Neuroscience and Neurobiology Commons^™

Characterizing The Function Of B Cells That Accumulate In The Inflamed Central Nervous System In Anti-Myelin Autoimmunity, Lika Chowdhury

Electronic Thesis and Dissertation Repository

While the role of autoimmune T cells has been extensively studied in anti-myelin

autoimmunity, little is known about the function of B cells in multiple sclerosis (MS), a chronic inflammatory disease of the central nervous system (CNS). B cells form clusters with T cells in the meninges directly adjacent to demyelinating lesions. Previous studies have shown that disease progression is dependent on the depletion of specific populations of B cells, but it is not clear which contributes to pathology or how. The purpose of this thesis is to characterize the population of meningeal B cells to determine how they differ …

Postexercise Executive Function Benefits And Cerebral Blood Flow: In The Lab And At Home, Benjamin Tari

Electronic Thesis and Dissertation Repository

A single bout of aerobic exercise improves executive function; however, the mechanism, or mechanisms, supporting this improvement remain unclear. One candidate mechanism is an exercise-mediated increase in cerebral blood flow (CBF) that enhances the efficiency of executive-related frontoparietal networks. To evaluate the link between exercise, CBF and executive function, three separate experiments were conducted. In the first study, separate 10-min sessions of moderate-to-heavy-intensity aerobic exercise, and a hypercapnic environment (i.e., 5% CO₂) were implemented. The hypercapnic condition was included because it increases CBF independent of the metabolic demands of exercise. The second study investigated whether exercise intensity-specific changes …

Regulation Of Hedgehog And Wnt Signaling In Neural Differentiation Of P19 Embryonal Carcinoma Cells, Danielle Margaret Spice

Electronic Thesis and Dissertation Repository

The Hedgehog (Hh) and Wnt protein signaling pathways are essential in the differentiation of neurons and astrocytes. As there are many known and new players involved in regulating these pathways, the role of the regulators Suppressor of Fused (SUFU) and Never in Mitosis Kinase 2 (Nek2) have either not been previously reported or have not been thoroughly explored. To address this shortfall CRISPR gene editing was used to target SUFU and Nek2 in the mouse P19 embryonal carcinoma cell model of neural differentiation. Hh and Wnt signaling were explored in normal P19 neural differentiation, which occurs in the presence of …

The Clinical Value Of Oculomotor Assessments Across The Continuum Of Concussion, Dillon Richards

Electronic Thesis and Dissertation Repository

Concussions are complex conditions that are difficult to manage medically. Variations in symptom presentation, intricate neurophysiological processes, and the availability of a variety of possible assessment tools may contribute to this complexity. Clinicians must use a broad approach, employing both subjective symptom assessment and objective assessments to confirm a diagnosis and/or monitor progression and recovery. Oculomotor function after concussion may be an important indicator of injury, given the interconnectedness of oculomotor function, vestibulo-ocular and visual systems, and even cognition. Oculomotor function may be assessed objectively or indirectly using patient-reported symptom checklists as part of subjective assessments. One way of objectively …

The Effect Of Active Learning On Viewpoint Dependence For Novel Objects, Cassandra Wallace Bacher

Electronic Thesis and Dissertation Repository

Active learning of novel objects can facilitate subsequent object recognition and discrimination, but the reasons for its beneficial effects remain unclear. One potential explanation is that active learning enables the formation of a more detailed, realistic, or useful neural object representation than does passive learning. The current study addressed the question of whether active vs. passive learning of objects affects viewpoint discrimination. Participants learned novel wire-like objects either actively or passively and then completed a psychophysical task which they discriminated object orientation. This study did not find a significant difference in viewpoint discrimination between actively and passively learned object representations, …

Using Machine Learning To Identify Neural Mechanisms Underlying The Development Of Cognition In Children And Adolescents With Adhd, Brian Pho

Electronic Thesis and Dissertation Repository

Childhood and adolescence are marked by improvements to cognition and by the emergence of neurodevelopmental disorders such as attention deficit hyperactivity disorder (ADHD). What neural mechanisms are associated with cognitive development in ADHD? In this study, I applied machine learning models to functional connectivity profiles to identify patterns of network connectivity that predict various cognitive abilities in a group of participants ages 6 to 16 with ADHD. The models successfully predicted IQ, visual spatial, verbal comprehension, and fluid reasoning in children ages 6 to 11, but not adolescents. Furthermore, the models identified connections with the default mode, memory retrieval, and …

The Express Sensorimotor Response Selects Visual Features Based On Instruction, David Youhanna Mekhaiel

Electronic Thesis and Dissertation Repository

In time-sensitive situations, orienting reflexes allow us to move rapidly in response to stimuli. The express sensorimotor response (ESR) is an orienting reflex presenting as a brief burst of muscle recruitment. Previous studies have identified commonalities between ESRs and express saccades, another orienting reflex.

In this study, we investigate if ESRs share in a characteristic of express saccades: preference for faces. In separate blocks, participants were instructed to reach toward one of two simultaneously appearing targets: a face and another image. Muscle activity in the pectoralis major muscle of the reaching arm was recorded using skin surface EMGs.

We …

Investigation Of Neurotransmitter’S Knockdown Effect On Drosophila Melanogaster Female Aggression, Asil N. El Galad

Undergraduate Student Research Internships Conference

Drosophila melanogaster (D. melanogaster) is a popular model organism in neurobiology. While aggression has been studied heavily in male drosophila, there's minimal research on aggression in female drosophila. Neurotransmitters influencing aggressive behaviour in female D. melanogaster are poorly understood. Various neurotransmitters such as dopamine, octopamine, and serotonin influence aggression in D. melanogaster Further investigation of the role of neurotransmitters on aggression is thus important. The purpose of our experiment is to observe the effect of the knockdown of dopamine, octopamine and glutamate on aggression in female D. melanogaster.

Human Neuroimaging Reveals That Agency In A Video Game Boosts Functional Connectivity Within And Between Networks, Emily J. Davidson

Electronic Thesis and Dissertation Repository

In naturalistic settings, brains continuously interface with a dynamic and interactive external environment. The inclusion of such an environment in an fMRI study is difficult, given the practical constraints imposed by the machine itself. This study sought to test whether the ecological validity of fMRI could be enhanced by testing a new paradigm that incorporated a dynamic and interactive virtual environment (DIVE). To determine the viability of this paradigm, functional connectivity was assessed during a DIVE condition and compared to functional connectivity patterns acquired in conditions with equally dynamic stimuli but that lacked interactivity with the environment. This study found …

The Effects Of Prenatal Cannabis Exposure On The Basolateral Amygdala, Karen Kw Wong

Undergraduate Student Research Internships Conference

Clinical and preclinical studies indicate prenatal cannabis exposure (PCE) pathologically affects fetal brain development and may increase vulnerability to neuropsychiatric disorders, including schizophrenia and mood/anxiety disorders. In review research from our lab suggests that fetal exposure to Δ9-THC sex-selectively impairs mesocorticolimbic (MCL) circuit function. However, there is a distinct lack of focus on PCE models on the BLA. The BLA plays a central role within the MCL where it directly interacts with the VTA, PFC and HIPP. Importantly, our model exhibits significant VTA hyperdopaminergic activity, and sex-specific alterations to PFC/HIPP glutamate firing, alongside region- and sex-specific changes in dopamine (DA), …

The Effect Of Propionic Acid On The Habituation To Social And Non-Social Odour Cues In Adult Male Rats, Cashmeira-Dove P. Tyson

Electronic Thesis and Dissertation Repository

The enteric bacterial metabolite, propionic acid (PPA), elicits physiological and behavioural changes in rodents reminiscent of autism spectrum disorder (ASD). This includes abnormal sensory processing and social behaviour. ASD may contribute to social deficits through impaired habituation; therefore, the present study examined the effects of intraperitoneal PPA on the habituation to social and non-social odours. Adult male rats were injected daily with PPA or the vehicle control, and for 3 days, habituated to a conspecific odour or vanilla extract for 10 minutes. On day 4, rats were exposed to a novel conspecific odour or almond extract for 10 minutes to …

