Systems Neuroscience Commons^™

Individual Differences In Age And Testosterone Are Uniquely Associated With Neural Oscillatory Activity Serving Verbal Working Memory In Children And Adolescents, Abraham D. Killanin

Theses & Dissertations

During the sensitive period of adolescence, the human brain undergoes dynamic changes in structure and function resulting in vast executive function gains. Verbal working memory (VWM) is one executive function that serves as a foundation to language acquisition, reading, and learning. Many have examined the development of VWM in youth, but few have probed age-related changes in the underlying neural oscillatory dynamics, and none have examined testosterone-related changes. We recorded magnetoencephalography during a modified Sternberg VWM task in 82 youth participants aged 6 – 14 years old and collected salivary testosterone samples. Significant oscillatory responses were identified and imaged using …

Evaluating Environmental Enrichment As A Preventative Treatment In A Zebrafish (Danio Rerio) Model Of Alzheimer's Disease, Ainsley Craddock

Undergraduate Honors Theses

Alzheimer’s Disease (AD) is a progressive neurodegenerative disorder that leads to several cognitive deficits, including impairments in spatial memory (Alzheimer’s Association, “What is Alzheimer’s Disease?,” 2024). This is thought to occur due to atrophy in the hippocampus and cholinergic system (Ferreira-Vieira et al., 2016). Acetylcholine receptor antagonists, such as scopolamine, can mimic the effects of AD by decreasing acetylcholine activity at muscarinic receptors in the hippocampus. Scopolamine is an antiemetic that is FDA approved to treat certain kinds of nausea, but it has become a popular pharmacological model for studying the cognitive impairments associated with AD (Bajo et al., 2015). …

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

Dissertations & 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 …

Dissecting The Tissue-Specific Contributions To Seizures, Cardiorespiratory Dysfunction, And Sudden Death In The Kv1.1 Mouse Model Of Epilepsy Using Conditional Knockout Approaches, Kelsey Paulhus

Biological Sciences Theses and Dissertations

Sudden unexpected death in epilepsy (SUDEP), the primary cause of mortality in epilepsy, remains poorly understood. Studies suggest seizures may trigger dangerous signals affecting the heart and lungs leading to collapse and death. The Kv1.1 deficiency mouse model mirrors clinical SUDEP cases, showing spontaneous seizures, cardiorespiratory issues, and premature death. However, this model lacks regional specificity in Kv1.1 deletion, hindering insights into SUDEP’s mechanisms and anatomical substrates.

This dissertation employs three distinct conditional knockout (cKO) techniques to investigate the individual roles for the forebrain, brainstem, and heart in SUDEP related phenotypes. The findings reveal that the forebrain alone can trigger …

Frontoparietal Circuitry Underlying Saccade Control In The Common Marmoset, Janahan Selvanayagam

Electronic Thesis and Dissertation Repository

Our visual world is full of far more stimuli than can be processed simultaneously. Yet we are able to efficiently extract behaviourally relevant information from a scene, primarily by performing rapid saccadic eye movements. These processes are under the control the frontoparietal network, two critical nodes of which are: the lateral intraparietal area (LIP) and the frontal eye fields (FEF). Extensive research in the macaque has causally implicated these areas in visual attention and oculomotor control. However, the organization of the activity of single neurons in these areas across cortical layers remains poorly understood as these regions are deep within …

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 …

Evaluating The Potential Of Using Eeg To Monitor Cognitive Workload In Simulated Suborbital Flight, Erik Seedhouse Phd

Journal of Aviation/Aerospace Education & Research

Mental workload can be assessed using electrophysiological measures of brain activity, such as electroencephalography (EEG). EEG signals reveal cortical electrical activity. This cortical activity was recorded using specialized headsets. The focus of this research was to study cognitive performance (CP) in four pilots during simulated suborbital flights under nominal day and night profiles and under contingency day and night profiles. A 14-channel EMOTIV EEG headset measured the participants' brain activity while they flew simulated flights in a Suborbital Spaceflight Simulator (SSFS). Several sessions of EEG data were recorded from each subject, and feature extraction was applied. Data revealed that real-time …

