Neurosciences Commons^™

Greater Magnocellular Saccadic Suppression In High Versus Low Autistic Tendency Suggests A Causal Path To Local Perceptual Style., David P Crewther, Daniel Crewther, Stephanie Bevan, Melvyn A Goodale, Sheila G Crewther

Brain and Mind Institute Researchers' Publications

Saccadic suppression-the reduction of visual sensitivity during rapid eye movements-has previously been proposed to reflect a specific suppression of the magnocellular visual system, with the initial neural site of that suppression at or prior to afferent visual information reaching striate cortex. Dysfunction in the magnocellular visual pathway has also been associated with perceptual and physiological anomalies in individuals with autism spectrum disorder or high autistic tendency, leading us to question whether saccadic suppression is altered in the broader autism phenotype. Here we show that individuals with high autistic tendency show greater saccadic suppression of low versus high spatial frequency gratings …

Neurophysiological Activity Related To Speech Production: An Erp Investigation, Adithya Chandregowda

USF Tampa Graduate Theses and Dissertations

The event related potential (ERP) technique is enjoying widespread application in neurophysiological research due to its fine temporal resolution. Of relevance to this study are ERPs related to voluntary movements. The precision with which movement related processes could be recorded using the ERP technique was demonstrated by Gilden, Vaughan and Costa (1966) and Kutas and Donchin (1974, 1977, and 1980) who found that the readiness potential (RP) immediately preceding hand movement was larger over the hemisphere contralateral to the responding hand. Given that left hemisphere controls right hand movements and vice versa, their findings confirmed that the lateralized readiness potential …

An Animal Model Of Flashbulb Memory: Insights Into The Time-Dependent Mechanisms Of Memory Enhancement, Laura Ashley Bullard

USF Tampa Graduate Theses and Dissertations

The vivid memory of an emotional event, as well as memory for incidental details associated with the arousing event, has been referred to collectively as a “flashbulb memory”. An important aspect of flashbulb memory in people is that an emotional event enhances memory of contextual details, such as the weather, or clothes one was wearing at the time of the event. Therefore, an emotional event not only produces a detailed memory of the event, itself, but also enhances memory for contextual details that would otherwise not be remembered. The first goal of this work is to describe the development of …

Functional Differences Between Statistical Learning With And Without Explicit Training., Laura J Batterink, Paul J Reber, Ken A Paller

Brain and Mind Institute Researchers' Publications

Humans are capable of rapidly extracting regularities from environmental input, a process known as statistical learning. This type of learning typically occurs automatically, through passive exposure to environmental input. The presumed function of statistical learning is to optimize processing, allowing the brain to more accurately predict and prepare for incoming input. In this study, we ask whether the function of statistical learning may be enhanced through supplementary explicit training, in which underlying regularities are explicitly taught rather than simply abstracted through exposure. Learners were randomly assigned either to an explicit group or an implicit group. All learners were exposed to …

Dual Optimization Method Of Radiofrequency And Quasistatic Field Simulations For Reduction Of Eddy Currents Generated On 7t Radiofrequency Coil Shielding., Yujuan Zhao, Tiejun Zhao, Shailesh B Raval, Narayanan Krishnamurthy, Hai Zheng, Chad T Harris, William B Handler, Blaine A Chronik, Tamer S Ibrahim

Brain and Mind Institute Researchers' Publications

PURPOSE: To optimize the design of radiofrequency (RF) shielding of transmit coils at 7T and reduce eddy currents generated on the RF shielding when imaging with rapid gradient waveforms.

METHODS: One set of a four-element, 2 × 2 Tic-Tac-Toe head coil structure was selected and constructed to study eddy currents on the RF coil shielding. The generated eddy currents were quantitatively studied in the time and frequency domains. The RF characteristics were studied using the finite difference time domain method. Five different kinds of RF shielding were tested on a 7T MRI scanner with phantoms and in vivo human subjects. …

Behavioral, Perceptual, And Neural Alterations In Sensory And Multisensory Function In Autism Spectrum Disorder., Sarah H Baum, Ryan A Stevenson, Mark T Wallace

Brain and Mind Institute Researchers' Publications

Although sensory processing challenges have been noted since the first clinical descriptions of autism, it has taken until the release of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) in 2013 for sensory problems to be included as part of the core symptoms of autism spectrum disorder (ASD) in the diagnostic profile. Because sensory information forms the building blocks for higher-order social and cognitive functions, we argue that sensory processing is not only an additional piece of the puzzle, but rather a critical cornerstone for characterizing and understanding ASD. In this review we discuss what …

