Life Sciences Commons^™

Apoaequorin Differentially Modulates Fear Conditioning In Adult And Aged Rats, Vanessa Ehlers

Theses and Dissertations

Normal aging is associated with a number of changes in behavioral and cellular function, and is often linked to increased susceptibility to cognitive impairment. The hippocampus has been widely implicated in learning and memory, and many forms of learning that are hippocampus-dependent (e.g. trace fear conditioning) are impaired in aged animals. A proposed contributor to aging-related cognitive impairment is aging-related calcium (Ca2+) dysregulation. This dysregulation is thought to result from changes in specific Ca2+-regulatory mechanisms, including abnormal Ca2+ ion channel activity or expression, as well as reduced Ca2+-binding protein (CaBP) expression, which is associated with cognitive and synaptic impairment. Previous …

The Effects Of Exercise Pattern And Intensity On The Expression Of Flk-1 And Flt-1 Receptors In The Hippocampus And Cerebellum, Morgan E. Stevenson

Theses and Dissertations

Aerobic exercise benefits the body and brain. In the brain, these benefits include neuroprotection and improved cognition. These exercise-induced changes are attributed in part to angiogenesis: the growth of new capillaries from preexisting vessels. One critical factor involved in the regulation of angiogenesis is VEGF and its receptors Flk-1 and Flt-1. Although exercise is generally found to be beneficial, there are wide variations in the exercise regimens used across experiments. This study standardized some of these variations. In this study, rats were either assigned to a voluntary wheel running or a forced wheel running exercise condition. Within each condition, animals …

Neural Circuitry Underlying The Intrusion Of Task-Irrelevant Threat Into Working Memory In Anxiety, Daniel Stout

Theses and Dissertations

Dispositional anxiety is an important risk factor for the development of anxiety and other psychological disorders. Symptoms commonly expressed by highly anxious individuals include intrusive memories, uncertainty, and worry — all occurring in the absence of immediate threat. This raises the possibility that anxious individuals have difficulty governing threat’s access to working memory, the mental workspace where goal-related information is actively retained for guiding on-going behavior. Using functional magnetic resonance imaging (fMRI) while 81 subjects completed a well-validated working memory task, I show that threat-related and neutral distracters unnecessarily gain access to working memory, as evidenced by increased neural activity …

The Mechanisms Underlying Cocaine-Induced Overexpression Of Basic Fibroblast Growth Factor (Bfgf, Fgf2), An Effect Reversed By Extinction, Madalyn Hafenbreidel

Theses and Dissertations

Drug addiction is characterized by compulsive drug use and chronic relapse despite negative consequences. Drug-induced structural and functional changes in the brain are thought to underlie these characteristics. One mechanism that may mediate these characteristics are growth factors, such as basic fibroblast growth factor (bFGF or FGF2), as they are necessary for cellular growth, survival, differentiation, and have roles in memory, mood, and anxiety disorders. bFGF mRNA and protein expression is increased following stimulant administration and is necessary for stimulant-induced changes in dendrites and behavioral sensitization. Moreover, addiction is maintained by cues associated with the drug, as they can can …

Spectral Domain-Optical Coherence Tomography For The Assessment Of Cerebrovascular Plasticity, Jacob James Michael Kay

Theses and Dissertations

Vascular pathologies represent the leading causes of mortality worldwide, accounting for 31% of all deaths in 2012. Cerebral hypoxia is a condition that often manifests as a result of these medical conditions. Remarkably, the nervous system has evolved mechanisms to compensate for oxygen deprivation. The dilation of existing vessels and the growth of new blood vessels are two prominent physiological responses to hypoxia, both of which play a critical role in maintaining cerebral homeostasis. More recently, exercise has been shown to induce a mild state of hypoxia in the brain, leading to several robust morphological changes within the cerebrovascular system …

Neural Plasticity Of Extinction: Relations With Anxiety And Extinction Retention, Emily Louise Belleau

Theses and Dissertations

ABSTRACT

NEURAL PLASTICITY OF EXTINCTION LEARNING: RELATIONS WITH ANXIETY AND EXTINCTION RETENTION

by

Emily L. Belleau

The University of Wisconsin-Milwaukee, 2016

Under the Supervision of Associate Professor Christine Larson

Anxiety is a significant public health problem characterized by substantial psychological, physical, and economic burden. A key feature of anxiety is the inability to regulate fear. Aberrant extinction of conditioned fear is one prominent model of the etiology of anxiety disorders. Previous studies have shown that the neural circuitry underlying anxiety pathology overlaps with that mediating fear extinction learning. Recently, more precise pathways supporting the expression (CMA-aMCC) and inhibition (BLA-vmPFC) of …

