Neuroscience and Neurobiology Commons^™

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 …

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 …

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 …

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 …

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, …

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 …

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). …

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 …

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 …

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 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 …

The Neural And Cognitive Basis Of Cumulative Lifetime Familiarity Assessment, Devin Duke

Electronic Thesis and Dissertation Repository

Perirhinal cortex (PrC) has been implicated as a brain region in the medial temporal lobes (MTL) that critically contributes to familiarity-based recognition memory, a process that allows for recognition to occur independently of contextual recollection. Informed by neurophysiological research in non-human primates, fMRI, as well as behavioural work in humans, the current thesis research tests the novel hypothesis that PrC cortex functioning also underlies the ability to assess cumulative lifetime familiarity with object concepts that are characterized by a lifetime of experiences. In Chapter 2, a patient (NB) with a left anterior temporal lobe (ATL) lesion that included PrC as …

Hierarchical Organization In Auditory Cortex Of The Cat Using High-Field Functional Magnetic Resonance Imaging, Amee J. Hall

Electronic Thesis and Dissertation Repository

Sensory localization within cortex is a widely accepted and documented principle. Within cortices dedicated to specific sensory information there is further organization. For example, in visual cortices a more detailed functional division and hierarchical organization has been recorded in detail. This organization starts with areas dedicated to analysis of simple visual stimuli. Areas higher in the organization are specialized for processing of progressively more complex stimuli. A similar hierarchical organization has been proposed within auditory cortex and a wealth of evidence supports this hypothesis. In the cat, the initial processing of simple auditory stimuli, such as pure tones, has been …

Characterizing Persistent Developmental Dyscalculia: A Cognitive Neuroscience Approach, Stephanie D. Bugden

Electronic Thesis and Dissertation Repository

Developmental dyscalculia (DD) is a specific learning disorder of calculation abilities. In the present thesis I report a series behavioural and functional neuroimaging studies to further elucidate the core numerical deficits underlying DD. I recruited a sample of children with DD who demonstrated persistent impairments in arithmetic. In Chapter 2, to validate the selection criteria, I compared the performance of children with and without persistent DD on a test of numerical magnitude processing. The data showed that only children with persistent DD presented with deficits in numerical magnitude processing, while those with inconsistent DD perform at the level of age-matched …

Advances In Image Acquisition And Filtering For Mri Neuroimaging At 7 Tesla, Andrew T. Curtis

Electronic Thesis and Dissertation Repository

Performing magnetic resonance imaging at high magnetic field strength promises many improvements over low fields that are of direct benefit in functional neuroimaging. This includes the possibility of improved signal-to-noise levels, and increased BOLD functional contrast and spatial specificity. However, human MRI at 7T and above suffers from unique engineering challenges that limit the achievable gains. In this thesis, three technological developments are introduced, all of which address separate issues associated with functional magnetic resonance neuroimaging at very high magnetic field strengths.

First, the image homogeneity problem is addressed by investigating methods of RF shimming — modifying the excitation portion …

Neural Circuits Involved In Mental Arithmetic: Evidence From Customized Arithmetic Training, Christian Battista

Electronic Thesis and Dissertation Repository

An arithmetic training study was conducted using a novel paradigm known as Customized Arithmetic Training (CAT). Using the CAT system, self-reports obtained from the participants were used to generate individually tailored problem sets. These problem sets balanced strategy use such that each participant started with an equal amount of problems solved by fact retrieval (e.g., 2 + 2 = 4) and an equal amount of problems solved by procedural calculation (e.g., 34 + 37). Following the training period, participants solved trained and untrained problems from their customized arithmetic sets while undergoing an fMRI scan, after which they again provided self-reported …

The Influence Of Proficiency And Age Of Acquisition On Second Language Processing: An Fmri Study Of Mandarin-English Bilinguals, Emily S. Nichols

