Autism Spectrum Disorder (ASD) refers to a heterogeneous neurological condition characterized by repetitive and restrictive behaviors and social communication deficits. ASD diagnoses are at a record high, at approximately 1 in 59 children according to the US Center for Disease Control. Currently, there are no available interventions that effectively treat the core symptoms of ASD. All pharmaceutical options address comorbid side effects of ASD but not core deficits and are particularly associated with negative side effects. Additionally, there are economic and geographic barriers that can prevent families of individuals with ASD from seeking or receiving effective interventions. Many of the available interventions are extremely costly, time-consuming, and age dependent. These factors, as well as others, have led to an increase in families independently utilizing complementary and alternative interventions. Due to the large amount of misinformation available on the Internet, families have become more susceptible to trying alternative forms of interventions that have not been scientifically proven as effective, and in some cases, are significantly detrimental. Thus, the need for accessible and inexpensive evidence-based nonpharmaceutical interventions is critical and must be addressed. Fortunately, recent groundbreaking research has discovered two strains of probiotics, Bacteroides fragilis and Lactobacillus reuteri, that have been shown to ameliorate behavioral and social deficits respectively, in validated ASD mouse models in a non-age-dependent manner. Probiotic intervention with a combination of these specific strains would effectively target both repetitive behaviors and social deficits, core ASD symptoms, and provide families with an accessible and inexpensive form of intervention. The mechanisms underlying the efficacy of these probiotics are thought to be associated with the gastrointestinal (GI) system and the oxytocin pathway. This study seeks to examine the necessity of accessible nonpharmaceutical interventions and to provide an effective intervention that is neither expensive or age dependent. This study also aims to provide greater insight into the pathways and systems in which these probiotics operate.

Prenatal alcohol exposure (Fetal Alcohol Syndrome [FAS] and Fetal Alcohol Spectrum Disorders [FASD’s]) represents the leading preventable cause of intellectual disabilities in the western world, with FASDs estimated to affect approximately 2-5% of live births in the United States at an approximate annual cost of $3.6 billion (CDC, 2015; May et al., 2009). Ethanol (ETOH) exposure during development can lead to a variety of long-term behavioral impairments including problems with executive functioning, motor coordination, spatial learning, attention, and hyperactivity (Jones, 2011; Mattson & Riley, 1998). Much research has been conducted to develop pharmacological and/or environmental interventions to reduce these deficits, however, there are currently no clinically approved medications to treat the deficits related to fetal ETOH exposure. The current study used a developmental “3rd trimester” ETOH exposure model in neonatal rats to test the hypothesis that compounds targeting the nicotinic system will reduce deficits associated with ETOH exposure. Both compounds demonstrated promise in reducing some of the effects of developmental ethanol exposure, with DMXB-A treatment after ethanol exposure reducing balance deficits in females and spatial memory deficits in males. Solidago nemoralis treatment after ETOH exposure reduced learning and memory deficits in males and balance and executive functioning deficits in both sexes. With these results and previous work in this lab and others there appears to be ample evidence for their usefulness in reducing various forms of neurotoxicity. The long-term goal of this research is to evaluate the usefulness of both DMXB-A & Solidago nemoralis (SN) in treating deficits related to developmental ETOH exposure in humans and hopefully develop a treatment for these disorders.

A growing body of evidence implicates the importance of the endogenous cannabinoid 2-arachidonyl glycerol (2-AG) in memory regulation. The biosynthesis of 2-AG occurs primarily through the diacylglycerol lipases (DAGL-α and -β), with 2-AG serving as a bioactive lipid to both activate cannabinoid receptors and as a rate limiting precursor for the production of arachidonic acid and subsequent pro-inflammatory mediators. Gene deletion of DAGL-α shows decrements in synaptic plasticity and hippocampal neurogenesis suggesting this biosynthetic enzyme may be important for processes of normal spatial memory. Additionally, 2-AG is elevated in response to pathogenic events such as traumatic brain injury (TBI), suggesting its regulatory role may extend to conditions of neuropathology. As such, this dissertation investigates the in vivo role of DAGL-α and -β to regulate spatial learning and memory in the healthy brain and following neuropathology (TBI). The first part of this dissertation developed a mouse model of learning and memory impairment following TBI, using hippocampal-dependent tasks of the Morris water maze (MWM). We found modest, but distinct differences in MWM performance between left and right unilateral TBI despite similar motor deficits, histological damage, and glial reactivity. These findings suggest that laterality in mouse MWM deficit might be an important consideration when modeling TBI-induced functional consequences. The second part of this dissertation work evaluated DAGL-β as a target to protect against TBI-induced learning and memory deficit given its selective expression on microglia and the role of 2-AG as a precursor for eicosanoid production. The gene deletion of DAGL-β did not protect against TBI-induced MWM or motor deficits, but unexpectedly produced a survival protective phenotype. These findings suggest that while DAGL-β does not contribute to injury-induced memory deficit, it may contribute to TBI-induced mortality. The third and final set of experiments investigated the role of DAGL-α in mouse spatial learning and memory under physiological conditions (given the predominantly neuronal expression of DAGL-α). Complementary pharmacological and genetic manipulations produced task specific impaired MWM performance, as well as impaired long-term potentiation and alterations to endocannabinoid lipid levels. These results suggest that DAGL-α may play a selective role in the integration of new spatial information in the normal mouse brain. Overall, these data point to DAGL-α, but not DAGL-β, as an important contributor to hippocampal-dependent learning and memory. In contrast, DAGL-β may contribute to TBI-induced mortality.

