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Nancy A Dennis - One of the best experts on this subject based on the ideXlab platform.
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sensory representations supporting memory specificity Age effects on behavioral and neural discriminability
The Journal of Neuroscience, 2019Co-Authors: Caitlin R Bowman, Jordan D Chamberlain, Nancy A DennisAbstract:Older adults9 difficulty in distinguishing between old and new information contributes to memory decline, which may occur because older adults are less likely than young adults to retrieve specific sensory details necessary to distinguish between similar items. In male and female human subjects, the present study measured the extent of Age differences in the specificity of memory representations using a false memory paradigm in which studied items were linked to retrieval items at multiple levels of similarity. Older adults showed poorer behavioral discrimination than young adults, driven primarily by false recognition of lures that differed from targets only in perceptual details. Patterns of activation across several regions within ventral visual cortex could be used to distinguish between targets and lures when they differed in both perceptual details and a semantic label. However, of ventral visual regions, only signals in the midline occipital cortex could be used to distinguish targets from lures when they differed only in perceptual details. Although there was an overall Age Deficit for this neural discrimination in this region, the positive relationship between neural and behavioral discriminability did not differ across Age groups. In contrast, Age moderated the relationship between neural and behavioral discriminability in lateral occipital and fusiform cortices, suggesting that activation patterns within these regions represent different types of information in each Age group. Therefore, the quality of perceptual signals is a key contributor to memory discrimination across Age groups, with evidence that Age differences in the nature of representations emerges outside early visual cortex. SIGNIFICANCE STATEMENT Age-related memory decline is due in part to older adults9 difficulties in discriminating between old and new information. We tested whether this Deficit arises from lack of specificity in the sensory representations underlying older adults9 recognition judgments. Using pattern classification analyses in ventral visual cortices, we found that signals in a region early in the visual stream could distinguish between targets and lures at the highest level of similarity. The discriminability of targets and lures in this region was positively related to behavioral discriminability across Age groups despite an overall Age Deficit in classification accuracy. Together, results showed that older adults9 memory Deficits are related to reduced discriminability of cognitive processes (old/new recognition) in portions of visual cortex.
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using attribute amnesia to test the limits of hyper binding and associative Deficits in working memory
Psychology and Aging, 2018Co-Authors: John M Mccormickhuhn, Hui Chen, Bradley Paul Wyble, Nancy A DennisAbstract:Previous work has shown mixed evidence regarding Age-related Deficits for binding in working memory. The current study used the newly developed attribute amnesia effect (H. Chen & Wyble, 2015a) to test the associative-Deficit hypothesis during working memory and to probe whether hyper-binding extends to include binding of de-selected information. In studies of attribute amnesia, participants use target attributes (e.g., identity, color) to demonstrate near ceiling levels of reporting of a second target attribute (e.g., location) across a series of trials (H. Chen & Wyble, 2015a, 2016). Yet, despite having just processed the target-defining attribute, they have difficulty reporting it on a surprise trial. This effect provides several predictions for associative binding in aging. The associative-Deficit hypothesis predicts Age-related decline on the surprise trial, whereas an extension of hyper-binding predicts Age-related increase in performance in older adults. In Experiment 1, when working memory load was low, older adults demonstrated attribute amnesia equal to that found in younger adults. When load increased in Experiment 2, older adults again demonstrated attribute amnesia as well as an Age Deficit for reporting target attributes. In lieu of spontaneous binding, results suggest that expectancy plays a critical role in older adults' propensity to encode and bind target attributes in working memory. Results further suggest that expectancy alone is not enough for older adults to form bound representations when task demands are high. Taken together results revealed a boundary condition of hyper-binding and further provided conditional support for the associative-Deficit hypothesis in working memory. (PsycINFO Database Record
John M Mccormickhuhn - One of the best experts on this subject based on the ideXlab platform.
