Neurosciences Commons^™

Mechanisms Of Value-Biased Prioritization In Fast Sensorimotor Decision Making, Kivilcim Afacan-Seref

Dissertations and Theses

In dynamic environments, split-second sensorimotor decisions must be prioritized according to potential payoffs to maximize overall rewards. The impact of relative value on deliberative perceptual judgments has been examined extensively, but relatively little is known about value-biasing mechanisms in the common situation where physical evidence is strong but the time to act is severely limited. This research examines the behavioral and electrophysiological indices of how value biases split-second perceptual decisions and the possible mechanisms underlying the process. In prominent decision models, a noisy but statistically stationary representation of sensory evidence is integrated over time to an action-triggering bound, and value-biases …

Brain Development: Why The Young Sleep Longer, Budhaditya Chowdhury, Orie T. Shafer

Advanced Science Research Center

From absorbing new languages to mastering musical instruments, young children are wired to learn in ways that adults are not (Johnson and Newport, 1989). This ability coincides with periods of intense brain plasticity during which neurons can easily remodel their connections (Hubel and Wiesel, 1970). Many children are also scandalously good sleepers, typically getting several more hours of sleep per night than their parents (Jenni and Carskadon, 2007). As sleep deprivation has negative effects on learning and memory, learning like a child likely requires sleeping like one (Diekelmann and Born, 2010). Yet, how the ability to sleep for longer is …

Inference Of Language Functional Network In Healthy, Cancerous And Bilingual Brains By Fmri And Network Modeling, Qiongge Li

Dissertations, Theses, and Capstone Projects

We study the underlying mechanism by which language processing occurs in the human brain using inference methods on functional magnetic resonance imaging data. The data analyzed stems from several cohorts of subjects; a monolingual group, a bilingual group, a healthy control group and one diseased case. We applied a complex statistical inference pipeline to determine the network structure of brain components involved with language. This healthy network reveals a fully connected triangular relationship between the pre-Supplementary Motor Area (pre-SMA), the Broca's Area (BA), and the ventral Pre-Motor Area (PreMA) in the left hemisphere. This "triangle'' shows consistently in all the …

Electroencephalographic Asymmetry, Emotion Regulation, And Their Relationships With Depression Risk, Aliza Jacob

Dissertations, Theses, and Capstone Projects

Background: Research investigating patterns of electroencephalographic (EEG) brain asymmetry aids our understanding of neural systems involved in the processing of emotion, motivation, and psychopathology. Withdrawal-motivated negative emotions characteristic of depression are associated with relative right prefrontal cortex (PFC) activity, whereas approach- motivated positive emotions are associated with relative left PFC activity. Styles of emotion regulation (ER), or modulation of the intensity and duration of emotional responses, are also associated with presence (e.g., suppression, or maladaptive ER) versus absence (e.g., cognitive reappraisal, or adaptive ER) of depression vulnerability. Most PFC asymmetry studies of emotion, depression, and/or ER rely upon EEG recorded …

Competitive Frontoparietal Interactions Mediate Implicit Inferences, Martijn E. Wokke, Tony Ro

Publications and Research

Frequent experience with regularities in our environment allows us to use predictive information to guide our decision process. However, contingencies in our environment are not always explicitly present and sometimes need to be inferred. Heretofore, it remained unknown how predictive information guides decision-making when explicit knowledge is absent and how the brain shapes such implicit inferences. In the present experiment, 17 human participants (9 females) performed a discrimination task in which a target stimulus was preceded by a predictive cue. Critically, participants had no explicit knowledge that some of the cues signaled an upcoming target, allowing us to investigate how …

Effects Of The Kcnq Channel Opener Ezogabine On Functional Connectivity Of The Ventral Striatum And Clinical Symptoms In Patients With Major Depressive Disorder, Aaron Tan, Sara Costi, Laurel S. Morris, Nicholas T. Van Dam, Marin Kautz, Alexis E. Whitton, Allyson K. Friedman, Katherine A. Collins, Gabriella Ahle, Nisha Chadha, Brian Do, Diego A. Pizzagalli, Dan V. Iosifescu, Eric J. Nestler, Ming-Hu Han, James W. Murrough

