Cognitive Neuroscience Commons^™

The Cognitive Thalamus: Source Analysis Of Scene Working Memory Delay Activity, Bernard A. Gomes

Dissertations, Theses, and Capstone Projects

Working Memory represents a limited-capacity store for maintaining information and manipulating the store's contents over a short period for the guidance of goal-directed behavior. Working Memory is an essential component of executive functions that are intricately associated with the prefrontal cortex (PFC). The PFC has been implicated in maintaining task-related information online for brief periods in the absence of relevant information. This active maintenance phase is called the delay period that occurs between encoding and retrieval of the stimulus. Previous studies have attempted to understand the relationship between working memory and the PFC, especially during the delay or maintenance phase …

Rehabilitative Movement Approaches And Dance Interventions In Parkinson’S Disease, Cecilia Fontanesi

Dissertations, Theses, and Capstone Projects

The scope of this work is to address the functional deficits and symptoms experienced by those living with Parkinson’s Disease through movement interventions.

Chapter 1 offers a brief overview of current pharmacotherapy and rehabilitation approaches in Parkinson’s, focusing on dance in particular as a movement intervention that may be particularly suited to this population.

Chapter 2 focuses on brain plasticity and motor learning in PD, reporting the effects of rTMS applied after the acquisition of a motor skill. In this study, adaptation tested in patients with PD was comparable in the sham and TMS sessions, while retention indices tested on …

Investigating The Neural Mechanisms Of Unconscious And Illusory Touch Perception, Lua Koenig

Dissertations, Theses, and Capstone Projects

Despite our everyday reliance on touch, from manipulating tools to dressing ourselves, relatively little is known about the neural correlates of tactile perception. As with other modalities, our conscious, reportable experiences of touch can dissociate from the physical tactile stimulation processed by the skin. In unconscious touch perception, tactile stimuli can be processed and guide our behavior without an accompanying conscious percept. For example, we may swat away a mosquito without having consciously registered its presence on our skin. In tactile illusions, conscious tactile experiences occur without a corresponding tactile stimulus. Multisensory tactile illusions arise when stimulation of a different …

A Glance At The Mirror: Ensemble Perception Of Symmetry, Gene Jerskey

Dissertations, Theses, and Capstone Projects

A growing body of research has demonstrated the ability of subjects to extract representative statistics from visual ensembles, images of similar but distinct groups of objects, without conscious effort or attention focused on individual members of the ensemble. When presented with ensembles, subjects have been able to accurately report the mean, range, and even distribution of various features in the ensemble. Research into ensemble perception, as it has become known, has divided mainly into studies of either low-level features, such as orientation, motion, and color, which are processed in early visual areas, at least for individual objects, or high-level features, …

The Temporal Dynamics Of Ensemble Perception, Michael L. Epstein

Dissertations, Theses, and Capstone Projects

The striking disparity between the subjective richness of experience and the considerable limitations of perceptual processing has emerged as an essential, enduring question in both vision science and philosophy of mind. A potential solution to this issue is ensemble perception: the ability for the visual system to compute the statistical summaries of object groups, effectively compressing an otherwise overwhelming amount of information. Previous work has supported that ensemble statistics can be perceived quickly and accurately for a wide range of object features. This has motivated models of ensemble perception as an early process in vision, providing an initial sense of …

The Impact Of A Single Session Of Mindfulness Meditation On The Attentional Blink In Non-Meditators, Arielle L. Klopsis

Dissertations, Theses, and Capstone Projects

Attentional resources are limited therefore a stimulus can go undetected if it closely follows another target by 200-500ms. This phenomenon is known as the attentional blink. Mindfulness meditation has been shown to be beneficial in target detection and in decreasing the attentional blink. Since there is no standard for the type of meditation or duration of practice that leads to attention benefits, this study compares the two most popular types of meditation in a group of non-meditators: focused attention and open monitoring meditation. This study utilized an attentional blink paradigm to measure if a single session of mindfulness meditation can …

Proactive And Reactive Aggression, Respiratory Sinus Arrhythmia, And Sleep In Adolescents, Allison L. Brasch

