Bioelectrical and Neuroengineering Commons^™

A Functional Ultrasound Imaging (Fusi) Pipeline For Investigating Brain-Wide Hemodynamics During Torpor-Like Hypothermia, Owen J. Culver

McKelvey School of Engineering Graduate Student Theses & Dissertations

Torpor is a regulated state of reduced metabolic demand that enables animals to conserve energy under unfavorable environmental conditions. The controlled induction of a similar state, termed synthetic torpor, has potential applications in ischemic protection, organ preservation, cancer treatment, radiation protection, and long-term spaceflight. Although neuronal populations within the preoptic hypothalamus have been shown to initiate hypothermic and hypometabolic states, the distributed cerebral hemodynamic dynamics accompanying their induction and maintenance remain poorly understood. In this thesis, we developed an accessible functional ultrasound imaging (fUSI) acquisition and analysis pipeline and applied it to investigate cerebral hemodynamics during chemogenetic activation of the …

Enhancing The Performance Of Brain-Computer Interfaces Via A Spatially-Aware Framework, Ahmed Ayman Eloraby

Theses and Dissertations

Electroencephalography (EEG)-based brain–computer interfaces (BCIs) provide a non-invasive pathway for communication, with the P300 speller being one of the most established paradigms. Despite its practicality, EEG signals present inherent challenges, including low signal-to-noise ratio, high dimensionality, and limited spatial resolution. These characteristics complicate the extraction of discriminative spatial patterns, which are critical for accurate P300 detection and character-level decoding.

This thesis addresses these challenges through the development of AttenPCA-Net, a deep learning framework that integrates spatially-aware processing with dimensionality reduction. Principal Component Analysis (PCA) is employed to reduce redundancy and noise while preserving the most informative components of the EEG …

Electrically Evoked Emg Decomposition Using The Perturbative Generalized Series Expansion, William R. Walker

Master's Theses

Electrically evoked electromyography records the muscle's response to nerve stimulation and has been used for clinical assessment of neuromuscular function, as well as treatments such as functional electrical stimulation or stroke rehabilitation. In every muscular contraction, an electrical signal is generated. These signals come from the summation of simultaneously recruited motor units, enabling decomposition techniques to reveal information about motor unit recruitment.  By improving the ability to decompose and analyze these signals, clinical treatments involving neuromuscular electrical stimulation can be optimized and better understood. Much of the research on EMG analysis focuses on voluntary EMG, leaving a gap in the …

Computational Modeling To Evaluate Bipolar Flexible Electrode Designs For Use In Sciatic Nerve Stimulation, Krystyna S. Allman

Master's Theses

Peripheral nerve stimulation is clinically used to manage pain, rehabilitate motor function, and promote nerve regeneration. The sciatic nerve is often studied for stimulation due to its accessibility and clinical relevance. A conventional nerve cuff electrode is the least invasive method for nerve stimulation, but the mismatch of mechanical properties of the electrode with the nerve tissue can cause damage to the nerve and the electrode itself. This study investigated a novel bipolar, gold nanowire-based cuff electrode design and its ability to selectively activate fibers in the rat sciatic nerve at varying interelectrode spacings. In COMSOL, A finite element model …

Vergence Task-Based Neural Pathways With Binocularly Normal Vision And Comorbid Persistent Post-Concussive Symptoms -Convergence Insufficiency, Ayushi Sangoi

Dissertations

Binocular dysfunctions are more prevalent in the persistent post-concussive symptoms (PPCS) population than in the general population. The most prevalent binocular disorder is convergence insufficiency (CI), affecting 3-17% of the general population and up to 10 times as many people with PPCS. CI makes it difficult to fuse or maintain fusion on targets at near, and its symptoms include double or blurry vision and headaches when performing close-range tasks such as reading, which can exacerbate PPCS symptoms. Given controversy over the subjectivity and effectiveness of diagnostic tools and symptom surveys for both PPCS and CI, understanding why CI has high …

Transcranial Ac Modulation Of Cerebellar Nuclear Activity In Awake Animals, Nuran Kavakli

Dissertations

Entrainment of cerebellar nuclear (CN) cells via cerebellar transcranial alternating current stimulation (ctACS) has been reported in animals under ketamine/xylazine anesthesia. Our main objective was to demonstrate modulation of CN activity in unanesthetized, freely moving animals using ctACS. Multi-channel carbon-fiber electrodes were implanted into the interpositus nucleus for recording multi-unit (MU) activity, and thin-film electrodes were implanted subcutaneously over the posterior cerebellum for stimulation. A frequency-domain-based metric was developed to quantify modulation from MU signals. The results demonstrated modulation in a wide range of frequencies (4 Hz-300 Hz) as in anesthetized animals. In contrast, the amplitude of the peak in …

