Neurosciences Commons^™

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 …

The Plight Of The Lucluc: Examining The Deadly Mystery Of Nodding Syndrome, Ethan K. Mcgann

Senior Honors Theses

Nodding syndrome (NS) is an emerging epidemic neurological disease that is shrouded in mystery. It is currently only found in the post-conflict regions of South Sudan, northern Uganda, and Tanzania. NS occurs in children from the ages of five to fifteen and is characterized by a loss of motor control in the neck muscles. Seizure episodes can range in intensity from atonic to tonic-clonic, and the onset of the first episode generally marks the beginning of a decline in the child’s physical and mental health. NS is a progressive disease that generally results in physical wasting, stunted growth, behavioral difficulties, …

Motor Skill Learning Between Selection And Execution., Jörn Diedrichsen, Katja Kornysheva

Brain and Mind Institute Researchers' Publications

Learning motor skills evolves from the effortful selection of single movement elements to their combined fast and accurate production. We review recent trends in the study of skill learning which suggest a hierarchical organization of the representations that underlie such expert performance, with premotor areas encoding short sequential movement elements (chunks) or particular component features (timing/spatial organization). This hierarchical representation allows the system to utilize elements of well-learned skills in a flexible manner. One neural correlate of skill development is the emergence of specialized neural circuits that can produce the required elements in a stable and invariant fashion. We discuss …

The Human Motor System Alters Its Reaching Movement Plan For Task-Irrelevant, Positional Forces., Joshua G A Cashaback, Heather R Mcgregor, Paul L Gribble

Brain and Mind Institute Researchers' Publications

The minimum intervention principle and the uncontrolled manifold hypothesis state that our nervous system only responds to force perturbations and sensorimotor noise if they affect task success. This idea has been tested in muscle and joint coordinate frames and more recently using workspace redundancy (e.g., reaching to large targets). However, reaching studies typically involve spatial and or temporal constraints. Constrained reaches represent a small proportion of movements we perform daily and may limit the emergence of natural behavior. Using more relaxed constraints, we conducted two reaching experiments to test the hypothesis that humans respond to task-relevant forces and ignore task-irrelevant …

Seasonal Change In The Avian Hippocampus., David F Sherry, Scott A Macdougall-Shackleton

Brain and Mind Institute Researchers' Publications

The hippocampus plays an important role in cognitive processes, including memory and spatial orientation, in birds. The hippocampus undergoes seasonal change in food-storing birds and brood parasites, there are changes in the hippocampus during breeding, and further changes occur in some species in association with migration. In food-storing birds, seasonal change in the hippocampus occurs in fall and winter when the cognitively demanding behaviour of caching and retrieving food occurs. The timing of annual change in the hippocampus of food-storing birds is quite variable, however, and appears not to be under photoperiod control. A variety of factors, including cognitive performance, …

Developmental Specialization Of The Left Parietal Cortex For The Semantic Representation Of Arabic Numerals: An Fmr-Adaptation Study, Stephan E. Vogel, Celia Goffin, Daniel Ansari

Brain and Mind Institute Researchers' Publications

The way the human brain constructs representations of numerical symbols is poorly understood. While increasing evidence from neuroimaging studies has indicated that the intraparietal sulcus (IPS) becomes increasingly specialized for symbolic numerical magnitude representation over developmental time, the extent to which these changes are associated with age-related differences in symbolic numerical magnitude representation or with developmental changes in non-numerical processes, such as response selection, remains to be uncovered. To address these outstanding questions we investigated developmental changes in the cortical representation of symbolic numerical magnitude in 6- to 14-year-old children using a passive functional magnetic resonance imaging adaptation design, thereby …

Different Neural Mechanisms For Causal Processing In Language And Perception: An Fmri Study, Brett B. Bankson, Dirk B. Den Ouden

Communication Sciences and Disorders Faculty Articles and Research

Information that is used to establish and evaluate causal relationships between objects and events can be gleaned from many sources, especially those that rely on language and perception. For example, sentences with a verb structure using change of state verbs such as “to break” or “to freeze” imply sequential events that express understood causal relationships. At this time, little research has examined the neural correlates of causal verb processing or has compared them to the more well researched brain activity involved in perceptual causal processing. This study investigated the extent to which the evaluation of causal verbs and causal image …

