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Trey Hedden

Publications and source records attributed to Trey Hedden.

16 recordsLinked to original sources
PubMed2025

The Consortium for Clarity in ADRD Research Through Imaging (CLARiTI): Overview of consortium sites and anticipated enrollment.

INTRODUCTION: The Consortium for Clarity in Alzheimer's disease related dementias (ADRD) Research Through Imaging (CLARiTI) is a study that aims to collect standardized imaging and plasma biomarkers on 2000 Clinical Core participants enrolled across all Alzheimer's Disease Research Centers (ADRC) sites. We sought to summarize the known heterogeneity across centers regarding scientific focus and initial enrollment plans for CLARiTI. METHODS: We developed and distributed a survey capturing information on the 36 CLARiTI site's theme/expertise, recruitment plans, and the intersection of CLARiTI with other ADRC imaging efforts. RESULTS: Anticipated CLARiTI enrollees spanned 11 different categories of suspected etiologies underlying impairment. A wide range of risk factors were endorsed across sites regarding the enrollment of unimpaired individuals. Variability also existed regarding site-level strategies in enrollment into CLARiTI versus other imaging efforts. DISCUSSION: We anticipate that the 2000 individuals that will enroll into CLARiTI will reflect the clinical heterogeneity already in place across the ADRC network. HIGHLIGHTS: The ADRC Consortium for Clarity in ADRD Research Through Imaging (CLARiTI) will leverage and contribute to the existing Alzheimer's Disease Research Centers (ADRC) program by supporting standardized imaging and plasma collection across all centers. We summarize the variation in scientific focus and enrollment plans across ADRC sites participating in CLARiTI. The anticipated CLARiTI cohort will reflect the clinical heterogeneity that already exists across the ADRC network. CLARiTI will contribute to scientific goals related to the detection of multi-etiological signatures relevant for Alzheimer's disease and related disorders (ADRDs).

Humans↗
PubMed2006

Individual differences in executive processing predict susceptibility to interference in verbal working memory.

Recent theories have suggested that resistance to interference is a unifying principle of executive function and that individual differences in interference may be explained by executive function (M. J. Kane & R. W. Engle, 2002). Measures of executive function, memory, and perceptual speed were obtained from 121 older adults (ages 63-82). We used structural equation modeling to investigate the relationships of these constructs with interference in a working memory task. Executive function was best described as two related subcomponent processes: shifting and updating goal-relevant representations and inhibition of proactive interference. These subcomponents were distinct from verbal and visual memory and speed. Individual differences in interference susceptibility and recollection were best predicted by shifting and updating and by resistance to proactive interference, and variability in familiarity was predicted by resistance to proactive interference and speed.

Aged↗
PubMed2006

Categorical organization in free recall across culture and age.

BACKGROUND: Cross-cultural differences in cognition suggest that Westerners use categories more than Easterners, but these differences have only been investigated in young adults. OBJECTIVE: The contributions of cognitive resource and the extent of cultural exposure are explored for free recall by investigating cross-cultural differences in categorical organization in younger and older adults. Cultural differences in the use of categories should be larger for elderly than young because categorization is a well-practiced strategy for Westerners, but age-related cognitive resource limitations may make the strategy difficult for elderly Easterners to implement. Therefore, we expect that cultural differences in categorization will be magnified in elderly adults relative to younger adults, with Americans categorizing more than Chinese. METHODS: Across two studies, 112 young and 112 elderly drawn from two cultures (American and Chinese) encoded words presented in their native language. One word list contained categorically-unrelated words and the other, categorically-related words; both lists were presented in the participants' native language. In experiment 1, the words were strong category associates, and in experiment 2, the words were weak category associates. Participants recalled all the words they could remember, and the number of words recalled and degree of clustering by category were analyzed. RESULTS: As predicted, cultural differences emerged for the elderly, with East-Asians using categories less than Americans during recall of highly-associated category exemplars (experiment 1). For recall of low-associate exemplars, East-Asians overall categorized less than Americans (experiment 2). Surprisingly, these differences in the use of categories did not lead to cultural differences in the number of words recalled. The expected effects of age were apparent with elderly recalling less than young, but in contrast to previous studies, elderly also categorized less than young. CONCLUSION: These studies provide support for the notion that cultural differences in categorical organization are larger for elderly adults than young, although culture did not impact the amount recalled. These data suggest that culture and age interact to influence cognition.

Adolescent↗
PubMed2005

Contributions of processing ability and knowledge to verbal memory tasks across the adult life-span.

