Digital Commons Network^™

White Matter Connectome Associations With Reading Functions In Children, Chenglin Lou

Electronic Thesis and Dissertation Repository

This thesis investigated associations between the white matter connectome and reading in children with a wide range of reading abilities. It is well established that the connectome supports the interplay among brain regions and connections within an integrated system. In this dissertation, I examine the hypothesis that it could therefore represent multiple mapping processes among reading components and further explain variations in reading performance. Such associations between the organization of the connectome and reading skills have not been well explored. This thesis aimed to address this issue by considering both the relationship between connectome measures and standardized reading performance out …

Fraction Magnitude Understanding Across Learning Formats: An Fmri Study, Chloe A. Henry

Electronic Thesis and Dissertation Repository

Knowledge of fraction magnitudes are an important, but notoriously difficult mathematical concept to master. Behavioural work has begun to explore and compare the instructional tools used for fraction learning. However, how fraction instructional tools are processed in the brain remains an underexplored question. Therefore, in the present thesis, we used functional brain MRI methodology to examine the neural activity of adult participants while completing a fraction verification task using the number line and area model, two common methods of fraction learning. We found that both models commonly recruited fronto-parietal activity, the neural regions typically implicated in number processing. However, we …

Investigating The Roles Of The Dorsal And Ventral Striatum In Humor Comprehension And Appreciation Throughout Health, Aging, And Parkinson’S Disease, Maggie Prenger

Electronic Thesis and Dissertation Repository

Humor processing is thought to involve two distinct components. The first, humor comprehension, involves detecting and resolving incongruities that are present within a humorous stimulus. This is related to cognitive processes such as ambiguity resolution, response inhibition, working memory, and cognitive flexibility, functions that are mediated in part by the dorsal portion of the striatum (DS). Humor appreciation, on the other hand, refers to the subjective amusement and mirth that one experiences in response to a joke. This is related to reward processing, which implicates the ventral portion of the striatum (VS). Across three separate studies, we investigated the involvement …

Neural Correlates Of Online Movement Preparation, Mahdiyar Shahbazi

Electronic Thesis and Dissertation Repository

The ability to prepare future action while controlling the ongoing execution is a fundamental characteristic of complex sequential behavior. Recent evidence suggests that when movement preparation and execution are separated in time, brain activity patterns for preparation are highly correlated with those underlying execution. But what happens when the brain needs to prepare and execute movements at the same time, as in the context of rapid movement sequences? We designed a 7T functional magnetic resonance imaging experiment with conditions where the next response preparation either overlapped with the current response execution or did not. Although overlap and non-overlap conditions were …

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 …

Neural Correlates Of Familiarity Across Time Scales And Their Involvement In Explicit Memory Decisions, Haopei Yang

Electronic Thesis and Dissertation Repository

Familiarity is a type of memory signal that can support recognition of prior occurrences without retrieval of associated contextual information. It is typically probed with respect to recent laboratory exposure in recognition-memory studies involving human participants. This line of work has revealed several neural correlates including event-related potentials (ERPs) and blood-oxygenation-level-dependent (BOLD) activity in several regions. However, few studies have examined familiarity accumulated outside of laboratory settings through lifetime experience. Hence, it is currently unclear whether similar neural correlates are involved. The fluency-attribution framework decomposes familiarity judgement into automatic and decision-related processes. Since recent and lifetime familiarity are phenomenologically and …

Can Novel Findings From Emerging Neuroscientific Technologies Be Incorporated Into Trademark Law In Canada?, Pankhuri Malik

Electronic Thesis and Dissertation Repository

American scholar, Mark Bartholomew, predicted in 2018 that a new kind of neuroscientific evidence would help businesses involved in lawsuits connect their trademarks with the public’s perception of their trademarks. Bartholomew coined the term "neuromarks’ for this evidence. Bartholomew focused on U.S. trademark law. This research demonstrates, looking at both Canada’s domestic law and Canada’s relevant international treaties and trade agreements, that such evidence has not yet been used (in 2022) in trademark litigation in Canadian courts or tribunals but that there appears to be no legal barrier to its use in future in Canada. This research notes that neuroscience …