Examining The Relationships Between Socio-Cognitive Factors And Neural Synchrony During Movie Watching Across Development, Kathleen M. Lyons

Electronic Thesis and Dissertation Repository

While different cognitive abilities mature, the conscious experiences of children likely become richer and more elaborate. A challenge in investigating relationships between cognitive development and real-world experiences is having measures that assess naturalistic processing. Movie watching offers a solution, since following the plot of a film requires cognitive processes that are similar to real-world experiences. When different adults watch the same film, their brain activity begins to align (known as neural synchrony). The strength of this alignment has been shown to reflect the degree to which different individuals are having a similar experience of the movie. While this phenomenon has …

Role Of The Default-Mode Network During Narrative Integration In Major Depressive Disorder, Darren Ri-Sheng Liang

Electronic Thesis and Dissertation Repository

How brain activity is synchronized across individuals during narrative comprehension has previously been characterized by functional magnetic resonance imaging (fMRI) in healthy and patient populations. To our knowledge, there has been limited investigation as to how it is affected by major depressive disorder (MDD). We addressed this issue with fMRI through examination of inter-subject synchronization in the default mode network (DMN), brain structures which have previously been implicated in MDD pathology. Twenty-two patients with MDD and 20 matched control participants listened to Intact versus Scrambled versions of an auditory narrative; these experimental conditions differed in the degree of temporal integration …

Exploring The Inter-Relationship Between Cognitive And Motor Function In People With Lower Limb Amputations, Humberto Adolfo Omaña Moreno

Electronic Thesis and Dissertation Repository

The main objective of the present dissertation was to expand our understanding of the inter-relationship between cognition and mobility in people with lower limb amputations (PLLA). Study 1 systematically reviewed the literature to assess the effects of dual-task testing on the balance and gait of PLLA. A total of twenty-two studies were included. Overall, PLLA demonstrated a disproportionately greater dual-task effect than controls, characterized by increased sway velocity and reduced pace and rhythm, and increased asymmetry when balance or walking was paired with a secondary task. Additionally, the dual-task effect was not influenced by differences in etiology, level of amputation, …

The Effects Of Transcranial Direct Current Stimulation On Beat Perception And Motor Performance, Marina Emerick

Electronic Thesis and Dissertation Repository

Humans have an intrinsic tendency to move to music. However, our understanding of the neural mechanisms underlying the music-movement connection remains limited, and most studies have used correlational methods. Here, we used transcranial direct current stimulation (tDCS) to causally investigate the role of four motor brain regions involved in movement timing and beat perception: the supplementary motor area (SMA), left and right premotor cortices (PMC), and cerebellum. Subjects were randomly assigned to a brain region to be stimulated and received anodal, cathodal, or sham stimulation on three different days while they reproduced rhythmic sequences. The sequences had either a strong …

Resistance Training Improves White Matter Structural Connectivity In Older Adults At-Risk For Cognitive Decline, Ryu Lien

Undergraduate Student Research Internships Conference

Diabetes is a global health concern that impacts 415 million people worldwide. Individuals who are at-risk for diabetes (characterized by high blood glucose and/or being overweight) have white matter atrophy, decreased cognitive function, and an increased risk of Alzheimer’s disease (AD). Recently, resistance training (RT) has been shown to lower white matter atrophy and white matter lesion volume. However, investigating changes in white matter tracts is complex, hence previous findings remain inconclusive. Diffusion tensor imaging (DTI) serves as a highly sensitive tool that enables visualization and characterization of white matter tracts and has the potential to combat this complexity. The …

Human Claustrum Activation During Pain, Zoravar S. Sidhu, David A. Seminowicz, Brent W. Stewart

Undergraduate Student Research Internships Conference

Chronic pain is one of the principal causes of disability in the world. Many if not all of us deal with or know of someone who deals with chronic pain. Interestingly, it appears that a mysterious part of the brain known as the claustrum has a hand in chronic pain. Although little is known about the actual function of the claustrum, it is hypothesized to synchronize cortical networks during tasks which have a cognitive load.