Publications and Research

Major depressive disorder (MDD) is a leading cause of disability worldwide, yet current treatment strategies remain limited in their mechanistic diversity. Recent evidence has highlighted a promising novel pharmaceutical target—the KCNQ-type potassium channel—for the treatment of depressive disorders, which may exert a therapeutic effect via functional changes within the brain reward system, including the ventral striatum. The current study assessed the effects of the KCNQ channel opener ezogabine (also known as retigabine) on reward circuitry and clinical symptoms in patients with MDD. Eighteen medication-free individuals with MDD currently in a major depressive episode were enrolled in an open-label study and …

Anterior Insular Cortex Plays A Critical Role In Interoceptive Attention, Xingchao Wang, Qiong Wu, Laura Egan, Xiaosu Gu, Pinan Liu, Hong Gu, Yihong Yang, Jing Luo, Yanhong Wu, Zhixian Gao, Jin Fan

Publications and Research

Accumulating evidence indicates that the anterior insular cortex (AIC) mediates interoceptive attention which refers to attention towards physiological signals arising from the body. However, the necessity of the AIC in this process has not been demonstrated. Using a novel task that directs attention toward breathing rhythm, we assessed the involvement of the AIC in interoceptive attention in healthy participants using functional magnetic resonance imaging and examined the necessity of the AIC in interoceptive attention in patients with AIC lesions. Results showed that interoceptive attention was associated with increased AIC activation, as well as enhanced coupling between the AIC and somatosensory …

Transspinal Stimulation Increases Motoneuron Output Of Multiple Segments In Human Spinal Cord Injury, Lynda M. Murray, Maria Knikou

Publications and Research

Targeted neuromodulation strategies that strengthen neuronal activity are in great need for restoring sensorimotor function after chronic spinal cord injury (SCI). In this study, we established changes in the motoneuron output of individuals with and without SCI after repeated noninvasive transspinal stimulation at rest over the thoracolumbar enlargement, the spinal location of leg motor circuits. Cases of motor incomplete and complete SCI were included to delineate potential differences when corticospinal motor drive is minimal. All 10 SCI and 10 healthy control subjects received daily monophasic transspinal stimuli of 1-ms duration at 0.2 Hz at right soleus transspinal evoked potential (TEP) …

Testing A Cognitive Control Model Of Human Intelligence, Yu Chen, Alfredo Spagna, Tingting Wu, Tae Hyeong Kim, Qiong Wu, Caiqi Chen, Yanhong Wu, Jin Fan

Publications and Research

The definition of human intelligence and its underlying psychological constructs have long been debated. Although previous studies have investigated the fundamental cognitive functions determining intellectual abilities, such as the broadly defined executive functions including working memory, the core process has yet to be identified. A potential candidate for such a role might be cognitive control, a psychological construct for the coordination of thoughts and actions under conditions of uncertainty. In this study, we tested a cognitive control model of intellectual ability by examining the association between cognitive control, measured by a perceptual decision-making task and by the attention network test, …

Translational Modeling Of Non-Invasive Electrical Stimulation, Dennis Quangvinh Truong

Dissertations and Theses

Seminal work in the early 2000’s demonstrated the effect of low amplitude non-invasive electrical stimulation in people using neurophysiological measures (motor evoked potentials, MEPs). Clinical applications of transcranial Direct Current Stimulation (tDCS) have since proliferated, though the mechanisms are not fully understood. Efforts to refine the technique to improve results are on-going as are mechanistic studies both in vivo and in vitro. Volume conduction models are being applied to these areas of research, especially in the design and analysis of clinical montages. However, additional research on the parameterization of models remains.

In this dissertation, Finite Element Method (FEM) models of …

Using Fundamental Properties Of Light To Investigate Photonic Effects In Condensed Matter And Biological Tissues, Laura A. Sordillo

Dissertations and Theses

Light possesses characteristics such as polarization, wavelength and coherence. The interaction of light and matter, whether in a semiconductor or in a biological sample, can reveal important information about the internal properties of a system. My thesis focuses on two areas: photocarriers in gallium arsenide and biomedical optics. Varying the excitation wavelength can be used to study both biological tissue and condensed matter. I altered the excitation wavelengths to be in the longer near-infrared (NIR) optical windows, in the shortwave infrared (SWIR) range, a wavelength region previously thought to be unusable for medical imaging. With this method, I acquired high …

Resting-State Functional Connectivity In Youth With Gender Dysphoria, Felix L. Garcia

Dissertations, Theses, and Capstone Projects

Current developmental models of gender identity and gender dysphoria (GD) lack sex-specific profiles of brain function that differentiate between typically-developing and cross-gender identified youth, as postulated by models like the unified theory of the origins of sex differences (Arnold, 2009) and the neurobiological theory of the origins of transsexuality (Swaab & Garcia-Falgueras, 2009). Previously, investigators have used brain imaging modalities such as Resting-State functional Magnetic Resonance Imaging (R-fMRI) to demonstrate differences in resting-state functional connectivity (RSFC) between typically-developing male and female youth, and between typically-developing and GID-diagnosed youth. In the present pilot study, I used R-fMRI to investigate differences in …

Spinal Control Of Locomotion: Individual Neurons, Their Circuits And Functions, Marie-Pascale Côté, Lynda M. Murray, Maria Knikou

Publications and Research

Systematic research on the physiological and anatomical characteristics of spinal cord interneurons along with their functional output has evolved for more than one century. Despite significant progress in our understanding of these networks and their role in generating and modulating movement, it has remained a challenge to elucidate the properties of the locomotor rhythm across species. Neurophysiological experimental evidence indicates similarities in the function of interneurons mediating afferent information regarding muscle stretch and loading, being affected by motor axon collaterals and those mediating presynaptic inhibition in animals and humans when their function is assessed at rest. However, significantly different muscle …

Multiple Sclerosis Identification Based On Fractional Fourier Entropy And A Modified Jaya Algorithm, Shui-Hua Wang, Hong Cheng, Preetha Phillips, Yu-Dong Zhang

Publications and Research

Aim: Currently, identifying multiple sclerosis (MS) by human experts may come across the problem of “normal-appearing white matter”, which causes a low sensitivity. Methods: In this study, we presented a computer vision based approached to identify MS in an automatic way. This proposed method first extracted the fractional Fourier entropy map from a specified brain image. Afterwards, it sent the features to a multilayer perceptron trained by a proposed improved parameter-free Jaya algorithm. We used cost-sensitivity learning to handle the imbalanced data problem. Results: The 10 × 10-fold cross validation showed our method yielded a sensitivity of 97.40 ± 0.60%, …

Increased Salience Network Activity In Patients With Insomnia Complaints In Major Depressive Disorder, Chun-Hong Liu, Jing Guo, Shun-Li Lu, Li-Rong Tang, Jin Fan, Chuan-Yue Wang, Lihong Wang, Qing-Quan Liu, Cun-Zhi Liu

Publications and Research

Background:

Insomnia is one of the main symptom correlates of major depressive disorder (MDD), but the neural mechanisms underlying the multifaceted interplay between insomnia and depression are not fully understood.

Materials and methods:

Patients with MDD and high insomnia (MDD-HI, n = 24), patients with MDD and low insomnia (MDD-LI, n = 37), and healthy controls (HCs, n = 51) were recruited to participate in the present study. The amplitude of low-frequency fluctuations (ALFF) during the resting state were compared among the three groups.

Results:

We observed ALFF differences between the three groups in the right inferior frontal gyrus/anterior insula …

Transspinal Direct Current Stimulation Produces Persistent Plasticity In Human Motor Pathways, Lynda M. Murray, Behdad Tahayori, Maria Knikou

Publications and Research

The spinal cord is an integration center for descending, ascending, and segmental neural signals. Noninvasive transspinal stimulation may thus constitute an effective method for concomitant modulation of local and distal neural circuits. In this study, we established changes in cortical excitability and input/output function of corticospinal and spinal neural circuits before, at 0–15 and at 30–45 minutes after cathodal, anodal, and sham transspinal direct current stimulation (tsDCS) to the thoracic region in healthy individuals. We found that intracortical inhibition was different among stimulation polarities, however remained unchanged over time. Intracortical facilitation increased after cathodal and anodal tsDCS delivered with subjects …

Functional Dissociation Of The Posterior And Anterior Insula In Moral Disgust, Xiaoping Ying, Jing Luo, Chi-Yue Chiu, Yanhong Wu, Yan Xu, Jin Fan

Publications and Research

The insula is thought to be involved in disgust. However, the roles of the posterior insula (PI) and anterior insula (AI) in moral disgust have not been clearly dissociated in previous studies. In this functional magnetic resonance imaging study, the participants evaluated the degree of disgust using sentences related to mild moral violations with different types of behavioral agents (mother and stranger). The activation of the PI in response to the stranger agent was significantly higher than that in response to the mother agent. In contrast, the activation of the AI in response to the mother agent was significantly higher …

Saccade Adaptation Deficits In Developmental Dyslexia Suggest Disruption Of Cerebellar-Dependent Learning, Edward G. Freedman, Sophie Molholm, Michael J. Gray, Daniel Belyusar, John J. Foxe

Publications and Research

Background: Estimates of the prevalence of developmental dyslexia in the general population range from 5% to as many as 10%. Symptoms include reading, writing, and language deficits, but the severity and mix of symptoms can vary widely across individuals. In at least some people with dyslexia, the structure and function of the cerebellum may be disordered. Saccadic adaptation requires proper function of the cerebellum and brainstem circuitry and might provide a simple, noninvasive assay for early identification and sub-phenotyping in populations of children who may have dyslexia.

Methods: Children between the ages of 7 and 15 served as participants in …

Spinal Excitability Changes After Transspinal And Transcortical Paired Associative Stimulation In Humans, Maria Knikou

Publications and Research

Paired associative stimulation (PAS) produces enduring neuroplasticity based on Hebbian associative plasticity. This study established the changes in spinal motoneuronal excitability by pairing transcortical and transspinal stimulation. Transcortical stimulation was delivered after (transspinal-transcortical PAS) or before (transcortical-transspinal PAS) transspinal stimulation. Before and after 40 minutes of each PAS protocol, spinal neural excitability was assessed based on the amplitude of the transspinal-evoked potentials (TEPs) recorded from ankle muscles of both legs at different stimulation intensities (recruitment input-output curve). Changes in TEPs amplitude in response to low-frequency stimulation and paired transspinal stimuli were also established before and after each PAS protocol. TEP …

Whose Expertise Is It? Evidence For Autistic Adults As Critical Autism Experts, Kristen Gillespie-Lynch, Steven K. Kapp, Patricia J. Brooks, Jonathan Pickens, Ben Schwartzman

Publications and Research

Autistic and non-autistic adults’ agreement with scientific knowledge about autism, how they define autism, and their endorsement of stigmatizing conceptions of autism has not previously been examined. Using an online survey, we assessed autism knowledge and stigma among 636 adults with varied relationships to autism, including autistic people and nuclear family members. Autistic participants exhibited more scientifically based knowledge than others. They were more likely to describe autism experientially or as a neutral difference, and more often opposed the medical model. Autistic participants and family members reported lower stigma. Greater endorsement of the importance of normalizing autistic people was associated …

Remodeling Brain Activity By Repetitive Cervicothoracic Transspinal Stimulation After Human Spinal Cord Injury, Lynda M. Murray, Maria Knikou