Neuroimaging Depression Risk In A Sample Of Never-Depressed Children, Matthew R. J. Vandermeer

Electronic Thesis and Dissertation Repository

Children of mothers with a history of depression are at significantly higher risk for developing depression themselves. Although numerous mechanisms explaining this relationship have been proposed (Goodman & Gotlib, 1999), relatively little is known about the neural substrates of never-depressed children’s depression risk. Of the few studies that have used neuroimaging techniques to characterize risk-based differences in children’s neural structure, function, and functional connectivity, most have used samples that include participants with a personal history of depression or older samples (i.e., past the typical age of onset for depressive disorders). These approaches limit what can be determined regarding whether findings …

Investigating Bone Cement Susceptibility Related Artifacts And Adhesion, Eric Kuindersma

Electronic Thesis and Dissertation Repository

Blood Oxygen Level Dependent (BOLD) functional Magnetic Resonance Imaging (fMRI) utilizes pulse sequences sensitive to changes in concentration of deoxyhemoglobin to indirectly measure neural activity. Sequences used for BOLD are sensitive to magnetic susceptibility differences that may cause signal voids. Our lab has designed an awake marmoset head coil that eliminates confounds associated with imaging an animal under anesthesia. This design requires a head chamber attached to an animal’s skull with a cement that may cause a susceptibility artifact. Motivation behind this project was to find an MRI compatible cement that remains secure to the skull with minimal artifacts. Four …

Neural Markers Of Musical Memory In Young And Older Adults, Avital Sternin

Electronic Thesis and Dissertation Repository

Memory for music can be preserved in the presence of neurodegenerative disorders even when other memories are forgotten. However, understanding how the brain remembers music has proven difficult despite decades of research. The central goal of this thesis was to elucidate the neural correlates of musical memory by exploring how the presence of language and music information affect the way young and older adults remember music. To that end, I 1) used a controlled training paradigm to familiarize participants with novel stimuli that manipulated the presence of language and music, and 2) collected functional magnetic resonance imaging data to compare …

Inter-Subject Correlation Using Movie-Driven Fmri In Drug-Resistant Epilepsy, Hana H. Abbas

Electronic Thesis and Dissertation Repository

Treating drug-resistant epilepsy with surgery requires the localization of the epileptic focus. We explored the potential for movie-driven functional magnetic resonance imaging (fMRI) to act as a sensitive, non-invasive, and cost-effective tool to identify functionally disturbed networks. We assessed neural synchronization (inter-subject correlation; ISC) between presurgical epilepsy patients (n = 18) and healthy controls (n = 24) as they watched a suspenseful movie clip in the scanner. To optimize denoising, we compared ISC values with and without an automated Independent Components Analysis-based denoising step (ICA-AROMA). We found that denoising with ICA-AROMA elicited augmented correlation values, supporting its use …

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, …

The Hijacked Self: Midbrain And Default Mode Network Functional Patterns In Ptsd, Braeden A. Terpou

Electronic Thesis and Dissertation Repository

In post-traumatic stress disorder (PTSD), self-related processing disturbances are demonstrated commonly and have been linked to the default mode network (DMN), a large-scale, neural network altered significantly after trauma. However, emerging evidence suggests the midbrain may be underlying self-related processing disturbances as well, yet midbrain systems remain poorly characterized in PTSD. Here, we evaluated midbrain activity and functional connectivity during subliminal, trauma-related stimulus processing (Chapters 2–4), as well as during moral injury-related (MI) memory recall (Chapter 5) in participants with PTSD as compared to healthy controls. Initially, during subliminal, trauma-related stimulus processing, we revealed stronger midbrain periaqueductal gray (PAG) activity …