This study investigated the relationships of processing capacity and knowledge to memory measures that varied in retrieval difficulty and reliance on verbal knowledge in an adult life-span sample (N = 341). It was hypothesized that processing ability (speed and working memory) would have the strongest relationship to tasks requiring active retrieval and that knowledge (vocabulary ability) would be related to verbal fluency and cued recall, as participants relied upon verbal knowledge to retrieve category items (fluency) or develop associations (cued recall). Measurement and structural equation models were developed for the entire sample and separately for younger (aged 20-54 years, n = 168) and older (aged 55-92 years, n = 173) subgroups. In accordance with the hypotheses, processing ability was found to be most highly related to free recall, with additional significant relationships to cued recall, verbal fluency, and recognition. Knowledge was found to be significantly related only to verbal fluency and to cued recall. Moreover, knowledge was more important for older than for younger adults in mediating variance in cued recall, suggesting that older adults may use age-related increases in knowledge to partially compensate for processing declines when environmental support is available in memory tasks.

Adult↗
PubMed2005

Healthy and pathological processes in adult development: new evidence from neuroimaging of the aging brain.

PURPOSE OF REVIEW: Recent research has revealed that the population of older adults is composed not only of individuals who are either healthy or have an age-related disease, most commonly Alzheimer's disease, but also individuals with mild cognitive impairment who are at-risk for or already in the prodromal stage of Alzheimer's disease. These variations in cognitive aging can be related to their neural bases via structural and functional neuroimaging methods. RECENT FINDINGS: Healthy aging appears to primarily affect a frontal-striatal system that undergirds executive control of cognition, while minimally affecting medial temporal lobe structures. Functional imaging studies suggest that enhanced prefrontal engagement may offer compensatory plasticity that minimizes age-related cognitive losses. Mild cognitive impairment appears to affect the entorhinal cortex in particular, with functional consequences in other brain regions. Alzheimer's disease is characterized by severe hippocampal injury, although early-stage Alzheimer's disease may relatively spare some cortical regions. SUMMARY: Advances in in-vivo imaging methods are providing the tools for identifying different trajectories of neurocognitive aging, and knowledge about these brain changes may promote opportunities for treatment.

Age Factors↗
PubMed2005

Aging and the neural correlates of successful picture encoding: frontal activations compensate for decreased medial-temporal activity.

We investigated the hypothesis that increased prefrontal activations in older adults are compensatory for decreases in medial-temporal activations that occur with age. Because scene encoding engages both hippocampal and prefrontal sites, we examined incidental encoding of scenes by 14 young and 13 older adults in a subsequent memory paradigm using functional magnetic resonance imaging (fMRI). Behavioral results indicated that there were equivalent numbers of remembered and forgotten items, which did not vary as a function of age. In an fMRI analysis subtracting forgotten items from remembered items, younger and older adults both activated inferior frontal and lateral occipital regions bilaterally; however, older adults showed less activation than young adults in the left and right parahippocampus and more activation than young adults in the middle frontal cortex. Moreover, correlations between inferior frontal and parahippocampal activity were significantly negative for old but not young, suggesting that those older adults who showed the least engagement of the parahippocampus activated inferior frontal areas the most. Because the analyses included only the unique activations associated with remembered items, these data suggest that prefrontal regions could serve a compensatory role for declines in medial-temporal activations with age.

Adult↗
PubMed2004

Category norms as a function of culture and age: comparisons of item responses to 105 categories by american and chinese adults.

Understanding how aging influences cognition across different cultures has been hindered by a lack of standardized, cross-referenced verbal stimuli. This study introduces a database of such item-level stimuli for both younger and older adults, in China and the United States, and makes 3 distinct contributions. First, the authors specify which item categories generalize across age and/or cultural groups, rigorously quantifying differences among them. Second, they introduce novel, powerful methods to measure between-group differences in freely generated ranked data, the rank-ordered logit model and Hellinger Affinity. Finally, a broad archive of tested, cross-linguistic stimuli is now freely available to researchers: data, similarity measures, and all stimulus materials for 105 categories and 4 culture-by-age groups, comprising over 10,000 fully translated unique item responses.

Adolescent↗
PubMed2004

A cross-culturally standardized set of pictures for younger and older adults: American and Chinese norms for name agreement, concept agreement, and familiarity.

The present study presents normative measures for 260 line drawings of everyday objects, found in Snodgrass and Vanderwart (1980), viewed by individuals in China and the United States. Within each cultural group, name agreement, concept agreement, and familiarity measures were obtained separately for younger adults and older adults. For a subset of 57 pictures (22%), there was equivalence in both name agreement and concept agreement, and for an additional subset of 29 pictures (11%), there was nonequivalent name agreement but equivalent concept agreement, across all culture-by-age groups. The data indicate substantial differences across culture-by-age groups in name agreement percentages and number of distinct name responses provided. We discovered significant differences between older and younger American adults in both name agreement percentages (67 pictures, or 26%) and concept agreement percentages (44 pictures, or 17%). Written naming responses collected for the entire set of Snodgrass and Vanderwart pictures showed shifts in both naming and concept agreement percentages over the intervening decades: Although correlations in name agreement were strong (r = .71, p < .001) between our younger American samples and those of Snodgrass and Vanderwart, name agreement percentages have changed for a substantial proportion (33%) of the 260 pictures; moreover, 63% of the stimuli for which Snodgrass and Vanderwart reported concept agreement now appear to differ. We provide comprehensive comparison statistics and tests for both the present study and prior ones, finding differences across numerous item-level measures. The corpus of data suggests that substantial differences in all measures can be found across age as well as culture, so that unequivocal conclusions with respect to cross-cultural or age-related differences in cognition can be made only when appropriate stimuli are selected for studies. Data for all 260 pictures, for each of the four groups, and all supporting materials and tests are freely archived at http://agingmind.cns.uiuc.edu/Pict_Norms. The full set of these norms may be downloaded from www.psychonomic.org/archive/.