Dissertations, Theses, and Capstone Projects

Current research evaluating the relationship between proactive and reactive aggression, sleep, and autonomic dysfunction has shown inconsistencies. The unique etiologies, manifestations, and presentation of these two aggressive subtypes have garnered much speculation, and research has shown mixed, and oftentimes conflicting, results. Generally speaking, insufficient sleep has been linked to increased agitation, cognitive impairment, emotional dysregulation, and poorer physical health. Many studies have provided support for an inverse relationship existing between sleep problems and sympathovagal health, implicating hypo- or hyper-autonomic function with proactive and reactive aggression, respectively. Concurrently and conflictingly, additional research has shown support for the exact opposite relationships between …

The Effects Of Self-Esteem And Motivation On Cognitive Control, Andrea Benavides

Dissertations, Theses, and Capstone Projects

Cognitive control describes a set of mechanisms that guide behavior towards a goal (Cohen, 2017). The successful execution of cognitive control is essential for effective learning, information processing, problem solving, and academic achievement (Visu-Petra et al., 2011). The Expected Value of Control framework (EVC; Shenhav et al., 2013) suggests that control carries an inherent cost, which is weighed against the potential benefits of expending it. This cost-benefit analysis determines the direction and intensity that a goal is pursued. Importantly, motivation plays a role in this cost-benefit analysis and may function as the factor that offsets the cost of control expenditure …

Mapping The Spatial And Temporal Dynamics Of Visual Percepts Elicited By A Non-Invasive Brain Stimulation Technique, Kelly Webster

Dissertations, Theses, and Capstone Projects

While many of us rely on vision to interact with and experience the world, for people with damage or disease to the eye or visual cortex, experience through this modality is extremely limited. Brain and retinal stimulation devices show exciting promise for restoring vision, but little is understood about where and when vision percepts can be induced through stimulation. Using a non-invasive brain stimulation technique called transcranial magnetic stimulation (TMS), we characterized the spatial and temporal dynamics of perception induced through brain stimulation. In the first set of experiments, we explore the importance of higher visual and non-visual areas vs. …

Blocking Visual Awareness With Continuous Flash Suppression Prevents Cognitive Control, Jonathan Lovoi

Dissertations, Theses, and Capstone Projects

Cognitive control refers to a set of functions that allow for the execution of goal-directed behavior while remaining flexible to changes in task demands. Findings addressing whether or not awareness is necessary to elicit cognitive control are inconsistent, possibly stemming from the short stimulus presentation times employed in most masking paradigms, which could prevent sufficient processing time in some cases or provide a gist of the masked stimulus in other cases. The present study examined the necessity of awareness in cognitive control using Continuous Flash Suppression (CFS) to suppress stimulus awareness for periods of time longer than possible with other …

Neural Correlates Of Automatic Emotional Processing And Emotion Regulation In Empathy And Psychopathy-Related Coldheartedness, Danielle Difilipo

Dissertations, Theses, and Capstone Projects

Psychopathy is a personality disorder that is defined, in part, by a lack of empathy. Psychopathy-related empathic deficits have been associated with atypical behavioral and neural responses to emotional facial expressions. Although the mirror neuron system (MNS) has been implicated in empathy, very few studies have examined the role of MNS functioning as it pertains to empathy impairments in psychopathy. Moreover, there is very little empirical research regarding emotion regulation in psychopathy, and specifically whether emotional responses can be intentionally upregulated. The present study sought to clarify whether the MNS is functionally intact in adults with subclinical psychopathic traits, particularly …

The Interaction Of Attention And Memory On The Reorienting Negativity, John C. Moses

Dissertations, Theses, and Capstone Projects

The three-stage model of distraction asserts that when we are presented with salient but task-irrelevant information, our sensory systems first detect the distracting stimulus by way of sensory memory buffers, which is indicated electrophysiologically by the mismatch negativity (MMN). Following detection, attentional resources are involuntarily allocated towards the processing of the distraction, as represented by the P3a. Finally, attentional resources are shifted away from the distracting stimulus and returned to the task-relevant information, as indicated by the reorienting negativity (RON). A great deal of research has focused on this last step in the model, largely centering around defining the mechanisms …

Emotion Processing Deficits In Psychopathy: Does Cueing To Relevant Facial Features Increase Cognitive And Emotional Empathy?, Shawn E. Fagan

