Biomedical Engineering and Bioengineering Commons^™

Monitoring Neuronal Activity In Vivo With A Novel Implantable Battery-Free Wireless System, Carolina Moncion

FIU Electronic Theses and Dissertations

Intracranial neuronal recordings are essential for understanding neuronal function. They can be classified into levels like electrocorticography (ECoG)/local field potentials (LFP) and neuronal spiking activity. Typically, wired systems have been used to conduct these recordings; however, they have been linked to drawbacks, including infections, subdural hematomas, and are limited to a clinical setting, all of which can be detrimental to the patients’ quality of life. To address these issues, wireless biotelemetric devices have been increasingly adopted; nevertheless, they are coupled with their own drawbacks like bulky components and heat-generating batteries. Miniaturized battery-free systems have been developed for addressing these concerns, …

Volitional Control Of Lower-Limb Prosthesis With Vision-Assisted Environmental Awareness, S M Shafiul Hasan

FIU Electronic Theses and Dissertations

Early and reliable prediction of user’s intention to change locomotion mode or speed is critical for a smooth and natural lower limb prosthesis. Meanwhile, incorporation of explicit environmental feedback can facilitate context aware intelligent prosthesis which allows seamless operation in a variety of gait demands. This dissertation introduces environmental awareness through computer vision and enables early and accurate prediction of intention to start, stop or change speeds while walking. Electromyography (EMG), Electroencephalography (EEG), Inertial Measurement Unit (IMU), and Ground Reaction Force (GRF) sensors were used to predict intention to start, stop or increase walking speed. Furthermore, it was investigated whether …

Understanding The Underlying Mechanism Of Age-Related Underactive Bladder And Proposing A Treatment Option To Mitigate Its Symptoms, Arezoo Gerami Pour

FIU Electronic Theses and Dissertations

The prevalence of underactive bladder (UAB) increases with age, suggesting a link between age-related processes and lower urinary tract (LUT) symptoms; however, the underlying mechanisms of age-related UAB are poorly understood. UAB is characterized by inefficient voiding and bladder overdistension. Due to the unknown etiology, current therapeutic options are insufficient. Thus, a detailed understanding of its mechanism will facilitate the discovery of new treatments.

In Aim 1, we investigated the relationship between age and systems-level function of the LUT reflexes in three age groups of rats, testing the hypothesis that aging causes voiding reflexes to weaken. We systematically investigated the …

Functional And Dysrhythmic Slow Waves In The Stomach - An In Silico Study, Md Ashfaq Ahmed

FIU Electronic Theses and Dissertations

Peristalsis, the coordinated contraction and relaxation of the muscles of the stomach, is important for normal gastric motility and is impaired in motility disorders. Coordinated electrical depolarizations that originate and propagate within a mutually coupled network of interstitial cells of Cajal (ICC) and smooth muscle cells of the stomach wall as a slow-wave, underly peristalsis. Normally, the gastric slow-wave (GSW) oscillates with a single period and uniform rostro-caudal lag, exhibiting network entrainment. Loss of entrainment in the coupled network and the resulting impairment in slow-wave propagation is associated with various gastric motility disorders. Our study provides an enhanced understanding of …

Engineering Electromagnetic Systems For Next-Generation Brain-Machine Interface, Brayan Ricardo Navarrete

FIU Electronic Theses and Dissertations

MagnetoElectric Nanoparticles (MENPs) are known to be a powerful tool for a broad range of applications spanning from medicine to energy-efficient electronics. MENPs allow to couple intrinsic electric fields in the nervous system with externally controlled magnetic fields. This thesis exploited MENPs to achieve contactless brain-machine interface (BMIs). Special electromagnetic devices were engineered for controlling the MENPs’ magnetoelectric effect to enable stimulation and recording. The most important engineering breakthroughs of the study are summarized below.

(I) Metastable Physics to Localize Nanoparticles: One of the main challenges is to localize the nanoparticles at any selected site(s) in the brain. The fundamental …

Enhanced Surface Electrical Neurostimulation (Esens): A Non-Invasive Platform For Peripheral Neuromodulation, Andres Eduardo Pena

FIU Electronic Theses and Dissertations

Electrical stimulation of peripheral afferents has been used to study the sensory neural code and restore lost sensory function after amputation. Recently, implantable neural interfaces have prompted multiple breakthroughs in artificial somatosensory feedback for individuals with amputation, resulting in functional and psychological benefits. Although promising, the invasive nature of these approaches limits wide clinical applications, hindering the development of advanced neuromodulation strategies for intuitive sensory feedback. Transcutaneous (surface) stimulation is a potential non-invasive alternative. However, traditional surface stimulation methods are hampered by inadequate electrode and stimulation parameter fitting, localized discomfort, poor selectivity, and limited percept modulation.

