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Full-Text Articles in Neuroscience and Neurobiology

Contrastive Learning For Unsupervised Auditory Texture Models, Christina Trexler Dec 2021

Contrastive Learning For Unsupervised Auditory Texture Models, Christina Trexler

Computer Science and Computer Engineering Undergraduate Honors Theses

Sounds with a high level of stationarity, also known as sound textures, have perceptually relevant features which can be captured by stimulus-computable models. This makes texture-like sounds, such as those made by rain, wind, and fire, an appealing test case for understanding the underlying mechanisms of auditory recognition. Previous auditory texture models typically measured statistics from auditory filter bank representations, and the statistics they used were somewhat ad-hoc, hand-engineered through a process of trial and error. Here, we investigate whether a better auditory texture representation can be obtained via contrastive learning, taking advantage of the stationarity of auditory textures to …


The Classification Of Basket Neural Cells In The Mammalian Neocortex, Sreya Pudi Oct 2021

The Classification Of Basket Neural Cells In The Mammalian Neocortex, Sreya Pudi

Senior Theses

Basket neuronal cells of the mammalian neocortex have been classically categorized into two or more groups. Originally, it was thought that the large and small types are the naturally occurring groups that emerge from reasons that relate to neurobiological function and anatomical position. Later, a study based on anatomical and physiological features of these neurons introduced a third type, the net basket cell which is intermediate in size as compared to the large and small types. In this study, multivariate analysis was used to test the hypothesis that the large and small types are morphologically distinct groups. The results of …


A Generative-Discriminative Approach To Human Brain Mapping, Deepanshu Wadhwa Aug 2021

A Generative-Discriminative Approach To Human Brain Mapping, Deepanshu Wadhwa

Electronic Thesis and Dissertation Repository

During everyday behaviours, the brain shows complex spatial patterns of activity. These activity maps are very replicable within an individual, but vary significantly across individuals, even though they are evoked by the same behaviour. It is unknown how differences in these spatial patterns relate to differences in behavior or function. More fundamentally, the structural, developmental, and genetic factors that determine the spatial organisation of these brain maps in each individual are unclear. Here we propose a new quantitative approach for uncovering the basic principles by which functional brain maps are organized. We propose to take an generative-discriminative approach to human …


Tracking The Mechanisms Of Short-Term Motor Adaptation Within The Framework Of A Two-State Model, Susan K. Coltman Aug 2021

Tracking The Mechanisms Of Short-Term Motor Adaptation Within The Framework Of A Two-State Model, Susan K. Coltman

Electronic Thesis and Dissertation Repository

The motor system is continuously monitoring our performance, ensuring that our actions are occurring as planned. Sensory prediction errors, which arise from a discrepancy between the expected and actual sensory consequence of a motor command (i.e., a planned action), are assumed to drive sensorimotor adaptation. Sensorimotor adaptation is thought to involve changes in motor output that allow the motor system to regain its former level of performance in perturbed circumstances. We employed experimental paradigms that involved both mechanical and visual perturbations to evoke sensory prediction errors while participants performed planar reaching movements. Movement error activates learning processes in the brain, …


Brain Representations Of Dexterous Hand Control: Investigating The Functional Organization Of Individuated Finger Movements And Somatosensory Integration, Spencer Arbuckle Aug 2021

Brain Representations Of Dexterous Hand Control: Investigating The Functional Organization Of Individuated Finger Movements And Somatosensory Integration, Spencer Arbuckle

Electronic Thesis and Dissertation Repository

Using our hands to manipulate objects in our daily life requires both dexterous movements and the integration of somatosensory information across fingers. Although the primary motor (M1) and somatosensory cortices (S1) are critical for these two complementary roles, it is unclear how neural populations in these regions functionally represent these processes. This thesis examined the functional organization of brain representations (the representational geometry) in M1 and S1 for dexterous hand control and somatosensory processing. To that end, representational geometries were estimated from fine-grained brain activity patterns measured with functional MRI (fMRI). Since fMRI measures a blood-based proxy of neural activity, …


