Systems Neuroscience Commons^™

The Rhesus Macaque Corticospinal Connectome, Sydney Talmi

CMC Senior Theses

The corticospinal tract (CST), which carries commands from the cerebral cortex to the spinal cord, is vital to fine motor control. Spinal cord injury (SCI) often damages CST axons, causing loss of motor function, most notably in the hands and legs. Our preliminary work in rats suggests that CST circuitry is complex: neurons whose axons project to the lower cervical spinal cord, which directly controls hand function, also send axon collaterals to other locations in the nervous system and may engage parallel motor systems. To inform research into repair of SCI, we therefore aimed to map the entire projection pattern ...

Rapid Visuomotor Integration As A Window Into Multisensory Processing, Margaret Schrayer

Georgia Undergraduate Research Conference (GURC)

Introduction: Neurological conditions such as Parkinson’s Disease (PD) cause changes in the subcortical and cortical structures of the brain, affecting interactions between the dorsal and ventral visual streams. The dorsal stream processes the location of objects in the visual workspace while the ventral stream identifies those objects. We expect that, in individuals with PD, motor deficits will occur as a result of disruptions in online interactions between the dorsal and ventral streams.

Purpose: In the experiment, participants identify object shape while shapes are either moving or stationary, and make accurate reaching movements to the objects. Our hypothesis is that ...

Learning Expands The Preplanning Horizon In Finger Sequence Tasks, Neda Kordjazi

Electronic Thesis and Dissertation Repository

Many everyday skills involve the production of complex sequences of movements. However, the dynamics of the interplay between action selection and execution processes in sequential movements is poorly understood.Here, we set out to investigate the extent to which information regarding upcoming actions is utilized by the motor system to preplan into the future and furthermore, how this ability is influenced by learning. We designed a finger sequence taskwhere participants were shown only a fixed number of upcoming cues regarding future presses in every trial (viewing window, W). W varied between 1 (next digit revealed with pressing the current digit ...

Combinatorial Geometry Of Threshold-Linear Networks, Christopher Langdon

Annual Symposium on Biomathematics and Ecology: Education and Research

No abstract provided.

Characterizing The Cortical Contributions To Working Memory-Guided Obstacle Locomotion, Carmen Wong

Electronic Thesis and Dissertation Repository

While walking in complex environments, the ability to acquire information about objects in our surroundings is essential for successful obstacle negotiation. Furthermore, the ease with which most animals can traverse cluttered terrain while grazing, exploring, or hunting is facilitated by the capacity to store obstacle information in working memory (WM). However, the underlying neural substrates supporting such complex behaviours are poorly understood. Therefore, the goal of this thesis is to examine the neural underpinnings of WM-guided obstacle negotiation in the walking cat.

Obstacle locomotion was studied in two main paradigms, characterized by whether obstacle presence was detected via vision or ...

How Auditory And Visual Working Memory Tasks Affect Misophonic Response Levels, Erin Ansusinha, Melette Devore, Dr. Daniel Corts

Celebration of Learning

Misophonia is characterized by an extreme aversion towards auditory triggers, such as chewing, tapping, and other repetitive sounds, making ignoring or directing attention away from the sounds nearly impossible. It is not classified as a psychological disorder, but it is associated with significant, reflexive emotional disturbances. Studies have shown that the anterior insular cortex (AIC), an area involved in detecting irregularities or errors, functions differently in people with misophonia, which translates to difficulty in controlling emotional reactions. The present study examines how misophonic reactions might interact with cognition with particular attention to how cognitive demands may exacerbate the emotional response ...

Cholinergic Control Of Cortical Circuit Activity, Rajan Dasgupta

UT GSBS Dissertations and Theses (Open Access)

Cholinergic neurons of the basal forebrain send extensive projections to all regions of the neocortex and are critically involved in a diverse array of cognitive functions, including sensation, attention and learning. Cholinergic signaling also plays a crucial role in the moment-to-moment control of ongoing cortical state transitions that occur during periods of wakefulness. Yet, the underlying circuit mechanisms of synaptic cholinergic function in the neocortex remain unclear. Moreover, acetylcholine continues to be widely viewed as a slow and diffuse neuromodulator, despite the preponderance of in vivo evidence demonstrating rapid cholinergic function. In this study, we used a combination of optogenetics ...

Organization And Development Of Cholinergic Input To The Mouse Visual Thalamus., Guela Sokhadze

Electronic Theses and Dissertations

Cholinergic signaling plays a vital role in modulating the flow of sensory information through thalamic circuits in a state-dependent manner. In the dorsal lateral geniculate nucleus (dLGN), the thalamic visual relay, release of acetylcholine (ACh) contributes to enhanced thalamocortical transfer of retinal signal during behavioral states of arousal, wakefulness, and sleep/wake transitions. Moreover, ACh modulates activity of the thalamic reticular nucleus (TRN), a structure which provides inhibitory input to dLGN. While several cholinergic nuclei have been shown to innervate dLGN and TRN, it is unclear how projections from each area are organized. Furthermore, little is known of how or ...

Population Codes And Their Correlates In Decision Making, Neda Shahidi

UT GSBS Dissertations and Theses (Open Access)

This dissertation was organized in two parts: in part 1, we discussed Neural Correlates of Perceptual Accuracy” and in part 2 we discussed “Strategy encoding in Prefrontal Cortex”.

Abstract of part 1_The accurate transmission of electrical signals within neocortex is central to sensory perception and cognition. Theoretical studies have long proposed that the temporal coordination of cortical spiking activity controls signal transmission and cognitive function. In reality, whether and how the precise temporal coordination in neuronal populations during wakefulness influences perception remains a mystery. Here, we simultaneously recorded populations of neurons in early and mid-level visual cortex (areas V1 ...

Mapping Molecular Datasets Back To The Brain Regions They Are Extracted From: Remembering The Native Countries Of Hypothalamic Expatriates And Refugees, Arshad M. Khan, Alice H. Grant, Anais Martinez, Gully Apc Burns, Brendan S. Thatcher, Vishwanath T. Anekonda, Benjamin W. Thompson, Zachary S. Roberts, Daniel H. Moralejo, James E. Blevins

Arshad M. Khan, Ph.D.

Contextual Fear Retrieval-Induced Fos Expression Across Early Development In The Rat: An Analysis Using Established Nervous System Nomenclature Ontology, Anthony J. Santarelli, Arshad M. Khan, Andrew M. Poulos

Arshad M. Khan, Ph.D.

No abstract provided.

Brightness Perception Involves Local Adaptation Opposed By Lateral Interaction, Qasim Zaidi, Romain Bachy, Jose-Manuel Alonso

MODVIS Workshop

No abstract provided.

Effect Of Noise On Mutually Inhibiting Pyramidal Cells In Visual Cortex: Foundation Of Stochasticity In Bi-Stable Perception, Naoki Kogo, Felix Kern, Thomas Nowotny, Raymond Van Ee, Richard Van Wezel, Takeshi Aihara

MODVIS Workshop

Bi-stable perception has been an important tool to investigate how visual input is interpreted and how it reaches consciousness. To explain the mechanisms of this phenomenon, it has been assumed that a mutual inhibition circuit plays a key role. It is possible that this circuit functions to resolve ambiguity of input image by quickly shifting the balance of competing signals in response to conflicting features. Recently we established an in vitro neural recording system combined with computerized connections mediated by model neurons and synapses (“dynamic clamp” system). With this system, mutual inhibition circuit between two pyramidal cells from primary visual ...

Modeling Emmetropization In An Incessantly Moving Eye, Michele Rucci, Jonathan D. Victor

MODVIS Workshop

Many questions remain unanswered regarding the specific cues and mechanisms for emmetropization, the process by which, during development, the eye adjusts itself so that distant objects are in focus. Research has so far primarily focused on the spatial cues present in the image on the retina, such as the degree of blur. However, eye movements incessantly transform a mostly static scene into temporal modulations, so that the input to the retina is not an image, but a spatiotemporal flow of luminance. Models of retinal input signals indicate that this space-time reformatting caused by eye movements yields additional cues to the ...

