working memory processing or, in the case of patient findings, dysfunction beyond the medial temporal lobe (MTL). Instead, these studies point toward a role for the hippocampus in higher-order spatial perception. We suggest that the hippocampus processes complex conjunctions of spatial features, and that it may be more appropriate to consider the representations for which this structure is critical, rather than the cognitive processes that it mediates.

17.
Psychiatry Res ; 193(2): 101-6, 2011 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-21680159

RESUMO

White matter hyperintensities (WMH) are areas of increased signal on T2-weighted magnetic resonance imaging (MRI), including fluid attenuated inverse recovery sequences. Total and regional WMH burden (i.e., volume or severity) has been associated with myriad cognitive, neurological, and psychiatric conditions among older adults. In the current report, we illustrate two approaches to quantify periventricular, deep, and total WMH and examine their reliability and criterion validity among 28 elderly patients enrolled in a depression treatment trial. The first approach, an operator-driven quantitative approach, involves visual inspection of individual MRI scans and manual labeling using a three-step series of procedures. The second approach, a fully automated quantitative approach, uses a processing stream that involves image segmentation, voxel intensity thresholding, and seed growing to label WMH and calculate their volume automatically. There was good agreement in WMH quantification between the two approaches (Cronbach's alpha values from 0.835 to 0.968). Further, severity of WMH was significantly associated with worse depression and increased age, and these associations did not differ significantly between the two quantification approaches. We provide evidence for good reliability and criterion validity for two approaches for WMH volume determination. The operator-driven approach may be better suited for smaller studies with highly trained raters, whereas the fully automated quantitative approach may be more appropriate for larger, high-throughput studies.


Assuntos
Envelhecimento/patologia , Mapeamento Encefálico , Encéfalo/patologia , Fibras Nervosas Mielinizadas/patologia , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/efeitos dos fármacos , Antidepressivos/farmacologia , Antidepressivos/uso terapêutico , Encéfalo/efeitos dos fármacos , Depressão/tratamento farmacológico , Depressão/patologia , Método Duplo-Cego , Processamento Eletrônico de Dados , Feminino , Humanos , Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Fibras Nervosas Mielinizadas/efeitos dos fármacos , Nortriptilina/farmacologia , Nortriptilina/uso terapêutico , Escalas de Graduação Psiquiátrica , Sertralina/farmacologia , Sertralina/uso terapêutico
18.
Int J Eat Disord ; 44(5): 406-11, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21661001

RESUMO

OBJECTIVE: To measure brain volume deficits among underweight patients with anorexia nervosa (AN) compared to control participants and evaluate the reversibility of these deficits with short-term weight restoration. METHOD: Brain volume changes in gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) were examined in 32 adult women with AN and compared to 21, age and body mass index-range matched control women. RESULTS: Patients with AN had a significant increase in GM (p = .006, η(2) = 0.14) and WM volume (p = .001, η(2) = 0.19) following weight restoration. Patients on average had lower levels of GM at low weight (647.63 ± 62.07 ml) compared to controls (679.93 ± 53.31 ml), which increased with weight restoration (662.64 ± 69.71 ml), but did not fully normalize. DISCUSSION: This study suggests that underweight adult patients with AN have reduced GM and WM volumes that increase with short-term weight restoration.


Assuntos
Anorexia Nervosa/patologia , Encéfalo/patologia , Aumento de Peso , Adulto , Índice de Massa Corporal , Peso Corporal , Feminino , Humanos , Tamanho do Órgão
19.
Neurobiol Aging ; 32(9): 1588-98, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19926168

RESUMO

OBJECTIVE: White matter hyperintensities (WMH), visualized on T2-weighted MRI, are thought to reflect small-vessel vascular disease. Much like other markers of brain disease, the association between WMH and cognition is imperfect. The concept of reserve may account for this imperfect relationship. The purpose of this study was to test the reserve hypothesis in the association between WMH severity and cognition. We hypothesized that individuals with higher amounts of reserve would be able to tolerate greater amounts of pathology than those with lower reserve. METHODS: Neurologically healthy older adults (n=717) from a community-based study received structural MRI, neuropsychological assessment, and evaluation of reserve. WMH volume was quantified algorithmically. We derived latent constructs representing four neuropsychological domains, a measure of cognitive reserve, and a measure of brain reserve. Measures of cognitive and brain reserve consisted of psychosocial (e.g., education) and anthropometric (e.g., craniometry) variables, respectively. RESULTS: Increased WMH volume was associated with poorer cognition and higher cognitive and brain reserve were associated with better cognition. Controlling for speed/executive function or for language function, those with higher estimates of cognitive reserve had significantly greater degrees of WMH volume, particularly among women. Controlling for cognitive functioning across all domains, individuals with higher estimates of brain reserve had significantly greater WMH volume. CONCLUSIONS: For any given level of cognitive function, those with higher reserve had more pathology in the form of WMH, suggesting that they are better able to cope with pathology than those with lower reserve. Both brain reserve and cognitive reserve appear to mitigate the impact of pathology on cognition.


Assuntos
Encéfalo/patologia , Transtornos Cognitivos/diagnóstico , Reserva Cognitiva/fisiologia , Demência Vascular/diagnóstico , Idoso , Idoso de 80 Anos ou mais , Transtornos Cognitivos/patologia , Transtornos Cognitivos/fisiopatologia , Estudos de Coortes , Demência Vascular/patologia , Demência Vascular/fisiopatologia , Diagnóstico Diferencial , Imagem de Difusão por Ressonância Magnética/métodos , Feminino , Humanos , Processamento de Imagem Assistida por Computador/métodos , Masculino , Fibras Nervosas Mielinizadas/patologia , Valor Preditivo dos Testes , Estudos Prospectivos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA