Molecular and Cellular Neuroscience Commons^™

Oxidative Stress Mediated Glutamate Release And Nmda Receptor-Dependent Synaptic Remodeling In Radiation-Induced Cognitive Dysfunction, Thanh Lam

Dissertations and Theses (Open Access)

In children younger than 14 years old, the brain and other parts of the central nervous system are the most common sites for solid tumors. Radiotherapy is an effective treatment for central nervous system (CNS) tumors. However, it often causes a progressive decline in cognitive functions, which is especially devastating for pediatric patients. Although post-mitotic neurons are generally considered resistant to radiation-induced immediate cell death, ionizing radiation causes complex neurochemical and structural changes that damage synaptic integrity. In this study, we examined the molecular cascades following a 10 Gy radiation dose applied to mouse cortical neurons. We found that radiation-induced …

Rhythms Of Hippocampal Function And Memory After Moderate Prenatal Alcohol Exposure, Lilliana May Sanchez

Psychology ETDs

Fetal Alcohol Spectrum Disorders involve morphologic and neurobiological abnormalities in offspring subjected to prenatal alcohol exposure. Although not as well studied as high exposure, moderate prenatal alcohol exposure represents the most common and undetected form in humans. While learning and memory deficits have been well characterized at the behavioral level in humans with Fetal Alcohol Spectrum Disorders and in animal models of moderate prenatal alcohol exposure, few studies have determined the circuit or systems level mechanisms of the behavioral deficits. A complete understanding of the neural bases of memory deficits after moderate prenatal alcohol exposure is needed to ultimately identify …

Design And Advancement Of Analytical Frameworks For In Vivo Single-Photon Calcium Imaging To Characterize Temporal- And Treatment-Dependent Neural Adaptations To Opioid Exposure And Withdrawal In The Medial Prefrontal Cortex, Alexia R. Alsum Dr.

Theses and Dissertations--Pharmacy

Despite the availability of several approved medications for opioid use disorder (OUD), it remains a significant public health concern characterized by persistent neurobiological adaptations that drive relapse and impede successful recovery. The medial prefrontal cortex (mPFC), a region critical for executive control and decision-making, undergoes pronounced functional changes during chronic opioid exposure and withdrawal, yet the cellular mechanisms underlying these adaptations remain poorly understood. This dissertation aims to investigate longitudinal alterations in mPFC neural activity across opioid exposure and withdrawal using in vivo single-photon calcium imaging and newly developed computational frameworks.

Following standard preprocessing to extract and normalize calcium traces, …

The Serotonin 1b Receptor In Psilocybin’S Therapeutic-Like Mechanisms: From Behavior To Network Reorganization, Sixtine Fleury

Dartmouth College Ph.D Dissertations

Mood disorders represent a substantial and growing global health crisis, with ~10 million adults in the US meeting criteria for a major depressive disorder (MDD). Current first-line treatments such as SSRIs require long-term daily administration and fail a significant proportion of patients, driving renewed interest in rapid-acting alternatives. Psilocybin, a serotonergic psychedelic, shows growing clinical evidence of efficacy in treating depressive and anxiety disorders, often producing therapeutic effects persisting weeks to months following a single dose. Yet, the neural mechanisms underlying these enduring effects remain poorly understood and have been largely attributed to the serotonin 2A receptor (5-HT2AR) based on …

Stress During Adolescence: A Characterization Of Anxiety-Like Behavior, And The Mrna Expression Of Neuroimmune Factors, Clock And Stress Genes In Corticolimbic Areas., Annette Fernandez Oropeza, Annette K. Fernandez Oropeza

Biomedical Sciences ETDs

Adolescence represents a critical window of frontal cortex (FC) maturation and corticolimbic circuit refinement that supports stress and emotion regulation. Disruption of these processes by early-life insults such as prenatal alcohol exposure (PAE) or adolescent stress increases vulnerability to anxiety and mood disorders, in part through circadian–immune dysregulation. The circadian transcription factor Bmal1 and the proinflammatory cytokine tumor necrosis factor-alpha (TNFα) have emerged as key regulators of neuroimmune signaling and synaptic communication, yet their interactions across developmental risk contexts remain poorly understood. This dissertation examined the effects of mild adolescent isolation stress, with and without PAE, on anxiety-like behaviors and …

The Sonic Hedgehog Effector Smoothened Modulates Cholinergic Interneuron Activity, Physiology, And Striatum-Dependent Behaviors, Santiago Uribe-Cano