Dissertations, Theses, and Capstone Projects

Psychopathy is a multifaceted disorder characterized by a lack of cognitive and emotional empathy. The traditional model of psychopathy divides the disorder into two factors: Factor 1 consists of the interpersonal and affective traits of psychopathy while Factor 2 measures antisocial behaviors and lifestyle choices. The attention-to-the-eyes hypothesis argues that psychopathic individuals have impaired emotion recognition (specifically for fear) due to deficits in orienting attention to salient facial features like the eyes. Psychopathic individuals also display blunted autonomic responding to emotional stimuli, though whether this is due to attention-orienting deficits remains to be clarified. The present project investigated whether empathy-related …

Voluntary Oral Methamphetamine Reveals Susceptibilities To Spatial Memory Deficits, Decreased Dopamine Marker Expression And Increased Neuroinflammation In The Hippocampus Of Male And Female Mice, Jorge A. Avila

Dissertations, Theses, and Capstone Projects

Methamphetamine is an addictive illicit psychostimulant that produces lasting neurochemical and behavioral changes. The mechanisms underlying these deficits have been characterized in animal models using extremely high doses. Currently, better translational models are needed to understand the onset and progression of these deficits that more accurately reflect the gradual and voluntary dosing parameters as chosen by an abuser. To that end, a new model of methamphetamine administration, labeled Voluntary Oral Methamphetamine Administration (VOMA), offers a means to examine the progression of neurotoxicity, behavioral deficits, and the addiction process through a voluntary consumption framework.

Female populations show consistent vulnerabilities to methamphetamine, …

Visual Entrainment Of Perception-Related Neural Oscillations As A Mechanism For Maintaining Rhythmic Temporal Expectations Across A Wide Range Of Frequencies, Michael James Gray

Dissertations, Theses, and Capstone Projects

Visual sensitivity fluctuates rhythmically, in-synch with ongoing, EEG-recorded neural oscillations across a wide range of frequencies (~1-25hz). Some recent work has suggested that these perception-related neural oscillations can be entrained by rhythmic visual stimulation. Evidence is also emerging that the entrainment of ongoing oscillations in visual and auditory cortices is involved in rhythmic temporal expectations. In the introduction chapter, I attempt to bridge these bodies of literature and hypothesize that rhythmic visual stimuli automatically entrain ongoing, perception-related neural oscillations and that this mechanism supports the maintenance of rhythmic temporal expectations. Chapters 2 and 3 address this hypothesis from different angles. …

The 5-Ht1a-R Knockout Mouse As A Model Of Later Life Anxiety Disorders: Implications For Sex Differences, Tatyana Budylin

Dissertations, Theses, and Capstone Projects

Anxiety affects nearly twice as many women as it affects men across all cultures and economic groups. Importantly, girls have a higher chance of inheriting anxiety disorders than boys, and many anxiety disorders appear at a very young age. However, little is known about sex differences in brain and behavioral development and how they relate to anxiety in adulthood. Serotonin 1A receptor (5-HT_1A-R) mediated signaling has been implicated in depression and anxiety, however most studies that focus on the involvement of the 5-HT_1A-R have been conducted in adults. Little is known about how the 5-HT_{1A …}

Interhemispheric Communication And Lateralization In The Mouse Hippocampus, Jake Jordan

Dissertations, Theses, and Capstone Projects

The hippocampus is essential for memory and spatial navigation. Many theories have been proposed to explain how the hippocampus contributes to cognition; however, none has fully explained relevant neurophysiological and behavioral data. Hemispheric lateralization of hippocampal function has been reported in humans and in rodents, and lateralization of hippocampal neural circuitry has been reported in rodents. Most theories of hippocampal function fail to consider the hippocampus as a bilateral structure with hemispheric differences. Further, proposed theories of hippocampal lateralization have their own limitations in explaining empirical data concerning left/right function. Little is known about communication between the hippocampi across hemispheres. …

Post-Synaptic Mechanisms Of Early And Late Prepulse Inhibition In The Goldfish, Daniel Bronson

Dissertations, Theses, and Capstone Projects

Sensorimotor gating, or prepulse inhibition (PPI), attenuates the startle response during sensory processing by limiting sensory input to the startle circuit. In the goldfish startle circuit, a single action potential in the Mauthner-cell (M-cell) triggers the startle response. PPI in the M-cell is mediated by multiple post-synaptic mechanisms, including the activation of a tonic, shunting inhibition as well as a voltage-sensitive conductance, both of which briefly reduce M-cell excitability. However, the specific channels and pathways that modulate PPI are not fully known. This work further characterizes the post-synaptic conductances that mediate PPI by blocking voltage-gated and inward-rectifying potassium channels, antagonizing …

