Engineering Commons^™

Carbon Fiber Electrodes For In Vivo Neural Recording, Esma Cetinkaya

Theses

Multi-channel micro electrodes for neural recording is a growing field that thrives on novel materials and fabrication techniques offered by micro fabrication technology. The material and the design of microelectrodes have a critical role on the quality of neural signals recorded. The neural signals collected by chronic implantation of these devices in experimental animals reveal new information about the brain functions and guide the development of new diagnostic and treatment options for neurological disorders.

Ideally, a microelectrode should meet two important criteria: longevity after implantation and minimal tissue insult. Carbon fibers` high tensile strength and flexibility allow fabrication of micro-scale …

Interaction Of Voluntary Activity And Functional Electrical Stimulation In The Upper Extremity As A Method For Short-Term Alteration Of Corticospinal Excitability And Force Control, Katherine Maia Gerton

Theses

Repetitive movement training (RMT) is a well-established method for rehabilitating functional movement. However, many stroke survivors are not able to participate in RMT for the necessary duration to produce results due to rapid muscle fatigue or inability to perform the desired movement at all. Often, functional electrical stimulation (FES) is applied passively, as a rehabilitative therapy, to stroke subjects who are unable to participate in RMT. The effects of voluntary contraction and FES are not well understood for the upper extremity following a stroke. This experiment was designed to elucidate the mechanisms of functional and neurophysiological changes associated with combining …

Spatial And Temporal Deformation Pattern Of The Brain From Blunt Trauma, Abdus Ali

Theses

It is widely accepted that under extreme loadings the soft tissue of the brain will deform inside the skull, creating large amounts of both stress and strain on the tissue. This can result in a focal injury, or in the case of acceleration and deceleration, diffuse injuries. Any attempt at understanding the underlying mechanisms and effects of TBI, have to start by focusing on what is actually occurring within the brain. The objective of this experiment is to record differences in the spatial and temporal patterns of deformation within the brain during blunt trauma when changing impact parameters. A linear …

Subject And Group Level Changes And Comparison In Functional Connectivity Under Low Vs. High Cognitively Demanding Naturalistic Viewing Conditions Using Fmri, Rakibul Hafiz

Theses

Resting State fMRI is used extensively for analysing brain regions. fMRI is also used to determine task induced activations from cerebral networks. This study involves both rest and task activation data and implements statistical methods applied on Blood Oxygenation Level Dependent (BOLD) signals. The conventional task based designs are very specific and may not reflect day to day activities. The two task conditions in this study are watching a movie called INSCAPE with low cognitive load and segments of contextual Hollywood movies under continuous and natural conditions.

The aim is to investigate individual and group level Functional Connectivity changes between …

Profiling The Neurovascular Cell Interactions In Alcohol Exposure And Hiv-1 Infection, Agnieszka Agas

Theses

Alcohol use is known to exacerbate the progression of human immunodeficiency virus associated acquired immunodeficiency syndrome or HIV/AIDS in the brain, known as the NeuroAIDS. The mechanisms of this accelerated progression are still poorly understood. The purpose of my thesis is to review the parameters contributing to the co-morbid effects of alcohol in the progression of NeuroAIDS. The first aim will evaluate the exacerbating effects of alcohol on HIV-1 transmission, infection, and the role of metabolic energy imbalance during NeuroAIDS progression, which will enable me to formulate the possible mechanism for NeuroAIDS progression. The second aim will help me establish …

Experimental Study Of Bubble Rupture During Shock-Fluid Interaction, Subhalakshmi Chandrasekaran

Theses

Head injuries are associated with exposure to high energy explosive detonation. There are four distinct types of blast induced neurotrauma (BINT): 1) these caused by supersonic shock waves propagating in the atmosphere (primary), 2) high velocity impact of shrapnel and debris (secondary) 3) acceleration and deceleration of the body and collision with the solid objects in the field (tertiary) and 4) exposure to high temperature and toxic gases (quaternary). One of the mechanisms implicated in non-impact primary blast-induced traumatic brain injury (bTBI) is cavitation. It is hypothesized that cavitation can occur in the cerebrospinal fluid (CSF) layer, brain interstitial fluid, …

Measurement Of Finger Coordination During A Motor Learning Task, Robert Ebel

Theses

The focus of this study is to observe the changes in whole hand grasp strategy, in healthy subjects, over time in a series of isometric force control learning tasks. During a series of trials with real-time visual feedback of the five finger forces, subjects adapted their grasp strategy in order to reach the target in a time efficient manner. In early trials, it is very evident that subjects focus on controlling the force output of one finger at a time until they reach the goal. As the block of trials progresses, subjects alter their strategy to a more coordinated movement …

Denoising Techniques Reveal Neural Correlates Of Modulation Masking Release In Auditory Cortex, Sahil Chaubal

Theses

Hearing aids allow hearing impaired (HI) individuals to regain auditory perception in quiet settings. However, despite advances in hearing aid technology, HI individuals do not perform as well in situations with background sound as normally hearing (NH) listeners. An extensive literature demonstrates that when comparing tone detection performance in background noise, NH listeners have better thresholds when that noise is temporally modulated as compared to temporally unmodulated. However, this perceptual benefit, called Modulation Masking Release (MMR), is much reduced in HI listeners, and this is thought to be a reason for why HI listeners struggle in the presence of background …