Brain Signatures Of Human Skill Learning: From Single Movements To Movement Sequences, Eva Berlot

Electronic Thesis and Dissertation Repository

Sequences of finger movements, such as making a cup of coffee or playing the piano, have a key role in our lives. An important neuroscientific question is how such movement sequences are represented in the brain. The central goal of this thesis was to investigate how different brain regions represent individual movements, and how these representations change when learning sequences of movements. To that end, we used 1) high-field functional magnetic resonance imaging (fMRI) to measure brain activation in humans while they produced finger movements on a keyboard-like device, and 2) advanced multivariate analyses to characterize the brain representations underlying …

Evaluating Anesthetic Protocols For Non-Human Primate Functional Neuroimaging, Megha Verma

Electronic Thesis and Dissertation Repository

Functional magnetic resonance imaging (fMRI) is a non-invasive technique that can be used to measure a proxy of neural activity in vivo with high spatial specificity. One subject can be followed for a long period of time to assess changes in functional brain organization. However, fMRI is extremely sensitive to motion. The challenges of training non-human primates to reduce motion in an MRI scanner motivate the study of anesthesia which is commonly used to substitute for this training. In this thesis, I compare three different commonly used anesthetic protocols: isoflurane, propofol-fentanyl in combination, and fentanyl alone, to test which of …

Optimizing Preprocessing Of Fmri Data To Maximize Correspondence Of Functional Anatomy Across Individuals, Nargess Ghazaleh

Electronic Thesis and Dissertation Repository

In movie-activation fMRI, intersubject correlation (ISC) indicates a functional correspondence across viewers. Brains di↵er in shape; spatial normalization and smoothing enhance inter-subject functional overlap. We compare three normalization methods and six smoothing levels to discover which method yields the best functional overlap, indexed by ISC. This is key to optimizing data analysis in clinical studies using movie-activation fMRI in future. In a 3T scanner, 44 healthy subjects watched an 8-min movie. Both normalization and smoothing a↵ected the strength and extent of the ISC. ISC values were more robust for ANTs and DARTELthanforSPM12andwere(asymptotically)thestrongestat12mmsmoothing. When image data are preprocessed with high-dimensional volumetric …

Homotopic Coupling In Persons With Epilepsy Using Movie-Driven And Resting-State Fmri, Caroline M. Chadwick

Electronic Thesis and Dissertation Repository

For the 30-40% of persons with epilepsy (PWE) with refractory epilepsy, seizure freedom following surgery is affected by the localization of the epileptogenic zone (EZ). However, functional abnormalities can exist at a distance from the EZ, which may contribute to variable outcomes after surgery. Considering epilepsy as a network disorder (Pittau & Vulliemoz, 2015), and evaluating functional coupling among homotopic brain areas, may help predict cognitive outcomes. Homotopic areas are well connected anatomically and undoubtedly work synchronously to generate cognition. We evaluated 22 persons with focal epilepsy and 24 neurologically healthy controls using fMRI at rest and while watching a …

Cognitive, Neural, And Educational Contributions To Mathematics Performance: A Closer Look At The Roles Of Numerical And Spatial Skills, Zachary C.K. Hawes

Electronic Thesis and Dissertation Repository

The principal aims of this thesis were to (1) provide new insights into the cognitive and neural associations between spatial and mathematical abilities, and (2) translate and apply findings from the field of numerical cognition to the teaching and learning of early mathematics.

