Neurosciences Commons^™

Electroencephalographic Asymmetry, Emotion Regulation, And Their Relationships With Depression Risk, Aliza Jacob

Dissertations, Theses, and Capstone Projects

Background: Research investigating patterns of electroencephalographic (EEG) brain asymmetry aids our understanding of neural systems involved in the processing of emotion, motivation, and psychopathology. Withdrawal-motivated negative emotions characteristic of depression are associated with relative right prefrontal cortex (PFC) activity, whereas approach- motivated positive emotions are associated with relative left PFC activity. Styles of emotion regulation (ER), or modulation of the intensity and duration of emotional responses, are also associated with presence (e.g., suppression, or maladaptive ER) versus absence (e.g., cognitive reappraisal, or adaptive ER) of depression vulnerability. Most PFC asymmetry studies of emotion, depression, and/or ER rely upon EEG recorded …

Inference Of Language Functional Network In Healthy, Cancerous And Bilingual Brains By Fmri And Network Modeling, Qiongge Li

Dissertations, Theses, and Capstone Projects

We study the underlying mechanism by which language processing occurs in the human brain using inference methods on functional magnetic resonance imaging data. The data analyzed stems from several cohorts of subjects; a monolingual group, a bilingual group, a healthy control group and one diseased case. We applied a complex statistical inference pipeline to determine the network structure of brain components involved with language. This healthy network reveals a fully connected triangular relationship between the pre-Supplementary Motor Area (pre-SMA), the Broca's Area (BA), and the ventral Pre-Motor Area (PreMA) in the left hemisphere. This "triangle'' shows consistently in all the …

Competitive Frontoparietal Interactions Mediate Implicit Inferences, Martijn E. Wokke, Tony Ro

Publications and Research

Frequent experience with regularities in our environment allows us to use predictive information to guide our decision process. However, contingencies in our environment are not always explicitly present and sometimes need to be inferred. Heretofore, it remained unknown how predictive information guides decision-making when explicit knowledge is absent and how the brain shapes such implicit inferences. In the present experiment, 17 human participants (9 females) performed a discrimination task in which a target stimulus was preceded by a predictive cue. Critically, participants had no explicit knowledge that some of the cues signaled an upcoming target, allowing us to investigate how …

Effects Of The Kcnq Channel Opener Ezogabine On Functional Connectivity Of The Ventral Striatum And Clinical Symptoms In Patients With Major Depressive Disorder, Aaron Tan, Sara Costi, Laurel S. Morris, Nicholas T. Van Dam, Marin Kautz, Alexis E. Whitton, Allyson K. Friedman, Katherine A. Collins, Gabriella Ahle, Nisha Chadha, Brian Do, Diego A. Pizzagalli, Dan V. Iosifescu, Eric J. Nestler, Ming-Hu Han, James W. Murrough

Publications and Research

Major depressive disorder (MDD) is a leading cause of disability worldwide, yet current treatment strategies remain limited in their mechanistic diversity. Recent evidence has highlighted a promising novel pharmaceutical target—the KCNQ-type potassium channel—for the treatment of depressive disorders, which may exert a therapeutic effect via functional changes within the brain reward system, including the ventral striatum. The current study assessed the effects of the KCNQ channel opener ezogabine (also known as retigabine) on reward circuitry and clinical symptoms in patients with MDD. Eighteen medication-free individuals with MDD currently in a major depressive episode were enrolled in an open-label study and …

Transspinal Stimulation Increases Motoneuron Output Of Multiple Segments In Human Spinal Cord Injury, Lynda M. Murray, Maria Knikou

Publications and Research

Targeted neuromodulation strategies that strengthen neuronal activity are in great need for restoring sensorimotor function after chronic spinal cord injury (SCI). In this study, we established changes in the motoneuron output of individuals with and without SCI after repeated noninvasive transspinal stimulation at rest over the thoracolumbar enlargement, the spinal location of leg motor circuits. Cases of motor incomplete and complete SCI were included to delineate potential differences when corticospinal motor drive is minimal. All 10 SCI and 10 healthy control subjects received daily monophasic transspinal stimuli of 1-ms duration at 0.2 Hz at right soleus transspinal evoked potential (TEP) …

Using Fundamental Properties Of Light To Investigate Photonic Effects In Condensed Matter And Biological Tissues, Laura A. Sordillo

Dissertations and Theses

Light possesses characteristics such as polarization, wavelength and coherence. The interaction of light and matter, whether in a semiconductor or in a biological sample, can reveal important information about the internal properties of a system. My thesis focuses on two areas: photocarriers in gallium arsenide and biomedical optics. Varying the excitation wavelength can be used to study both biological tissue and condensed matter. I altered the excitation wavelengths to be in the longer near-infrared (NIR) optical windows, in the shortwave infrared (SWIR) range, a wavelength region previously thought to be unusable for medical imaging. With this method, I acquired high …

Translational Modeling Of Non-Invasive Electrical Stimulation, Dennis Quangvinh Truong

Dissertations and Theses

Seminal work in the early 2000’s demonstrated the effect of low amplitude non-invasive electrical stimulation in people using neurophysiological measures (motor evoked potentials, MEPs). Clinical applications of transcranial Direct Current Stimulation (tDCS) have since proliferated, though the mechanisms are not fully understood. Efforts to refine the technique to improve results are on-going as are mechanistic studies both in vivo and in vitro. Volume conduction models are being applied to these areas of research, especially in the design and analysis of clinical montages. However, additional research on the parameterization of models remains.

In this dissertation, Finite Element Method (FEM) models of …