Neuroscience and Neurobiology Commons^™

Vertex-Based Analysis Of Cerebral Blood Flow And Fractional Amplitude Of Low-Frequency Fluctuations (Cbf-Falff) Coupling In Moderate-To-Severe Traumatic Brain Injury During The First Year Post-Injury, Vaidehi Hemkumar Patel

Dissertations, Theses, and Capstone Projects

Traumatic brain injury (TBI) is known to involve damage in the neurovascular unit. TBI may disrupt the brain’s neurovascular coupling–the relationship between cerebral blood flow and neural activity–that can lead to cognitive and functional impairments. This study attempted to non-invasively investigate neurovascular coupling in patients with moderate to severe TBI (msTBI) during the first year post-injury using a combined metric of cerebral blood flow (CBF) and fractional amplitude of low-frequency fluctuations (fALFF), a proxy for spontaneous neural activity. Using arterial spin labeling (ASL) and functional MRI sequences, CBF and fALFF were measured in 29 msTBI patients 3-, 6- and 12-months …

An Erp Study Of Attentional Blink And Inhibition Of Return, Caesar Ekya

Dissertations, Theses, and Capstone Projects

Attention can be allocated over time and space and it has long been speculated whether these are a part of the same or different attentional mechanisms. Attentional Blink (AB) and Inhibition of Return (IOR) are cognitive phenomena that are used in experimental settings to study temporal attention (AB) and spatial attention (IOR) respectively. Though known for being representative of different types of attention, they nevertheless display similar characteristics, making them intriguing choices to study the interplay between temporal and spatial attention. For this study we chose a dual-stream rsvp paradigm that would elicit both AB and IOR within the same …

Evidence For Interactive Effects Of Inhibitory And Prospective Intolerance Of Uncertainty And Stimulus-Level Uncertainty On Threat Safety Discrimination Learning, Kyoko Yazaki

Dissertations, Theses, and Capstone Projects

Fear is a fundamental component of human learning, critical for survival, and extensively studied through Pavlovian conditioning paradigms (LeDoux & Pine, 2016). This thesis examines the interplay between stimulus-level uncertainty and individual differences in intolerance of uncertainty (IU) on threat-safety discrimination learning. Using a within-subject design, participants were conditioned to certain (100% reinforcement), uncertain (50% reinforcement), and safety (0% reinforcement) cues through the pairing of colored visual stimuli with aversive electrical shocks. Discrimination learning was assessed using both implicit (SCR) and explicit (self-reported US expectancy estimates and unpleasantness ratings) measures.

The present study (n = 102) replicated previous findings showing …

Resting-State Eeg Microstate Features For Major Depressive Disorder Classification, George M. V. Quinn

Dissertations, Theses, and Capstone Projects

Neuroimaging studies have revealed consistent abnormalities in functional connectivity within specific neural networks that may serve as biomarkers for major depressive disorder (MDD). It is important to find inexpensive, non-invasive techniques that target these biomarkers to make diagnosis easier and more objective. EEG microstates are quasi-stable potential topographies that are thought to reflect the quasi-stable network activity of the underlying neural generators. MDD has been shown to alter features of the four canonical EEG microstates (A, B, C, D) with some conflicting results. The most consistent network abnormalities in MDD are found in the anterior default mode network, and this …

Voltage Set Points For Sodium Channel Inactivation: Intrinsic And Modulatory Mechanisms, Akshay Sharma

Dissertations, Theses, and Capstone Projects

During an action potential, voltage-gated sodium channels (VGSC) control sodium ion flow into the cytoplasm of cells by using membrane voltage to alter channel conformation. These membrane proteins exhibit three main functional conformations: closed, open, and fast-inactivated, with transitions between these states dependent on membrane voltage and kinetics. The channels open within 1 millisecond and swiftly transition from open to fast-inactivated within 1-2 milliseconds following membrane depolarization. Subsequent membrane repolarization resets the channels to the closed state. Notably, even at mildly depolarized potentials that preclude channel opening, VGSCs can undergo transitions between the closed and inactivated states, known as closed-state …

Repurposing Bt-11 To Treat Alzheimer’S Disease: Exploring The Glutathione-S-Transferase Lancl2 As A Target, Emily Birnbaum