Study 1 investigated the structure and interrelations amongst cognitive constructs related to numerical, spatial, and executive function (EF) skills and mathematics achievement in 4- to 11-year old children (N=316). Results revealed evidence of highly related, yet separable, cognitive constructs. Together, numerical, spatial, and EF skills explained 84% of the variance in mathematics achievement (controlling for chronological age). …

Individual Variability Of Functional Connectivity In Resting-State And Naturalistic Fmri Paradigms, Mark O'Reilly

Electronic Thesis and Dissertation Repository

Resting-state functional magnetic resonance imaging (fMRI) studies are criticized for their lack of control over cognitive states of individuals during observation, which may lead to increased variability in estimates of functional connectivity (FC). Engaging movies have been used in an attempt to synchronize the cognitive states of individuals during the scan, potentially reducing intersubject variability in connectivity estimates. The objective of this study was to investigate the differences in intersubject variability of FC between rest and movie conditions in a healthy cohort. The results demonstrate widespread reductions of intersubject variability of FC in the movie condition compared to the resting-state …

Pattern Separation In The Ventral Visual Stream, Kayla Ferko

Electronic Thesis and Dissertation Repository

Pattern separation is a neural computation thought to underlie our ability to form distinct memories of similar events. It involves transforming overlapping inputs into less overlapping outputs. In the ventral visual stream (VVS) there is considerable evidence for hierarchical transformation from feature-based visual representations to conjunctive whole-object representations, with the latter allowing for distinct coding even when objects have significant feature overlap. In the current study, we asked whether this transformation can be understood as pattern separation, and whether pattern separation can be observed even outside the context of classic recognition-memory tasks. To investigate pattern separation in the VVS, we …

Characterizing The Familiar-Voice Benefit To Intelligibility, Beatriz Ysabel Domingo

Electronic Thesis and Dissertation Repository

Everyday listening often occurs in the presence of background noise. Listeners with normal hearing can often successfully segregate competing sounds from the signal of interest. To do this, listeners exploit a variety of cues to facilitate the separation of simultaneous sounds into separate sources, and group sequential sounds into intelligible speech streams. One of the cues that has been shown to be an effective facilitator of speech intelligibility is familiarity with a talker’s voice. A recent study by Johnsrude et al. (2013) measured speech intelligibility of a naturally familiar voice (i.e., that of a long-term spouse) and showed a …

Object Processing In The Medial Temporal Lobe: Influence Of Object Domain, Anna Blumenthal

Electronic Thesis and Dissertation Repository

We live in a rich visual world, surrounded by many different kinds of objects. While we may not often reflect on it, our ability to recognize what an object is, detect whether an object is familiar or novel, and bring to mind our general knowledge about an object, are all essential components of adaptive behavior. In this dissertation, I investigate the neural basis of object representations, focusing on medial temporal lobe (MTL) structures, namely, perirhinal cortex, parahippocampal cortex, and hippocampus. I use what type of thing an object is, or more specifically, the broader category (e.g., “face” or “house”) or …

Movie-Driven Fmri Reveals Network Asynchrony And Connectivity Alterations In Temporal Lobe Epilepsy, Alenka Bullen

Electronic Thesis and Dissertation Repository

Mesial temporal lobe epilepsy (TLE) is the most common form of focal epilepsy and is often resistant to medication. Recent studies have noted brain-wide disruptions to several neural networks in so-called “focal” epilepsy, notably TLE, leading to it being recognized as a network disease. We aimed to assess the integrity of functional networks while they were simultaneously activated in an ecologically valid manner, using an actively engaging, richly stimulating audio-visual film clip. This stimulus elicits widespread, dynamic patterns of time-locked brain activity, measurable using functional magnetic resonance imaging. Thirteen persons with drug-resistant TLE (persons with epilepsy; PWE) and 10 demographically …

Neurocircuits Of Posttraumatic Stress Disorder And Its Dissociative Subtype, Andrew A. Nicholson

Electronic Thesis and Dissertation Repository

The amygdala and insula are highly implicated in the pathophysiology of posttraumatic stress disorder (PTSD), where both have been shown to be hyper/hypoactive in PTSD and dissociative subtype (PTSD+DS) PTSD patients, respectively, during symptom provocation. However, the functional connectivity of individual amygdala and insula subregions have not previously been compared in PTSD, PTSD+DS and healthy controls. In two separate studies, we examined amygdala complex (chapter 2) and insula subregion (chapter 3) functional connectivity patterns using resting-state fMRI. Patients with PTSD and PTSD+DS were found to display unique amygdala complex functional connectivity patterns to prefrontal cortex (PFC) regions involved in emotion …

