Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 3 of 3
Full-Text Articles in Entire DC Network
Reinforcement Learning In Individuals At Risk For Alzheimer's Disease, Christina Marie Figueroa
Reinforcement Learning In Individuals At Risk For Alzheimer's Disease, Christina Marie Figueroa
Master's Theses (2009 -)
Explicit memory is the hallmark of impairment in Alzheimer’s disease (AD) while implicit memory has mixed task-dependent results. Models of memory processes have posited that hippocampal function is sensitive to reinforcement learning (RL), which involves both explicit and implicit memory. The hippocampus is also vital for the transfer of learned associations to novel situations. Nevertheless, RL paradigms have been underutilized in assessing memory processes in individuals at risk for AD, which may aid in early identification of cognitive decline. Thirty-six apolipoprotein-E (APOE) genotyped older adults (Male n=8; Mage=80; Meducation=15 years) performed word stem completion, word recognition, and RL tasks. The …
Neural Dedifferentiation In Relation To Risk For Alzheimer's Disease, Nathan C. Hantke
Neural Dedifferentiation In Relation To Risk For Alzheimer's Disease, Nathan C. Hantke
Master's Theses (2009 -)
Functional magnetic resonance imaging (fMRI) research indicates that as an individual's age increases, the task-related spatial extent of neural activation increases. This decrease in neural specificity, or dedifferentiation, is often demonstrated by older adults during challenging cognitive tasks. Cognitively intact individuals at-risk for Alzheimer's disease (AD), as deemed by having an apolipoprotein-E ε4 allele or a family history of AD, demonstrate increased fMRI activation as compared to individuals at lower risk. Using a low effort, high accuracy event-related semantic memory task involving the presentation of famous and non-famous names, we examined spatial neural specificity through a measure of dedifferentiation using …
Functional Resting State Connectivity In Individuals At-Risk For Alzheimer's Disease, Alissa M. Butts
Functional Resting State Connectivity In Individuals At-Risk For Alzheimer's Disease, Alissa M. Butts
Master's Theses (2009 -)
Resting state functional magnetic resonance imaging studies have examined the connectivity between the hippocampus (HIPP) and the posterior cingulate (PC) in individuals with Alzheimer's disease (AD), mild cognitive impairment (MCI), and younger individuals at risk for AD. The present study aimed to examine the functional connectivity between these two memory structures and targets of AD neurodegeneration in cognitively intact elders at risk for AD (positive for ApolipoE protein (ε4) and family history of dementia), MCI, and healthy controls. Seeds and regions of interest were defined in the bilateral hippocampus and posterior cingulate, and the time courses were cross-correlated to generate …