Publications and Research

Interventions that can produce targeted brain plasticity after human spinal cord injury (SCI) are needed for restoration of impaired movement in these patients. In this study, we tested the effects of repetitive cervicothoracic transspinal stimulation in one person with cervical motor incomplete SCI on cortical and corticospinal excitability, which were assessed via transcranial magnetic stimulation with paired and single pulses, respectively. We found that repetitive cervicothoracic transspinal stimulation potentiated intracortical facilitation in flexor and extensor wrist muscles, recovered intracortical inhibition in the more impaired wrist flexor muscle, increased corticospinal excitability bilaterally, and improved voluntary muscle strength. These effects may have …

Statistical Learning In Specific Language Impairment And Autism Spectrum Disorder: A Meta-Analysis, Rita Obeid, Patricia J. Brooks, Kasey L. Powers, Kristen Gillespie-Lynch, Jarrad A. G. Lum

Publications and Research

Impairments in statistical learning might be a common deficit among individuals with Specific Language Impairment (SLI) and Autism Spectrum Disorder (ASD). Using metaanalysis, we examined statistical learning in SLI (14 studies, 15 comparisons) and ASD (13 studies, 20 comparisons) to evaluate this hypothesis. Effect sizes were examined as a function of diagnosis across multiple statistical learning tasks (Serial Reaction Time, Contextual Cueing, Artificial Grammar Learning, Speech Stream, Observational Learning, and Probabilistic Classification). Individuals with SLI showed deficits in statistical learning relative to age-matched controls. In contrast, statistical learning was intact in individuals with ASD relative to controls. Effect sizes did …

The Relationship Between Lexical Performance And Regional Gray Matter Volumes: A Longitudinal Study Of Cognitively Healthy Elderly, Jungmoon Hyun

Dissertations, Theses, and Capstone Projects

This study investigated the longitudinal relationship among aging, performance on lexical tasks, and regional gray matter volumes over 2-7 years. A total of 137 older participants who remained cognitively normal were administered four lexical tasks at each time point: the Boston Naming Test (BNT), Vocabulary Test, Semantic- and Phonemic-Fluency task. In addition, they underwent repeated magnetic resonance imaging (MRI) scanning acquired within two months of the lexical tasks. The average interval between time points was 2.36 years (range 1.50-7.64) and the average number of time points was 2.65 times (range 2-5).

Results indicated that age differentially affects lexical task performance …

Modulation Of Gamma And Alpha Spinal Motor Neurons Activity By Trans-Spinal Direct Current Stimulation: Effects On Reflexive Actions And Locomotor Activity, Zaghloul Ahmed

Publications and Research

Spontaneous and evoked spinal activities interact to set the characteristics of emergent motor responses. Gamma motor neurons have feedforward and feedback functions in motor control, which are crucial for transforming motor commands into action. Meanwhile, the intrinsic excitability and functional connectivity of alpha motor neurons determine the accuracy of actions. In this study, we investigated the effects of trans-spinal direct current stimulation (tsDCS) on spontaneous and cortically evoked activity of well-isolated single units of gamma and alpha motor neurons in mice. We also investigated the effects of tsDCS on reflexive and locomotor actions. In general, motor neurons showed increased responses …

Theory Of Mind Indexes The Broader Autism Phenotype In Siblings Of Children With Autism At School Age, Tawny Tsang, Kristen Gillepsie-Lynch, Ted Huntman

Publications and Research

Subclinical variants of the social-communicative challenges and rigidity that define autism spectrum disorder (ASD) are known as the broader autism phenotype (BAP). The BAP has been conceptualized categorically (as specific to a subset of relatives of individuals with ASD) and dimensionally (as continuously distributed within the general population). The current study examined the compatibility of these two approaches by assessing associations among autism symptoms and social-communicative skills in young school-age children with ASD, children who have a sibling with ASD, and children without a sibling with ASD. Autism symptomswere associated with reducedTheory ofMind (ToM), adaptive skills, cognitive empathy, and language …

Dynamics Of Alpha Control: Preparatory Suppression Of Posterior Alpha Oscillations By Frontal Modulators Revealed With Combined Eeg And Event-Related Optical Signal, Kyle E. Mathewson, Diane M. Beck, Tony Ro, Edward L. Maclin, Kathy A. Low, Monica Fabiani, Gabriele Gratton