Identification And Delineation Of Neuronal Pathways Underlying Hypophagia, Jing Cai

Dissertations & Theses (Open Access)

In terms of metabolism, eating disorders manifest in two extreme directions: overnutrition, which can lead to obesity, and malnutrition, which can result in underweight or even starvation. Both extremes compromise the quality of life. According to the Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5) standard, eating disorders affect up to 17.9% of young women and 2.4% of young men. Although eating disorders are primarily defined as mental disorders rather than metabolic disorders, they are intertwined with complex emotions and sensory perceptions. However, in contemporary animal research related to eating disorders and feeding behaviors, the majority of neuroscientists still examine …

An Investigation Of The Role Of Amygdalar Circuits In The Production Of Social Behavior, Joseph Fd Dwyer

Doctoral Dissertations

Adaptive social behaviors allow animals to survive, thrive, and successfully reproduce. These behaviors, including mating, parenting, affiliation, and aggression, can be stereotyped in response to specific stimuli but often display sex-specific, and interoceptive-dependent variations in their execution. A conserved set of brain regions collectively known as the social behavior network (SBN) interprets sensory information about social cues and generates an appropriate behavioral response. In this dissertation I present 5 chapters. Chapter 1 introduces historical research focusing on the neural circuits that drive social behavior and the potential impact of environmental factors on the activity of these circuits. Chapter 2 describes …

A Multi-Modal Imaging Analysis Of Inter-Community Hub Nodes In Subjective Cognitive Decline Linking Longitudinal Hub Function Disruption To White Matter Integrity Kurtosis, Duncan Nowling

MUSC Theses and Dissertations

Subjective Cognitive Decline (SCD) has garnered much interest as a potential identifiable preclinical stage and indicator of risk for cognitive decline in Alzheimer’s Disease and related dementias (ADRD). Identification of individuals in this stage though is difficult, as they present with objectively normal cognitive evaluation scores, relying instead upon self-report of concern about decline in cognitive abilities. The use of non-invasive in-vivo imaging methods like BOLD functional imaging and diffusion tensor have allowed for complex mapping of both the functional and structural network features unique to this condition. This study furthers this network biomarker map of SCD by investigating the …

Differential Cortical Monoamines Release During Exercise In Rats Chronically Implanted With Microdialysis Probes, Christine G. Gerin

Research Symposium

Physical exercise is known to positively influence mood, to reduce anxiety and to improve reaction to stress. Cerebral monoaminergic systems are thought to underly the neurochemical influence of exercise on mood and behavior. We hypothesized that beneficial effects of exercise can be shown by variations of neurotransmitters release in the cerebral cortex. We aimed at demonstrating that there is a temporal relationship between release of plasma and cerebral monoamines (A, NA, 5-HT, DA) and spontaneous running exercise in rats. Ten Spague Dawley rats (250 g) were chronically implanted (for up to 39 days) with a left common carotid cannula and …

Sex Differences In Mood And Anxiety-Related Outcomes In Response To Adolescent Nicotine Exposure, Tsun Hay Jason Ng

Electronic Thesis and Dissertation Repository

Nicotine dependence is causally linked to increased risk of mood/anxiety disorders in later life. Females are reported to experience a higher prevalence of anxiety/depressive disorders and challenges in smoking cessation therapies, suggesting a potential sex-specific response to nicotine exposure and mood/anxiety disorder risk. However, pre-clinical evidence of sex-specific responses to adolescent nicotine exposure is unclear. Thus, to determine any sex differences in anxiety/depressive-related outcomes, adolescent male and female Sprague Dawley rats received nicotine (0.4 mg/kg; 3x daily) or saline injections for 10 consecutive days, followed by behavioural testing, in-vivo electrophysiology and Western Blot analyses. Our results revealed that adolescent nicotine …

