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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
211

The Contextual Specificity of Backward Compatibility Effects / Context of Backward Compatibility Effects

Kim, Kyung-Hyun January 2017 (has links)
Dual task studies have found that Task 2 response information is activated during Task 1 response selection, and can have a priming effect on Task 1. This is called the backward compatibility effect (BCE). Giammarco et al. (2016) found that single-task practice of Task 2 in the context of a random, filler task (Practice-T2 condition) extinguished BCE development in a subsequent dual-task. On the other hand, practicing Task 2 in the context of Task 1 (Practice-Both condition) promoted BCE development in subsequent dual-tasks. Experiment 1a sought to replicate this context-specific disruption of BCE development by presenting participants with a single-task practice phase where they practiced Task 2 along with a filler task, and then observed BCE development in a subsequent dual-task phase. Experiment 1b addressed a counterbalancing issue in Experiment 1a. Experiment 2 was an exact replication of the Practice-T2 condition used in Giammarco et al. (2016). Overall, we conceptually replicated the context-specific disruption of BCE in Experiment 2, but not in Experiments 1a and 1b. Further study is warranted to determine the effect of specific response features on the learning context of Task 2. / Thesis / Master of Science (MSc) / Backward compatibility effects (BCEs) have been consistently observed in dual task paradigms. BCEs occur when Task 1 and Task 2 response information are congruent: participants respond faster to Task 1 when the two tasks require congruent responses than when they require incongruent ones. This suggests that there is some parallel processing of Task 2 while performing Task 1. The purpose of this study was to explore the episodic account of BCE development. Since episodic memories are context-specific, BCEs should also be context-specific, according to the episodic account. By manipulating the context of Task 2 learning, we tested whether this affected subsequent BCE development. Our findings suggest that context-specific disruption of BCE development is possible, but depends on other factors as well.
212

Verbal Information Hinders Young Children's Ability to Gain Modality Specific Knowledge

Waters, Gillian M., Beck, S.R. 30 January 2015 (has links)
No / In two experiments, we investigated whether having prior experience of objects influenced young children's ability to solve a metacognitive search task, based on the objects' perceptual properties. In Experiment 1, 100 children (mean age 77months) chose whether to look or feel to locate one of two hidden balls (identifiable by sight or touch). Before choosing, children were told about the balls' perceptual properties (i.e. their colour and feel'), and/or saw and touched them, or had no pre-trial experience of them at all. Children who only had self-directed contact with the balls performed best, but children who heard the objects described by an adult performed relatively poorly. In Experiment 2, 116 children (mean age 72months) either heard only relevant, relevant and irrelevant, or no information about the objects before completing the task. Verbal descriptions of the balls (whether or not they contained irrelevant information) caused children difficulties.
213

Amnesia and future thinking: Exploring the role of memory in the quantity and quality of episodic future thoughts

Cole, S.N., Morrison, Catriona M., Barak, O., Pauly-Takas, K., Conway, M.A. 21 August 2015 (has links)
Yes / Objectives To examine the impact of memory accessibility on episodic future thinking. Design Single-case study of neurological patient HCM and an age-matched comparison group of neurologically Healthy Controls. Methods We administered a full battery of tests assessing general intelligence, memory, and executive functioning. To assess autobiographical memory, the Autobiographical Memory Interview (Kopelman, Wilson, & Baddeley, 1990. The Autobiographical Memory Interview. Bury St. Edmunds, UK: Thames Valley Test Company) was administered. The Past Episodic and Future Episodic sections of Dalla Barba's Confabulation Battery (Dalla Barba, 1993, Cogn. Neuropsychol., 1, 1) and a specifically tailored Mental Time Travel Questionnaire were administered to assess future thinking in HCM and age-matched controls. Results HCM presented with a deficit in forming new memories (anterograde amnesia) and recalling events from before the onset of neurological impairment (retrograde amnesia). HCM's autobiographical memory impairments are characterized by a paucity of memories from Recent Life. In comparison with controls, two features of his future thoughts are apparent: Reduced episodic future thinking and outdated content of his episodic future thoughts. Conclusions This article suggests neuropsychologists should look beyond popular conceptualizations of the past–future relation in amnesia via focussing on reduced future thinking. Investigating both the quantity and quality of future thoughts produced by amnesic patients may lead to developments in understanding the complex nature of future thinking disorders resulting from memory impairments. / Institute of Psychological Sciences, University of Leeds
214

Episodic intertrial learning of younger and older participants: Effects of age of acquisition