The Dissociable Effects Of Punishment And Reward On Motor Learning, Joseph M. Galea, Elizabeth Mallia, John Rothwell, Jorn Diedrichsen

Brain and Mind Institute Researchers' Publications

A common assumption regarding error-based motor learning (motor adaptation) in humans is that its underlying mechanism is automatic and insensitive to reward- or punishment-based feedback. Contrary to this hypothesis, we show in a double dissociation that the two have independent effects on the learning and retention components of motor adaptation. Negative feedback, whether graded or binary, accelerated learning. While it was not necessary for the negative feedback to be coupled to monetary loss, it had to be clearly related to the actual performance on the preceding movement. Positive feedback did not speed up learning, but it increased retention of the …

Attentional Filtering Of Visual Information By Neuronal Ensembles In The Primate Lateral Prefrontal Cortex., Sébastien Tremblay, Florian Pieper, Adam Sachs, Julio Martinez-Trujillo

Brain and Mind Institute Researchers' Publications

The activity of neurons in the primate lateral prefrontal cortex (LPFC) is strongly modulated by visual attention. Such a modulation has mostly been documented by averaging the activity of independently recorded neurons over repeated experimental trials. However, in realistic settings, ensembles of simultaneously active LPFC neurons must generate attentional signals on a single-trial basis, despite the individual and correlated variability of neuronal responses. Whether, under these circumstances, the LPFC can reliably generate attentional signals is unclear. Here, we show that the simultaneous activity of neuronal ensembles in the primate LPFC can be reliably decoded to predict the allocation of attention …

Age Related Decline In Memory: Examining The Mediation Effect Of Processing, Executive Functioning And Intelligence In Normal Adults, Jada J. Stewart

Theses and Dissertations

Multiple mediation analyses that collectively examine the prominent theories of cognitive aging (i.e., Common Cause, Processing, and Executive Decline Hypotheses) along with other cognitive domains that are sensitive to aging are rare. Moreover, having identified that cognition begins to decline as early as 30 years old, few studies have examined the mechanisms that underlie memory change among younger aging individuals. As a result, it is unclear whether relevant mediating variables have been excluded from early research on age-related memory decline, or to what extent rehabilitative strategies are applicable as early interventions for maintaining cognitive functioning into late life.

The present …

Deficits In Audiovisual Speech Perception In Normal Aging Emerge At The Level Of Whole-Word Recognition., Ryan A Stevenson, Caitlin E Nelms, Sarah H Baum, Lilia Zurkovsky, Morgan D Barense, Paul A Newhouse, Mark T Wallace

Brain and Mind Institute Researchers' Publications

Over the next 2 decades, a dramatic shift in the demographics of society will take place, with a rapid growth in the population of older adults. One of the most common complaints with healthy aging is a decreased ability to successfully perceive speech, particularly in noisy environments. In such noisy environments, the presence of visual speech cues (i.e., lip movements) provide striking benefits for speech perception and comprehension, but previous research suggests that older adults gain less from such audiovisual integration than their younger peers. To determine at what processing level these behavioral differences arise in healthy-aging populations, we administered …

Prevalence Of Increases In Functional Connectivity In Visual, Somatosensory And Language Areas In Congenital Blindness., Lizette Heine, Mohamed A Bahri, Carlo Cavaliere, Andrea Soddu, Steven Laureys, Maurice Ptito, Ron Kupers

Brain and Mind Institute Researchers' Publications

There is ample evidence that congenitally blind individuals rely more strongly on non-visual information compared to sighted controls when interacting with the outside world. Although brain imaging studies indicate that congenitally blind individuals recruit occipital areas when performing various non-visual and cognitive tasks, it remains unclear through which pathways this is accomplished. To address this question, we compared resting state functional connectivity in a group of congenital blind and matched sighted control subjects. We used a seed-based analysis with a priori specified regions-of-interest (ROIs) within visual, somato-sensory, auditory and language areas. Between-group comparisons revealed increased functional connectivity within both the …

Nicotine Receptors Mediating Sensorimotor Gating And Its Enhancement By Systemic Nicotine., Farena Pinnock, Daniel Bosch, Tyler Brown, Nadine Simons, John R Yeomans, Cleusa Deoliveira, Susanne Schmid