Brain Mechanism For Enhanced Hand Function With Remote Sensory Stimulation, Kishor Lakshminarayanan

Theses and Dissertations

The neurological bases for remote vibration enhanced sensory feedback and motor function are yet poorly understood. The purpose of this dissertation was to identify and examine the effect of vibration on finger tactile sensation in healthy adults and how imperceptible random vibration applied to the wrist changes cortical activity for fingertip sensation and precision grip. In a series of studies on healthy adults, white-noise vibration was applied to one of four locations (dorsum hand by the second knuckle, thenar and hypothenar areas, and volar wrist) at one of four intensities (zero, 60%, 80%, and 120% of the sensory threshold for …

Investigation Of Neural Mechanisms Of Grip Relaxation, Binal Motawar

Theses and Dissertations

Neural mechanisms for grip relaxation are relatively unknown and understudied, as compared to mechanisms for grip initiation. Yet, termination of motor activity is as important as initiation in daily function. This knowledge gap presents incomplete understanding of neural control of hand function and its impairment with aging and neurologic disorders. The purpose of this dissertation was to identify and examine neural mechanisms of grip relaxation in healthy young adults, with aging, and in chronic stroke survivors. A series of experiments in healthy young adults showed that the relaxation from a maximum power grip was mediated by increase in the short-interval …

Eye Movement Effects In Simulated Object Recognition Memory Impairment, Dmitriy Kazakov

Theses and Dissertations

Malingering is the purposeful fabrication of symptoms for secondary gain. Memory problems are the most reported symptom, and object recognition tests are often used in clinical settings to evaluate these claims. Past research has shown that eye movements can indirectly index memory, in that greater viewing is directed at studied stimuli 500-750 ms after display onset. The present study evaluated eye movements as a potential method of detecting feigned memory impairment. Forty-eight participants, half simulators, studied standardized images and took a memory test. Several levels of analysis were used to detect broad trends and brief effects. Simulators performed significantly worse …

Cannabis Use And Affective Processing: A Brain Structure Analysis, Kristin E. Maple

Theses and Dissertations

Cannabis is the most commonly used illicit drug amongst adolescents and young adults in the United States. Previously, cannabis and its components have been associated with differences in affective processing and neural functioning. Participants (ages 16-25) were cannabis users and non-users excluded for psychiatric disorders, major medical conditions, and excessive other drug use. A series of multiple regressions examined whether past year cannabis use and cannabis x gender predicted measures of emotional face processing (using the PennCNP affective battery) as well as volumes in bilateral prefrontal, temporal, limbic, and cerebellar regions, as well as frontolimbic white matter tracts. Subsequently, Pearson …

Gap Junction Communication In Memory Retrieval And Extinction Of Cocaine Seeking, Michael Fitzgerald

Theses and Dissertations

Blocking drug-associated memory retrieval or enhancing extinction of drug-seeking behavior are two strategies that could limit relapse in drug addicts. The loci of retrieval and extinction memory processes include the prelimbic medial prefrontal cortex and the infralimbic medial prefrontal cortex, respectively. The neurochemical and synaptic mechanisms underlying drug-related behavior have received considerable attention, but extrasynaptic mechanisms are relatively unexplored. One form of cellular communication, gap junction communication, may play a role in drug-related learning and memory. Gap junction communication between neurons and astrocytes provide a cytoplasmic continuity between connected cells and both neuronal and astrocytic gap junction communication have been …

Foot Kinematics And Neuromuscular Preactivation In Habitual Forefoot And Rearfoot Runners, Rhiannon Seneli

Theses and Dissertations

As the rate of running related injuries has failed to decline despite advances in footwear, many researchers have begun focusing on different foot strike patterns possible contribution to injury risk. While many studies have focused on the differences between RFS and FFS running, few have investigated kinematic differences within the distal foot in habitual RFS and FFS runners and have failed to consider mechanical and neuromuscular changes due to fatigue. The purpose of this study, therefore, was to investigate foot kinematics and neuromuscular differences between RFS and FFS runners at the beginning and end of an exhaustive run. Fifteen habitual …