Dissertations, Theses, and Capstone Projects

The striatum is a central node in action selection and associative learning, integrating cortical, thalamic, and neuromodulatory input. Among its principal modulators, dopamine (DA) and acetylcholine (ACh) are known for their temporally coordinated yet mechanistically distinct influences on striatal output. However, the upstream signals that regulate their dynamic interplay, particularly within cholinergic interneurons (CINs)—the primary source of striatal ACh—remain incompletely characterized. This dissertation investigates the role of Smoothened (Smo), a G protein-coupled receptor (GPCR) effector of Sonic Hedgehog (Shh) signaling, in modulating ACh signaling dynamics in the striatum.

Building on evidence that midbrain DA neurons co-release Shh and that CINs …

Detecting Sonic Hedgehog Expression In The Adult Mouse Brain Using A Gene Expression Tracer, Kendra Stephens-Jones

Dissertations, Theses, and Capstone Projects

Sonic Hedgehog (Shh) is best known for its role in development, yet evidence supports Shh signaling plays a functional role in the adult brain. Previous work demonstrated that Shh is expressed by dopamine (DA) neurons in the ventral midbrain and that loss of Shh from these neurons leads to late-onset motor and structural abnormalities resembling Parkinson’s disease. However, the extent of Shh expression and its connectivity to the striatum in the adult mouse brain remain unclear due to the lack of reliable antibodies for Shh detection. To address this gap, the present study employed Shh ^L/L and DAT-Cre^+/- mice …

Parvalbumin Interneuron-Oligodendrocyte Interactions In The Infralimbic Cortex Promote Extracellular Plasticity Mechanisms After Safety Learning, Lucy Emma Denholtz

Dissertations, Theses, and Capstone Projects

The ability to differentiate between threat and safety cues is essential for adaptive behavior, yet this process is disrupted in psychiatric disorders, such as post-traumatic stress disorder (PTSD), where safety cues fail to downregulate fear expression. To better understand the neurobiological mechanisms of safety learning, I investigate how safety conditioning vs contextual fear conditioning modify behavioral and cellular mechanisms in the infralimbic (IL) region of the medial prefrontal cortex (mPFC) at several time points after learning. Through this work, I identify a novel mechanism whereby safety learning promotes learning dependent neuro-glial interactions that promote conditions for plasticity in the mPFC. …

Neural Mechanisms Of Context-Sensitive Behavior In The Adult Male Zebra Finch, Katherine L. Anderson

Dissertations, Theses, and Capstone Projects

Adapting behaviors to the perceived external environment is key to the success and survival of individuals in social species. This context-sensitive modulation of behavior is critical for informative interactions with conspecifics, like alerting a neighbor to a nearing predator or capturing the attention of a potential mate. For the adult male zebra finch (Taeniopygia guttata), a vocal-learning songbird, context-sensitive adaptions to a learned song are key for developing and maintaining pair-bonds with females who are extremely attentive to subtle modulations of song structure. In this thesis, I explore the hypothesis that the influence of a social behavior network …

Assessing The Behavioral Impact Of Pyridostigmine Bromide In Rats, Noah A. Martin

Honors Theses

Pyridostigmine bromide (PB) is an organophosphate (OP) nerve agent prophylactic used to protect warfighters against chemical warfare agents. OPs inhibit the neural enzyme acetylcholinesterase (AChE) in the brain. This leads to the buildup of acetylcholine, causing respiratory failure, seizures, and death. PB functions by inhibiting ~30% of peripheral AChE temporarily, protecting the enzymes so that the body is able to restore sufficient cholinergic function post-exposure. PB does not cross the blood-brain barrier, though it may still indirectly affect toxicity in the brain due to repeated AChE inhibition throughout treatment, or by inhibition of non-target ChE’s in the blood. The aim …

The Role Of Cholinergic Ventral Pallidum Cells In Effortful Motivation, Elizabeth A. Bien

Dartmouth College Ph.D Dissertations

Maladaptive reward-seeking behavior can be driven by one of several different components including excessive craving elicited by cues that predict rewards, failing to effortfully pursue rewards when it is beneficial to do so, and compulsively seeking rewards when it is no longer advantageous to do so. This thesis includes experiments focusing on these three different components of reward-seeking behavior to better understand how reward-seeking can become maladaptive. First, we wanted to examine the role that sex plays in the acquisition and compulsiveness of sign-tracking behavior in the Long Evans rat, a strain that is commonly used as the background for …