Brain and Mind Institute Researchers' Publications

Prepulse inhibition (PPI) of startle occurs when intensity stimuli precede stronger startle-inducing stimuli by 10-1000 ms. PPI deficits are found in individuals with schizophrenia and other psychiatric disorders, and they correlate with other cognitive impairments. Animal research and clinical studies have demonstrated that both PPI and cognitive function can be enhanced by nicotine. PPI has been shown to be mediated, at least in part, by mesopontine cholinergic neurons that project to pontine startle neurons and activate muscarinic and potentially nicotine receptors (nAChRs). The subtypes and anatomical location of nAChRs involved in mediating and modulating PPI remain unresolved. We tested the …

Prolonged In Vivo Retention Of A Cathepsin D Targeted Optical Contrast Agent In A Mouse Model Of Alzheimer's Disease., Jonatan A Snir, Mojmir Suchy, Keith St Lawrence, Robert H E Hudson, Stephen H Pasternak, Robert Bartha

Brain and Mind Institute Researchers' Publications

BACKGROUND: Cathepsin D (CatD) is a lysosomal protease that is elevated early in Alzheimer's disease (AD). We have previously developed a Targeted contrast agent (CA) to detect CatD activity in vivo, consisting of a magnetic resonance imaging/fluorescent moiety linked to a cell penetrating peptide (CPP) by means of a CatD cleavage site and have demonstrated its uptake in the brain of an AD mouse model.

OBJECTIVE: The purpose of this study was to characterize the in vivo retention of a near infra-red fluorescent dye labeled version of this CA.

METHODS: Six adult C57Bl/6 wild-type mice and six adult 5XFAD transgenic …

High-Field Functional Imaging Of Pitch Processing In Auditory Cortex Of The Cat., Blake E. Butler, Amee J Hall, Stephen G Lomber

Brain and Mind Institute Researchers' Publications

The perception of pitch is a widely studied and hotly debated topic in human hearing. Many of these studies combine functional imaging techniques with stimuli designed to disambiguate the percept of pitch from frequency information present in the stimulus. While useful in identifying potential "pitch centres" in cortex, the existence of truly pitch-responsive neurons requires single neuron-level measures that can only be undertaken in animal models. While a number of animals have been shown to be sensitive to pitch, few studies have addressed the location of cortical generators of pitch percepts in non-human models. The current study uses high-field functional …

Automatic Segmentation Of The Hippocampus For Preterm Neonates From Early-In-Life To Term-Equivalent Age., Ting Guo, Julie L Winterburn, Jon Pipitone, Emma G Duerden, Min Tae M Park, Vann Chau, Kenneth J Poskitt, Ruth E Grunau, Anne Synnes, Steven P Miller, M Mallar Chakravarty

Brain and Mind Institute Researchers' Publications

INTRODUCTION: The hippocampus, a medial temporal lobe structure central to learning and memory, is particularly vulnerable in preterm-born neonates. To date, segmentation of the hippocampus for preterm-born neonates has not yet been performed early-in-life (shortly after birth when clinically stable). The present study focuses on the development and validation of an automatic segmentation protocol that is based on the MAGeT-Brain (Multiple Automatically Generated Templates) algorithm to delineate the hippocampi of preterm neonates on their brain MRIs acquired at not only term-equivalent age but also early-in-life.

METHODS: First, we present a three-step manual segmentation protocol to delineate the hippocampus for preterm …

Are There Right Hemisphere Contributions To Visually-Guided Movement? Manipulating Left Hand Reaction Time Advantages In Dextrals., David P Carey, E Grace Otto-De Haart, Gavin Buckingham, H Chris Dijkerman, Eric L Hargreaves, Melvyn A Goodale

Brain and Mind Institute Researchers' Publications

Many studies have argued for distinct but complementary contributions from each hemisphere in the control of movements to visual targets. Investigators have attempted to extend observations from patients with unilateral left- and right-hemisphere damage, to those using neurologically-intact participants, by assuming that each hand has privileged access to the contralateral hemisphere. Previous attempts to illustrate right hemispheric contributions to the control of aiming have focussed on increasing the spatial demands of an aiming task, to attenuate the typical right hand advantages, to try to enhance a left hand reaction time advantage in right-handed participants. These early attempts have not been …

