Laboratory and Basic Science Research Commons^™

Motor Unit Firing Rate Control Of Agonist Skeletal Muscle During Voluntary Isometric And Shortening Contractions With Limb Movement, Eric A. Kirk

Electronic Thesis and Dissertation Repository

Voluntary movements throughout mammalian lifespan require skeletal muscle contractions that are controlled by time- and recruitment-dependent firing rate patterns. Single motor unit (MU) activity reflects the final efferent neural drive to the muscle, yet the underlying neural control of movement at the MU level is not well understood. Using intramuscular electromyography single MU recordings, relationships between voluntary contraction kinematics and MU firing rates were evaluated in vivo, in groups of young and older adult participants.

The purpose of study one was to characterize how MU firing rates are differently scaled among muscles relative to voluntary contraction intensity. Across 12 …

Long-Term Impacts Of Acute Stressor Exposure On Locus Coeruleus Function And Anxiety-Like Behavior In Rats, Olga Borodovitsyna

Graduate School of Biomedical Sciences Theses and Dissertations

Stress is a physiological state characterized by behavioral arousal that occurs during exposure to harmful or threatening stimuli, and usually facilitates an adaptive behavioral response. The persistence of stress sometimes causes it to become maladaptive, potentially contributing to disease development, including physiological complications with altered neuroendocrine signaling and impaired function of organ systems, and psychological conditions including depression and anxiety. Anxiety disorders in particular are associated with a history of stress and are the most common class of mental disorders, with a lifetime prevalence of 33.7% in the general population. The locus coeruleus (LC) is a major node in the …

Developmental Influences On The Initial Subjective Rewarding Effects Of Etoh, Madison Waldron

Master’s Theses

The present studies were aimed to better understand developmental contributions to the risk for disordered drinking, and facilitate the long-term goal of developing effective interventions for individuals at high risk for alcohol use disorders. Experiment 1 assessed the effect of adolescent pre-exposure to ethanol on adult place preference, as well as, sex- and beta-endorphin(bE)-related contributions. Adolescent C57BL/6J and bE deficient mice were injected with 1.5g/kg of ethanol or saline and put back into their home cages. At the time of adulthood, we employed a single-exposure conditioned place preference paradigm (SE-CPP) to investigate the impact of preexposure on the initial subjective …

Manipulating The Perineuronal Net In The Deep Cerebellar Nucleus, Deidre E. O'Dell

Graduate Theses, Dissertations, and Problem Reports

Perineuronal nets (PNN) are a type of specialized extracellular matrix in the central nervous system. The PNN forms during postnatal development but the ontogeny of the PNN has yet to be elucidated. Studying the PNN in the rat brain may allow us to further understand the PNN’s role in development, learning, and memory. The PNN is fully developed in the deep cerebellar nuclei (DCN) of rats by post-natal day 18. By using enzymatic digestion of the PNN with chondroitinase ABC (ChABC), we studied how digestion of the PNN affects cerebellar-dependent eyeblink conditioning (EBC) and performed electrophysiological recordings from DCN neurons. …

Estrogen Disruption Of Hypothalamic Neural Activity, Princess Dickson

Cal Poly Humboldt theses and projects

The brain is highly dependent on the endocrine system for proper neurodevelopment, as it plays a key role in many biological processes. Bisphenol A is a chemical found in plastics that has the potential to mimic the effects of Estrogen in the body, at least weakly. People interact with plastic that contains BPA regularly, and people are at risk for exposure even before being born. The abundance of BPA, along with other exogenous estrogens, makes examining the relationship between early exposure and changes in brain activity imperative. The current study aims to establish a relationship between disrupted estrogen function and …

Mitochondrial Aspects Of Neuronal Pathology In Triple-Transgenic Alzheimer’S Disease Mice, John Zachary Cavendish

Graduate Theses, Dissertations, and Problem Reports

Alzheimer’s disease (AD) is a fatal, progressive neurodegenerative disease afflicting millions of people in the United States alone and is the only one of the top leading causes of morbidity and mortality with no effective disease-modifying therapies. It is the most common form of dementia, affecting one in three people over the age of 85. While the hallmarks of the disease include accumulation of beta-amyloid-based extracellular plaques and hyperphosphorylated tau-based intracellular neurofibrillary tangles, treatment strategies centered on removing or mitigating these components of AD have all failed in humans. Mitochondrial dysfunction has been increasingly recognized as an early and consistent …