Novel Biobehavioral Methods For Assessing The Anxiety-Related Attention Bias, Samantha Denefrio

Dissertations, Theses, and Capstone Projects

Anxiety disorders will affect an estimated one in three Americans, significantly impacting emotional health and quality of life. High personal and economic costs make research on the etiology, maintenance, and treatment of anxiety a crucial public health goal. Selective and exaggerated attention towards threat, termed attention bias (AB), has been identified as a core behavioral and neurocognitive mechanism in anxiety. A novel treatment, attention bias modification training (ABMT), targets AB and aims to ameliorate anxiety. Rarely acknowledged, however, are the challenges in the conceptualization and measurement of AB. First, associations between anxiety and AB in anxious populations have been increasingly …

The Fragmented Mind: Working Memory Cannot Implement Consciousness, Javier Gomez-Lavin

Dissertations, Theses, and Capstone Projects

In both philosophy and the sciences of the mind there is a shared commitment to the idea that there is a center—the seat of consciousness, the source of deliberation and reflection, and the core of personal identity—in the mind. My dissertation challenges this deeply entrenched view. I review the empirical literature on working memory, psychology’s best candidate for the workspace of the mind, and argue that it is not a natural kind and cannot inform these central cognitive processes. This deflationary view directly imperils many naturalistic theories of consciousness that rely on working memory, which are reviewed in this project. …

The Inter-Subject Correlation Of Eeg In Response To Naturalistic Stimuli, Samantha S. Cohen

Dissertations, Theses, and Capstone Projects

Inter-subject correlation is a measure of the similarity of the brain activity of a group of people as they respond to the same naturalistic stimulus, typically a story or video, meant to simulate a real world experience. This thesis tests the hypothesis that the correlation of the brain responses of a group of people is indicative of stimulus engagement. The rationale is that the content of the stimulus drives brain activity in a consistent manner, while internal thoughts are divergent and result in uncorrelated activity. The inter-subject correlation (ISC) of neural responses have previously been assessed with fMRI, EEG, and …

Underlying Contribution Of Executive Functioning To Cognition And Academic Achievement In Individuals With Dystrophinopathy, Robert Fee

Dissertations, Theses, and Capstone Projects

Dystrophinopathy is a genetic disorder that results in the lack of or abnormal expression of the protein dystrophin. It is a disorder that alters cell structure and function, impacts the developing brain and brain function, presents with multi-domain cognitive deficits, and influences both mood and behavior. Cognitive impairments appear to be more localized to specific areas of functioning rather than a global deficit; however, deficits have been identified across multiple cognitive domains including language and aspects of executive functioning. A careful examination of the cognitive phenotype and its association to mutations affecting CNS isoforms is necessary to clarify the neuropsychological …

The Relationship Between Cognitive And Neural Bases Of Metamemory Judgments, Alexandra M. Gaynor

Dissertations, Theses, and Capstone Projects

Metamemory monitoring, the process of making subjective assessments of the status of one’s own memory, is crucial to guiding behavior and effective learning. Past cognitive research has shown that subjective confidence judgments are inferential in nature, and based on cues available at the time of the judgment. When confidence is based on cues that are related to objective memory performance, metamemory accuracy is high. However, past studies have shown that metamemory monitoring tends to be inaccurate because individuals base their confidence on information that is not predictive of memory success, such as the fluency with which items were encoded during …

Event-Related Potential Studies Of Error Monitoring To Affective And Non-Affective Stimuli In Adolescents And Emerging Adults, Rebecca K. Reed

Dissertations, Theses, and Capstone Projects

It is hypothesized that prefrontal cortex (PFC) and anterior cingulate cortex (ACC) function may be still under development in adolescents. As the generator of the error-related negativity (ERN) and the N2, the ACC is expected to be sensitive to the degree of development with age. In adults, these top-down control areas ideally serve to direct attention to goal-relevant information, which can increase the likelihood of making a correct choice, even in fast-response laboratory based tasks. However, adolescents may show increased susceptibility in these top-down control areas when the stimulus is social and emotional. In the first study, event-related potentials were …