Recent literature has indicated that during chronic pain conditions, neural network recruitment is modified. In addition, an analysis of an existing fMRI data set determined …

Assessing The Impact Of Lipopolysaccharide On Learning And Memory In Rats, Anahat Luthra

Undergraduate Student Research Internships Conference

The immune system and the central nervous system (CNS) have a bi-direction relationship, modulating one another.⁴ Proinflammatory cytokines released from CNS immune cells have an impact on cognitive processes such as learning and memory.¹ Liposaccharide (LPS), a cell wall component of Gram-negative bacteria, which is used to activate proinflammatory cytokine release has been found to impact learning and memory processes, such as in the anticipatory nausea paradigm (ANP).² Anticipatory nausea and vomiting is that which may occur before a chemotherapy treatment session begins in a patient who has had chemotherapy before. It is caused by triggers like …

Functional Neuroimaging Techniques To Examine Falls And Cognition In Older Adults: A Systematic Review, Tia M. Seleem, Raphael Gabiazon

Undergraduate Student Research Internships Conference

Falls in older adults have been attributed to impaired cognition. There is potential for neuroimaging techniques to understand the biological components that are involved in the cognitive processes pertaining to falls. Therefore, the purpose of this systematic review was to analyze how functional neuroimaging can be used to examine the relationship between falls and cognition among older adults. The following five electronic databases were selected to identify peer-reviewed articles in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses: 1) Medline (via OVID), 2) PsycINFO (via OVID), 3) CINAHL (via EBSCO), 4) EMBASE (via OVID), and 5) Pubmed. …

Using A Musical Beat To Influence Linguistic Statistical Learning, Aspen Leung

Undergraduate Student Research Internships Conference

The similarities between music and language continue to provide research questions in the area of psychology. Despite the large amount of research on this area of knowledge, there are still many existing questions in regards to the processing of musical and linguistic stimuli. Statistical learning involves the ability to extract statistical regularities from a stimulus and continues to be studied in both domains due to the similar hierarchical structure of music and language. Recently, neural entrainment (the synchronization of neural oscillations with the rhythm of an external stimulus) has been studied as a mechanism of statistical learning. Music has been …

Stimulus Duration Alters Temporal Sensitivity In Rat Model Of Audiovisual Perception, Juwairiya F. Ahmad

Undergraduate Student Research Internships Conference

The aim of this experiment was to investigate the effect of stimulus duration on the perceived temporal order judgement in Long Evans rats.

Entropic Voxels Indicate Large Brain-State Repertoires, Adam Hull

Undergraduate Student Research Internships Conference

Brain entropy is a measure that has been increasingly studied in neuroscience over the past decade. It is based on Shannon Entropy, a measure from Information Theory that quantifies the information capacity of a system from the probability distribution of its states. Brain entropy is thus posited to reflect the information capacity of the brain and has been linked to various cognitive abilities and states. However, most studies on brain entropy measure the time-series entropy of each voxel independently, ignoring any patterns that emerge from the relations between voxels. Here, we measured brain entropy of resting-state fMRI data based on …

The Ommaba Project, Katsiaryna Buchko

Undergraduate Student Research Internships Conference

The Open Multimodal Music and Auditory Brain Archive (OMMABA) is the first multimodal (behavioural, EEG, and neuroimaging) database characterizing normal human auditory processing. My project aims to shed light on the importance of this collaborative project that is transforming the field of auditory cognitive neuroscience.

Prefrontal Coding Of Naturalistic Working Memory: Mechanisms During Normal Maintenance And Modelled Disease, Megan P. Roussy

Electronic Thesis and Dissertation Repository

Neural activity in the primate lateral prefrontal cortex (LPFC) has been causally linked to working memory (WM) ⁠— the brief maintenance and mental manipulation of information. Primates use WM to perform tasks in complex contexts; however, neural mechanisms of WM and the pathophysiology related to WM deficits have traditionally been studied using simple tasks that deviate from naturalistic conditions. This raises the question, how is WM processed in naturalistic conditions? To explore this, I trained two macaque monkeys on a spatial WM task set in a naturalistic virtual environment. During the task, a target was presented in 1 of 9 …