Interactive Visualization Of Multimodal Brain Connectivity: Applications In Clinical And Cognitive Neuroscience, Saeed Mahdizadeh Bakhshmand

Electronic Thesis and Dissertation Repository

Magnetic resonance imaging (MRI) has become a readily available prognostic and diagnostic method, providing invaluable information for the clinical treatment of neurological diseases. Multimodal neuroimaging allows integration of complementary data from various aspects such as functional and anatomical properties; thus, it has the potential to overcome the limitations of each individual modality. Specifically, functional and diffusion MRI are two non-invasive neuroimaging techniques customized to capture brain activity and microstructural properties, respectively. Data from these two modalities is inherently complex, and interactive visualization can assist with data comprehension.

The current thesis presents the design, development, and validation of visualization and computation …

A Naturalistic Paradigm To Probe Conscious Information Processing During Sleep, Max M. Silverbrook

Electronic Thesis and Dissertation Repository

Sleep was long considered a passive mental state. The extent to which external information is integrated in, and consciously processed during sleep remains unknown. Here, simultaneous electroencephalographic (EEG) and functional magnetic resonance imaging (fMRI) data were collected from sleeping participants. First, the stimulus elicited significantly correlated fMRI activity in the auditory and fronto-parietal networks of awake participants. Behavioural testing found individuals to perceive the story’s suspense similarly. Then neural activity related to high-level processing of the story was investigated in 5 individuals who slept through it. Fronto-parietal activity in 1 individual in rapid eye movement (REM) sleep followed that of …

The Neural Mechanisms Of Musical Rhythm Processing: Cross-Cultural Differences And The Stages Of Beat Perception, Daniel J. Cameron

Electronic Thesis and Dissertation Repository

Music is a universal human behaviour, is fundamentally temporal, and has unique temporal properties. This thesis presents research on the cognitive neuroscience of the temporal aspects of music: rhythm, beat, and metre. Specifically, this work investigates how cultural experience influences behavioural and neural measures of rhythm processing, and the different neural mechanisms (with particular interest in the role of the striatum) that underlie different stages of beat perception, as musical rhythms unfold.

Chapter 1 presents an overview of the existing literature on the perceptual, cognitive, and neural processing of rhythm, including the entrainment of neural oscillations to rhythm and the …

The Neurocognitive Underpinnings Of Arithmetic In Children And Adults: Examining The Roles Of Domain General And Domain Specific Abilities, Anna A. Matejko

Electronic Thesis and Dissertation Repository

What are the cognitive underpinnings of arithmetic and how do they contribute to individual differences in children’s calculation abilities? Behavioural research has provided insights into which domain general (e.g. working memory) and domain specific (e.g. symbol-quantity associations) competencies are important for the acquisition of arithmetic skills. However, how domain general and domain specific skills are related to arithmetic at the neural level remains unclear. This thesis investigates the interplay between arithmetic and both domain general and specific competencies in the brain.

In Chapter 2 I examine how visuo-spatial working memory (VSWM) networks overlap with those for arithmetic in children and …

The Effects Of Concurrent Cognitive Load On The Processing Of Clear And Degraded Speech, Harrison Ritz

Electronic Thesis and Dissertation Repository

A previous study has found that perceiving degraded speech requires attention, with compromised behavioral and neurological measures of speech processing for degraded speech, but not clear speech, when participants are distracted (Wild et al., 2012b). We extended these findings by examining behavioral and neural correlates of speech perception under different levels of cognitive load using multiple object tracking. We also investigated the role of attention in perceiving degraded speech that was as intelligible as clear speech, in order to separate perceptual outcomes (i.e., intelligibility) from the requisite processing demands. We found that the speech perception system is heterogeneous in its …