Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 7 of 7
Full-Text Articles in Psychology
Relating Spontaneous Activity And Cognitive States Via Neurodynamic Modeling, Matthew Singh
Relating Spontaneous Activity And Cognitive States Via Neurodynamic Modeling, Matthew Singh
Arts & Sciences Electronic Theses and Dissertations
Stimulus-free brain dynamics form the basis of current knowledge concerning functional integration and segregation within the human brain. These relationships are typically described in terms of resting-state brain networks—regions which spontaneously coactivate. However, despite the interest in the anatomical mechanisms and biobehavioral correlates of stimulus-free brain dynamics, little is known regarding the relation between spontaneous brain dynamics and task-evoked activity. In particular, no computational framework has been previously proposed to unite spontaneous and task dynamics under a single, data-driven model. Model development in this domain will provide new insight regarding the mechanisms by which exogeneous stimuli and intrinsic neural circuitry …
Neural Mechanisms Of Cognitive Individual Difference: An Investigation Of The Human Connectome Project, Shelly Renee Cooper
Neural Mechanisms Of Cognitive Individual Difference: An Investigation Of The Human Connectome Project, Shelly Renee Cooper
Arts & Sciences Electronic Theses and Dissertations
Considering individual differences in task activation functional magnetic resonance imaging (t-fMRI) can be challenging because they may arise from variability in activity in brain regions, in the tasks themselves, or some combination thereof. Delineating sources of between-subjects variance is particularly important for cognitive control where task goals are at the forefront. Here we applied structural equation modeling (SEM) to the Human Connectome Project to examine if activity could be partitioned into separable brain and task individual difference dimensions. A series of SEMs were defined with varying numbers of latent factors, where the inputs were parcels of two cognitive control-related brain …
Isolating Item And Subject Contributions To The Subsequent Memory Effect, Jihyun Cha
Isolating Item And Subject Contributions To The Subsequent Memory Effect, Jihyun Cha
Arts & Sciences Electronic Theses and Dissertations
The subsequent memory effect (SME) refers to the greater brain activation during encoding of subsequently recognized items compared to subsequently forgotten items. Previous literature regarding SME has been primarily focused on identifying the role of specific regions during encoding or factors that potentially modulate the phenomenon. The current dissertation examines the degree to which this phenomenon can be explained by item selection effects; that is, the tendency of some items to be inherently more memorable than others. To estimate the potential contribution of items to SME, I provided participants a fixed set of items during encoding, which allowed me to …
Levels Of Processing And The Parietal Memory Network, Hung-Yu Chen
Levels Of Processing And The Parietal Memory Network, Hung-Yu Chen
Arts & Sciences Electronic Theses and Dissertations
The parietal memory network (PMN) is a functional brain network that has been recently described through the convergence of task-based fMRI and resting-state functional MRI studies (Gilmore et al., 2015). The networkճ characteristic encoding/retrieval flip (deactivation at encoding and activation at later retrieval, discussed by Gilmore and colleagues) and its manifestation of a negative subsequent memory effect (greater deactivation at encoding for items that will later be recognizedѩ.e., subsequent hitsѴhan for those that will notѳubsequent misses) (Cabeza et al., 2004; Daselaar, Prince, & Cabeza, 2004; De Chastelaine & Rugg, 2014; Elman, Rosner, Cohn-Sheehy, Cerreta, & Shimamura, 2013; Kim, 2011; Otten …
The Impact Of Delay On Retrieval Success In The Parietal Memory Network, Nathan Anderson
The Impact Of Delay On Retrieval Success In The Parietal Memory Network, Nathan Anderson
Arts & Sciences Electronic Theses and Dissertations
Recent work has identified a Parietal Memory Network (PMN), which exhibits regular patterns of activation during memory encoding and retrieval. Among these characteristic patterns, this network displays a strong “retrieval success” effect, showing greater activation for correctlyremembered studied items (hits) compared to correctly-rejected novel items (CRs). To date, most relevant studies have used short retention intervals. Here, we ask if the retrieval success effect seen in the PMN would remain consistent over a delay. Twenty participants underwent fMRI while encoding and recognizing scenes. Greater activity for hits than for correctly-rejected lures within PMN regions was observed after a short delay …
Perceiving Oldness In Parietal Cortex: Fmri Characterization Of A Parietal Memory Network, Adrian Gilmore
Perceiving Oldness In Parietal Cortex: Fmri Characterization Of A Parietal Memory Network, Adrian Gilmore
Arts & Sciences Electronic Theses and Dissertations
The manner in which the human brain recognizes certain stimuli as novel or familiar is a matter of ongoing investigation. The overarching goal of this dissertation is to improve our understanding of how this may be accomplished. More specifically, work contained herein focuses on a recently described "parietal memory network" (PMN; Gilmore et al., 2015) that shows opposite patterns of activity when perceiving novel or familiar stimuli: deactivating in response to novelty, and activating in response to familiarity. Critically, our understanding of this network is based on explicit memory tasks, in which subjects are deliberately instructed to learn or remember …
Are There Multiple Kinds Of Episodic Memory? An Fmri Investigation Comparing Autobiographical And Recognition Memory Tasks, Hung-Yu Chen
Are There Multiple Kinds Of Episodic Memory? An Fmri Investigation Comparing Autobiographical And Recognition Memory Tasks, Hung-Yu Chen
Arts & Sciences Electronic Theses and Dissertations
What brain regions underlie retrieval from episodic memory? The bulk of research addressing this question has relied upon laboratory-based recognition memory. Another, less dominant tradition has employed autobiographical methods, whereby people recall events from their lifetime, often after being cued with words or pictures. Previous research comparing regions underlying successful memory retrieval between these two methodological approaches has shown mixed results. To examine the neural processes underlying recognition memory for materials encountered in the laboratory and autobiographical memory, we conducted a within-subject study using fMRI. We showed participants indoor and outdoor scenes under two types of instructions: In the lab-based …