Beatriz Luna - US grants

The aim of this career development plan is for the applicant to acquire the skills necessary to characterize changes in brain function subserving the acquisition of higher-order executive cognitive functions during late childhood and adolescence. This period is the time when higher-order cognitive abilities such as abstract thought, goal directed planning, and voluntary inhibitory control begin to achieve adult levels concurrently with significant reorganization of neural connectivity in neocortex. These higher level cognitive skills fail to develop normally in several major psychiatric disorders of presumed neurodevelopmental origin. These crucial cognitive and brain maturational processes during late childhood and adolescence are very poorly understood, and the field needs broadly trained developmental investigators to begin comprehensive and programmatic studies of this important epoch. In order to establish a research career dedicated to elucidating the neural substrates of normal and abnormal cognitive development, the applicant will obtain additional training in: 1) cognitive and other developmental processes pertinent to the time period of interest, 2) skills in designing and implementing a broader ranger of cognitive and imaging methodologies sensitive to developmental changes during this period, and 3) clinical aspects of neuropsychiatric disorders with a neurodevelopmental changes during this period, and 3) clinical aspects of neuropsychiatric disorders with a neurodevelopmental basis. She will also initiate a series of studies to examine patters of development in cognition and brain organization using tasks that probe spatial working memory, voluntary response suppression and attention shifting abilities both behaviorally and using fMRI. Studies at the end of the research program will begin to investigate abnormal development in autism and individuals at familial risk for schizophrenia. To the extent that the proposed research program can elucidate the developmental trajectories of pivotal executive functions, the proposed line of work can potentially provide crucial information needed for designing more effective programs for the early recognition, treatment, and preention of psychopathology.

DESCRIPTION (provided by applicant): We do not yet understand how brain and cognitive processes integrate to support the emergence of healthy adult-level cognitive control of behavior, subsequently;our understanding of neurodevelopmental models of psychiatric illnesses is also limited. The broad goal of this application is to gain knowledge regarding the neurobiological basis of cognitive development from childhood to adulthood. We propose to use well-established cognitive neuroscience methods, devised to investigate the link between basic cognitive processes and brain processes. Oculomotor and neuropsychological tasks will be performed by 132 eight to 22 year-old healthy subjects in a hybrid cross-sectional longitudinal design that will span 15 years of development. A subgroup of 88 subjects will also participate in whole-brain fMRI and DTI studies. The aim of this proposal is to delineate the shape, peak, and variability of cognitive development, characterize how it is subserved by changes in brain activation, and identify the maturation of brain connectivity that supports the transition to adult level brain circuitry. Based on our preliminary findings from an NIMH-funded K01 award and review of the literature, we hypothesize that response inhibition, working memory, and multi-level cognitive processes, such as high level planning, will continue to improve throughout adolescence as widely distributed brain function integrating cortical and subcortical systems emerges supported by increases in indices of myelination connecting these regions. Different rates of development will be characterized by a unique profile of subject characteristics related to puberty, IQ, and gender. Developmental improvements in the performance of multi-level cognitive tasks will be supported by the independent maturation of response inhibition and working memory. This work will result in a normative template of the maturation of basic cognitive control, which will be significant in identifying impairments of cognitive maturation in developmental psychopathologies, including schizophrenia and mood disorders that emerge in adolescence.

DESCRIPTION (provided by applicant): Reward processing is a crucial component of decision making and has implications for risk taking behavior, mood disorders, and substance abuse. Adolescence is a period of development when risk taking behavior peaks and mood disorders and substance abuse can emerge. We do not yet have a clear understanding of how reward and punishment alter behavior in adolescence. We have even less of an understanding of how reward/punishment influences the brain circuitry that is recruited to make decisions at this developmental stage. We propose to study 120 ten to 20 year-old healthy subjects in a hybrid longitudinal/cross-sectional design that spans ten years of development. We will assess the developmental changes related to the effects of monetary incentives on the ability to suppress task inappropriate responses, using eye movements as a model system. Using fMRI, we will investigate developmental changes in the recruitment of frontostriatal circuitry supporting reward/punishment processing and characterize how these affect known mechanisms supporting cognitive control. Diffusion Tensor Imaging (DTI) will be used to assess the contribution of myelination to observed changes in the recruitment of frontostriatal circuitry and subsequent behavioral changes with development. Associations between these results and age, pubertal status, gender, and sensation seeking indices will be investigated to account for individual variability in developmental trajectories. This work will result in a normative template of the maturation of reward/punishment processes through adolescence, a critical step toward understanding vulnerabilities in the adolescent brain for risk taking behavior, mood disorders, and substance abuse. PUBLIC HEALTH RELEVANCE: Adolescence is a period marked by an increase in risk-taking behavior (substance abuse, unprotected sex, extreme sports) that has lead to a strikingly high mortality rate. Additionally, most major psychiatric illnesses emerge during the period of transition from adolescence to adulthood. We propose studies that can inform these literatures by providing information regarding the limitations and vulnerabilities in brain processing present in adolescence and how these affect reward assessment and decision making.

