Matching Items (2)
Filtering by
- Creators: McClure, Samuel
Description
The frontostriatal reward circuit serves an underlying role in reward processing, cognitive planning, and motor control in the context of achieving a goal. Furthermore, research suggests a relationship between the reward circuits and behavior expressed in Attention Deficit Hyperactivity Disorder (ADHD); however, the specific structural differences of the reward circuits in those with ADHD remain ambiguous. Diffusion tensor imaging (DTI) techniques were used to analyze diffusion weighted magnetic resonance imaging (DWI) data in order to examine the structural connectivity of frontostriatal reward pathways in ADHD adolescents compared to typically developing (TD) adolescents. It was hypothesized that measures of impulsivity would be predicted by white matter tract integrity measures in frontostriatal tracts related to affective processing (ventromedial prefrontal cortex to ventral striatum, vmPFC) in adolescents with ADHD, and that there would be reduced tract integrity in tracts related to executive control (dorsolateral prefrontal and anterior cingulate cortex—dlPFC and ACC, respectively). Frontostriatal tracts as well as the hippocampus and amygdala were examined in relation to age and impulsivity using both correlation and regression models. Results indicated that impulsivity declined with age in the TD group while no significant trend was identified for the ADHD group. The hypotheses were not supported and results for both predictions on the affective and executive circuits showed opposite trends from what was expected.
ContributorsHarrison, Sydney Rae (Author) / McClure, Samuel (Thesis director) / Brewer, Gene (Committee member) / Davis, Mary (Committee member) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2017-12
Description
The need to fully understand the possible consequences of young-adult cannabis use has become increasingly critical as a result of major cannabis policy changes. The purpose of this study was to determine if young-adult users exhibit cognitive deficits on laboratory-based tests and memory and attention deficits in everyday life. Participants were 152 students from a large U.S. university enrolled in introductory psychology courses and the top and bottom 10% of the 12-item Yale University PRIME Screening Test for psychotic-like experiences. Participants were asked about their cannabis use and were given six cognitive tests spanning executive function and memory. To test functional impairment in memory and attention, participants were asked to nominate informants (people who knew them well) and these rated the participants on an attention problems scale of four items and a memory problems scale of three items. Results showed that individuals who used cannabis more frequently were rated as having more attention and memory problems and that, consistent with prior research, more frequent cannabis use was associated with worse memory test performance, though the association was not present between frequency of use and executive function test performance. Additionally, it was found that informant-reported attention problems were associated with poorer performance on two of the executive function cognitive tests. The present findings suggest that individuals who use cannabis more frequently experience noticeable memory and attention problems in everyday life, despite the lack of significant correlation between this functional impairment and cognitive test performance. Informant reports, therefore, may be useful in future research for understanding or predicting cognitive impairment in young adults.
ContributorsCarbajal, Lucia (Author) / Meier, Madeline (Thesis director) / McClure, Samuel (Committee member) / Department of Psychology (Contributor) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12