Neuroscience and Neurobiology Commons^™

Disposal Of Nanoplastics By The Brain: Plastic Persistence And Upregulation Of A Putative Plastic-Degrading Enzyme After Exposure To Polystyrene-Infused Food, Callie C. Mauersberg

College of Graduate Studies: Theses & Dissertations

Plastic is a ubiquitous material used in many domestic and commercial applications. Widespread use of plastic has led to environmental accumulation of plastic waste, and microplastics have inundated human food and water sources. Once consumed, it is well established that microplastics translocate from the gut to other tissues, including the brain, via the circulatory system. However, it is unknown if nanoplastics persist permanently in the brain. Additionally, it is not known if microplastics can be enzymatically degraded by phagocytic cells in the CNS, such as microglia and astrocytes. Alkane monooxygenase-homolog 7 (Alkbh7) is a mitochondrial enzyme that may …

Précis Of The Edge Of Sentience: Risk And Precaution In Humans, Other Animals, And Ai, Jonathan Birch

Animal Sentience

We often face grave practical decisions that seem to hinge on whether a system is sentient. This family of cases includes invertebrate animals, people who are unresponsive after brain injury, fetuses, neural organoids, and now AI technologies. We must decide what to do despite ongoing disagreement about the nature of sentience. In our state of uncertainty, we should pragmatically transform the question from “Is it sentient?” to “Is it a sentience candidate, an investigation priority, or neither?”. When a system is a sentience candidate, it is negligent to fail to consider precautions. We should instead evaluate precautions for their proportionality …

Nanotube Spectral Fingerprinting And Machine Learning For Optimized Bioimaging/Sensing And Disease Detection Applications In Als, Rodrigo Monroy Lopez

Open Access Master's Theses

Single-walled carbon nanotubes (SWCNTs) possess unique physicochemical and optical properties that make them ideal candidates for biomedical imaging, biosensing, and disease diagnostics. This thesis explores the potential of SWCNT-based spectral fingerprinting combined with ML (Machine Learning) algorithms to optimize bioimaging, disease detection and prediction, with a specific focus on differentiating between healthy and amyotrophic lateral sclerosis (ALS) lymphoblastic patient samples. By functionalizing SWCNTs with single-stranded DNA, we enhance their stability and target specificity, enabling their application in serum patient samples.

A comprehensive spectral analysis of DNA-SWCNTs was conducted using near-infrared fluorescence spectroscopy and other characterization techniques, including UV-Vis-absorption spectroscopy. The …

The P3 Event-Related Potential (Erp) In Visual And Auditory Tasks: Implications For Executive Functioning In Adhd Preadolescent Children, Alex Visal Seng

Open Access Master's Theses

Attention-Deficit/Hyperactivity Disorder (ADHD) is a widespread psychological disorder in children, poorly impacting executive functioning domains of inhibitory control and working memory. Event-related potentials (ERPs) provide neuroelectric insight into these cognitive processes. However, most ERP research focuses on one task type, limiting direct comparisons of cognitive demands across different task paradigms. This study examined P3 amplitude and latency in ADHD children using a visual NoGo task (response inhibition) and an auditory oddball task (working memory), and associations between the P3 ERP and behavioral measures of executive functions.

Cross-sectional data of symptomatic ADHD children (N=13; F=5; aged 9.15 ± 1.86 years) were …

Alterations Of Serotonin Receptor 7 Expression In The Spinal Cord In A Model Of Cerebral Palsy, Tracy Santos

Open Access Master's Theses

Cerebral palsy often results from perinatal hypoxia-ischemia and is characterized by motor and sensory dysfunction associated with altered serotonergic signaling in the spinal cord. The 5-HT₇ receptor, a G-protein-coupled receptor implicated in both motor control and nociceptive modulation, may thus play a critical role in these post-injury changes. However, the regional and developmental patterns of expression of 5-HT₇ following HI injury are not well understood.