Differential Modification Of Cortical And Thalamic Projections To Cat Primary Auditory Cortex Following Early- And Late-Onset Deafness., Nicole Chabot, Blake E Butler, Stephen G Lomber

Brain and Mind Institute Researchers' Publications

Following sensory deprivation, primary somatosensory and visual cortices undergo crossmodal plasticity, which subserves the remaining modalities. However, controversy remains regarding the neuroplastic potential of primary auditory cortex (A1). To examine this, we identified cortical and thalamic projections to A1 in hearing cats and those with early- and late-onset deafness. Following early deafness, inputs from second auditory cortex (A2) are amplified, whereas the number originating in the dorsal zone (DZ) decreases. In addition, inputs from the dorsal medial geniculate nucleus (dMGN) increase, whereas those from the ventral division (vMGN) are reduced. In late-deaf cats, projections from the anterior auditory field (AAF) …

Preserved Haptic Shape Processing After Bilateral Loc Lesions., Jacqueline C Snow, Melvyn A Goodale, Jody C Culham

Brain and Mind Institute Researchers' Publications

UNLABELLED: The visual and haptic perceptual systems are understood to share a common neural representation of object shape. A region thought to be critical for recognizing visual and haptic shape information is the lateral occipital complex (LOC). We investigated whether LOC is essential for haptic shape recognition in humans by studying behavioral responses and brain activation for haptically explored objects in a patient (M.C.) with bilateral lesions of the occipitotemporal cortex, including LOC. Despite severe deficits in recognizing objects using vision, M.C. was able to accurately recognize objects via touch. M.C.'s psychophysical response profile to haptically explored shapes was also …

Maternal Postsecondary Education Associated With Improved Cerebellar Growth After Preterm Birth., Mikaela L Stiver, Daphne Kamino, Ting Guo, Angela Thompson, Emma G Duerden, Margot J Taylor, Emily W Y Tam

Brain and Mind Institute Researchers' Publications

The preterm cerebellum is vulnerable to impaired development impacting long-term outcome. Preterm newborns (<32 >weeks) underwent serial magnetic resonance imaging (MRI) scans. The association between parental education and cerebellar volume at each time point was assessed, adjusting for age at scan. In 26 infants, cerebellar volumes at term (P = .001), but not birth (P = .4), were associated with 2-year volumes. For 1 cm(3) smaller cerebellar volume (4% total volume) at term, the cerebellum was 3.18 cm(3) smaller (3% total volume) by 2 years. Maternal postsecondary education was not associated with cerebellar volume at term (P = .16). Maternal …

A Neurobiological Pathway That Mediates Stress-Induced Drug Use, Oliver Vranjkovic

Dissertations (1934 -)

Cocaine addiction represents a tremendous health and financial burden on our society and the high rate of relapse to cocaine use in abstinent addicts represents a major barrier to effective therapy. Thus, understanding the factors that contribute to relapse and the underlying neurobiological processes is important for guiding the development of treatment for addiction. Stressful life events often trigger drug use in recovering addicts. The contribution of stress to drug use is problematic due to the unpredictable and often uncontrollable nature of stress. A growing literature indicates that norepinephrine and corticotropin releasing factor (CRF) in the brain play key roles …

Finding The Engram., Sheena A Josselyn, Stefan Köhler, Paul W Frankland

Brain and Mind Institute Researchers' Publications

Many attempts have been made to localize the physical trace of a memory, or engram, in the brain. However, until recently, engrams have remained largely elusive. In this Review, we develop four defining criteria that enable us to critically assess the recent progress that has been made towards finding the engram. Recent 'capture' studies use novel approaches to tag populations of neurons that are active during memory encoding, thereby allowing these engram-associated neurons to be manipulated at later times. We propose that findings from these capture studies represent considerable progress in allowing us to observe, erase and express the engram.

Relationships Between Age And White Matter Integrity In Children With Phenylketonuria, Erika M. Wesonga

Arts & Sciences Electronic Theses and Dissertations

Objective: Phenylketonuria (PKU) is a hereditary metabolic disorder associated with cognitive compromise. Diffusion tensor imaging (DTI) has allowed detection of poorer microstructural white matter integrity in children with PKU, with decreased mean diffusivity (MD) in comparison with healthy children. However, very little research has been conducted to examine the trajectory of white matter development in this population. The present study investigated potential differences in the developmental trajectory of MD between children with early- and continuously-treated PKU and healthy children across a range of brain regions.