Dissertations, Theses, and Capstone Projects

Approximately 99.6% of potential Alzheimer’s drugs fail, thus developing successful drugs is a high priority. The failure at developing successful drugs relates to the complex nature of the disease itself. Many components act together to trigger a cascade that ultimately results in neurodegeneration and cognitive dysfunction associated with the disease. In building a multiplex model of Alzheimer’s it is important to understand its specific biological mechanisms. One of these key pathological mechanisms is neuroinflammation. Understanding the pathways involved in neuroinflammation in Alzheimer’s is an urgent need, as it poses a promising avenue for future effective therapeutics. Specifically, as many investigational …

Meconium: A Potential Means To Predicting Later-Life Cognition, Leah Duran

Dissertations, Theses, and Capstone Projects

Maternal perinatal stress is a commonly experienced, yet chronically undiagnosed condition (CDC, 2010). Literature has suggested that perinatal stress exposure has long lasting implications of the developing child both physically and mentally (Behrman et al., 2007; Hobel et al., 2008; Bowman et al., 2004; Polanska et al., 2017; Van de Bergh et. al, 2020). The use of meconium in the clinical setting has become one that serves a purpose of detection in medical conditions like in utero drug exposure. Using meconium as a predictor for brain behavior, however, is still an emerging concept in the literature. It is quickly gaining …

Competitive And Noncompetitive Credit Assignment To Reward Cues In The Lateral Orbitofrontal Cortex, Mihwa Kang

Dissertations, Theses, and Capstone Projects

This dissertation investigates the mechanisms underlying variations in credit assignment to reward cues, with a focus on the lateral orbitofrontal cortex (lOFC). The lOFC has long been implicated in signaling reward expectancies, with controversy as to whether it signals the economic value of future outcomes, their sensory features to guide behavior or both. However, whether the lOFC signals the relative (competition-dependent) or absolute (contiguity-dependent) credit of cues is unknown. To address this, I employed a combination of novel behavioral assays, in-vivo electrophysiological recordings and optogenetic stimulation in rats. In Chapter 2, I tested the suitability of a self-initiating variant of …

Flanker Task Performance In Young And Older Adults: A Behavioral And Erp Study, Fatima Medrano

Dissertations, Theses, and Capstone Projects

Research suggests that as we get older, executive function abilities decline (Hasher & Zacks, 1988; Salthouse, 1996). One affected ability is that of inhibitory control, which aids in monitoring our responses to non-target stimuli or information. Current research on inhibition reveals inconsistencies across studies. Monitoring brain responses during the Flanker (used to measure inhibitory control) task may add valuable insight into the processes underlying group differences behaviorally, by studying the N200 and P300 event-related potentials which have been associated with inhibitory control processes. This study investigated whether there are differences between older and younger adults in inhibitory control and whether …

Cross-Linguistic Differences In Neural Encoding And Processing Of Stop Consonants: The Impact Of Language Experience On Attention Allocation, Aline Dos Santos Oliveira

Dissertations, Theses, and Capstone Projects

This study aims to examine the intricate relationship between language experience and the neural processing of stop consonant speech sounds. Previous research has shown minimal differences in amplitudes and latencies of cortical Auditory Evoked Potentials (AEPs) to speech sounds across listeners from various language backgrounds. It is only towards the later latencies (around the P2 peak at 200 ms), that there have been suggestions of cross-linguistic differences. In addition, a recent study, observed an AEP difference between monolinguals and bilinguals when processing speech, specifically an "Nd effect”. The Nd effect, which is an increased negativity of the AEP is proposed …

The Divided Self: Internal Conflict In Literature, Philosophy, Psychology, And Neuroscience, Yulia Greyman

Dissertations, Theses, and Capstone Projects

This thematic project examines the notion of self-division, particularly in terms of the conflict between cognition and metacognition, across the fields of philosophy, psychology, and, most recently, the cognitive and neurosciences. The project offers a historic overview of models of self-division, as well as analyses of the various problems presented in theoretical models to date. This work explores how self-division has been depicted in the literary works of Edgar Allan Poe, Don DeLillo, and Mary Shelley. It examines the ways in which artistic renderings alternately assimilate, resist, and/or critique dominant philosophical, psychological, and scientific discourses about the self and its …

Methamphetamine-Induced Dna Double-Stranded Breaks: The Impact Of The Dopamine Transporter And Insights Into The Mechanisms Of Dna Damage In Mouse Neuro 2a Cells, Lizette Couto

Dissertations, Theses, and Capstone Projects

Methamphetamine (METH) abuse remains a global health concern, with emerging evidence highlighting its genotoxic potential. In the central nervous system METH enters dopaminergic cells primarily through the dopamine transporter (DAT), which controls the dynamics of dopamine (DA) neurotransmission by driving the reuptake of extracellular DA into the presynaptic neuronal cell. Additional effects of METH on the storage of DA in synaptic vesicles lead to the dysregulated cytosolic accumulation of DA. Previous studies have shown that after METH disrupts intracellular vesicular stores of DA, the excess DA in the cytosol is rapidly oxidized. This generates an abundance of reactive oxygen species …