An enhanced surface electrical …

Offset Electrodes For Enhanced Neural Recording In Microchannels, Iian Black

FIU Electronic Theses and Dissertations

Microchannel electrodes have emerged in recent years as promising interfaces for recording signals in peripheral nerves. Unlike many technologies, microchannels maintain stable long-term connections and can record activity in individual or small groups of axons. Unfortunately, a traditional symmetrical mid-channel electrode configuration, designed to reduce noise artifacts, prevents microchannels from being used to distinguish between signals traveling in opposite directions. This is a profound limitation given that most nerves contain a mix of efferent and afferent axons and microchannels were initially conceived and later used as the basic building block in arrays designed to record bi-directional neural traffic in regenerated …

Synergistic Activation Of Inspiratory Muscles By An Adaptive Closed-Loop Controller, Rabeya Zinnat Adury

FIU Electronic Theses and Dissertations

During diaphragmatic pacing reverse recruitment of muscle fibers causes muscle fatigue. Current diaphragmatic pacing paradigms also do not permit sigh-like behavior. In spontaneously breathing anesthetized rats, studies were carried out to determine if synergized pacing of external intercostal muscles and the diaphragm would increase the efficiency of diaphragm stimulation and thus a) achieve the desired ventilatory breath volume profile with reduced diaphragm muscle fatigue, and/or b) be able to elicit sigh-like behavior by periodically increasing stimulation. Under combined inspiratory muscle stimulation, a fatigue index calculated for the diaphragm muscle (n=6 rats) was significantly lower (p<0.05) than in the …

Adaptive Closed-Loop Neuromorphic Controller For Use In Respiratory Pacing, Ricardo Siu

FIU Electronic Theses and Dissertations

Respiratory pacing can treat ventilatory insufficiency through electrical stimulation of the respiratory muscles, or the respective innervating nerves, to induce ventilation. It avoids some of the adverse effects associated with mechanical ventilation such as risk of diaphragm atrophy and lung damage. However, current respiratory pacing systems provide stimulation in an open-loop manner. This often requires users to undergo frequent tuning sessions with trained clinicians if the specified stimulation parameters are unable to induce sufficient ventilation in the presence of time-varying changes in muscle properties, chest biomechanics, and metabolic demand. Lack of adaptation to these changes may lead to complications arising …

Multiscale Model Of Cerebral Blood Flow Control: Application To Small Vessel Disease And Cortical Spreading Depression, Arash Moshkforoush

FIU Electronic Theses and Dissertations

An in-time delivery of oxygen-rich blood into areas of high metabolic demand is pivotal in proper functioning of the brain and neuronal health. This highly precise communication between neuronal activity and cerebral blood flow (CBF) is termed as neurovascular coupling (NVC) or functional hyperemia. NVC is disrupted in major pathological conditions including Alzheimer’s disease, dementia, small vessel pathologies (SVD) and cortical spreading depression. Despite the utmost importance of NVC, its underlying mechanisms are not fully understood. This dissertation presents a multiscale mathematical modeling framework for studying unresolved mechanisms of NVC with major focus on K⁺ ions as a mediator …

Connectivity Analysis Of Electroencephalograms In Epilepsy, Panuwat Janwattanapong

FIU Electronic Theses and Dissertations

This dissertation introduces a novel approach at gauging patterns of informa- tion flow using brain connectivity analysis and partial directed coherence (PDC) in epilepsy. The main objective of this dissertation is to assess the key characteristics that delineate neural activities obtained from patients with epilepsy, considering both focal and generalized seizures. The use of PDC analysis is noteworthy as it es- timates the intensity and direction of propagation from neural activities generated in the cerebral cortex, and it ascertains the coefficients as weighted measures in formulating the multivariate autoregressive model (MVAR). The PDC is used here as a feature extraction …

Brain Connectivity Networks For The Study Of Nonlinear Dynamics And Phase Synchrony In Epilepsy, Hoda Rajaei

FIU Electronic Theses and Dissertations

Assessing complex brain activity as a function of the type of epilepsy and in the context of the 3D source of seizure onset remains a critical and challenging endeavor. In this dissertation, we tried to extract the attributes of the epileptic brain by looking at the modular interactions from scalp electroencephalography (EEG). A classification algorithm is proposed for the connectivity-based separation of interictal epileptic EEG from normal. Connectivity patterns of interictal epileptic discharges were investigated in different types of epilepsy, and the relation between patterns and the epileptogenic zone are also explored in focal epilepsy.