Methods: Children with PKU (n = 31, mean age = 12.2 years) were …

Tract-Based Spatial Statistics In Preterm-Born Neonates Predicts Cognitive And Motor Outcomes At 18 Months., E G Duerden, J Foong, V Chau, H Branson, K J Poskitt, R E Grunau, A Synnes, J G Zwicker, S P Miller

Brain and Mind Institute Researchers' Publications

BACKGROUND AND PURPOSE: Adverse neurodevelopmental outcome is common in children born preterm. Early sensitive predictors of neurodevelopmental outcome such as MR imaging are needed. Tract-based spatial statistics, a diffusion MR imaging analysis method, performed at term-equivalent age (40 weeks) is a promising predictor of neurodevelopmental outcomes in children born very preterm. We sought to determine the association of tract-based spatial statistics findings before term-equivalent age with neurodevelopmental outcome at 18-months corrected age.

MATERIALS AND METHODS: Of 180 neonates (born at 24-32-weeks' gestation) enrolled, 153 had DTI acquired early at 32 weeks' postmenstrual age and 105 had DTI acquired later at …

Implicit And Explicit Contributions To Statistical Learning., Laura J Batterink, Paul J Reber, Helen J Neville, Ken A Paller

Brain and Mind Institute Researchers' Publications

Statistical learning allows learners to detect regularities in the environment and appears to emerge automatically as a consequence of experience. Statistical learning paradigms bear many similarities to those of artificial grammar learning and other types of implicit learning. However, whether learning effects in statistical learning tasks are driven by implicit knowledge has not been thoroughly examined. The present study addressed this gap by examining the role of implicit and explicit knowledge within the context of a typical auditory statistical learning paradigm. Learners were exposed to a continuous stream of repeating nonsense words. Learning was tested (a) directly via a forced-choice …

Transient Visual Responses Reset The Phase Of Low-Frequency Oscillations In The Skeletomotor Periphery., Daniel K Wood, Chao Gu, Brian D Corneil, Paul L Gribble, Melvyn A Goodale

Brain and Mind Institute Researchers' Publications

We recorded muscle activity from an upper limb muscle while human subjects reached towards peripheral targets. We tested the hypothesis that the transient visual response sweeps not only through the central nervous system, but also through the peripheral nervous system. Like the transient visual response in the central nervous system, stimulus-locked muscle responses (< 100 ms) were sensitive to stimulus contrast, and were temporally and spatially dissociable from voluntary orienting activity. Also, the arrival of visual responses reduced the variability of muscle activity by resetting the phase of ongoing low-frequency oscillations. This latter finding critically extends the emerging evidence that the feedforward visual sweep reduces neural variability via phase resetting. We conclude that, when sensory information is relevant to a particular effector, detailed information about the sensorimotor transformation, even from the earliest stages, is found in the peripheral nervous system.

The Effect Of Sleep On Perceptual Learning And Memory Consolidation, Vanessa Claire Irsik

UNLV Theses, Dissertations, Professional Papers, and Capstones

An ability to segregate speech accurately is essential given that most auditory environments contain other overlapping conversations or environmental noise. While perceiving speech among background noise can be difficult in and of itself, those with hearing impairments can experience considerable difficulty. While training has been shown to benefit perceptual segregation of trained sounds, it is unclear how such training transfers to sounds not included in a training regimen. The current study aimed to address this question by training listeners on a portion of sounds during a vowel segregation task, and subsequently testing on both the trained sounds and untrained sounds. …

Halting The Hallmarks: A Cellular Automaton Model Of Early Cancer Growth Inhibition, Jenna Butler, Frances Mackay, Colin Denniston, Mark Daley

Brain and Mind Institute Researchers' Publications

Cancer treatment is a fragmented and varied process, as ‘‘cancer’’ is really hundreds of different diseases. The ‘‘hallmarks of cancer’’ proposed by Hanahan and Weinberg (Cell 100(1):57–70, 2000) are a framework for viewing cancer within a common set of underlying principles—ten properties that are common to almost all cancers, allowing them to grow uncontrollably and ravage the body. We used a cellular automaton model of tumour growth paired with lattice Boltzmann methods modelling oxygen flow to simulate combination drugs targeted at knocking out pairs of hallmarks. We found that knocking out some pairs of cancer-enabling hallmarks did not prevent tumour …

Disruption Of White Matter Integrity In Adult Survivors Of Childhood Brain Tumors: Correlates With Long-Term Intellectual Outcomes, Tricia Z. King, Liya Wang, Hui Mao

Psychology Faculty Publications

Background

Although chemotherapy and radiation treatment have contributed to increased survivorship, treatment-induced brain injury has been a concern when examining long-term intellectual outcomes of survivors. Specifically, disruption of brain white matter integrity and its relationship to intellectual outcomes in adult survivors of childhood brain tumors needs to be better understood.