Brain-Based Mechanisms Of Behavioral Impairment In Fetal Alcohol Spectrum Disorder (Fasd): The Neuroimaging Biomarkers Of Inhibitory Control, Zinia Pervin

Biomedical Engineering ETDs

The developing brain is highly susceptible to alcohol-induced toxicity, often resulting in long-term deficits in executive function and behavioral regulation. Inhibitory control impairments are among the most prominent deficits observed in Fetal Alcohol Spectrum Disorder (FASD). This study investigated the neural mechanisms of inhibitory dysfunction using a multimodal MEG–DTI approach in 67 children aged 6–8 years (34 with FASD, 33 controls) who performed a Go/No-Go task. Source-level MEG analyses revealed reduced stimulus-locked cortical activation in the anterior cingulate cortex and significant group-by-hemisphere interactions in the superior parietal cortex and cuneus. Time–frequency analyses showed diminished response-locked beta power in the sensory-motor …

Voltage-Sensor–Targeting Modulators Of Iks: Identifying Critical Functional Groups Of C28 Via Electrophysiology And Sar Modeling, Jiacheng Huang

McKelvey School of Engineering Graduate Student Theses & Dissertations

I_Ks (KCNQ1/KCNE1) channels are essential for cardiac repolarization, and their dysfunction contributes to arrhythmogenic disorders such as Long QT Syndrome type 1 (LQT1). Pharmacological activation of I_Ks has therefore emerged as a promising therapeutic strategy. C28, a recently identified voltage-sensor–targeting activator, has been shown to markedly shift KCNQ1/KCNE1 voltage dependence and enhance current amplitude, validating the voltage-sensing domain (VSD) as a druggable site. However, the structural determinants that underlie C28’s activity remain incompletely understood. In this study, we aimed to identify critical functional groups of C28 by screening a structurally diverse set of C28-like analogs and evaluating their …

Early Detection And Objective Assessment Of Neonatal Hypoxic-Ischemic Encephalopathy Severity, Soheila Norasteh

Bioengineering Dissertations

Hypoxic–ischemic encephalopathy (HIE) is a neonatal brain injury caused by reduced oxygen and blood flow to the brain around the time of birth. It remains a major cause of neonatal mortality and long-term neurodevelopmental impairment worldwide. Therapeutic hypothermia is the standard treatment for moderate-to severe HIE and improves outcomes when initiated within the first six hours of life. Therefore, accurate assessment of injury severity during this period is essential. Cur rently, HIE severity is determined primarily through neurological examination and classified as mild, moderate, or severe. However, these examinations are subjective, cannot provide continuous monitoring of brain function, and may …

Probing Proficiency-Related Neural Representations With Pca And Ica, Onila R. Narayana Mudalige Don

Graduate Student Theses, Dissertations, & Professional Papers

How proficiency-related information is represented in task fMRI depends not only on the data themselves, but on the representational lens used to summarize them. This thesis examines second-language (L2) proficiency as a problem of representational organization rather than as a simple classification exercise. Using task fMRI from adult language learners performing semantic animacy judgments in their native language (L1) and second language (L2), I derive shared low-dimensional network representations with principal component analysis (PCA) and independent component analysis (ICA), then evaluate those representations under matched leakage-controlled decoding pipelines.

Across analyses, the central comparison is between representational frameworks rather than between …

Beyond The Square Pulse: Waveform Shape, Eeg Correlates, And The Pursuit Of Natural Sensation In Tens, Jason Whitson

Honors Undergraduate Theses

This study investigates the relationship between electrical stimulus characteristics of shape and charge on evoked sensations and electroencephalogram (EEG) data during multi-waveform transcutaneous electrical nerve stimulation (TENS) of the median nerve. Neuromodulation methods have traditionally had little control over the location and quality of their associated evoked sensation (e.g., electric, vibration, touch). This experiment utilized five unique stimulus waveforms during TENS stimulation. EEG data were collected concurrently to provide an introductory objective measure of the neural responses underlying these sensory changes. Eleven participants completed three tasks (thresholding, super-threshold stimulation, two-alternative forced choice) using a two-electrode TENS approach. Stimulus waveforms were …

Empirical Dynamical Modeling Of Cortico-Hippocampal Information Transfer During Memory Encoding, Sam Y. Cole