In this study, we investigated the expression of spinal 5-HTR₇ in a neonatal rabbit model of HI injury at P1, P5, and P8 using Western blot analyses normalized to total protein. Tissue was …

Exploring The Placebo Effect On The Cortisol Stress Response, Povheng Yam

Cal Poly Humboldt theses and projects

The placebo effect is well-studied on pain perception and is often observed to have a pain-reducing effect in patients. A few studies suggest that the placebo effect can influence physiological changes in people. To date, not many studies have examined the placebo effect on stress; thus, the current study explored the placebo effect on participants’ cortisol stress response and self-reported stress while undergoing a modified acute stress task, the Sing-a-Song Stress Test (SSST). The current study includes 44 participants (22 in the control group and 22 in the treatment group). A deceptive stress-reducing tincture (filled with water) was used as …

Characterization Of Corticotropin Releasing Factor Receptor 2 In Stress-Regulating Regions Of The Mouse Brain, Jennifer J. Lafrican

Electronic Theses & Dissertations (2024 - present)

Sex differences in the morphology of the brain are thought to underlie the sex differences we see in anxiety and depression, where women are twice as likely to be diagnosed when compared to men. Stress, or a disruption to homeostasis, can exacerbate these mood disorders. Corticotropin releasing factor (CRF), and its receptors, play an important role in regulating the stress response. Binding of CRF with CRFR2 has been shown to reduce behavioral and neuroendocrine stress responses, yet whether there are sex differences in CRFR2 expressing neurons and stress-induced activation of these neurons in mice is unknown, in part due to …

The Role Of The Nasal Migratory Mass In Olfactory Bulb Formation And Fertility, Charisse Martin

Electronic Theses & Dissertations (2024 - present)

The olfactory migratory mass plays an essential role in the development of the olfactory bulb by facilitating the migration of the gonadotropin-releasing hormone neurons from the olfactory placode to the pre-optic hypothalamic area in the brain. In mammals, the migration of GnRH neurons is critical for establishing the hypothalamic-pituitary-gonadal axis (HPG axis), which regulates reproductive function through the production and secretion of gonadotropins. Luteinizing hormone (LH) and Follicle-stimulating hormone (FSH) instruct the gonads to function appropriately, ensuring sexual maturation and fertility. Disruptions in this migratory pathway have been linked with Kallmann syndrome, a condition characterized by low levels of GnRH, …

Computational Approaches For Diagnosing Neurological Impairments And Restoring Functional Movement, Serhii Bahdasariants

Graduate Theses, Dissertations, and Problem Reports (ETD)

Movement is the primary means by which the nervous system converts intention into interaction with the environment. Voluntary limb motion enables standing, walking, reaching, and grasping—actions that underpin self‑care, communication, and economic participation. When diseases or injuries disrupt the pathways that couple neural commands to muscle forces—whether through cortical stroke, spinal cord injury, or peripheral nerve damage—mechanical outcomes such as weakness, loss of coordination, and ultimately reduced mobility emerge. These impairments cascade into secondary complications, increased dependence on caregivers, and diminished quality of life. Quantifying how the lesion alters the mechanics of movement is therefore essential for designing targeted interventions …

The Effect Of Cerebellar Feedback On The Spatial Processing Of Conspecific Signals In The Electrosensory System, Dakota Ray Miller

Graduate Theses, Dissertations, and Problem Reports (ETD)

Animals have evolved sensory systems to help decipher important environmental signals that are vital for their survival. Feedback pathways are necessary to allow these signals to stand out in a noisy background, enabling the animal to focus on them more effectively. The electrosensory system of Apteronotus leptorhynchus allows the fish to sense the modulations caused by other conspecifics to allow for proper responses during social interactions. Electroreceptors detect these EODs, and afferent nerves project these signals to the ELL, where electrosensory information is projected to other parts of the brain. Cerebellar feedback to the ELL allows the suppression of lower …