Methods

Fifty-four participants underwent diffusion tensor imaging in addition to structural MRI and an intelligence test (IQ). Voxel-wise group comparisons of fractional anisotropy calculated from DTI data were performed using Tract Based Spatial Statistics (TBSS) on 27 survivors (14 treated with radiation with and without chemotherapy and 13 treated without …

Genomic Copy Number Variation In Mus Musculus., M Elizabeth O Locke, Maja Milojevic, Susan T Eitutis, Nisha Patel, Andrea E Wishart, Mark Daley, Kathleen A. Hill

Brain and Mind Institute Researchers' Publications

BACKGROUND: Copy number variation is an important dimension of genetic diversity and has implications in development and disease. As an important model organism, the mouse is a prime candidate for copy number variant (CNV) characterization, but this has yet to be completed for a large sample size. Here we report CNV analysis of publicly available, high-density microarray data files for 351 mouse tail samples, including 290 mice that had not been characterized for CNVs previously.

RESULTS: We found 9634 putative autosomal CNVs across the samples affecting 6.87% of the mouse reference genome. We find significant differences in the degree of …

Hand Use Predicts The Structure Of Representations In Sensorimotor Cortex., Naveed Ejaz, Masashi Hamada, Jörn Diedrichsen

Brain and Mind Institute Researchers' Publications

Fine finger movements are controlled by the population activity of neurons in the hand area of primary motor cortex. Experiments using microstimulation and single-neuron electrophysiology suggest that this area represents coordinated multi-joint, rather than single-finger movements. However, the principle by which these representations are organized remains unclear. We analyzed activity patterns during individuated finger movements using functional magnetic resonance imaging (fMRI). Although the spatial layout of finger-specific activity patterns was variable across participants, the relative similarity between any pair of activity patterns was well preserved. This invariant organization was better explained by the correlation structure of everyday hand movements than …

Changes In Visual And Sensory-Motor Resting-State Functional Connectivity Support Motor Learning By Observing., Heather R Mcgregor, Paul L Gribble

Brain and Mind Institute Researchers' Publications

Motor learning occurs not only through direct first-hand experience but also through observation (Mattar AA, Gribble PL. Neuron 46: 153-160, 2005). When observing the actions of others, we activate many of the same brain regions involved in performing those actions ourselves (Malfait N, Valyear KF, Culham JC, Anton JL, Brown LE, Gribble PL. J Cogn Neurosci 22: 1493-1503, 2010). Links between neural systems for vision and action have been reported in neurophysiological (Strafella AP, Paus T. Neuroreport 11: 2289-2292, 2000; Watkins KE, Strafella AP, Paus T. Neuropsychologia 41: 989-994, 2003), brain imaging (Buccino G, Binkofski F, Fink GR, Fadiga L, …

Dualism And Doctrine, Dov Fox, Alex Stein

Indiana Law Journal

What kinds of harm among those that tortfeasors inflict are worthy of compensation? Which forms of self-incriminating evidence are privileged against government compulsion? What sorts of facts constitute a criminal defendant’s intent? Existing doctrine pins the answer to all of these questions on whether the injury, facts, or evidence at stake are “mental” or “physical.” The assumption that operations of the mind are meaningfully distinct from those of the body animates fundamental rules in our law.

A tort victim cannot recover for mental harm on its own because the law presumes that he is able to unfeel any suffering arising …

Neural Plasticity In Response To Intervention In Adolescents With Autism Spectrum Disorders, Sheryl Jayne Stevens

Dissertations (1934 -)

Current theories of Autism Spectrum Disorders (ASD) suggest that they may develop from the transactional interaction between biological risk factors and environmental processes (Dawson et al., 2009). Due to the brain’s experience-expectant nature, one’s degree of social exposure may have a significant impact on their brain development and behavioral presentation. In addition to the primary critical neurodevelopmental period identified in early childhood, recent research has demonstrated a second period of substantial neurodevelopment during the adolescent period (Sisk & Foster, 2004). This study investigated the neural and behavioral impact of participation in an empirically validated behavioral intervention (The Program for the …

Embracing Multiple Definitions Of Learning, Andrew B. Barron, Eileen A. Hebets, Thomas A. Cleland, Courtney L. Fitzpatrick, Mark E. Hauber, Jeffrey R. Stevens

Eileen Hebets Publications

Definitions of learning vary widely across disciplines, driven largely by different approaches used to assess its occurrence. These definitions can be better reconciled with each other if each is recognized as coherent with a common conceptualization of learning, while appreciating the practical utility of different learning definitions in different contexts.