A nonlinear recurrence-based method is …

A Biologically Plausible Supervised Learning Method For Spiking Neurons With Real-World Applications, Lilin Guo

FIU Electronic Theses and Dissertations

Learning is central to infusing intelligence to any biologically inspired system. This study introduces a novel Cross-Correlated Delay Shift (CCDS) learning method for spiking neurons with the ability to learn and reproduce arbitrary spike patterns in a supervised fashion with applicability tospatiotemporalinformation encoded at the precise timing of spikes. By integrating the cross-correlated term,axonaland synapse delays, the CCDS rule is proven to be both biologically plausible and computationally efficient. The proposed learning algorithm is evaluated in terms of reliability, adaptive learning performance, generality to different neuron models, learning in the presence of noise, effects of its learning parameters and classification …

Development Of A Lab-On-A-Chip Device For Rapid Nanotoxicity Assessment In Vitro, Pratikkumar Shah

FIU Electronic Theses and Dissertations

Increasing useof nanomaterials in consumer products and biomedical applications creates the possibilities of intentional/unintentional exposure to humans and the environment. Beyond the physiological limit, the nanomaterialexposure to humans can induce toxicity. It is difficult to define toxicity of nanoparticles on humans as it varies by nanomaterialcomposition, size, surface properties and the target organ/cell line. Traditional tests for nanomaterialtoxicity assessment are mostly based on bulk-colorimetric assays. In many studies, nanomaterials have found to interfere with assay-dye to produce false results and usually require several hours or days to collect results. Therefore, there is a clear need for alternative tools that can …

A Novel Signal Processing Method For Intraoperative Neurophysiological Monitoring In Spinal Surgeries, Krishnatej Vedala

FIU Electronic Theses and Dissertations

Intraoperative neurophysiologic monitoring is an integral part of spinal surgeries and involves the recording of somatosensory evoked potentials (SSEP). However, clinical application of IONM still requires anywhere between 200 to 2000 trials to obtain an SSEP signal, which is excessive and introduces a significant delay during surgery to detect a possible neurological damage. The aim of this study is to develop a means to obtain the SSEP using a much less, twelve number of recordings. The preliminary step involved was to distinguish the SSEP with the ongoing brain activity. We first establish that the brain activity is indeed quasi-stationary whereas …

Network Construction And Graph Theoretical Analysis Of Functional Language Networks In Pediatric Epilepsy, Anas Salah Eddin

FIU Electronic Theses and Dissertations

This dissertation introduces a new approach for assessing the effects of pediatric epilepsy on the language connectome. Two novel data-driven network construction approaches are presented. These methods rely on connecting different brain regions using either extent or intensity of language related activations as identified by independent component analysis of fMRI data. An auditory description decision task (ADDT) paradigm was used to activate the language network for 29 patients and 30 controls recruited from three major pediatric hospitals. Empirical evaluations illustrated that pediatric epilepsy can cause, or is associated with, a network efficiency reduction. Patients showed a propensity to inefficiently employ …

Bionano Electronics: Magneto-Electric Nanoparticles For Drug Delivery, Brain Stimulation And Imaging Applications, Rakesh Guduru

FIU Electronic Theses and Dissertations

Nanoparticles are often considered as efficient drug delivery vehicles for precisely dispensing the therapeutic payloads specifically to the diseased sites in the patient’s body, thereby minimizing the toxic side effects of the payloads on the healthy tissue. However, the fundamental physics that underlies the nanoparticles’ intrinsic interaction with the surrounding cells is inadequately elucidated. The ability of the nanoparticles to precisely control the release of its payloads externally (on-demand) without depending on the physiological conditions of the target sites has the potential to enable patient- and disease-specific nanomedicine, also known as Personalized NanoMedicine (PNM). In this dissertation, magneto-electric nanoparticles (MENs) …

Funtional Near Infrared Spectroscopy Study Of Language, Joint Attention And Motor Skills, Ujwal Chaudhary

FIU Electronic Theses and Dissertations

Near infrared spectroscopy (NIRS) is an emerging non-invasive optical neuro imaging technique that monitors the hemodynamic response to brain activation with ms-scale temporal resolution and sub-cm spatial resolution. The overall goal of my dissertation was to develop and apply NIRS towards investigation of neurological response to language, joint attention and planning and execution of motor skills in healthy adults. Language studies were performed to investigate the hemodynamic response, synchrony and dominance feature of the frontal and fronto-temporal cortex of healthy adults in response to language reception and expression. The mathematical model developed based on granger causality explicated the directional flow …