The Role Of The Female Reproductive Cycle In Social Communication And Relevance To Mental Health, Julissa Amaro Castillo, Fernando Dominguez, Ariana Hinojosa, Giselle Padilla, Mario Gil

Research Symposium

The female reproductive cycle is characterized by fluctuating hormones, including estrogens and progesterone, that are involved in reproductive health; however, they have also been linked to disorders like Premenstrual syndrome (PMS), Premenstrual Dysphoric Disorder (PMDD), mood swings, depression and others. The goal of this study is to use the Syrian hamster (Mesocricetus auratus) as an animal model to examine the influence of the reproductive cycle and hormones on behavior. Scent-marking activity known as flank marking is exhibited by territorial or sociable animals. In essence, animals mark their territory or convey information such as reproductive status by rubbing their flanks or …

Effects Of Arginine-Vasopressin In The Brain On Cardiovascular Function In A Psychosocial Stress Animal Model, Esmeralda Lopez-Garcia, Ariana V. Hinojosa, Esperanza I. Alaniz, Fernando Dominguez, Giselle Padilla, Mario Gil

Research Symposium

Background: Psychosocial stress impacts cardiovascular health, increasing the risk of events like myocardial infarction (MI), stress cardiomyopathy, and neuropsychiatric disorders, including Major Depressive Disorder (MDD) and Anxiety. However, our understanding of the biological mechanisms that connect psychosocial stress with negative cardiovascular and psychological outcomes remains incomplete. Arginine-vasopressin (AVP) is linked to both mental and physical health by regulating social behavior, blood pressure, and anxiety-related behaviors. This study investigates the potential cardioprotective effects of the neuropeptide AVP, in an effort to generate evidence that it may strengthen heart function and lessen the severity of adverse cardiovascular events caused by stress, brain …

Exploring The Effects Of Serotonin And Ssris On The Neurological, Behavioral, And Cardiovascular Systems Under Induced Stress –Using The Animal Model Of The Syrian Hamster, Ariana V. Hinojosa, Esperanza I. Alaniz, Esmeralda Lopez-Garcia, Giselle Padilla, Fernando Dominquez, Mario Gil

Research Symposium

Background: Serotonin is a neurotransmitter that has been found to have a wide range of effects on not just the neuropsychological processes but has also been found to exert effects outside the central nervous system (CNS); regulating numerous biological processes, such as metabolism, gastrointestinal system, reproductive function, and even the cardiovascular system. However, there is still a limited understanding of how serotonin affects all these systems due to its complexity and ability to regulate homeostasis. This project aims to create a stronger foundation of knowledge about serotonin and its influence on the interaction between the CNS, behavior, and cardiac function …

Use Of Synthetic Water-Soluble Kcc2 To Modulate Chloride Homeostasis In Cultured Dopamine-Neuron-Like Cells, Mason Terry, Andrew Payne, Dario Mizrachi

Annual Research Symposium

No abstract provided.

Influences Of Sex, Alcohol, And Stress On Conditioned Fear Responses, Heyam K. Mayberry

MUSC Theses and Dissertations

Learned fear responses are acquired through the identification and association of threatening stimuli with aversive outcomes. Fear responding and the proper maintenance of defensive behaviors is integral to survival. However, without the homeostasis of such systems, fear responses can become maladaptive and lead to dysregulated behavioral responding. Psychological conditions such as alcohol use disorder (AUD) and post-traumatic stress disorder (PTSD) often lead to impairments in fear learning, deficits in fear memory, and heightened fear responses. While there are clear sex differences in the prevalence of both AUD and PTSD, development of either disorder increases the risk for comorbid AUD/PTSD, leading …

Investigating The Role Of Dynamic Signaling Of Nrg3-Erbb4 In The Prefrontal Cortex In Mediating Nicotine Withdrawal Phenotypes, Emily Prantzalos

Theses and Dissertations--Pharmacy

While several pharmacotherapies are currently available for nicotine use disorder (NUD), smoking cessation success rates remain below 10% each year. The molecular mechanisms underlying failed quit attempts continue to represent a critical gap in our knowledge. However, recent advances in understanding the genetic contributions to nicotine dependence offer a promising avenue for developing more effective cessation therapies. Prior research has identified genetic variation in Neuregulin 3 (Nrg3) and its cognate receptor ErbB4 as potential contributors to affective nicotine withdrawal (WD) phenotypes and cessation outcomes. Therefore, this dissertation aims to systematically investigate the region-specific, functional role of the Neuregulin Signaling Pathway …