Stability Of Self-Referent Encoding Task Performance And Associations With Change In Depressive Symptoms From Early To Middle Childhood., Brandon L Goldstein, Elizabeth P Hayden, Daniel N Klein

Brain and Mind Institute Researchers' Publications

Depressed individuals exhibit memory biases on the self-referent encoding task (SRET), such that those with depression exhibit poorer recall of positive, and enhanced recall of negative, trait adjectives (referred to as positive and negative processing biases). However, it is unclear when SRET biases emerge, whether they are stable, and if biases predict, or are predicted by, depressive symptoms. To address this, a community sample of 434 children completed the SRET and a depressive symptoms measure at ages 6 and 9. Negative and positive processing exhibited low, but significant, stability. At ages 6 and 9, depressive symptoms correlated with higher negative, …

Fusion Analysis Of First Episode Depression: Where Brain Shape Deformations Meet Local Composition Of Tissue., Mahdi Ramezani, Purang Abolmaesumi, Amir Tahmasebi, Rachael Bosma, Ryan Tong, Tom Hollenstein, Kate Harkness, Ingrid Johnsrude

Brain and Mind Institute Researchers' Publications

Computational neuroanatomical techniques that are used to evaluate the structural correlates of disorders in the brain typically measure regional differences in gray matter or white matter, or measure regional differences in the deformation fields required to warp individual datasets to a standard space. Our aim in this study was to combine measurements of regional tissue composition and of deformations in order to characterize a particular brain disorder (here, major depressive disorder). We use structural Magnetic Resonance Imaging (MRI) data from young adults in a first episode of depression, and from an age- and sex-matched group of non-depressed individuals, and create …

An Fmri Comparison Of Neural Activity Associated With Recognition Of Familiar Melodies In Younger And Older Adults., Ritu Sikka, Lola L Cuddy, Ingrid S Johnsrude, Ashley D Vanstone

Brain and Mind Institute Researchers' Publications

Several studies of semantic memory in non-musical domains involving recognition of items from long-term memory have shown an age-related shift from the medial temporal lobe structures to the frontal lobe. However, the effects of aging on musical semantic memory remain unexamined. We compared activation associated with recognition of familiar melodies in younger and older adults. Recognition follows successful retrieval from the musical lexicon that comprises a lifetime of learned musical phrases. We used the sparse-sampling technique in fMRI to determine the neural correlates of melody recognition by comparing activation when listening to familiar vs. unfamiliar melodies, and to identify age …

Ego Depletion Interferes With Rule-Defined Category Learning But Not Non-Rule-Defined Category Learning., John P Minda, Rahel Rabi

Brain and Mind Institute Researchers' Publications

Considerable research on category learning has suggested that many cognitive and environmental factors can have a differential effect on the learning of rule-defined (RD) categories as opposed to the learning of non-rule-defined (NRD) categories. Prior research has also suggested that ego depletion can temporarily reduce the capacity for executive functioning and cognitive flexibility. The present study examined whether temporarily reducing participants' executive functioning via a resource depletion manipulation would differentially impact RD and NRD category learning. Participants were either asked to write a story with no restrictions (the control condition), or without using two common letters (the ego depletion condition). …

Neural Correlates Of Episodic Memory Formation In Children And Adults, Lingfei Tang

Wayne State University Theses

The medial temporal lobe (MTL) and prefrontal cortex (PFC) are two key brain regions that support episodic memory formation in both children and adults, but the functional developmental of these regions remains unclear. In this study, we investigated the development of neural correlates of episodic memory formation using functional MRI with a subsequent memory paradigm, administered to a cross-sectional sample of 83 children and adults. We found that MTL subregions showed an age-related increase in activation supporting memory formation of complex scenes. In addition, a functionally defined scene-sensitive region in the posterior MTL also showed similar increase and predicted better …

Influence Of Planning Resources On Gait Control In Parkinson’S Disease, Frederico P. Faria

Theses and Dissertations (Comprehensive)

Movement disturbances in individuals with Parkinson’s disease (PD) have been associated with difficulties to plan complex actions. Performance of simple and complex actions overloads resources for individuals with Parkinson’s disease (PD). However, it is unclear if central resources required to plan gait adjustments while walking exacerbate gait disturbances of patients with PD. More specifically, it is unclear how gait impairments, sensory processing, and the dopaminergic system influence the load on processing resources (e.g. cognitive load) during the planning of step modifications. In order to investigate the relative influence of these factors on cognitive load and its impact on gait control, …

