Systems Neuroscience Commons^™

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 …

Theta Burst Brain Stimulation In Painful Diabetic Neuropathy Patients: Investigating Neural Mechanisms, Bhushan Thakkar

Theses and Dissertations

Chronic pain (CP) is a significant contributor to disability and disease burden globally. In 2019, approximately 50.2 million adults (20.4% of the US population) experienced chronic pain, contributing to $560-635 billion in direct medical costs. In addition, the worldwide prevalence of diabetes mellitus has reached epidemic proportions and is set to increase to 629 million by 2045. Almost 50% of patients with diabetes present with diabetic neuropathy (DN), and one in five patients with diabetes presents with painful DN (pDN) which is the most common cause of neuropathic pain (NP) in the US. Symptomatic treatment is the mainstay of management …

Neuroplasticity Of The Corticospinal System: Applications Of Neuromodulation-Based Therapies, Alzahraa M. Amer

Dissertations, Theses, and Capstone Projects

The motor cortex and corticospinal tract are necessary for producing skilled movements. I use intermittent theta burst stimulation (iTBS), a high-frequency stimulation protocol known to promote neural plasticity, as a tool to characterize short- and long-term plasticity of the CS system.

Although it is well known that activity-dependent motor cortex (MCX) plasticity produces long-term potentiation (LTP) of local cortical circuits, leading to enhanced motor evoked potentials (MEPs), the effects produced by the corticospinal (CS) projection on spinal cord neurons have not yet been thoroughly studied. In Chapter 2, I determined if the CS tract (CST) is capable of producing LTP …

The Wiring Logic Of Identified Serotonergic Neurons Across Olfactory Networks In Drosophila, Kaylynn E. Coates

Graduate Theses, Dissertations, and Problem Reports (ETD)

Serotonin is a ubiquitous neuromodulator that confers flexibility in networks to modulate a wide array of behavioral and physiological processes. However, due to the complexity and heterogeneity of serotonergic systems, it has been challenging to determine the patterns of connectivity as well as the physiological contexts that influence individual serotonin neurons. In this dissertation, I use two serotonergic neurons which innervate the Drosophila olfactory system, the CSDns, as a model to explore these broad questions comprehensively using anatomical approaches. I first show that the CSDns have distinct connectivity relationships with populations of antennal lobe principal olfactory neurons and that their …

Structure And Function Of Dopamine In The Inner Ear And Auditory Efferent System Of A Vocal Fish, Jonathan T. Perelmuter

Dissertations, Theses, and Capstone Projects

The neuromodulator dopamine is considered essential for coordinating the internal motivational state of an organism with appropriate behavioral responses to stimuli in the external environment. This could be accomplished by modifying the function of neural circuits involved in sensory processing such that they are “tuned in” and optimally sensitive to important stimuli during critical time windows. While dopamine modulation of auditory processing has been studied in the central nervous system, neuromodulation can also occur outside the brain, in the inner ear. The majority of investigations of dopamine in the ear are conducted using rodents and focus on its role in …

The Integration Of Extrinsic And Intrinsic Neuromodulators In The Olfactory System, Kristyn M. Lizbinski

Graduate Theses, Dissertations, and Problem Reports (ETD)

Neuromodulation is a ubiquitous feature of neural systems, allowing flexible, context specific control over network dynamics by adjusting the biophysical and synaptic properties of neurons. Neuromodulation was first described in invertebrate motor systems and early work established a basic dichotomy for neuromodulation as having either an intrinsic origin (i.e. neurons that participate in network coding) or an extrinsic origin (i.e. neurons from independent networks). Although this dichotomy has been thoroughly considered in motor systems, it has received far less attention in sensory systems. Furthermore, nervous systems are continually subject to a dynamic cocktail of both intrinsic and extrinsic modulators. However, …