Social and Behavioral Sciences Commons^™

Alcohol Use Disorders And An Fmri Stress Task: A Connectivity Analysis, Natasha E. Wright

Theses and Dissertations

Little research has been conducted on neuronal stress processing in individuals

with alcohol dependence (AD). The present study examined neural stress response in AD individuals compared to controls using an fMRI stress task, assessing amygdala

activation and its connectivity to the medial prefrontal cortex (mPFC). Further, the study

analyzed the impact of hormone levels and subjective stress on frontal-limbic

connectivity patterns.

Ten abstinent AD individuals and 11 controls were recruited. Subjects

participated in an fMRI stress task. A region of interest (amygdala) analysis was

conducted using area-under-the-curve. This activation was then examined in a whole brain functional connectivity analysis. Follow-up …

The Role Of Brain-Synthesized E2 In Hippocampal Learning And Memory Consolidation In Female Mice, Jennifer Tuscher

Theses and Dissertations

The potent estrogen 17beta-Estradiol (E2) plays a critical role in neuroprotection, serving as an important trophic factor for neurons in the hippocampus, basal forebrain, and prefrontal cortex (Brinton, 2001). In the hippocampus, E2 promotes neurogenesis (Tanapat et al., 1999, Prange-Kiel et al., 2006), protects against cell death after ischemic injury (Garcia-Segura et al., 2001, Zhao and Brinton, 2007), and helps maintain spine morphology crucial for synaptic connectivity and memory (Woolley et al., 1990; Gould et al., 1990, Woolley and McEwen, 1992, Li et al., 2004). However, the mechanisms through which E2 promotes synaptic plasticity and enhances memory function are largely …

Neurophysiological And Morphological Plasticity In Rat Hippocampus And Medial Prefrontal Cortex Following Trace Fear Conditioning, Chenghui Song

Theses and Dissertations

Pavlovian fear conditioning provides a useful model system for investigating the mechanisms underlying associative learning. In recent years, there has been an increasing interest in "trace" fear conditioning, which requires conscious awareness of the contingency of CS and US therefore considered as a rodent model of explicit fear. Acquisition of trace fear conditioning requires an intact hippocampus and medial prefrontal cortex (mPFC), but the underlying mechanisms are still unclear. The current set of studies investigated how trace fear conditioning affects neuronal plasticity in both hippocampus and mPFC in adult rats. Trace fear conditioning significantly enhanced both intrinsic excitability and synaptic …

Memory Retrieval Is Maintained By Intrinsic And Synaptic Plasticity In Prelimbic Cortex, James Otis

Theses and Dissertations

Abnormally strong memories underlie common disorders including addiction and post-traumatic stress disorder (PTSD). Memory disruption would therefore be beneficial for treatment of these disorders. Evidence reveals that cocaine conditioned place preference (CPP) memories are susceptible to long-lasting disruption during memory retrieval. For example, inhibition of β-adrenergic receptor (β-AR) activity within the prelimbic medial prefrontal cortex (PL-mPFC) prevents cocaine CPP memory retrieval, and this retrieval impairment is both long-lasting and prevents subsequent reinstatement of the CPP. Despite this, whether PL-mPFC β-AR activity is a fundamental mechanism required to maintain retrieval of other memories is unclear. Furthermore, how PL-mPFC β-AR activity maintains …

Changes In Resting-State Functional Connectivity Following Delay And Trace Fear Conditioning Acquisition And Extinction, Douglas Hank Schultz

Theses and Dissertations

Consolidation is the process of stabilizing a recently acquired memory into a more permanent or durable form. Several studies with laboratory animals have uncovered valuable information about the process of consolidation, but less is known about the process of consolidation in healthy humans. The current study examined the consolidation of emotional memories in different brain circuits in healthy humans using resting-state fMRI. We used the acquisition and extinction of two variations of Pavlovian fear conditioning, delay and trace, which rely on slightly different circuits to examine changes in functional connectivity related to a general fear learning process and also to …

Impact Of Faah Genotype And Marijuana Use On Brain Structure And Neuropsychological Performance In Emerging Adults, Skyler Gabriel Shollenbarger

Theses and Dissertations

Introduction: Chronic MJ use may be associated with higher cognitive ability impairments (see Lisdahl et al., 2013). Regions undergoing later maturation (Gogtay 2004), may be at increased risk for MJ-induced alterations. Endogenous cannabinoid signaling (ECS) is modulated by the function the enzyme Fatty Acid Amide Hydrolase (see Ho & Hilard, 2005), thus the gene encoding for this enzyme (FAAH) impacts ECS (Sipe et al., 2002). Here, we examine the impact of MJ use and FAAH genotype on PFC complexity and underlying frontal white matter (WM) integrity in young adults. Methods: Participants included 37 MJ users and 37 non-using young adults …

Is Contextual Cue Learning Flexible? An Eye-Movement Study Of The Contextual Cueing Task, Youcai Yang

Theses and Dissertations

Visual searching can be facilitated without awareness when the target is repeatedly presented in an invariant context in tasks such as contextual cueing (Chun & Jiang 1998). A behavioral cost (increased reaction time) was observed when the target was moved to a new location but no such cost was observed when the target returned to the initial location. The lack of cost for return suggests two possible explanations: One is that the learning can update the initial learning to acquire both target locations, which suggests the implicit learning is flexible. The other is that the contextual cue leaning cannot update …