Theses and Dissertations

Understanding how brain dynamics support successful memory formation remains a central challenge in neuroscience. This dissertation applies tools from empirical dynamical systems theory to investigate the neural mechanisms underlying episodic encoding, with a focus on cortico-hippocampal interactions. Using stereoelectroencephalography (sEEG) data recorded during a delayed free recall of word lists task, this work reveals nonlinear, state-dependent shifts in directed information flow between cortex and hippocampus that distinguish successful from unsuccessful encoding. To further characterize these dynamics, state-space trajectories are reconstructed using time-delay embedding and recurrence-based methods, and features derived from these trajectories are used to classify memory outcomes. By integrating …

Mechanisms Of Correlated Neuronal Activity In The Globus Pallidus, Hamza Albawaliz

Electronic Theses and Dissertations

This thesis investigates the mechanisms of correlated neuronal activity in the globus pallidus externus (GPe), a key structure in the basal ganglia. Neuronal activity in the GPe is reportedly decorrelated in healthy subjects but can become highly correlated in Parkinson’s disease. However, high-density neuronal recordings in the GPe of healthy rats reveal a surprising degree of correlated activity. This raises the question of whether intrinsic properties or network connectivity alone can account for such patterns. To explore this, a computational model was developed in which GPe neurons are represented as coupled phase oscillators influenced by experimentally derived phase-response curves and …

Development Of A Non-Faradaic Impedimetric Biosensor Based On Reduced Graphene Oxide For The Detection Of Brain-Derived Neurotrophic Factor (Bdnf), Mariana N. Martins

Electronic Theses and Dissertations

Neurological disorders affect millions of people worldwide. In the case of Alzheimer’s disease (AD), the rising number of cases significantly increases global healthcare costs. Therefore, early detection of biomarkers at the onset of the disease is essential for early diagnosis. This study presents an electrochemical biosensor designed for the detection of Brain-Derived Neurotrophic Factor (BDNF) in human plasma, incorporating reduced graphene oxide (rGO) to enhance signal sensitivity. Dielectrophoresis (DEP) was employed to deposit rGO flakes on the electrode surface, improving conductivity and sensor performance. Electrochemical impedance spectroscopy (EIS) was used to monitor changes in impedance associated with BDNF binding events, …

Modulation Of Cerebellar Cells By Transcranial Ac Stimulation In Anesthetized Rats, Qi Kang

Dissertations

Noninvasive brain stimulation (NIBS) is increasingly utilized in clinical trials for the treatment of neurological disorders. Each NIBS technique offers distinct advantages. Transcranial electrical stimulation (tES) is easy to apply and requires only simple equipment, while transcranial magnetic stimulation (TMS) can penetrate deeper than tES into the brain and it is more focal. Transcranial focused ultrasound stimulation (FUS) is superior to both in terms of penetration and focal stimulation. This study focuses on the modulation of the cerebellum, traditionally believed to be associated with motor coordination but increasingly recognized for its role in cognition and emotion as well. While tES …

Blink-Related Brainwaves As Digital Biomarkers For Cognition Assessment During Complex Tasks, Lexine Carmlixa Sibert-Jolissaint

Theses and Dissertations

Blink-related oscillations (BROs) are neurophysiological responses observed in electroencephalography (EEG) following spontaneous blinking, reflecting the brain processing of new visual information. Prior research has demonstrated BRO responses across various cognitive states, such as resting, cognitive loading, and sensory stimulation, highlighting their potential as a non-invasive biomarker of brain function. We conducted the first investigation of BRO responses during a verbal fluency (VF) task, which is a complex, dynamic task state combining memory, visual perception, executive function, and language processing. Using publicly available EEG data from 22 healthy adults, we measured BRO responses over the left anterior frontal region corresponding to …

Evervital Patch: The Design And Development Of A Continuous Cardiac Monitoring Device For Post-Operative, In-Hospital Patients, Abigail Moeller, Jonathan Seid

Honors Theses

In the United States, due to the increasing prevalence of cardiovascular disease, over 900,000 cardiac surgeries are performed annually, with projections exceeding 1.3 million by 2029. Many post-surgical patients require continuous in-hospital cardiac monitoring, which is typically conducted using electrocardiograms (EKGs). However, traditional EKG systems such as bedside cardiac monitors and cardiac telemetry monitors rely on wired leads that can easily tangle, degrade signal quality, and require frequent readjustments or replacements due to wire breakage, and for the patient, this can cause discomfort from prolonged use. To overcome these challenges, our company, CardioSync, aims to develop a wireless cardiac monitoring …

Peripheral Vagus Nerve Stimulation (Pvns) Device For Epilepsy, Logan P. Beckstrand, Alexander P. Crary, Grace E. Heller

Biomedical Engineering

Our research team developed a PVNS for Epilepsy device which is intended to act as a preventative measure against seizures for patients with epilepsy. The device is a less invasive alternative to the VNS device on the market using electroacupuncture at the Shenmen and Xin points along the posterior pinna to stimulate the vagus nerve.