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using attribute amnesia to test the limits of hyper binding and associative Deficits in working memory
Psychology and Aging, 2018Co-Authors: John M Mccormickhuhn, Hui Chen, Bradley Paul Wyble, Nancy A DennisAbstract:Previous work has shown mixed evidence regarding Age-related Deficits for binding in working memory. The current study used the newly developed attribute amnesia effect (H. Chen & Wyble, 2015a) to test the associative-Deficit hypothesis during working memory and to probe whether hyper-binding extends to include binding of de-selected information. In studies of attribute amnesia, participants use target attributes (e.g., identity, color) to demonstrate near ceiling levels of reporting of a second target attribute (e.g., location) across a series of trials (H. Chen & Wyble, 2015a, 2016). Yet, despite having just processed the target-defining attribute, they have difficulty reporting it on a surprise trial. This effect provides several predictions for associative binding in aging. The associative-Deficit hypothesis predicts Age-related decline on the surprise trial, whereas an extension of hyper-binding predicts Age-related increase in performance in older adults. In Experiment 1, when working memory load was low, older adults demonstrated attribute amnesia equal to that found in younger adults. When load increased in Experiment 2, older adults again demonstrated attribute amnesia as well as an Age Deficit for reporting target attributes. In lieu of spontaneous binding, results suggest that expectancy plays a critical role in older adults' propensity to encode and bind target attributes in working memory. Results further suggest that expectancy alone is not enough for older adults to form bound representations when task demands are high. Taken together results revealed a boundary condition of hyper-binding and further provided conditional support for the associative-Deficit hypothesis in working memory. (PsycINFO Database Record
Ricardo Ventura Santos - One of the best experts on this subject based on the ideXlab platform.
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diarrhea and health inequity among indigenous children in brazil results from the first national survey of indigenous people s health and nutrition
BMC Public Health, 2015Co-Authors: Ana Lucia Escobar, Carlos E A Coimbra, Ricardo Ventura Santos, James R Welch, Bernardo L Horta, Andrey Moreira CardosoAbstract:Globally, diarrhea is the second leading cause of death among children under five. In Brazil, mortality due to diarrhea underwent a significant reduction in recent decades principally due to expansion of the primary healthcare network, use of oral rehydration therapy, reduced child undernutrition, and improved access to safe drinking water. The First National Survey of Indigenous People’s Health and Nutrition in Brazil, conducted in 2008–2009, was the first survey based on a nationwide representative sample to study the prevalence of diarrhea and associated factors among Indigenous children in the country. The survey assessed the health and nutritional status of Indigenous children < 5 years of Age based on a representative sample of major Brazilian geopolitical regions. A stratified probabilistic sampling was carried out for Indigenous villAges. Within villAges, children < 5 years of Age in sampled households were included in the study. Interviews were based on a seven day recall period. Prevalence rates of acute diarrhea were calculated for independent variables and hierarchical multivariable analyses were conducted to assess associations. Information on diarrhea was obtained for 5,828 children (95.1% of the total sample). The overall prevalence of diarrhea was 23.5%. Regional differences were observed, with the highest rate being in the North (38.1%). Higher risk of diarrhea was observed among younger children and those who had less maternal schooling, lower household socioeconomic status, undernutrition (weight-for-Age Deficit), presence of another child with diarrhea in the household, and occurrence of upper respiratory infection. According to results of the First National Survey of Indigenous People’s Health and Nutrition, almost a quarter of Indigenous children throughout the country had diarrhea during the previous week. This prevalence is substantially higher than that documented in 2006 for Brazilian children < 5 years generally (9.4%). Due to its exceedingly multicausal nature, the set of associated variables that remained associated with child diarrhea in the final multivariable model provide an excellent reflection of the diverse social and health inequities faced by Indigenous peoples in contemporary Brazil.