Characterization Of A Descending Neuron That Modulates Flight Performance And Provides Input Onto A Flight-Related Predictive Motor Circuit, Andisheh Balouchi

Graduate Theses, Dissertations, and Problem Reports (ETD)

Descending neurons (DNs) play a critical role in sensorimotor integration by relaying motor information to the ventral nerve cord (VNC). Within the VNC, local interneurons, other DNs, and ascending neurons (ANs) make circuits with sensory and motor neurons to modify flies’ behavior. One important AN pair in Drosophila Melanogaster is mesothoracic ascending histaminergic neurons (MsAHNs), which are known to convey predictive wing motor signals to the brain. DNg32 is the primary upstream synaptic partner of MsAHNs, integrating DNg32 input with other inputs to generate predictive motor signals. The goals of this study were to 1) map the synaptic connectivity of …

Mdma Enantiomers: An Exploration Into 5-Ht2ar Necessity In Non-Hallucinogen Induced Frontal Cortex Plasticity, Maya C. Gaines-Smith

Theses and Dissertations

Entactogen 3,4-methylenedioxymethamphetamine (MDMA) has gained increasing attention as a potential psychotherapeutic, particularly for psychiatric disorders that have proven to be resistant to traditional treatments. Despite its growing popularity, the complete neurobiological mechanism of MDMA enantiomers, as well as the role of sex in these mechanisms, remains to be fully elucidated. Current ongoing research implicates agonism of the serotonin (5-HT) 2A receptor (5-HT_2AR) and neuroplastic growth in the success of other psychoactive and hallucinogenic pharmacotherapeutics, highlighting the importance of understanding the role that the 5-HT_2AR plays in the therapeutic mechanism of action of MDMA enantiomers. The culmination …

Effects Of Pubertal Stress On Later Pup-Directed Behavior In Pregnant And Non-Pregnant Adult Female Mice, Marissa Marylin Nicodemus

Graduate Theses, Dissertations, and Problem Reports (ETD)

Beginning in adolescence and throughout adulthood, women are at an increased risk for anxiety and mood disorders compared to men. Several risk factors for these disorders have been identified, but it is not clear how they interact. One such factor is pregnancy. The normative changes to the brain and behavior that occur during and after pregnancy are associated with an increased risk for anxiety and mood disorders. Exposure to adverse childhood experiences (ACEs) has also been associated with an increased risk of mood disorders, and compared to men, women appear to be particularly vulnerable to the lasting effects of stress …

Neural And Computational Approach To Understanding Environmental Modulation Of Behavioral Identity In Zebrafish, John W. Hageter

Graduate Theses, Dissertations, and Problem Reports (ETD)

Organisms rely on behavior for survival. Animals engage in behaviors that allow for feeding, mating, exploring and navigating their environment among others. Necessary for these behaviors to develop are the environmental factors and underlying circuitry which make behavior possible. Specifically, how the environment guides underlying neural circuitry to develop unique facets or phenotypes of a larger behavior are key to understanding why unique behaviors exist. In this thesis, I build foundational evidence for determining these mechanisms through the use of the zebrafish local search behavior. This is a behavior that zebrafish employ following the loss of environmental illumination where they …

A Framework For Biomimetic Robot Design Applied To The Development Of A Robotic Model Of Drosophila Melanogaster, Clarissa A. Goldsmith

Graduate Theses, Dissertations, and Problem Reports (ETD)

For decades, the field of biologically inspired robotics has leveraged insights from animal locomotion to improve the walking ability of legged robots. Recently, “biomimetic” robots have been developed to model how specific animals walk. By prioritizing biological accuracy to the target organism rather than the application of general principles from biology, these robots can be used to develop detailed biological hypotheses for animal experiments, ultimately improving our understanding of the biological control of legs while improving technical solutions. Much of this work involves biologically inspired walking controllers informed by the morphology and dynamics of the insect nervous system, which necessitate …