Longitudinal Tracking Of Physiological State With Electromyographic Signals., Robert Warren Stallard

Electronic Theses and Dissertations

Electrophysiological measurements have been used in recent history to classify instantaneous physiological configurations, e.g., hand gestures. This work investigates the feasibility of working with changes in physiological configurations over time (i.e., longitudinally) using a variety of algorithms from the machine learning domain. We demonstrate a high degree of classification accuracy for a binary classification problem derived from electromyography measurements before and after a 35-day bedrest. The problem difficulty is increased with a more dynamic experiment testing for changes in astronaut sensorimotor performance by taking electromyography and force plate measurements before, during, and after a jump from a small ...

Time-Evolving Dynamics In Brain Networks Forecast Responses To Health Messaging, Nicole Cooper, Javier O. Garcia, Steven Tompson, Matthew B. O'Donnell, Emily B. Falk, Jean M. Vettel

Departmental Papers (ASC)

Neuroimaging measures have been used to forecast complex behaviors, including how individuals change decisions about their health in response to persuasive communications, but have rarely incorporated metrics of brain network dynamics. How do functional dynamics within and between brain networks relate to the processes of persuasion and behavior change? To address this question, we scanned forty-five adult smokers using functional magnetic resonance imaging while they viewed antismoking images. Participants reported their smoking behavior and intentions to quit smoking before the scan and one month later. We focused on regions within four atlas-defined networks and examined whether they formed consistent network ...

Computer Vision Evidence Supporting Craniometric Alignment Of Rat Brain Atlases To Streamline Expert-Guided, First-Order Migration Of Hypothalamic Spatial Datasets Related To Behavioral Control, Arshad M. Khan, Jose G. Perez, Claire E. Wells, Olac Fuentes

Arshad M. Khan, Ph.D.

Moderate Prenatal Alcohol Exposure Impairs Performance In An Object-Place-Paired-Associate Task, Lilliana May Sanchez

Psychology ETDs

Memory impairments, including spatial and object processing, are often observed in individuals with Fetal Alcohol Spectrum Disorder. Much attention has been directed towards the hippocampus, which displays significant alterations after moderate prenatal alcohol exposure (PAE). In the present study, we tested a moderate PAE rat model in an object-place-paired-associate (OPPA) task, previously shown to require hippocampal processing. The OPPA task was composed of training rats to discriminate between an identical pair of objects presented in 180° opposite arms of a radial arm maze. Animals were given a total of 10 trials per day over 14 consecutive days of training and ...

The Role Of The Chorda Tympani Nerve In The Structural Development Of Brainstem Neurons, Louis Martin

Student Research and Creative Activity Fair

The brain changes substantially throughout development. In the taste system, brainstem neurons undergo dramatic structural alterations after birth. Most notably, these cells’ dendrites, branch-like projections that that receive sensory input, grow 3-4 times longer by adulthood. It is not clear whether incoming signals about taste are necessary for these structural changes to occur. We have consistently found that when the chorda tympani taste nerve (CT) is cut at an early age in rats, it does not regenerate. With this manipulation, we can permanently limit the amount of taste information that reaches the brain. To determine the role of taste input ...

Mapping A Pup-Responsive Pathway From The Medial Preoptic Area To The Ventral Tegmental Area., Matias Andina

Masters Theses

Maternal behavior is the complex array of caregiving behaviors females display towards offspring. In rats, the transition to motherhood depends on the action of various hormones, especially estradiol near parturition, which primes the maternal circuitry to respond to pups upon first encounter at parturition with appropriate maternal behavior. Although virgin rats avoid pups, new mothers are highly motivated to interact with pups, and their maternal behavior depends on the functional interaction between the medial preoptic area (mPOA) and the ventral tegmental area (VTA). However, a precise mapping of the VTA-projecting mPOA neurons remains to be elucidated. To determine whether pup-responsive ...