Internal and personal strengths are associated with positive academic outcomes in the higher educational setting and are particularly relevant to the 21st century learner in the modern complex and global society. There is limited research addressing the connection between intrapersonal intelligence, resilience, and academic success. This information is important to better assist students in developing qualities that foster academic success and sustainability. The purpose of this study was to investigate the correlations between intrapersonal intelligence, as measured by the Multiple Intelligences Development Assessment Scales (MIDAS); resilience, as measured by the Connor-Davidson Resilience Scale (CD-RISC); and academic success, as measured by the Scale of Implicit Theory of Intelligence (SITI), grade point average (GPA), and grade level. Ninety-one undergraduate students recruited through an online research pool and flyers distributed on campus participated in the study. Participants were asked to complete 3 surveys and a demographic questionnaire. Constructivist and transformative learning theories were used to frame the study and address self-development in the learning process. Results of a multiple regression analysis revealed a significant correlation between intrapersonal intelligence and GPA (a component of academic success). This research study promotes positive social change by emphasizing the intrinsic strengthening and transformation of the learner for a sustainable education. To enhance academic outcomes, academic leaders could focus on developing curricula with objectives that support the increase of intrapersonal intelligence. Building awareness of the significance of intrapersonal intelligence and resilience is important for the development of a sustainable education and to equip students for the problem solving challenges of the 21st century.

Previous research has shown that cannabidiol (CBD), a non-psychoactive compound in the hemp plant Cannabis sativa, may be useful in treating drug craving, one of the hallmarks of drug addiction. However, the neural mechanism by which CBD attenuates craving is poorly understood. Studies from other laboratories have shown that neuroplastic changes associated with brain NMDA glutamate systems may at least partially serve as a neural mechanism for craving. In the current study, the noncompetitive NMDA receptor antagonist MK-801 maleate was used to induce locomotor sensitization, a form of NMDA glutamate-mediated neuroplasticity, in mice to test the sensitization-attenuating potential of CBD. Separate groups of mice (N=8) received either CBD (1.0 mg/kg, i.p.) or saline thirty minutes prior to an intraperitoneal injection of MK-801 (0.5 mg/kg, i.p.) or saline and tested for locomotor performance in an open field (Induction Trial). Seventy-two hours later all mice, regardless of drug pretreatment, were tested for locomotor activity following a second administration (0.5 mg/kg, i.p.) of MK-801 (Sensitization Trial). Results revealed a significant difference across groups for the Induction Trial, with groups receiving SAL-MK801 and CBD-MK801 significantly more active than SAL-SAL and CBD-SAL groups. Pretreatment with CBD had no effect on the locomotor activating effects of MK-801 during the Sensitization Trial with similar levels of locomotor performance across drug groups. Possibilities for the lack of CBD effects are discussed, as well as implications and future research directions.

Epilepsy is a neurological disorder characterized by recurrent seizures. Sleep problems can cooccur with epilepsy, and adversely affect seizure diagnosis and treatment. In fact, the relationship between sleep and seizures in individuals with epilepsy is a complex one. Seizures disturb sleep and sleep deprivation aggravates seizures. Antiepileptic drugs may also impair sleep quality at the cost of controlling seizures. In general, particular vigilance states may inhibit or facilitate seizure generation, and changes in vigilance state can affect the predictability of seizures. A clear understanding of sleep-seizure interactions will therefore benefit epilepsy care providers and improve quality of life in patients. Notable progress in neuroscience research—and particularly sleep and epilepsy—has been achieved through experimentation on animals. Experimental models of epilepsy provide us with the opportunity to explore or even manipulate the sleep-seizure relationship in order to decipher different aspects of their interactions. Important in this process is the development of techniques for modeling and tracking sleep dynamics using electrophysiological measurements. In this dissertation experimental and computational approaches are proposed for modeling vigilance dynamics and their utility demonstrated in nonepileptic control mice. The general framework of hidden Markov models is used to automatically model and track sleep state and dynamics from electrophysiological as well as novel motion measurements. In addition, a closed-loop sensory stimulation technique is proposed that, in conjunction with this model, provides the means to concurrently track and modulate 3 vigilance dynamics in animals. The feasibility of the proposed techniques for modeling and altering sleep are demonstrated for experimental applications related to epilepsy. Finally, preliminary data from a mouse model of temporal lobe epilepsy are employed to suggest applications of these techniques and directions for future research. The methodologies developed here have clear implications the design of intelligent neuromodulation strategies for clinical epilepsy therapy.