Biological Signatures Of Emotion Regulation In Children, Sarah Myruski

Dissertations, Theses, and Capstone Projects

Emotion regulation (ER) is a key predictor of positive adjustment throughout the lifespan. Despite decades of research on discrete ER strategy use, ER may be more appropriately measured in terms of the breadth of emotional range, or the degree to which one can flexibly modulate emotional responses. Yet little is known about ER flexibility in childhood. Also, given the crucial role of caregiver support in children’s emotional lives, ER may be most accurately measured in developmentally appropriate and ecologically valid social contexts. Further, few developmental studies have capitalized on the growing evidence base surrounding biological signatures of ER. This study …

Social Influences On Songbird Behavior: From Song Learning To Motion Coordination, Iva Ljubičić

Dissertations, Theses, and Capstone Projects

Social animals learn during development how to integrate successfully into their group. How do social interactions combine to maintain group cohesion? We first review how social environments can influence the development of vocal learners, such as songbirds and humans (Chapter 1). To bypass the complexity of natural social interactions and gain experimental control, we developed Virtual Social Environments, surrounding the bird with videos of manipulated playbacks. This way we were able to design sensory and social scenarios and test how social zebra finches adjust their behavior (Chapters 2 & 3). A serious challenge is that the color output of a …

Neural Underpinnings Of Walking Under Cognitive And Sensory Load: A Mobile Brain/Body Imaging Approach, Brenda R. Malcolm

Dissertations, Theses, and Capstone Projects

Dual-task walking studies, in which individuals engage in an attentionally-demanding task while walking, have provided indirect evidence via behavioral and biomechanical measures, of the recruitment of higher-level cortical resources during gait. Additionally, recent EEG and imaging (PET, fNIRS) studies have revealed direct neurophysiological evidence of cortical contributions to steady-state walking. However, there remains a lack of knowledge regarding the underlying neural mechanisms involved in the allocation of cortical resources while walking under increased load. This dissertation presents three experiments designed to provide a greater understanding of the cortical dynamics implicated in processing load (top-down or bottom-up) during locomotion. Furthermore, we …

The Role Of Glutamate Neurotransmission In The Ventral Tegmental Area In The Expression Of Conditioned Approach Learning, Priscila Hachimine-Merli

Dissertations, Theses, and Capstone Projects

Conditioned stimuli (CSs) come to function as CSs by acquiring the capacity to activate the same mesocorticolimbic dopamine (DA) neurons activated by primary rewards, producing conditioned activation of these neurons and their associated motivational states. This model stipulates that CSs activate mesocorticolimbic DA systems through the activation of glutamate receptors on DA neurons in the ventral tegmental area (VTA). We tested the hypothesis that glutamate receptor stimulation in the VTA is necessary for the expression of conditioned approach. Rats were tested in a conditioned approach protocol that consisted of 7 consecutive conditioning sessions (light presentations and food were paired), one …

Cognitive And Neurobiological Degeneration Of The Mental Lexicon In Primary Progressive Aphasia, Jet M. J. Vonk

Dissertations, Theses, and Capstone Projects

The ease with which we use the thousands of words in our vocabulary stands in stark contrast to our difficulty establishing how they are organized in our mind and brain. The breakdown of language due to cortical atrophy in primary progressive aphasia (PPA) creates conditions to study this organization at a cognitive and neurobiological level in that the three variants of this disease, namely non-fluent, logopenic, and semantic PPA, each bear their own signature of language-specific decline and cortical atrophy. As the impaired regions in each variant are linked to different lexical and semantic attributes of words, lexical decision performance …

The Nucleus Accumbens Core Dopamine D1 And Glutamate Ampa/Nmda Receptors Play A Transient Role In The Performance Of Pavlovian Approach Behavior, Veronica Dobrovitsky

Dissertations, Theses, and Capstone Projects

The role of the nucleus accumbens core (NAc core) continues to be redefined with newly acquired data on neurochemical mechanisms mediating the learning and performance of behavior. Previous empirical data showed that dopamine transmission at the D1 receptor (D1R) plays a transient role in the expression of learned Pavlovian approach behavior. Here we show that, prior to overtraining, dopamine activity at D1Rs specifically within the NAc core is critical for the performance of approach behavior elicited by the recently-acquired reward-paired cue. Blockade of D1Rs in the NAc core, but not the dorsomedial striatum or NAc shell, disrupted approach responses during …