Publications and Research

We investigated the dynamics of brain processes facilitating conscious experience of external stimuli. Previously, we proposed that alpha (8–12 Hz) oscillations, which fluctuate with both sustained and directed attention, represent a pulsed inhibition of ongoing sensory brain activity. Here we tested the prediction that inhibitory alpha oscillations in visual cortex are modulated by top–down signals from frontoparietal attention networks. We measured modulations in phase-coherent alpha oscillations from superficial frontal, parietal, and occipital cortices using the event-related optical signal (EROS), a measure of neuronal activity affording high spatiotemporal resolution, along with concurrently recorded EEG, while participants performed a visual target detection …

Direct Control Of Visual Perception With Phase-Specific Modulation Of Posterior Parietal Cortex, Andrew Jaegle, Tony Ro

Publications and Research

We examined the causal relationship between the phase of alpha oscillations (9–12 Hz) and conscious visual perception using rhythmic TMS (rTMS) while simultaneously recording EEG activity. rTMS of posterior parietal cortex at an alpha frequency (10 Hz), but not occipital or sham rTMS, both entrained the phase of subsequent alpha oscillatory activity and produced a phase-dependent change on subsequent visual perception, with lower discrimination accuracy for targets presented at one phase of the alpha oscillatory waveform than for targets presented at the opposite phase. By extrinsically manipulating the phase of alpha before stimulus presentation, we provide direct evidence that the …

Three‐Dimensional Brain Mri For Dbs Patients Within Ultra‐Low Radiofrequency Power Limits, Subhendra N. Sarkar, Efstathios Papavassiliou, David Hackney, David Alsop, Ananth Madhuranthakam, Ludy Shih, Reed Busse, Susan Laruche, Rafeeque Bhadelia

Publications and Research

Background: For patients with deep brain stimulators (DBS), local absorbed radiofrequency (RF) power is unknown and is much higher than what the system estimates. We developed a comprehensive, highquality brain magnetic resonance imaging (MRI) protocol for DBS patients utilizing three-dimensional (3D) magnetic resonance sequences at very low RF power. Methods: Six patients with DBS were imaged (10 sessions) using a transmit/receive head coil at 1.5 Tesla with modified 3D sequences within ultra-low specific absorption rate (SAR) limits (0.1 W/kg) using T2, fast fluid-attenuated inversion recovery (FLAIR) and T1- weighted image contrast. Tissue signal and tissue contrast from the low-SAR images …

Neural Basis Of Emotional Decision Making In Trait Anxiety, Pengfei Xu, Ruolei Gu, Lucas S. Broster, Runguo Wu, Nicholas T. Van Dam, Yang Jiang, Jin Fan, Yue-Jia Luo

Publications and Research

Although trait anxiety has been associated with risk decision making, whether it is related to risk per se or to the feeling of the risk, as well as the underlying neurocognitive mechanisms, remains unclear. Using a decision-making task with a manipulation of frame (i.e., written description of options as a potential gain or loss) and functional magnetic resonance imaging, we investigated the neurocognitive relationship between trait anxiety and decision making. The classic framing effect was observed: participants chose the safe option when it was described as a potential gain, but they avoided the same option when it was described as …

Gender Differences Associated With Orienting Attentional Networks In Healthy Subjects, Gang Liu, Pan-Pan Hu, Jin Fan, Kai Wang

Publications and Research

Background: Selective attention is considered one of the main components of cognitive functioning. A number of studies have demonstrated gender differences in cognition. This study aimed to investigate the gender differences in selective attention in healthy subjects. Methods: The present experiment examined the gender differences associated with the efficiency of three attentional networks: alerting, orienting, and executive control attention in 73 healthy subjects (38 males). All participants performed a modified version of the Attention Network Test (ANT). Results: Females had higher orienting scores than males (t=2.172, P < 0.05). Specifically, females were faster at covert orienting of attention to a spatially cued location. There were no gender differences between males and females in alerting (t=0.813, P >0.05) and executive control (t=0.945, P >0.05) attention networks. Conclusions: There was a …