DESCRIPTION (provided by applicant): The current proposal is a continuation from a parent grant focused on characterizing the neural basis of cognitive control through adolescence. Core cognitive control abilities are available during adolescence however there are continued refinements into adulthood in the reliability and flexibility of its use supporting optimal decision making. These immaturities appear to be the result of a still developing and vulnerable neural system that can lead to suboptimal decision making leading to increased risk taking, and susceptibility for the emergence of major psychopathology including mood disorders and schizophrenia. A growing literature has provided compelling evidence for immaturities in the function of specific brain regions underlying cognitive control in adolescence. Importantly, emerging evidence strongly indicates that these may be the result of immaturities in the functional integration of large-scale and highly specialized neural networks. Thus far, investigations of network-level function and integration have been hampered by limitations in spatial and temporal domains in unimodal neuroimaging approaches. We propose to use a multimodal approach where parallel studies using fMRI to accurately identify functionally relevant neural regions, DTI to characterize white matter structural connectivity between key regions, and MEG to delineate neural synchrony at high temporal resolution, will enable us to obtain an integrated and comprehensive understanding of the emergence of specific neural networks underlying behavior (Aim 1). In addition, limitations in decision making are often present in the context of emotional contexts, which may be especially relevant during adolescence. As such, we also want to investigate the effects of affect-related physiological arousal on cognitive control (Aim 2). Finally, risk taking behavior does not terminate at the end of adolescence, persisting through the college years. This suggests that key neural immaturities may continue into young adulthood, a period that is yet to be explored. In light of this, we propose to follow a subset of participants from the parent grant into young adulthood and characterize a trajectory of cognitive control that encompasses 10 years (Aim 3). Together, these studies will provide an integrated view of the maturation of systems level functioning and its vulnerabilities informing the biological bases of normative aberrant behavior in adolescence and the emergence of psychopathology. This proposal is novel in its multimodal, cross sectional and longitudinal approach, the implications of which has enormous potential for informing crucial aspects of the nature of development.

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The human brain is a complex, hierarchical network, in which billions of neurons are interconnected to form functional units that support complex behaviors. Cognitive functions likely arise and are constrained by dynamic neural activity propagating along this hierarchical network. The efficiency, accuracy, and stability of cognitive functions undergo significant development in the first 2 decades of life. Understanding how human functional brain networks develop during this critical developmental period will provide important insights into the relationship between brain function and the emergence of mature cognitive abilities. The goal of the current study is to characterize the development of human functional brain networks using graph-theoretic analyses. We will analyze resting-state functional magnetic resonance imaging (fMRI) data collected from 87 participants ages 8-22 years old. Resting-state fMRI measures the intrinsic, high-amplitude, low-frequency signal fluctuations of the brain, and high correlations among distant brain regions reflect functional connectivity. We will analyze functional brain networks by constructing whole-brain correlation matrices from resting-state fMRI data for each subject. We will further utilize graph-theoretic approaches to characterize the network topology of functional brain networks. Network measures of interest include centrality, path, clustering, efficiency, and small-worldness. Finally, network measures will be compared across age groups to characterize fully the development of functional brain networks. Graph theory analyses will be run using a C++ commandline application developed by our laboratory that utilizes two open-source libraries: GNU Scientific Library and Brain Connectivity ToolboxC++. The application compiles using the GNU C/C++ compiler (version 4.4.4 on our local machines). The application is designed to calculate all metrics of interest for a single subject and is single-threaded. Each subjects dataset is a square matrix approximately 1.5GB in size. The application requires approximately 200 hours to run per subject and uses 1.5-4GB RAM depending upon the calculation. We also hope to utilize the Teragrid supercomputer to calculate the optimal edge density for three aggregated datasets, with each dataset requiring approximately 300 hours to run.