Almond, N.M., Morrison, Catriona M. 23 October 2013 (has links)
No / There is clear evidence of a deficit in episodic memory for older adults compared to younger adults. Using an intertrial technique previous research has investigated whether this deficit can be attributed to a decline in encoding or consolidation. On standard memory tests, these two aspects of memory function can be measured by examining the items forgotten or acquired across multiple learning trials. The present study assessed whether age deficits in episodic memory were affected by stimulus characteristics, specifically age of acquisition (AoA). A standard intertrial design was implemented whereby participants studied word lists over several study-test trials. The stimulus characteristics of AoA were manipulated using a pure-list technique. Our findings showed that older adults demonstrate an overall recall deficit which appeared to be a consequence of both an encoding deficit and consolidation weakness. Earlier-acquired words were recalled significantly better than later-acquired words and this was apparently due to both enhanced encoding and consolidation of earlier- over later-acquired words. The key finding is that older adults show a recall advantage for earlier- compared to later-acquired words over the entire experiment to a greater degree than younger adults.
215

Testing the Reinforcer Pathology Theory: A New Insight into Novel Targets for Drug Addiction

Athamneh, Liqa 17 December 2019 (has links)
Despite decades of effort in developing evidence-based treatments, drug addiction remains one of the most problematic and enduring public health crises. Developing a new generation of theoretically-derived interventions constitutes an important clinical and scientific gap that, if addressed, may open innovative treatment opportunities. Based on the Reinforcer Pathology theory, altering the temporal window over which reinforcers are integrated (i.e., measured by delay discounting) would alter drug valuation and consumption. The first investigation—in 2 separate studies— test the Reinforcer Pathology theory by examining the effect of expanding and constricting the temporal window of integration using two mating narratives (long-term and short-term relationships, respectively) on cigarette valuation among cigarette smokers. The second investigation, test the Reinforcer Pathology theory by assessing the effect of remotely delivered Episodic Future Thinking (EFT) narratives (expands the temporal window) on real-world alcohol consumption among individuals with alcohol use disorder (AUD). Together, these investigations supported the Reinforcer Pathology theory and demonstrated its relevance for understanding and intervening in addiction. The current findings provide scientific justification to further investigate Reinforcer Pathology based interventions that expand the temporal window to change drug valuation and consumption. The construction of multi-component treatments that incorporate Reinforcer Pathology based interventions to systematically alter the temporal window may provide a novel intervention to reduce alcohol consumption. / Doctor of Philosophy / The following studies provide evidence that altering the temporal widow (how far in the future one can imagine and integrate into the present) would alter drug valuation. In the following studies, we used narratives describing long-term or short-term mating relationships (Study 1) and Episodic Future Thinking (EFT; represents one's capability to pre-experience the future; Study 2) to alter the valuation of cigarettes and alcohol, respectively. In the first study, cigarette smokers who read and vividly imagined long-term romance relationship narrative (expands the temporal window) valued cigarettes less than control (imagined looking for a lost key). In contrast, those who read and vividly imagined a short-term sexual encounter (shortens the temporal window) valued cigarettes more than controls. The second study employed EFT (expands the temporal window) as a strategy to reduce alcohol consumption, in real-world settings, over two weeks in individuals with alcohol use disorder. The study found that expanding the temporal window using EFT reduced alcohol consumption. Together, these two studies provide support to employing interventions that extend the temporal window to change drug valuation and consumption. The construction of multi-component treatments that incorporate interventions expanding the temporal window may reduce drug consumption.
216

How does context variability affect representational pattern similarity to support subsequent item memory?