Connectivity Of Amygdala Somatostatin-Expressing Neurons And Their Role In Taste-Guided Behavior., Jane Jeruto Bartonjo

Electronic Theses and Dissertations

The nucleus of solitary tract (NST) and parabrachial nucleus (PBN) represent the first and second central synapses of ascending gustatory information. Neural processing in these nuclei is influenced by descending input from forebrain regions such as the central nucleus of the amygdala (CeA). In mice, we have shown that somatostatin (Sst) expressing neurons of CeA that project to NST and PBN are largely distinct cell populations and optogenetic inhibition of the CeA/Sst-to-NST subpopulation increases the intake of high concentrations of quinine with no apparent effect on sucrose intake. Synaptic connectivity of these cells is needed to understand the possible mechanisms …

Gap Junctions And Synchronization Clusters In The Thalamic Reticular Nuclei, Anca R. Radulescu, Michael Anderson

Biology and Medicine Through Mathematics Conference

No abstract provided.

Physiological Rationale For Fixation Eye-Movements, Qasim Zaidi

MODVIS Workshop

No abstract provided.

Task-Driven Influences On Fixational Eye Movements, Jonathan Victor, Yen-Chu Lin, Michele Rucci

MODVIS Workshop

There is now compelling evidence that the spatiotemporal remapping carried out by fixational eye movements (FEMs) is an essential step in visual processing. Moreover, the overall Brownian-like statistics of FEMs are calibrated to map fine spatial detail into the temporal frequency range to which retinal circuitry is tuned. Here, we tested the hypothesis that the detailed spatial characteristics of FEMs can be adjusted to task demands via cognitive influences that operate even in the absence of a visual stimulus. We examined FEMs in a task that required subjects (N=6) to report which of two letters was displayed. Trials were blocked; …

Active Encoding Of Space Through Time, Michele Rucci, Jonathan D. Victor

MODVIS Workshop

No abstract provided.

Synaptic Properties Of Parabigeminal Circuits., Kyle Whyland

Electronic Theses and Dissertations

Subcortical structures of the visual system have been the subject of intense study in recent years, but there remain some important unanswered questions regarding the synaptic relationships linking the nuclei that comprise this important sensory network within the brain. In these studies, we use several modern and traditional approaches, including viral tract tracing, in vitro slice physiology, immunohistochemistry, optogenetics, and electron microscopy to characterize the circuits linking the superior colliculus (SC), parabigeminal nucleus (PBG), and lateral geniculate nucleus (LGN), with particular focus on GABAergic and cholinergic cell types. We found that the SC, an important visuomotor structure with connections to …

Chemosensory Processing By The Mediodorsal Thalamus., Kelly Fredericksen

Electronic Theses and Dissertations

The mediodorsal thalamus (MD) is thought to be key component of the network that processes chemosensory information to guide our consummatory choices. Previous studies show that the mediodorsal thalamus receives projections from both the piriform cortex (PC) and gustatory cortex (GC), suggesting that it may process chemosensory information from both areas. Although the mediodorsal thalamus has been shown to respond to odors detected by sniffing, it remains unknown how its neurons represent experienced odors, tastes, and odor-taste mixtures originating from the mouth. Importantly, humans and animals with mediodorsal thalamic lesions do not suffer from anosmia, but experience deficits in odor …

The Genomics Of Autism-Related Genes Il1rapl1 And Il1rapl2: Insights Into Their Cortical Distribution, Cell-Type Specificity, And Developmental Trajectories, Jacob Weaver

MUSC Theses and Dissertations

Neuropsychiatric disorders have a significant impact on modern society. These disorders affect a large percentage of the population: schizophrenia has a world-wide prevalence of 1% and autism spectrum disorders (ASD) affects 1 in 59 school-aged children in the US. There is substantial evidence that most neuropsychiatric disorders have a genetic component. Thus, with the advent of high throughput sequencing much effort has gone into identifying genetic variants associated with these disorders. The emerging picture from these studies is a complex one where hundreds of genes with small effects interact with a varied landscape of common variants to result in disease. …