Effects Of Nicotine Withdrawal On Motivation, Reward Sensitivity And Reward-Learning, Jason A. Oliver

USF Tampa Graduate Theses and Dissertations

Research on addictive behavior has traditionally emphasized the role that primary reinforcing effects of drugs of abuse plays in the development and maintenance of dependence. However, contemporary behavioral economic theory and animal models of nicotine dependence suggest the need for greater attention to the impact that response to alternative rewards may have on smoking behavior. The present study sought to investigate the impact of nicotine withdrawal on self-report, behavioral and neural indices of motivation, immediate response to rewards and the capacity to learn and modify behavior in response to positive and negative feedback. Heavy smokers (n = 48) completed two …

Development Of An Avian Model For Identifying Individual Differences In Drug Vulnerability, Beth A. Rice

Theses and Dissertations--Psychology

The attribution of incentive salience to cues that become associated with drugs of abuse is a critical characteristic of individuals who may be vulnerable to drug addiction. Rodents with the propensity to sign track are thought to be vulnerable to drug abuse. The goal of the current work was to investigate whether sign trackers (STs) would acquire cocaine conditioned place preference (CPP) to a discrete cue using an avian species. In Experiment 1, sign and goal trackers (GTs) were first identified using a one third rank order split. Following identification, cocaine-CPP was conducted with a discrete cue in each end …

Attentional Allocation In Language Processing In Adults Who Stutter: Erp Evidence, Wendy Lorraine Olsen

USF Tampa Graduate Theses and Dissertations

The aim of this study was to investigate how young adults who stutterer allocate attentional resources during two linguistic stages in picture naming, specifically lemma and lexeme retrieval. This study reports on behavioral and brain electrophysiological data collected during a simple auditory oddball task and a Dual Picture-Word Interference/Tone Monitoring Task.

Hemispheric Asymmetry In The Perception Of Musical Pitch Structure, Matthew Adam Rosenthal

UNLV Theses, Dissertations, Professional Papers, and Capstones

Both the left and right hemispheres contribute to the perception of pitch structure

in music. Music researchers have attempted to explain the observed asymmetries in the perception of musical pitch structure by characterizing the dominant processing style of each hemisphere. However, no existing characterizations have been able to account for all of the empirical findings. To better explain existing empirical findings, this dissertation characterizes the left hemisphere as dominant in temporal pitch processing (i.e. with respect to the sequential ordering of pitches) and the right hemisphere as dominant in non-temporal pitch processing (i.e. without respect to the sequential ordering of …

On Reporting The Onset Of The Intention To Move, Uri Maoz, Liad Mudrik, Ram Rivlin, Ian Ross, Adam Mamelak, Gideon Yaffe

Psychology Faculty Books and Book Chapters

"In 1965, Hans Kornhuber and Luder Deecke made a discovery that greatly influenced the study of voluntary action. Using electroencephalography (EEG), they showed that when aligning some tens of trials to movement onset and averaging, a slowly decreasing electrical potential emerges over central regions of the brain. It starts 1 second ( s) or so before the onset of the voluntary action1 and continues until shortly after the action begins. They termed this the Bereitschaftspotential, or readiness potential (RP; Kornhuber & Deecke, 1965).2 This became the first well-established neural marker of voluntary action. In that, the RP allowed for more …

Developmental Differences In The Influence Of Phonological Similarity On Spoken Word Processing In Mandarin Chinese., Jeffrey G Malins, Danqi Gao, Ran Tao, James R Booth, Hua Shu, Marc F Joanisse, Li Liu, Amy S Desroches

Brain and Mind Institute Researchers' Publications

The developmental trajectory of spoken word recognition has been well established in Indo-European languages, but to date remains poorly characterized in Mandarin Chinese. In this study, typically developing children (N=17; mean age 10; 5) and adults (N=17; mean age 24) performed a picture-word matching task in Mandarin while we recorded ERPs. Mismatches diverged from expectations in different components of the Mandarin syllable; namely, word-initial phonemes, word-final phonemes, and tone. By comparing responses to different mismatch types, we uncovered evidence suggesting that both children and adults process words incrementally. However, we also observed key developmental differences in how subjects treated onset …