Novel Electrophysiological Biomarkers In Pediatric Drug Resistant Epilepsy And Genetic Epilepsy Syndromes, Sakar Rijal

Bioengineering Dissertations - Archive

Pediatric epilepsies, particularly those that are drug-resistant or genetically driven, represent some of the most complex neurological disorders encountered in childhood. Central to their pathophysiology is a disruption in the delicate balance between cortical excitation and inhibition (E/I), often resulting from impaired GABAergic interneuron function. This imbalance manifests as aberrant network dynamics and altered neural oscillations, giving rise to seizures and long-term cognitive impairments. In this thesis, we developed a translational framework to identify electrophysiological biomarkers that (i) assess cortical E/I imbalance and (ii) map epileptogenic zones, with the aim of enhancing diagnosis, guiding surgical planning, and informing therapeutic monitoring …

Advancing Electrical Stimulation: Full-Head Mri Segmentation For Abnormal Brain Anatomy With Tdcs, Andrew Birnbaum

Dissertations and Theses

Evaluating the effectiveness of transcranial direct current stimulation (tDCS) is essential for guiding its integration into therapeutic and performance-enhancement applications. In our laboratory, we investigate the efficacy of tDCS across multiple experimental models, including both animal and human studies. I have contributed significantly to the execution and analysis of these experiments, which include studies in rats and healthy human participants aimed at evaluating whether electrical stimulation of the motor cortex can enhance motor learning. These studies assess improvements in fine motor performance resulting from tDCS. In stroke patients, I contribute to our investigation of tDCS as a rehabilitative intervention, particularly …

Development And Clinical Validation Of The Sensor-E Exoskeleton For Objective Hand Function Assessment In Stroke Rehabilitation, Madison Bates

Theses and Dissertations--Biomedical Engineering

Hand function is often impaired following neurological trauma or in conditions such as stroke, limiting independence and the ability to perform activities of daily living (ADLs). Current clinical assessments rely heavily on subjective rating scales that lack the resolution to detect subtle changes in motor performance, which can limit access to rehabilitation. Recent advances in wearable technologies highlight the potential for hand-worn devices to provide objective, real-time measures of hand function. However, most systems focus solely on kinematics and rarely capture both movement and exerted force. Moreover, integration into rehabilitation frameworks and brain-computer interface (BCI) protocols remains limited. To address …

Wearable Disposable Elecetrotherapy, Mohamad Fallahrad

Dissertations and Theses

Non-invasive electrotherapies offer promising treatments for a wide range of conditions such as pain, headaches, depression, addiction, cognitive decline, wound healing, and drug delivery. However, patient compliance remains low due to the high initial cost, cumbersomeness and inconvenience of existing technology compared to pharmaceuticals. Current electrotherapy devices are often bulky and require users to connect disposable electrodes, initiate programs, and manage charging cycles, which hinders widespread adoption.

We address these challenges by designing and validating a novel electrotherapy platform that is single-use, disposable, low-cost, and wearable. Activated automatically upon skin contact, the device delivers a preset dose of controlled electrical …

Characterization Of The Intrinsic Neural Timescale Indices As A Reliable Fingerprint Of Brain Dynamics, Helya Honarpisheh

Dissertations and Theses

Intrinsic neural timescales (INTs) characterize the persistence of neural activity over time and offer insight into the brain’s temporal hierarchy. This thesis evaluates and compares six autocorrelation-based INT metrics—AR(1) Coefficient (Autoregressive Coefficient at 1), First Zero Lag, Lag at ACF = 1/e, Sum of Positive ACFs, ACF at Half Lag, Exponential Decay Constant (τ)— using resting-state fMRI data from 400 cortical regions across a large, lifespan sample (ages 6– 85) from the NKI-Rockland dataset. A discriminability analysis revealed that the AR(1) coefficient provided the highest test-retest reliability and individual specificity across repeated scans, establishing it as the most reliable INT …

Neurovascular Coupling Impairments In Acute Traumatic Brain Injury: An Eeg-Nirs Analysis, Zachary Armstrong

Bioengineering Theses - Archive

Traumatic brain injury (TBI) is a major cause of neurological impairment, often leading to variable recovery and uncertain prognosis in the neurocritical care setting. There is a pressing clinical need for robust, physiologically grounded biomarkers to inform prognosis and therapeutic decision-making in acute TBI. This thesis investigates neurovascular coupling (NVC), the physiological coordination between neuronal activity and cerebral blood flow, as a candidate biomarker for brain function and recovery after injury.