Lim, Ye-Lim 13 September 2022 (has links)
Episodic memories are neurally coded records of personally experienced events across a lifetime. These records are encoded via medial temporal lobe structures in the brain, including the hippocampus, and are commonly called "representations" or "memory traces". Existing studies indicate that information about the neural signal corresponding to a memory representation can be found in functional magnetic resonance imaging (fMRI) data when the pattern across its smallest units (voxels, often 3mm3 sections of the brain) is measured. Many prior studies have measured these voxel patterns in response to stimuli as if they are a spontaneous brain function, regardless of cognitive factors. These studies sometimes find that similarity in the voxel patterns across repetition of a to-be-remembered event predicts later memory retrieval, but the results are inconsistent. The current fMRI study investigated the possibility that cognitive goals during encoding affect the type of neural representation (voxel pattern) that will later support memory retrieval. This seems likely because prior behavioral studies indicate that cognitive variability across repetitions of an event benefits later memory retrieval, which is difficult to reconcile with the common finding that voxel pattern variability across repetitions of an event harms later memory. We tested this hypothesis by comparing voxel patterns that support later memory retrieval to those associated with forgotten items in the medial temporal lobe, including the hippocampus, and lateral occipital cortex. Overall, as previously demonstrated, the behavioral results showed that exposure to variable cognitive goals across repetition of events during encoding benefited subsequent memory retrieval. Voxel patterns in the hippocampus indicated a significant interaction between cognitive goals (variable vs. consistent) and memory (remembered vs. forgotten) such that less voxel pattern similarity for the repeated events with variable cognitive goals, but not consistent cognitive goals, supported later memory success. In other words, variable hippocampal neural activations for the same events under different cognitive goals predicted better later memory performance. However, there was no significant interaction in neural pattern similarity between cognitive goals and memory success in medial temporal cortices or lateral occipital lobe. Instead, higher similarity in voxel patterns in right medial temporal cortices was associated with later memory retrieval, regardless of cognitive goals. In the lateral occipital lobe, the main effects of cognitive goals, hemisphere, and memory success were found but no interactions. In conclusion, we found that the relationship between pattern similarity and memory success in the hippocampus (but not the medial temporal lobe cortex) changes when the cognitive goal during encoding does or does not vary across repetitions of the event. / Master of Science / Episodic memory is a long-term memory of personal experiences which are encoded via the medial temporal lobe in the brain, primarily in the hippocampus. The records of personal experiences in these areas are commonly called "patterns", "representations", or "memory traces". Prior investigations indicate that the way of measuring the neural signals corresponding to personal events is functional magnetic resonance imaging (fMRI). The brain images taken by an fMRI scanner represent the patterns of the smallest unit (voxels, often 3mm3 sections of the brain). Many prior investigations of episodic memory used the voxel patterns but showed mixed results in whether similarity in the voxel patterns across repetition of a repeated event leads to subsequent memory retrieval. One of the possible explanations for mixed results is that the cognitive factors during encoding were neglected. Therefore, the current fMRI study examined how cognitive goals during encoding influence the voxel patterns that later support memory retrieval. During encoding, participants were shown an image repeated with the same or different questions and answered the question on the screen in an fMRI scanner. After 10 days, they were invited to the item memory test on the images that they were given during the encoding phase. The voxel patterns in the medial temporal lobe, including the hippocampus, and the lateral occipital lobe were compared across the repetitions of each image. The behavioral results showed that variable cognitive goals across repeated events during encoding benefited later memory retrieval. Furthermore, less similar voxel patterns in the hippocampus for the images repeated with different questions, but not the same questions, during encoding predicted better later memory success. In the right medial temporal cortices, higher similarity in voxel patterns was significantly associated with later memory retrieval, regardless of cognitive goals. In the lateral occipital lobe, higher voxel pattern similarity was found in the right hemisphere, for images repeated with the same question, and for images successfully retrieved later. In conclusion, we found that the relationship between voxel pattern similarity and memory success in the hippocampus (but not the medial temporal lobe cortex) changes when the cognitive goal during encoding does or does not vary across repetitions of the event.
217

Neural Coding of Episodic and Spatial Representations in Development

Nguyen, Kim, 0000-0002-5771-1327 05 1900 (has links)
Navigation and episodic memory are both fundamental cognitive processes that rely on the hippocampus and its connections to other cortical areas. However, the extent and nature of their interdependence is unclear. We investigated how they relate by testing children (8-13 years, i.e., over the age at which skills are refined towards adult levels) and young adults using a real-world encoding experience, and multiple tests of spatial and episodic memory. We found that the measures formed two latent factors. The memory structure factor included measures that require simultaneously representing all or part of the environment (finding routes, mapping the space, free recall of the experience, and spatial-temporal recognition). The perceptual/factual/locale factor included perceptual and semantic recognition along with JRD (which taxes egocentric and allocentric navigation). Univariate BOLD analysis identified a neural architecture that supports representations across both factors: right hippocampus (HC), lateral occipital area (LO), and entorhinal (ERC), perirhinal (PRC), and parahippocampal (PHC) cortices. Pattern analysis revealed that stable similarity of encoded representations in the anterior right HC related to better performance on the memory structure factor. Stable differentiation of encoded representations in the ERC related to better performance for both factors. Additionally, we found a developmental timeline that extends into early adolescence for spatial representations in the ERC and PRC and for stability of encoded information in the LO. In sum, we found that episodic memory and spatial representations are intertwined in the real world, in which humans seldom operate only spatially or only episodically. / Psychology
218

