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Postexercise Executive Function Benefits And Cerebral Blood Flow: In The Lab And At Home, Benjamin Tari Nov 2022

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 …


The Effect Of Propionic Acid On The Habituation To Social And Non-Social Odour Cues In Adult Male Rats, Cashmeira-Dove P. Tyson Aug 2022

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 …


Role Of The Default-Mode Network During Narrative Integration In Major Depressive Disorder, Darren Ri-Sheng Liang Aug 2022

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 …


Myeloarchitectonic Maps Of Cat Auditory Cortex, Austin Robertson Aug 2022

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 …


Examining The Association Between Brain Mri Measures At 7 Tesla And Cognition Following Covid-19 Infection, Helma Heidari Jul 2022

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 …


An Implementation Of Integrated Information Theory In Resting-State Fmri, Idan E. Nemirovsky Apr 2022

An Implementation Of Integrated Information Theory In Resting-State Fmri, Idan E. Nemirovsky

Electronic Thesis and Dissertation Repository

Integrated Information Theory (IIT) is a framework developed to explain consciousness, arguing that conscious systems consist of interacting elements that are integrated through their causal properties. In this study, we present the first application of IIT to functional magnetic resonance imaging (fMRI) data and investigate whether its principal metric, Phi, can meaningfully quantify resting-state cortical activity patterns. Data was acquired from 17 healthy subjects who underwent sedation with propofol, a short acting anesthetic. Using PyPhi, a software package developed for IIT, we thoroughly analyze how Phi varies across different networks and throughout sedation. Our findings indicate that variations in Phi …