Myeloarchitectonic Maps Of Cat Auditory Cortex, Austin Robertson

Electronic Thesis and Dissertation Repository

The cerebral cortex contains myriad cortical areas that differ in structure, function, and connectivity. Current methods of delineating cortical structures and their subregions are insufficient for in vivo applications, either being highly invasive or requiring a detailed knowledge of a region’s tuning properties. To address this, we seek to establish a structural biomarker capable of delineating the cortex that possesses a non-invasive correlate. We explore myelin as a potential candidate by evaluating its efficacy in parcellating the feline auditory cortex through the generation of depthwise myelin density profiles for each of the 13 auditory cortical subregions. Our analyses revealed significant …

Durability Of Motor Learning By Observation, Natalia Mangos

Electronic Thesis and Dissertation Repository

Recent evidence suggests that neural representations of novel movement dynamics can be acquired by observing someone else experiencing them first-hand. Visual information about another person’s movement kinematics can be transformed into an adaptation of feedforward limb control for the observer; however, little is known about the durability of this adaptation. Despite the longevity of changes in the motor system being a defining characteristic of motor learning, studies to date have only examined observation-related effects shortly after observation has occurred, leaving unknown whether such effects are transient phenomena or products of learned, durable changes in neural systems. We measured human participants’ …

Coordinate Frame For Proprioception Acuity Changes Accompanying Motor Learning, Heba Hussian

Electronic Thesis and Dissertation Repository

Proprioception is important for skilled motor control. Improvements in proprioception occur in conjunction with motor learning. However, it has not been established whether these improvements occur within intrinsic or extrinsic coordinate frames. In Experiment 1 we gave participants a perceptual test of sensed limb position and a motor learning task in the same location of the workspace or in two different locations of the workspace. Participants performed better on the proprioception test when the motor learning task was completed in the same location as the proprioception test. In Experiment 2 we tested whether this perceptual improvement occurred in an intrinsic …

Examining The Association Between Brain Mri Measures At 7 Tesla And Cognition Following Covid-19 Infection, Helma Heidari

Electronic Thesis and Dissertation Repository

The long-term neuropsychological, cognitive, and neurobiological effects of the severe acute respiratory syndrome (SARS-CoV-2) in survivors with milder symptoms are still poorly understood. In this thesis we evaluated cognitive and psychological changes approximately five weeks after a wide range of symptoms in COVID-19 illness and determined whether advanced diffusion magnetic resonance imaging measures within subcortical brain structures of the limbic system were related to neurological, respiratory, psychiatric, and gastric symptoms experienced during the acute phase of illness. Cognitive and neuropsychological evaluations were performed in 45 participants who experienced neurological symptoms during the acute phase of COVID-19 illness. Participants also underwent …

Neural Circuitry Of The Midbrain Pedunculopontine Tegmental Nucleus Regarding Its Role In Sensorimotor Gating, Niveen Fulcher

Electronic Thesis and Dissertation Repository

The brain is a complicated structure that receives copious amounts of information at any given time. The pedunculopontine tegmental nucleus (PPTg) is involved in many innate functions like arousal, rapid eye-movement (REM) sleep, reward association and sensorimotor gating. Although commonly referred to as a cholinergic structure, it also contains glutamatergic and GABAergic neurons. Based on chronic PPTg lesions that disrupted PPI, cholinergic PPTg neurons were long assumed to mediate prepulse inhibition (PPI) of startle, a measure of sensorimotor gating. Deficits of PPI are observed in a variety of neurological disorders, including Autism Spectrum Disorder (ASD), Obsessive-Compulsive Disorder (OCD), and is …

The Influence Of Intersegmental Dynamics On Limb Position Sense, Peyman R. Heidari

Electronic Thesis and Dissertation Repository

During multijoint limb movement, the motion of limb segments can be driven actively, by muscle torque, and/or passively, by interaction torque–rotational force that arises passively at one joint due to motion of an adjacent limb segment about another joint. Proprioception plays a critical role in compensating for interaction torques, and deafferented patients have marked deficits in this aspect of motor control. This observation is seemingly at odds with the widely-held belief that proprioceptive sense is poor during motion that is not driven by active muscle contraction, and suggests that proprioceptive acuity might be preserved during motion that is driven by …