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 …

Hippocampal Insulin Exists! In Vivo Sampling Methods, Basal Concentrations, Recurrent Hypoglycemia, And Behavioral Extracellular Insulin Responses, Starlette R. Douglass

Electronic Theses & Dissertations (2024 - present)

Insulin has widespread actions within the brain, including energy homeostasis, modulation of feeding, and as a key component of memory processes. Further, brain insulin dysfunction correlates with Alzheimer's disease and other neurodegenerative disorders. To this point, measurement of hippocampal insulin has been limited. Determining in vivo hippocampal insulin levels both at a healthy baseline and after, e.g., induction of a disease state or in response to cognitive challenge, is essential to advance our understanding of both insulin's procognitive actions and to guide potential therapeutic interventions.

We first sought to establish a sampling technique for insulin within awake and moving rats …

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 …

Regulation And Function Of Mec-2 Alternative Splicing In Single Cells, Canyon Calovich-Benne

Biological Sciences Theses and Dissertations

One mechanism for generating diversity at the single cell level is selective expression of a unique set of transcription factors (TFs) and RNA binding proteins (RBPs). These regulatory factors contribute to functions of cells by controlling cell fate, turning genes on and off, and processing of transcripts either co- or post-transcriptionally. Many genes, especially neuronal genes, have multiple different splicing events, promoters, and/or polyadenylation sites. Post-transcriptional coordination is in the infancy of being studied and the functional consequences of this coupling at the single cell level has yet to be explored. Here we show, mec-2 coordination of alternative transcription start …

Effects Of Retinal Gonadotropin-Releasing Hormone On Reproductive Behavior And Retinal Activity In The Cichlid Fish, Astatotilapia Burtoni, Chase Anselmo

LSU Master's Theses

Many animals use visual signals to evade predators, forage for food, and communicate with conspecifics. Some animals that shift into and out of breeding stages, such as fish, can modulate their visual sensitivity to better adapt to changing internal and external conditions. Previous work in our lab demonstrated that females of the cichlid fish Astatotilapia burtoni have improved visual sensitivity when they enter reproductive readiness. However, little is known about how fish and vertebrates more broadly modulate visual sensitivity across their reproductive cycle. We hypothesized that the hormone and neuromodulator gonadotropin-releasing hormone (GnRH) could modulate visual sensitivity because GnRH is …

Sex-Dependent Gene Expression Alterations In Social Defeat Stress Model Of Major Depression Disorder, Juan Diego Torres, Javier Vargas Medrano, Anapaula Themann, Elias Arellano Villanueva, Nina Mourao, Megan W. Szobody, Tori Sayers, Sriya Gullapalli, Tyler Torres, Sridhar Srinivasan, Anesu Karen Murambadoro, Kory Deshawn Punch, Kevin Valdez Garcia, Nikhilesh Anand, Kelsey Baker, Sergio Iniguez, Bharathi Shrikanth Gadad

Research Colloquium

Introduction: Major Depression Disorder (MDD) is a prevalent, recurrent, and chronic disorder that represents a leading cause of disability worldwide. Millions are affected with symptoms that go from constant sadness to even suicidal thoughts. In the U.S., major depression and fatal suicide have increased by 57.4% among adolescents and young adults. Myelin and inflammation-related genes have been found to play a role in individuals with MDD.

Methods: Adolescent males and females C57BL/6 mice underwent a vicarious defeat stress (VDS) procedure in which a mouse witnessed a conspecific being defeated. VDS and control (CON) mice underwent the Social Interaction (SI) test. …

Early Onset Alzheimer’S Disease Markers In Mouse Hippocampus Unveiled By Single-Cell Transcriptomic Analysis Following Cranial Radiotherapy, Tuba Aksoy

Dissertations and Theses (Open Access)

Cranial radiation therapy plays an integral role in the treatment of brain tumors but can lead to progressive cognitive deficits in survivors by mechanisms that are poorly understood. To develop preventive or mitigative strategies, it is crucial to better understand the underlying pathogenesis of radiation-induced cognitive impairments. The study investigated single-cell transcriptomics and DNA methylation changes as potential drivers of persistent cellular dysfunction after radiation exposure, specifically concentrating on the CA1-3 regions of the hippocampus and the prefrontal cortex due to their role in cognitive functions. Thirteen-week-old mice underwent whole-brain radiation at clinically relevant doses. Following whole-brain radiation, an assessment …