Understanding Autobiographical Memory of Children Through Self-Report

Howard, Megan 01 January 2006 (has links)
This research was designed to explore autobiographical memory in children, specifically, the personal events involved in memory and memory failures and to what extent children and adults realize what they have forgotten. Since previous research in this domain has focused mainly on adult's or children's ability to recall past events, few have ventured to investigate what underlies the process of forgetting for everyday events in parents and children, and if a link exists between the two. Survey data pertaining to self-reported memory failures along with information on the amount of interaction between parents and children was collected from parents and children at a local elementary school. The results showed that children and parents were more likely to report failure in prospective memory (forgetting to do something) than retrospective memory (forgetting something they already knew). Additionally, when asked what they thought had caused the failure, children were more likely to attribute the lapse to external distractions. Finally, the data showed that the degree of parent-child interaction was significantly related to the detail provided in a child's reported memory failures. The results are discussed in the context of developing a better understanding of, and suggest future avenues for, research in memory and memory failures in children, as well as understanding the relation between parent/child memory.
219

The relationship of self-reported reading habits and declarative memory

Álvarez, Bernardo January 2016 (has links)
The present study examined the possibility that reading books might support declarative memory, and potentially contribute to the cognitive reserve and thereby minimize age-related decline in memory functions. It was a crosssectional study, where data were taken from 566 Betula Study participants, as well as the scores of declarative memory assessment tasks, and book reading reports. The tasks of episodic memory were sentence learning with and without encoding enactment –free and cued recall. The tasks of semantic memory were word fluency, initial letter A, M fivewords, B profession names, and SRB –vocabulary. Three-way analysis of variance was performed for hypothesis testing. The results showed that book reading might support declarative memory. There was a significant relationship between education and book reading. Was not found if book reading might minimize age-related decline. In conclusion, the study showed that book reading and years of education might support declarative memory. / Denna studie undersökte om läsandet av böcker stödjer deklarativt minne, och eventuellt främjar den kognitivareserven, vilket medför en minimerad åldersbaserad reduktion i minnesfunktioner. I denna tvärsnittsstudie ingick datafrån 566 deltagare i Betulaprojektet som testats med avseende på deklarativa minnesfunktioner, samt enlitteraturanalys. Utvärderingarna som baserades på episodiskt minne var; menings-inlärning med och utan 'encodingenactment' -både fri och stödd återgivning. Test av semantiskt minne var ordflöde med första bokstav A, M fem-ord,B yrkesnamn, och SRB-ordförråd. Tre-vägs variansanalyer genomfördes för hypotestestning. Resultaten visade på enkoppling mellan utbildning och läsandet av böcker. Det är dock fortfarande oklart om läsandet av böcker minimeraråldersbaserad minnes-reducering. Sammanfattningsvis, visade studien att läsning och utbildning kan stödja deklarativtminne.
220

Brain function and glucocorticoids in obesity and type 2 diabetes including effects of lifestyle interventions / Effekter av livsstilsförändring på hjärnfunktion och stresshormoner vid fetma och typ 2 diabetes

Stomby, Andreas January 2015 (has links)
Background Obesity and associated metabolic dysregulation are linked to impaired cognitive function and alterations in brain structure, which increases the risk of age-related dementia. Increased glucocorticoid (GC) exposure may be a potential mediator of these negative effects on the brain. Methods and results In paper 1, we tested the relationship between cortisol levels, brain morphology and cognitive function in 200 women and men. Salivary cortisol levels were negatively related to cortical surface areas in prefrontal brain regions in both sexes. In participants with type 2 diabetes, high salivary cortisol levels were associated with lower memory performance. In paper 2, we tested in 70 overweight women the effects on tissue-specific GC metabolism of a Paleolithic diet or a diet following the Nordic nutrition recommendations. The 24-month interventions led to decreased expression of the GC-activating enzyme 11βHSD1 in adipose tissue, interpreted as a normalization of an obesity-related disturbance in GC metabolism. Furthermore, GC metabolism by 5α-reductase increased substantially after 2 years, an unexpected and novel result. The outcomes did not differ by diet. In paper 3, 20 women included in paper 2 were examined with functional magnetic resonance imaging (fMRI) while performing a memory task at baseline and after 6 months. Memory performance improved and functional brain responses increased in the hippocampus. Once again, the results were similar in both diet groups. In paper 4, 24 overweight participants with type 2 diabetes were examined with fMRI, using the same memory test as in paper 3, at baseline and after 12 weeks of intervention with a Paleolithic diet with or without exercise training. Functional brain response increased in the hippocampus, but memory was not improved. The addition of physical exercise did not alter the results. Conclusion Cortisol levels are linked to prefrontal brain structure and, at least in type 2 diabetes, lower memory performance. Furthermore, the dysregulated GC metabolism in obesity can be reversed by long-term diet- induced weight loss. Finally, dietary interventions with associated metabolic improvements alter functional brain responses during memory testing, including increased activation of the hippocampus. Whether these changes are linked to alterations in GC exposure and mediate improved cognition requires further study.

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