Adolescent↗
PubMed2003

Contributions of source and inhibitory mechanisms to age-related retroactive interference in verbal working memory.

Determining contributions of source-monitoring and inhibitory function to age-related forgetting has been an elusive goal for cognitive theorists. Five studies used a verbal working memory paradigm to examine mechanisms accounting for disproportionate retroactive interference (RI) experienced with adult aging. Participants distinguished studied target-word pairs from interfering pairs that were read aloud. Source-monitoring and inhibitory task components varied through manipulations of response requirements. RI effects were primarily due to source-monitoring failures rather than to inhibitory failures. Removing both source and inhibitory components eliminated age differences in RI. When source monitoring was emphasized, RI continued to be observed in all age groups but disproportionately for older adults. Process dissociation analyses of memory found recollection decreases and familiarity increases consistent with source failures.

Adult↗
PubMed2002

What do you think I think you think?: Strategic reasoning in matrix games.

In reasoning about strategic interpersonal situations, such as in playing games, an individual's representation of the situation often includes not only information about the goals and rules of the game, but also a mental model of other minds. Often such mental models involve a hierarchy of reflexive reasoning commonly employed in social situations ("What do you think I think you think..."), and may be related to the developmental notion of 'theory of mind'. In two experiments, the authors formally investigate such interpersonal recursive reasoning in college-age adults within the context of matrix games. Participants are asked to predict the moves of another player (experimenter's confederate) in a two-choice, sequential-move game that may terminate at various stages with different payoffs for each player. Participants are also asked to decide optimally on their own moves based on the prediction made. Errors concerning the prediction, or translation of those predictions into decisions about one's action, were recorded. Results demonstrate the existence of a "default" mental model about the other player in the game context that is dynamically modified as new evidence is accumulated. Predictions about this other player's behavior are, in general, used consistently in decision-making, though the opponent tends to be modeled, by default, to behave in a myopic fashion not anticipating the participant's own action.

Adult↗
PubMed2002

Cultural variation in verbal versus spatial neuropsychological function across the life span.

Established culture-invariant measures are needed for cross-cultural assessment of verbal and visuospatial speed of processing and working memory across the life span. In this study, 32 younger and 32 older adults from China and from the United States were administered numerically based and spatially based measures of speed of processing and working memory. Chinese superiority on the numerically based tasks was found for younger adults. Age and increasing task demands diminished this cultural effect, as predicted by the framework proposed by D. C. Park, R. Nisbett, and T. Hedden (1999). However, the visuospatial measures of both working memory and speed of processing did not differ cross-culturally for either age group. The authors concluded that these visuospatial measures provide culture-invariant estimates of cognitive processes in East Asian and Western cultures, but that numerically based tasks show evidence of cultural and linguistic biases in performance levels.

Adult↗
PubMed2002

Interpreting reaction time measures in between-group comparisons.

Although reaction time measures have been used extensively in many types of between-group comparisons, the assumptions and limitations of reaction time measurement are not always recognized. In this article we discuss three issues that should be considered when designing and interpreting comparisons involving reaction time. These concern speed-accuracy tradeoffs, methods of analyzing measures postulated to reflect specific processes, and methods for distinguishing group-related influences that are shared with other variables from those that are unique to a single variable.

Confounding Factors, Epidemiologic↗
PubMed2002

Models of visuospatial and verbal memory across the adult life span.

The authors investigated the distinctiveness and interrelationships among visuospatial and verbal memory processes in short-term, working, and long-term memories in 345 adults. Beginning in the 20s, a continuous, regular decline occurs for processing-intensive tasks (e.g., speed of processing, working memory, and long-term memory), whereas verbal knowledge increases across the life span. There is little differentiation in the cognitive architecture of memory across the life span. Visuospatial and verbal working memory are distinct but highly interrelated systems with domain-specific short-term memory subsystems. In contrast to recent neuroimaging data, there is little evidence for dedifferentiation of function at the behavioral level in old compared with young adults. The authors conclude that efforts to connect behavioral and brain data yield a more complete understanding of the aging mind.

Adult↗