A prospective cohort study was performed using simultaneous electroencephalography (EEG) and near-infrared spectroscopy (NIRS) recordings in patients with moderate-to-severe TBI and healthy controls. Wavelet transform coherence (WTC) analysis was …

Comparative Analysis Of Electrode Encapsulation Reliability: Planar Vs. Thermoformed Interdigitated Neural Electrodes In Biomedical Engineering, Tatum Peyerl

Graduate Theses, Dissertations, and Problem Reports (ETD)

Durable dielectric encapsulation is crucial for the long-term function of implantable neural electrodes; however, the reliability of curved, thermoformed coatings remains underexplored. This study addresses that gap by comparing planar (non-thermoformed) and thermoformed interdigitated neural electrodes (IDEs) encapsulated in Polyimide-2611. Both device types underwent accelerated in vitro aging in phosphate‑buffered saline (PBS) at 67 °C for approximately 91 days, simulating two years of physiological exposure. Post-accelerated aging evaluation included electrochemical impedance spectroscopy (EIS) from 0.1 Hz to 100 kHz to monitor moisture‑induced leakage, and high‑voltage breakdown testing under saline immersion to assess dielectric strength. After aging, all electrodes maintained impedance …

Finite Element Modeling And Experimental Characterization Of Overmolded Gold-Palladium Composite Leads And Their Mechanical Behavior Under Cyclic Fatigue For Long-Term Implant Applications, Tanner Davis

Graduate Theses, Dissertations, and Problem Reports (ETD)

Auditory Nerve Interface (ANI) devices, currently in developmental stages, represent an emerging neuroprosthetic approach to restore hearing in severe sensorineural loss patients by directly stimulating the auditory nerve via the Utah Slanted Electrode Array (USEA). Conventional implant leads are comprised of multiple wires made from materials such as platinum-iridium and MP35N stainless steel that are overmolded in an insulative material. These materials are not possible to bond with to electrode array used in the ANI device, necessitating the evaluation of a new material like Au-Pd to ensure its functionality and durability under cyclic stresses. This gap necessitates characterization of alternative …

Interfacing Neural Models: Biocompatibility And Fabrication Of A Flexible, Self-Folding Microelectrode Array, Fernando A. Pesantez Torres

Electronic Theses & Dissertations (2024 - present)

Neurodegenerative diseases pose a formidable challenge in modern medicine, necessitating the development of advanced research tools that can elucidate their complex pathophysiology. Recent advancements in neurodegenerative disease research have led to the development of three-dimensional (3D) neurodegenerative organoids using human induced pluripotent stem cells (hiPSCs). These organoids closely mimic human brain architecture and functionality, providing a valuable tool for understanding complex diseases. Additionally, the ability to generate and study brain organoids consistently and in large quantities holds potential for a controlled in vitro setting and high-throughput drug screening. However, these models are complex systems requiring specialized maintenance, analysis, and manipulation …

Development Of A Mediation Model Of Pain Cognition In Adult Patients With Sickle Cell Disease, Daniel M. Sop

Theses and Dissertations

Pain is a hallmark of Sickle Cell Disease (SCD), a genetic hemoglobinopathy characterized by chronic hemolytic anemia, vaso-occlusion, and organ damage. While acute vaso-occlusive crises (VOC) have been extensively studied, the mechanisms underlying chronic pain and its interplay with brain function remain unclear. This dissertation investigates the relationships between cerebral blood flow (CBF), fluid cognition, and pain sensitivity in adults with SCD, utilizing advanced imaging techniques and validated assessment tools.

Arterial spin labeling (ASL) and functional magnetic resonance imaging (fMRI) were employed to measure CBF and brain activity, respectively. Pain sensitivity was assessed using the Pain Sensitivity Questionnaire (PSQ), and …

Microwell Fabrication For Impedance And Ac Measurements Of Isolated Ventricular Cardiomyocytes, Fallon Wenck

Multidisciplinary Studies Theses and Dissertations

Electrophysiological behavior of human hearts have been extensively studied for hundreds of years. Even with elucidation of not just biological function, but also time and frequency-dependent current flow, the sheer intricacy of in vivo cardiac tissue function remains somewhat enigmatic. All while heart disease has been the leading cause of death in the United States for over a century, with its rates of occurrence still increasing annually [1]. Thus, new research techniques and tools to quantify cardiac function are still being pursued at smaller and smaller scales to decrease research/innovation time, cost, and diagnostic ambiguity. In fact, it remains incredibly …

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 …