Effects Of Transcranial Direct Current Stimulation On Metamemory Vary By Task Difficulty, Tiffanie T. Li

Dissertations, Theses, and Capstone Projects

Metamemory is broadly defined as the awareness of one’s memory and consists, in part, of a process referred to as monitoring, where one is assessing the contents of their memory. Feeling of knowing (FOK) is one metamemory monitoring judgment where one rates how strongly they believe they will remember a currently unrecalled item. Prior work has shown that HighDefinition Transcranial Direct Current Stimulation (HD-tDCS) over the dorsal lateral prefrontal cortex (DLPFC) led to greater metamemory accuracy and that HD-tDCS over the anterior temporal lobe (ATL) led to better recall for medium difficulty questions. Other work has also shown that effects …

Neurochemical Signaling Of Reward-Based Learning In Ventral Tegmental Area Dopamine Neurons, Kyla F. Wholley

Dissertations, Theses, and Capstone Projects

Ventral tegmental area (VTA) dopamine neurons signal and participate in reward-related learning. Specifically, dopamine is postulated to encode reward-related environmental stimuli to compute reward prediction errors (RPEs). It is through the computation and maintenance of RPEs that learning occurs. However, little is known about the neural mechanisms that underlie how dopamine neurons compute RPEs and facilitate reward-related learning. The present study utilized fiber photometry in conjunction with a Pavlovian reward-based task to identify how GABA inputs to VTA dopamine neurons contribute to the computation of RPEs and reward-based behavior. Activity of GABA inputs to VTA dopamine neurons increased for reward-predicting …

The Role Of Glutamate In The Medial Prefrontal Cortex In The Acquistion And Expression Of Conditioned Approach, Rudolf Nisanov

Dissertations, Theses, and Capstone Projects

A series of experiments were conducted to assess the role of glutamatergic stimulation in the dorsal and ventral regions of the medial prefrontal cortex (mPFC) in both the acquisition and expression of reward-related learning using a Pavlovian conditioning paradigm, the conditioned-approach paradigm. Rats with surgically implanted cannulas were exposed to Pavlovian conditioning sessions that occurred on three alternative days (acquisition) or seven consecutive days (expression). These 60-min conditioning sessions consisted of 30 pairings of light (CS) and food pellets (US) presented under a random time schedule. After a two-day break, rats underwent a session with no CS or US and …

A Causal Inference Approach For Spike Train Interactions, Zach Saccomano

Dissertations, Theses, and Capstone Projects

Since the 1960s, neuroscientists have worked on the problem of estimating synaptic properties, such as connectivity and strength, from simultaneously recorded spike trains. Recent years have seen renewed interest in the problem coinciding with rapid advances in experimental technologies, including an approximate exponential increase in the number of neurons that can be recorded in parallel and perturbation techniques such as optogenetics that can be used to calibrate and validate causal hypotheses about functional connectivity. This thesis presents a mathematical examination of synaptic inference from two perspectives: (1) using in vivo data and biophysical models, we ask in what cases the …

Characterization Of Pathological Tau Mutants, Charles J. Mcdonald

Dissertations, Theses, and Capstone Projects

Tau is a protein expressed exclusively in glia and neurons in the central nervous system and implicated in several neurogenerative diseases called “tauopathies”. Among all the tauopathies, one third is characterized by the presence of genetic mutations leading to the synthesis of tau proteins with single amino acid substitutions at specific locations and affecting protein function. While most of the initial studies have emphasize the functional role of tau as modulator of the axonal cytoskeleton, it has recently been well accepted that tau is also an intrinsically disordered protein that tends to form membraneless organelles called coacervates, due to a …

Metabolic Control Of Proliferation And Differentiation In Oligodendrocytes, Sami Sauma

Dissertations, Theses, and Capstone Projects

Oligodendrocytes (OLs) are specialized cells whose membrane extension, called myelin, wraps the axons providing insulation, trophic and metabolic support, and is essential for proper functioning of the central nervous system. Inappropriate myelin formation, damage or dysfunction of oligodendrocytes has been identified in several neurological disorders and often precedes the loss of neuronal cells. OLs derive from proliferating oligodendrocyte progenitor cells (OPCs), which exit from the cell cycle and undergo a series of transcriptional and epigenetic events, including histone post-translational modifications, resulting in morphological and functional changes. Our lab previously identified elevated levels of histone acetylation in proliferating OPCs during the …