Neuromuscular Control Strategy During Object Transport While Walking: Adaptive Integration Of Upper And Lower Limb Movements, Ahyoung Song Jul 2021

Neuromuscular Control Strategy During Object Transport While Walking: Adaptive Integration Of Upper And Lower Limb Movements, Ahyoung Song

LSU Doctoral Dissertations

When carrying an object while walking, a significant challenge for the central nervous system (CNS) is to preserve the object’s stability against the inter-segmental interaction torques and ground reaction forces. Studies documented several strategies used by the CNS: modulation of grip force (GF), alterations in upper limb kinematics, and gait adaptations. However, the question of how the CNS organizes the multi-segmental joint and muscle coordination patterns to deal with gait-induced perturbations remains poorly understood. This dissertation aimed to explore the neuromuscular control strategy utilized by the CNS to transport an object during walking successfully. Study 1 examined the inter-limb coordination …


Cortical Dynamics Of Language, Kiefer Forseth May 2021

Cortical Dynamics Of Language, Kiefer Forseth

Dissertations & Theses (Open Access)

The human capability for fluent speech profoundly directs inter-personal communication and, by extension, self-expression. Language is lost in millions of people each year due to trauma, stroke, neurodegeneration, and neoplasms with devastating impact to social interaction and quality of life. The following investigations were designed to elucidate the neurobiological foundation of speech production, building towards a universal cognitive model of language in the brain. Understanding the dynamical mechanisms supporting cortical network behavior will significantly advance the understanding of how both focal and disconnection injuries yield neurological deficits, informing the development of therapeutic approaches.


When The Brain Plays A Game: Neural Responses To Visual Dynamics During Naturalistic Visual Tasks, Jason Ki Jan 2021

When The Brain Plays A Game: Neural Responses To Visual Dynamics During Naturalistic Visual Tasks, Jason Ki

Dissertations and Theses

Many day-to-day tasks involve processing of complex visual information in a continuous stream. While much of our knowledge on visual processing has been established from reductionist approaches in lab-controlled settings, very little is known about the processing of complex dynamic stimuli experienced in everyday scenarios. Traditional investigations employ event-related paradigms that involve presentation of simple stimuli at select locations in visual space and discrete moments in time. In contrast, visual stimuli in real-life are highly dynamic, spatially-heterogeneous, and semantically rich. Moreover, traditional experiments impose unnatural task constraints (e.g., inhibited saccades), thus, it is unclear whether theories developed under the reductionist …


Investigating The Role Of Attention And Memory In Visual Exploration, Jacob E. Suffridge Jan 2021

Investigating The Role Of Attention And Memory In Visual Exploration, Jacob E. Suffridge

Graduate Theses, Dissertations, and Problem Reports

This research investigates the role that attention and memory plays in visual exploration through a comprehensive analysis of eye movement and behavioral data, alongside incorporation of a computational saliency model. The purpose of this project is to quantify differences in visual attention over repeated viewings of natural scene images by employing a free viewing task that contains a memory component. In Chapter 2, we explore the task’s behavioral data showing that participants generally memorize our images well before we investigate the effect of numerous object and individual feature inclusion. In Chapter 3, we develop four primary methods to quantify visual …


Morphological Changes In Dorsal Root Ganglia Macrophages Associated With Neuropathic Pain Mechanisms Suggest A Novel Target For Chronic Pain Therapy, Emily Kussick Jan 2021

Morphological Changes In Dorsal Root Ganglia Macrophages Associated With Neuropathic Pain Mechanisms Suggest A Novel Target For Chronic Pain Therapy, Emily Kussick

CMC Senior Theses

The present study examined morphological changes in the dorsal root ganglia (DRG) following an innate immune stimulus. The importance of the DRG has increasingly become recognized in pain processing as more than just the home of primary afferent cell bodies. All sensory information passes through the DRG via the primary afferents, and on to the spinal cord. The primary afferents synapse with second-order neurons in the spinal cord that ascend towards the brain, where they transmit the pain signal to the limbic forebrain and/or the somatosensory cortex for processing. The DRG is an interesting niche to study at as it …