Learning is a major focus of research in psychology, neuro- science, behavioral ecology, evolutionary theory, and computer science, as well as in many other disciplines. Despite its conceptual prevalence, definitions of learning differ enormously both within and between these disciplines, and new definitions continue to be proposed [1]. Ongoing disputes …

Fusion Analysis Of Functional Mri Data For Classification Of Individuals Based On Patterns Of Activation., Mahdi Ramezani, Purang Abolmaesumi, Kris Marble, Heather Trang, Ingrid Johnsrude

Brain and Mind Institute Researchers' Publications

Classification of individuals based on patterns of brain activity observed in functional MRI contrasts may be helpful for diagnosis of neurological disorders. Prior work for classification based on these patterns have primarily focused on using a single contrast, which does not take advantage of complementary information that may be available in multiple contrasts. Where multiple contrasts are used, the objective has been only to identify the joint, distinct brain activity patterns that differ between groups of subjects; not to use the information to classify individuals. Here, we use joint Independent Component Analysis (jICA) within a Support Vector Machine (SVM) classification …

Relative Reward Effects On Operant Behavior: Incentive Contrast,Induction And Variety Effects, Howard Cromwell

Howard Casey Cromwell

Comparing different rewards automatically produces dynamic relative outcome effects on behavior. Eachnew outcome exposure is to an updated version evaluated relative to alternatives. Relative reward effectsinclude incentive contrast, positive induction and variety effects. The present study utilized a novelbehavioral design to examine relative reward effects on a chain of operant behavior using auditory cues.Incentive contrast is the most often examined effect and focuses on increases or decreases in behavioralperformance after value upshifts (positive) or downshifts (negative) relative to another outcome. Weexamined the impact of comparing two reward outcomes in a repeated measures design with three ses-sions: a single outcome and …

Connectionist Perspectives On Language Learning, Representation And Processing., Marc F Joanisse, James L Mcclelland

Brain and Mind Institute Researchers' Publications

The field of formal linguistics was founded on the premise that language is mentally represented as a deterministic symbolic grammar. While this approach has captured many important characteristics of the world's languages, it has also led to a tendency to focus theoretical questions on the correct formalization of grammatical rules while also de-emphasizing the role of learning and statistics in language development and processing. In this review we present a different approach to language research that has emerged from the parallel distributed processing or 'connectionist' enterprise. In the connectionist framework, mental operations are studied by simulating learning and processing within …

Functional Capacity In Schizophrenia: Relationship Among Effort, Reinforcement Learning And Self-Beliefs, Sally J. Vogel

UNLV Theses, Dissertations, Professional Papers, and Capstones

Individuals with schizophrenia exhibit a wide range of complex neurocognitive, psychiatric and behavioral impairments. Recent research suggests that this complex array of symptoms can be at least partially accounted for by dysfunction in more basic mechanisms, such as the ability to learn from positive and negative reinforcement, or the ability to exert adequate effort when completing simple tasks. Evidence also suggests that deficits in these basic mechanisms may contribute to more complex symptoms, such as functional impairment. Also, the relationship between neurocognitive deficits and functional impairment has been found to be mediated by defeatist performance beliefs. However, studies have not …

A Comparison Of The Effects Of Different Doses Of Gabab Receptor Ligands On Spatial Learning And Memory And Memory Flexibility, Chelcie Heaney

UNLV Theses, Dissertations, Professional Papers, and Capstones

The principal inhibitory neurotransmitter in the brain, gamma amino-butyric acid (GABA), mediates several types of learning and memory. Of the two main receptor subtypes for GABA, the in vivo role of GABAB receptor in learning and memory is less well characterized and the current data often conflict. Based on the current literature, it is unclear, for instance, whether enhancing GABAergic activity via the GABAB receptor could be beneficial for or detrimental to learning and memory. Hippocampally-dependent learning and memory tasks are of particular interest due to their clinical relevance to patients with schizophrenia or Alzheimer’s disease, who exhibit impaired performance …

Cetaceans And Primates: Convergence In Intelligence And Self-Awareness, Lori Marino

Lori Marino, PhD

Cetaceans (dolphins, porpoises and whales) have been of greatest interest to the astrobiology community and to those interested in consciousness and selfawareness in animals. This interest has grown primarily from knowledge of the intelligence, language and large complex brains that many cetaceans possess. The study of cetacean and primate brain evolution and cognition can inform us about the contingencies and parameters associated with the evolution of complex intelligence in general, and, the evolution of consciousness. Striking differences in cortical organization in the brains of cetaceans and primates along with shared cognitive capacities such as self-awareness, culture, and symbolic concept comprehension, …