Neuroendocrine Regulation Of The Luteinizing Hormone Surge And Puberty Onset In Sheep, Max J. Griesgraber

Graduate Theses, Dissertations, and Problem Reports (ETD)

Gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH), and follicle stimulating hormone (FSH) are essential for the reproduction of all mammalian species, including both sheep and humans. GnRH is secreted by hypothalamic neurons into the hypophyseal portal vasculature in a pulsatile manner, which then acts within the anterior pituitary to elicit the release of LH and FSH into wider systemic circulation. In females LH and FSH act on the ovaries to promote estradiol (E2) production, follicular development, and under certain conditions in regard to LH, ovulation. Furthermore, while E2 inhibits GnRH and subsequent LH secretion under most conditions, at high concentrations E2 …

Co-Transmission Is Co-Opted For The Coordination Of Auditory Sensory Integration, Marryn M. Bennett

Graduate Theses, Dissertations, and Problem Reports (ETD)

Corollary discharge circuits (CDCs) are conserved mechanisms for sensory modulation during species specific behavioral programs. Many behaviors require multiplexed differential sensory modulation for proper execution. Co-transmission of fast and slow neurotransmitters allows for distinct modulation of different downstream targets within one sensorimotor circuit. However, studying co-transmission within the context of modulatory circuits like CDCs requires complete knowledge of behavioral circuits and precise tools for individually determining the implications of each transmitter on its targets. In this dissertation, I used a conserved set of corollary discharge interneurons in Drosophila melanogaster as a model to study the intricacies of sensory modulation through …

Individual And Collective Properties Of Tunable Photochemical Belousov-Zhabotinsky Micro-Reactors, Kudakwashe Benedict Shumba

Graduate Theses, Dissertations, and Problem Reports (ETD)

Cell-like model chemical systems are powerful tools that can be used to explore the role of intercellular coupling on population level behaviors in communities of biological cells. Firstly, we present a new method for fabricating such micro-reactors using the photosensitive Belousov–Zhabotinsky (BZ) reaction system employed in silica microparticles. These BZ micro-reactors have a tunable response to photochemical coupling, varying from a fully excitatory response to a fully inhibitory response. Their response can be tuned through variations in either the reactive mixture or, on an individual micro-reactor level, by changes in the synthesis temperature used during the fabrication of the silica …

Simulated Slot Machine Gambling In Relation To Sign-Tracking, Polina Krom

Graduate Theses, Dissertations, and Problem Reports (ETD)

The propensity to attribute incentive salience to reward-related cues, or sign-tracking (ST) has been linked to addiction in animal models and some initial human data. The current study explores the role of sign-tracking (ST), as a potential risk factor for problematic slot machine gambling, which abundantly features audiovisual reward-related cues, henceforth sensory features. A sample of healthy participants without gambling problems (n = 30) completed a Pavlovian-to-Instrumental Transfer (PIT) paradigm to assess ST propensity and played on a realistic slot machine simulator consisting of two versions: with sensory features (SF+) and without (SF-). Each game version had fixed bet sizes, …

Neurobiological Variables Mediating The Relationship Between Breast Cancer And Sleep Disruption, Brittany Domenique Elliott

Graduate Theses, Dissertations, and Problem Reports (ETD)

Neurobiological Variables Mediating the Relationship between

Breast Cancer and Sleep Disruption

Brittany D. Elliott, MS

Breast cancer is the most commonly diagnosed malignancy in women, with more than two million new cases diagnosed world-wide each year. Improvements in screening technology and diagnostics have increased survival rates, but cancer-associated sleep disruptions persist for the majority of breast cancer survivors well beyond the treatment period. In addition to reducing quality of life, reduced sleep quality is associated with greater incidences of affective dysfunction, reduced treatment efficiency, aggressive cancer progression, increased symptom severity, and increased mortality by all causes. Thus, identifying the variables …