A central theme of this dissertation is nervous system plasticity. Activity-dependent plasticity and dopaminergic modulation are two processes by which neural circuits adapt their function to developmental and environmental changes. These processes are involved in basic cognitive functions and can contribute to neurological disorder. An important goal in modern neurobiology is understanding how genotypic variation influences plasticity, and leveraging the quantitative genetics resources in model organisms is a valuable component of this endeavor. To this end I investigated activity-dependent plasticity and dopaminergic modulation in Drosophila melanogaster larvae using neurobiological and genetic approaches. Larval mechanosensory behavior is described in Chapter 2. The behavioral experiments in that chapter provide a system to study mechanisms of plasticity and decision-making, while the electrophysiological characterization shows that sensory-motor output depends on neural activity levels of the circuit. This system is used to investigate activity-dependent plasticity in Chapter 3, i.e., habituation to repetitive tactile stimuli. In Chapter 4, those assays are combined with pharmacological manipulations, genetic manipulations, and other experimental paradigms to investigate dopaminergic modulation. Bioinformatics analyses were used in Chapter 5 to characterize natural genetic variation and the influence of single nucleotide polymorphisms on dopamine-related gene expression. The impact and suggested future directions based on this work are discussed in Chapter 6. Dopamine also modulates cardiomyocytes. Chapter 7 describes biochemical pathways that mediate dopaminergic modulation of heart rate. The final two chapters describe neurobiology research endeavors that are separate from my work on dopamine. Experiments that have helped characterize a role for Serf, a gene that codes for a small protein with previously unknown function, are described in Chapter 8. In the final chapter I describe optogenetic behavioral and electrophysiology preparations that are being integrated into high school classrooms and undergraduate physiology laboratories. Assessment of student motivation and learning outcomes in response to those experiments is also discussed.

Alcohol use disorder (AUD) is the fourth leading cause of preventable death in the United States, and the fifth leading risk factor for premature death and disability, globally. There are currently very few treatment options for AUD and there is a need for effective preventive and treatment strategies for this condition. AUD risk has a significant hereditary component, with the contribution of genetic factors being estimated to be about 50%. The Davies-Bettinger laboratory uses C. elegans as a model organism to study the contribution of genetic factors in modulating neuronal responses to ethanol. In this project, we examined the role of mitochondrial beta-oxidation of fatty acids (FA) in altering ethanol responses using loss-of-function (lf) mutants and RNAi-mediated knockdown of specific genes in this pathway. We tested a total of 34 genes and found that lf in 13 genes significantly affected ethanol response phenotypes. We conclude that mitochondrial beta-oxidation of FA is essential for ethanol response behavior in C. elegans. Further experiments need to be conducted to dissect the specific contribution of various components of mitochondrial beta-oxidation in modifying the neuronal responses to ethanol.

Huntington’s disease (HD) is a heritable, neurodegenerative disorder characterized by motor, cognitive, and psychiatric disturbances. An unstable CAG expansion within the gene normally encoding for the Huntingtin protein is responsible. The expanded mutant form of Huntingtin and the putative protein co-factor Rhes interact and cause cell death within the striatum. We hypothesized chronic treatment with simvastatin, a cholesterol lowering drug, would disrupt the biosynthetical pathway which gives both Rhes and its target cells binding sites and render Rhes inactive. Healthy and HD mice were treated with simvastatin or a vehicle. Animals’ motor behavior was assessed with three separate tests over the first four months of life. No significant differences were found between the HD groups; however, the HD treated animals’ performance on the rotarod test, at month 4, was intermediate between healthy mice and HD vehicle treated mice. The results hint at simvastatin’s therapeutic potential, but are interpreted cautiously.

Male survivors of abuse who become fathers themselves face challenges different from female survivors, such as conceptualizing their roles as providers and heads of households after the traumatic and often belittling experiences of abuse. However, very few researchers have studied the connection between child abuse and fatherhood, and none specific to young African American fathers. An interpretative phenomenological approach enabled exploration of how African American fathers who were abused as children, conceptualized and perceived their own experiences with fatherhood. The theoretical framework for this study was identity theory, which indicates that how people conceptualize a social role influences their actions in that role. Research questions centered on how young African American fathers, who were abused as children, conceptualized fatherhood and carried out their roles as fathers. Data collected from 11 young African American fathers came through in-depth, semistructured interviews. Key findings showed participants conceptualized fatherhood as being present for, providing for, and protecting their children. These fathers worked to break the cycle of abuse they had experienced and to show support for their children. Implications to promote social change include use of study findings to develop parenting programs that address childhood trauma. Other benefits may come from developing groups for father with children in the foster care system, helping these men to understand why they parent the way they do and to break the destructive cycle of parenting they had experienced. Findings may also contribute to the establishment of fatherhood programs that match fathers with supportive role models who help in navigating the father role.