Electronic Thesis and Dissertation Repository

Research investigating the neural correlates of second language (L2) processing has usually studied age of acquisition (AoA) and proficiency separately. Presently, we examined both in parallel, treated as continuous variables. We used fMRI to study neural activity for L2 processing in adult native Mandarin speakers who are L2 English speakers. Behavioral measures of language proficiency and AoA were obtained from subjects prior to performing a picture-word matching task during an fMRI scan. Brain activity during L2 English processing was shown to be independently affected by AoA and proficiency; activity in left superior temporal gyrus and right parahippocampal gyrus was modulated …

Flexibly Adapting To Emotional Cues: Examining The Functional And Structural Correlates Of Emotional Reactivity And Emotion Control In Healthy And Depressed Individuals, Steven G. Greening

Electronic Thesis and Dissertation Repository

The ability of emotionally significant stimuli to bias our behaviour is an evolutionarily adaptive phenomenon. However, sometimes emotions become excessive, inappropriate, and even pathological, like in major depressive disorder (MDD). Emotional flexibility includes both the neural processes involved in reacting to, or representing, emotional significance, and those involved in controlling emotional reactivity. MDD represents a potentially distinct form of emotion (in)flexibility, and therefore offers a unique perspective for understanding both the integration of conflicting emotional cues and the neural regions involved in actively controlling emotional systems.

The present investigation of emotional flexibility began by considering the functional neural correlates of …

Fmri Reveals The Neural Correlates Of Real And Pantomimed Tool Use In Humans, Joseph Umberto Paciocco

Electronic Thesis and Dissertation Repository

Although functional magnetic resonance imaging (fMRI) can be used to study the neural mechanisms underlying greatly expanded cognitive functions in humans like tool use, surprisingly little fMRI research has been done on actual tool use. In fact, due to technical constraints, most fMRI studies have used pantomimed actions as a proxy for real use. However, human neuropsychology patients who are impaired at pantomiming often improve when handling a tool suggesting potential neural differences. We used fMRI to record brain activation while 13 right-handed participants performed one of two tasks, real or pantomime tool use with one of two tools, a …

Symbolizing Number: Fmri Investigations Of The Semantic, Auditory, And Visual Correlates Of Hindu-Arabic Numerals, Ian Douglas Holloway

Electronic Thesis and Dissertation Repository

Humans are born with a sensitivity to numerical magnitude. In literate cultures, these numerical intuitions are associated with a symbolic notation (e.g..Hindu-Arabic numerals). While a growing body of neuroscientific research has been conducted to elucidate commonalities between symbolic (e.g. Hinud-Arabic numerals) and non-symbolic (e.g. arrays of objects) representations, relatively little is known about the neural correlates specific to the symbolic processing of numerical magnitude. To address this, I conducted the three fMRI experiments contained within this thesis to characterize the neuroanatomical correlates of the auditory, visual, audiovisual, and semantic processing of numerical symbols.

In Experiment 1, the neural correlates of …

Brain Connectivity Studied By Fmri: Homologous Network Organization In The Rat, Monkey, And Human, R. Matthew Hutchison

Electronic Thesis and Dissertation Repository

The mammalian brain is composed of functional networks operating at different spatial and temporal scales — characterized by patterns of interconnections linking sensory, motor, and cognitive systems. Assessment of brain connectivity has revealed that the structure and dynamics of large-scale network organization are altered in multiple disease states suggesting their use as diagnostic or prognostic indicators. Further investigation into the underlying mechanisms, organization, and alteration of large-scale brain networks requires homologous animal models that would allow neurophysiological recordings and experimental manipulations. My current dissertation presents a comprehensive assessment and comparison of rat, macaque, and human brain networks based on evaluation …

Decoding Motor Intentions From Human Brain Activity, Jason P. Gallivan

Electronic Thesis and Dissertation Repository

“You read my mind.” Although this simple everyday expression implies ‘knowledge or understanding’ of another’s thinking, true ‘mind-reading’ capabilities implicitly seem constrained to the domains of Hollywood and science-fiction. In the field of sensorimotor neuroscience, however, significant progress in this area has come from mapping characteristic changes in brain activity that occur prior to an action being initiated. For instance, invasive neural recordings in non-human primates have significantly increased our understanding of how highly cognitive and abstract processes like intentions and decisions are represented in the brain by showing that it is possible to decode or ‘predict’ upcoming sensorimotor …