Host-Microbiome Interactions In The Teleost Brain, Amir Mani Varnoosfaderani

Biology ETDs

This dissertation investigates host-microbial interactions within the teleost brain, previously considered sterile. Reviewing current literature highlights significant gaps in understanding teleost brain immunity, despite prevalent neurotropic diseases. We mapped the immune profiles of rainbow trout brains and meninges, revealing the olfactory bulbs as the immune effector part of the brain and the optic tectum as a nod2 expression hub. High il6 and il10 levels were noted in the telencephalon. A persistent bacterial community within healthy salmonid brains shares diversity with gut and blood microbiota. Brain bacterial isolates exhibit genomic signatures for brain colonization and polyamine biosynthesis. The microbiota shifts across …

Local And Distal Projections Of Vta Gaba Neurons, Trinity M. Pirrone

Neuroscience Honors Projects

Substance use disorder (SUD) is a psychiatric disorder characterized by the abuse of drugs, compulsive drug seeking, and addiction. Addiction is facilitated by social, environmental, genetic, and neurobiological mechanisms. The underlying neural circuitry of addiction encompasses several brain regions, circuits, and cell types contributing to the reward system both collectively and independently. Evidence has shown that the ventral tegmental area of the brain is a control center of reward, an important mechanism for drug-seeking in addiction. Previous research has described the ventral tegmental area as a highly heterogeneous region containing various cell types serving different roles. GABAergic neurons of the …

The Relationship Between Amygdala And Orbitofrontal Cortex Volume In The Context Of Oppositional Defiant Disorder, Rahul Alla

Honors Scholar Theses

Disobedient and rebellious attitude in children is on the rise and this type of behavior is categorized as Oppositional Defiant Disorder (ODD). ODD in children can be identified as a persistent pattern of angry or irritable mood, argumentative or defiant behavior or vindictiveness toward others according to the Diagnostic and Statistical Manual (DSM-5, Fifth Edition) of Mental Disorders.1 Children with ODD typically have difficulty regulating and processing their emotions. Issues with regulating emotions is defined as the process by which individuals “influence which emotions they have, when they have them, and how they experience and express them”.2 Dysregulation of emotions …

Molecular Mechanisms Of Opioid Use Disorder In Human Brain Models, Emily Mendez

Dissertations and Theses (Open Access)

Opioid use disorder (OUD) is a national and global public health crisis with no end in sight. While studies from animal models hint at widespread epigenetic and transcriptomic alterations of opioid drugs, the molecular consequences of long-term exposure to opioid drugs in human brain is still unclear, and human-centered translational models are necessary to discern the human cell type-specific effects of OUD.

Using postmortem brain Brodmann area 9 (BA9) from the UTHealth Brain Collection for Research on Psychiatric Disorders, I identified angiogenic gene networks perturbed in the RNA and protein of OUD subjects, as well as downregulation of many neuron-correlated …

Biophysical Model Of Retraction Motor Neurons And Their Modification By Operant Conditioning, Maria Rasheed

Dissertations and Theses (Open Access)

Operant conditioning (OC) is a form of associative learning in which an animal modifies its behavior based on the consequences that follow that behavior. Despite its ubiquity, the underlying mechanisms of OC are poorly understood. Insights into the mechanisms of OC can be obtained by studying Aplysia feeding behavior as it can be modified by OC. This behavior is mediated by a central pattern generator (CPG) network in the buccal ganglia that contains a relatively small number of neurons. This CPG generates rhythmic motor patterns (BMPs) that move food into the gut by closing a tongue-like structure (i.e., radula) during …

The Role Of Spreading Depolarizations In Mild Traumatic Brain Injuries, Natalie J. Pinkowski

Biomedical Sciences ETDs

Mild traumatic brain injuries (mTBIs) often lead to acute symptoms like disorientation and discoordination, but the underlying mechanisms are unknown. Although most patients recover quickly from a single mTBI, repeated injuries can be debilitating. After an mTBI, a neurometabolic cascade produces metabolic burden and vulnerability. Spreading depolarizations (SDs) have been observed after mTBIs. Here we investigated SDs’ role in short-term motor behavioral deficits post-mTBI. We hypothesized that SDs contribute to the deficits, and exacerbated symptoms after repeated mTBIs. To test this, we used acute motor behavioral tests and long-term behavioral and cognitive tests after initiating SDs by mTBI, chemical, or …