Examining Metacognitive Access To Low-Level Ensemble Representations, Vladimir Mudragel

Dissertations, Theses, and Capstone Projects

Ensemble perception is a process that allows our sensory systems to rapidly extract summary information about the stimuli in the environment. For example, we are able to get a sense of the average number of items in a group of similar items (Burr & Ross, 2008; Halberda, Sires, & Feigenson, 2006) or the average size of a group of similar shapes of different sizes (Ariely, 2001). It is theorized that the qualitative result of ensemble perception is that it provides a gist impression of the current environment, which then enables attentional processes in the brain to determine which parts of …

A Novel Therapeutic Strategy For Alzheimer’S Disease: Sex-Dependent Mechanisms Altered By The Hdac Inhibitor Rg2833 In A Transgenic Rat Model, Kelechi Ndukwe

Dissertations, Theses, and Capstone Projects

Alzheimer’s disease (AD) is the most common cause of dementia. In the United States, AD affects about 6.2 million Americans and is projected to reach 13.8 million by 2050. Currently, there are no effective therapies for AD and therapies targeting epigenetic mechanisms have shown to be effective in improving cognitive performance in animal models of AD. However, until now no study has reported sex-dependent mechanisms leading to differential expression of genes that contribute to changes in AD pathology. From our in silico studies, we identified an FDA-approved drug, RG2833 (N-[6-(2-aminoanilino)-6-oxohexyl]-4-methylbenzamide) that penetrates the blood brain barrier and can potentially ameliorate …

Electrophysiological Signatures Of Stress Adaptability In The Bnst-Vta Pathway, Yuka Miura

Dissertations, Theses, and Capstone Projects

Chronic stress has detrimental effects on psychological and physiological health. Incapability to adapt to chronic stress can lead to depression, anxiety disorders, and addiction. The brain regions critical for reward processing share diverse physiological and molecular changes linked to depressive-like behaviors as a result of chronic stress. Cumulative evidence shows that counteraction or prevention of these alterations in neurons, occasionally in a projection-specific manner, can enhance stress adaptation or resilience.

Chronic stress induces various changes in the brain, including in the bed nucleus of the stria terminalis (BNST) and the ventral tegmental area (VTA). The neural projections from the BNST …

Automatic Analysis Of The Frequency, Vigor, And Complexity Of Spontaneous Locomotion Bouts Of Mice With Loss And Gain Of Function Of The G Protein-Coupled Receptor Smoothened In Cholinergic Neurons, Aleksandra Feshchenko

Dissertations, Theses, and Capstone Projects

Locomotion, a fundamental behavior, is classically assessed using simple metrics of velocity and total distance moved in an open field. This behavior however offers rich data about the organization and breadth of actions an animal can take while only facing limitations due to the bio-mechanical constraints of the organism. Importantly, these actions are not biased towards a particular task-solution space imposed by many behavioral paradigms. Here, to analyze motor complexity in freely ambulating mice, we developed a method for the automatic and unbiased identification of locomotor bouts which we call Bout Finder (BF). This analysis utilizes Open Feld data to …

You Hurt My Feelings: Autonomic And Behavioral Responses To Social Exclusion And The Moderating Effect Of Psychopathic Traits, Liat Kofler

Dissertations, Theses, and Capstone Projects

Humans have a fundamental need to form and maintain social connections, and thus experiencing social exclusion is extremely distressing as it threatens this basic human need. Individuals who are socially excluded often respond aggressively, not only towards their ostracizers but also towards innocent bystanders, with ostracism being implicated in extreme acts of violence such as school shootings. However, individual differences in behavior exist within the context of social exclusion as not everyone responds aggressively after being ostracized. Identifying risk factors for retaliatory aggressive behavior following experiences of social exclusion may facilitate the development of targeted interventions aimed at mitigating such …

Changes In The Epigenetic Landscape Of Oligodendrocyte Progenitor Cells With Time, David K. Dansu

Dissertations, Theses, and Capstone Projects

Most neonatal oligodendrocyte progenitors (nOPCs) give rise to myelinating oligodendrocytes during development, while a proportion are retained as proliferative undifferentiated cells in the adult brain (aOPCs). Previous studies have reported distinct properties for those two populations but the molecular mechanisms underlying these intrinsic differences are not well understood. Using RNA-sequencing and unbiased histone proteomics analysis, we identify transcripts and histone marks that are higher in aOPCs than nOPCs. The genome-wide ChIP-sequencing analysis of chromatin from aOPCs compared to nOPCs detects greater occupancy of the H4K8ac mark at loci corresponding to the higher transcript levels of oligodendrocyte-specific transcription factors and lipid …

