Medical Neurobiology Commons^™

Optimizing Decision-Making In A Cerebral Palsy Model Using Reinforcement Learning, Richard Ampah

Pitzer Senior Theses

This study presents an original interdisciplinary investigation into how reinforcement learning (RL) can model motor and cognitive defects and potentially improve motor and cognitive functions in individuals with cerebral palsy (CP), a non-progressive neurological disorder that impairs movement and adaptability. Integrating computational neuroscience and machine learning, the research applies policy gradient methods and Markov Decision Processes (MDPs) to simulate adaptive learning in agents with and without CP-related constraints.

The central aim is to compare the cumulative rewards of optimal policies, derived from value iteration, and human-like learning policies using the REINFORCE algorithm, both with and without the Bellman baseline. The …

Synthetic Neuroactive Steroids Targeting Gaba-A Receptors As A Potential Therapy For Contraceptive-Associated Mood Disorders, Alexandria A. Davis

Scripps Senior Theses

4-10% of women who use hormonal oral contraceptives (HOCs) discontinue use after experiencing symptoms of anxiety, irritability, and depression in the first 3 months of administration. Previous studies have acknowledged a relationship between HOCs and emotional dysregulation but have not identified mechanisms by which HOCs have this effect. As a result, effective treatment options for HOC-induced mood disorders are lacking. Current theories implicate combined-HOCs, particularly those containing ethinyl estradiol and levonorgestrel (EE-LNG), in reducing neuroactive steroid levels. Specifically, HOC users show decreases in allopregnanolone, a positive allosteric modulator associated with neuronal inhibition and emotional regulation. The objective of this study …

Copy Number Alterations Of Aggressive Pituitary Neuroendocrine Tumors, Grace Zhang

Scripps Senior Theses

Pituitary neuroendocrine tumors (PitNETs) are tumors of the pituitary gland. Although most are benign, they can cause severe morbidity if compression of surrounding tissue and/or endocrinopathies occur.

Aggressive PitNETs are notably detrimental and difficult to predict, and their effects are further exacerbated by challenges in treatment. Although histological studies can detect certain markers of tumor aggressiveness, they are insufficient at wholly predicting PitNET aggressiveness, making the clinical behavior of PitNETs challenging to determine. Since treatment of aggressive tumors also remains suboptimal, this further results in negative impacts on health and quality of life.

Genetic markers, such as copy number variations …

Visualization And Characterization Of The Immunological Synapse Between Chlorotoxin Chimeric Antigen (Cltx-Car) Redirected T Cells And Targeted Glioblastoma Tumors, Arianna Livi

CMC Senior Theses

Chimeric Antigen Receptor T (CAR-T) cells have demonstrated anti-tumor activity against aggressive and invasive cancers such as glioblastoma (GBM); however, clinical response rates remain low in clinical trial studies. Tumor heterogeneity and tumor microenvironment conditions pose significant challenges for treatment of GBM, thus continuous optimization of CAR-T cell therapies and identification of novel, widely expressed, and highly specific GBM antigens are vital to better patient outcomes. A newly developed CAR-T cell construct incorporating chlorotoxin (CLTX) as the targeting domain exhibited broad GBM-targeting capabilities and elicited potent cytotoxic effects during preclinical studies and is currently being tested in a phase I …

Noise, Delays, And Resonance In A Neural Network, Austin Quan

HMC Senior Theses

A stochastic-delay differential equation (SDDE) model of a small neural network with recurrent inhibition is presented and analyzed. The model exhibits unexpected transient behavior: oscillations that occur at the boundary of the basins of attraction when the system is bistable. These are known as delay-induced transitory oscillations (DITOs). This behavior is analyzed in the context of stochastic resonance, an unintuitive, though widely researched phenomenon in physical bistable systems where noise can play in constructive role in strengthening an input signal. A method for modeling the dynamics using a probabilistic three-state model is proposed, and supported with numerical evidence. The potential …