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nutritional status and anemia in surui indian children brazilian amazon
Jornal De Pediatria, 2006Co-Authors: Jesem Douglas Yamall Orellana, Carlos E A Coimbra, Ana Eliza Port Lourenco, Ricardo Ventura SantosAbstract:The objective was to assess the nutritional status of Surui Indian children Aged less than 10 years by means of anthropometric measurements and determination of hemoglobin concentration levels. The study was carried out from February to March 2005 in the Sete de Setembro Indian Reservation located on the boundary between the states of Rondonia and Mato Grosso Amazonia Brazil. Height and weight were measured according to standard procedures and then compared with the National Center for Health Statistics reference values (n = 284). Hemoglobin concentration was determined by a portable s-hemoglobinometer (Hemocue) (n = 268). The percentAges of children = -2 z scores for height for Age weight for Age and weight for height were 25.4 8.1 and 0% respectively. For children Aged less than 5 years the percentAges were 31.4 12.4 and 0%. Most children had anemia (80.6%) with a rate of up to 84.0% among those Aged 6 to 59 months. There is a high prevalence of protein-energy undernutrition and anemia among Surui children. Comparison with a previous survey indicated that the prevalence of height for Age Deficit significantly decreased between 1987 and 2005 (from 46.3 to 26.7% in children younger than 9 years). On the other hand 3.9% of the children were overweight in 2005 a finding that had not been reported in 1987. The prevalence of anemia did not change remarkably between these years. Despite the improvement in anthropometric parameters the prevalence of nutritional Deficit has been persistently higher than that observed in the Brazilian population at large. It is therefore necessary that systematic and regular monitoring of indigenous childrens growth and development be implemented focusing mainly on nutritional surveillance. (authors)
Larsgoran Nilsson - One of the best experts on this subject based on the ideXlab platform.
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selective adult Age differences in an Age invariant multifactor model of declarative memory
Psychology and Aging, 2003Co-Authors: Lars Nyberg, Scott B Maitland, Lars Backman, Michael Ronnlund, Roger A Dixon, Ake Wahlin, Larsgoran NilssonAbstract:Confirmatory factor analysis was used to test competing models of declarative memory. Data from middle-Aged participants provided support for a model comprised of 2 2nd-order (episodic and semantic memory) and 4 1st-order (recall, recognition, fluency, and knowledge) factors. Extending this model across young-old and old-old participants established support for Age invariance. Tests of group differences showed an Age Deficit in episodic memory that was more pronounced for recall than for recognition. For semantic memory, there was an increase in knowledge from middle to young-old Age and thereafter a decrease. Overall, the results support the view that episodic memory is more Age sensitive than semantic memory, but they also indicate that aging has differential effects within these 2 forms of memory.
Hui Chen - One of the best experts on this subject based on the ideXlab platform.
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using attribute amnesia to test the limits of hyper binding and associative Deficits in working memory
Psychology and Aging, 2018Co-Authors: John M Mccormickhuhn, Hui Chen, Bradley Paul Wyble, Nancy A DennisAbstract:Previous work has shown mixed evidence regarding Age-related Deficits for binding in working memory. The current study used the newly developed attribute amnesia effect (H. Chen & Wyble, 2015a) to test the associative-Deficit hypothesis during working memory and to probe whether hyper-binding extends to include binding of de-selected information. In studies of attribute amnesia, participants use target attributes (e.g., identity, color) to demonstrate near ceiling levels of reporting of a second target attribute (e.g., location) across a series of trials (H. Chen & Wyble, 2015a, 2016). Yet, despite having just processed the target-defining attribute, they have difficulty reporting it on a surprise trial. This effect provides several predictions for associative binding in aging. The associative-Deficit hypothesis predicts Age-related decline on the surprise trial, whereas an extension of hyper-binding predicts Age-related increase in performance in older adults. In Experiment 1, when working memory load was low, older adults demonstrated attribute amnesia equal to that found in younger adults. When load increased in Experiment 2, older adults again demonstrated attribute amnesia as well as an Age Deficit for reporting target attributes. In lieu of spontaneous binding, results suggest that expectancy plays a critical role in older adults' propensity to encode and bind target attributes in working memory. Results further suggest that expectancy alone is not enough for older adults to form bound representations when task demands are high. Taken together results revealed a boundary condition of hyper-binding and further provided conditional support for the associative-Deficit hypothesis in working memory. (PsycINFO Database Record