Brainwaves, Memory, And Reward, Rebecca Mccune

Dissertations, Theses, and Capstone Projects

The development of effective educational curricula for enhancing learning involves the crucial consideration of effort and rewards. In the realm of education, teachers commonly employ rewards as motivational tools. Traditionally, these rewards are given to students as a recognition of their successful performance. However, a thought-provoking idea emerges: What if we were to extend rewards to students not solely based on accurate answers, but also on the effort they invest, even in cases where their actual response might be incorrect? Our study explores the potential impact of this approach on the way information is absorbed and subsequently retained, specifically focusing …

Attenuated Typicality Effect In Category-Based Inferences: Implications For Autism Spectrum Disorder, Janani Rajagopalan

Dissertations, Theses, and Capstone Projects

Individuals diagnosed with Autism Spectrum Disorder (ASD) often encounter challenges in assimilating atypical exemplars into their categorical prototypes, a cognitive hurdle that can impact their interpretative and integrative capacities. Addressing this problem, the present research sought to develop a robust methodological approach to reduce the effect of this disparity. We examined the elements embedded within the category's internal structure, with the intention of experimentally attenuating the pronounced typicality effect, which is often exaggerated in ASD.

Across four experiments, the thesis investigated the cognitive and neural underpinnings that shape the access to the typicality gradient intrinsic to a category's structure. The …

Statistical And Biological Analyses Of Acoustic Signals In Estrildid Finches, Moises Rivera

Dissertations, Theses, and Capstone Projects

Acoustic communication is a process that involves auditory perception and signal processing. Discrimination and recognition further require cognitive processes and supporting mechanisms in order to successfully identify and appropriately respond to signal senders. Although acoustic communication is common across birds, classical research has largely disregarded the perceptual abilities of perinatal altricial taxa. Chapter 1 reviews the literature of perinatal acoustic stimulation in birds, highlighting the disproportionate focus on precocial birds (e.g., chickens, ducks, quails). The long-held belief that altricial birds were incapable of acoustic perception in ovo was only recently overturned, as researchers began to find behavioral and physiological evidence …

Transcranial Direct Current Stimulation Studies Investigating The Role Of The Dlpfc In Memory And Metamemory, Casey M. Imperio

Dissertations, Theses, and Capstone Projects

Metamemory, broadly defined as knowledge about one’s own memory, is thought to consist of two separate processes, monitoring, the ability to assess the contents of your own memory, and control, altering behavior in service of memory, that work together to aide in encoding and retrieval processes. Prior work has shown that metamemory monitoring accuracy can be improved in a semantic memory task via high-definition transcranial direct current stimulation (HD-tDCS), a form of non-invasive brain stimulation, over the left dorsolateral prefrontal cortex (DLPFC). Over three experiments, the current dissertation sought to replicate and extend this work by: 1) testing the effects …

Into The Unknown: Exploring The Role Of Uncertainty In Threat-Safety Discrimination, Maia Kinney-Petrucha

Dissertations, Theses, and Capstone Projects

Learning to predict the arrival of threat is crucial to survival. Key to this learning process is the ability to discriminate between which stimuli signify safety and which signify threat. The extent to which a threat is uncertain impacts this ability, but which factors of uncertainty are primarily responsible remains unresolved. Uncertainty at the level of the stimulus can be examined in threat learning paradigms by adjusting threat reinforcement rate, referring to the frequency at which a cue is reinforced with an aversive stimulus. Previous research has shown that a continuous (more certain) threat reinforcement is associated with enhanced threat …

The Effects Of Music Therapy On Elderly Adults With Dementia, Jeante J. Jackson

Dissertations, Theses, and Capstone Projects

As people age, the brain is more susceptible to changes that diminish cognitive function. In recent years neuroscience has found convergent evidence between music therapy and brain architecture, as it has shown the generation of new connections in the brain or a reorganization and possible strengthening of existing connections already in the brain. However, the literature regarding music training’s effects on executive control, selective attention, and speech processing is lacking particularly when it comes to older populations.

This study investigated Verbal Working Memory, Visuospatial Attention and Task Initiation, and Auditory Selective Attention in a 91-year-old adult (B.P.) diagnosed with dementia. …