DESCRIPTION (provided by applicant): Adolescence is a unique period of development characterized by heightened risk-taking indicating continued limitations in cognitive control and reward related behaviors as well as vulnerabilities for the emergence of psychopathology. Studies have shown significant developmental changes in frontostriatal function underlying reward and cognitive behaviors from adolescence to adulthood. However, the core mechanisms influencing the development of these processes are not well understood. Dopamine (DA) is a key neurotransmitter in the modulation of cognitive and reward-related processing in frontostriatal regions of the brain. During adolescence, the DA system demonstrates unique immaturities which may contribute to limitations in reward processing during this time. Imaging genetics studies have shown that subtle allelic variations in specific genes that directly impact DA processing, can have profound impact on behaviorally relevant neural activity. How genetically-driven variability in DA processing interacts with age-related differences in DA availablity are not well understood limiting our ability to understand variability in developmental trajectories of motivated complex behavior. Incorporating imaging genetics with brain-imaging studies during adolescent development can help clarify known age-related differences in reward processing and cognitive control as well as contribute to our basic understanding of DA's effect on behavior. Two crucial enzymes involved in the synaptic trafficking of DA and likely to have impact on reward and cognitive control systems are catechol-o-methyltransferase (COMT) and the dopamine transporter (DAT1). Because these enzymes have differential effects on PFC and striatum, investigating effects of their genotypic variation offers a new way to examine the integrity of frontostriatal networks. We will obtain saliva samples from subjects in our ongoing parent grant investigating behavioral and neuroimaging evidence for the effects of reward processing on the development of cognitive control. We will study a single nucleotide polymorphism (val158met) in the COMT gene, and a variable-nucleotide tandem repeat (VNTR) polymorphism of the SLC6A3 gene within the context of the development neural systems underlying incentive-based cognitive control. The specific aims of this revision are to 1) characterize the influence of genetically-driven DA variation expressed through SLC6A3 and COMT on brain function underlying reward processing and cognitive control; 2) To identify differences in the influence of genetically- driven variation on resulting behaviorally-relevant neural circuitry in adolescence compared to adulthood. Multiple regression and multi-variate imaging statistics methodologies will be used to explore age and genotype effects and interactions. This integrative neuroscience approach will allow greater understanding of associations between genes and the function of behaviorally relevant neural systems and support inferences about resulting behavioral implications, within a framework of adolescent development. PUBLIC HEALTH RELEVANCE: We propose to investigate biological mechanisms underlying the development of cognitive control and reward processing over adolescence. Results from this research can inform developmental neuroscience, education, and clinical approaches by elucidating the brain basis of inter-individual differences in adolescent behavior. The knowledge acquired can provide a normative template of the range of processes underlying adolescent motivated behavior that can be used to better characterize this period of development in order to identify neurobiological mechanisms of risk taking behavior that can undermine survival.

Impairments in attenfion and working memory are core disturbances in schizophrenia. The Central Hypothesis posits that these arise due to molecular (Project 1) and morphological (Project 2) abnormalifies in the layer 3 pyramidal cells that that interconnect the dorsolateral prefrontal cortex (DLPFC) and posterior parietal cortex (PPC). The goal of Project 5 is use information from the normal properties of PPC-DLPFC circuitry in monkeys (Projects 3 and 4) to determine how these cellular abnormalifies give rise to cortical network and cognitive disturbances in medication naive, first-episode psychosis. We will use tasks that rely to different degrees on 'bottom-up' or 'top-down' processing to determine how activity within and communicafion between DLPFC and PPC are impaired, whether such disturbances are reflected equally or differentially in 'bottom-up' and 'top-down' processing, and if cortical oscillations provide signatures for such local and distributed circuit disturbances. We will employ a mulfimodal imaging approach taking advantage of the high temporal resolufion of concurrent MEG and EEG (M/EEG) together with the high spafial resolution of fMRI. M/EEG will evaluate the synchrony of frequency band-specific neural acfivity in local and distributed circuits, including cross-frequency coordination, through integrated spectral and connectivity approaches. fMRI will evaluate, with precise and definitive anatomic localization, activity of local and distributed circuits using regional BOLD and funcfional connectivity approaches. Abnormalities in cortical layer 3 pyramidal cell function are predicted to have a direct impact on both local and distributed circuit processing. These abnormalities are refiected in impaired functional connectivity and cortical synchrony within and between DLPFC and PPC. Our findings will provide novel insights into the local and distributed circuit pathophysiology underlying executive control disturbances in schizophrenia, providing a systems-level link to cellular abnormalifies, thereby identifying physiological biomarkers for future novel therapeutic approaches.

DESCRIPTION (provided by applicant): The developmental period from adolescence to young adulthood is associated with vulnerabilities that undermine survival (e.g., risk-taking behaviors) and increase the risk for the emergence of psychopathology (e.g., substance abuse, mood disorders, and schizophrenia). These vulnerabilities may be specifically linked with striatal and dopamine (DA) function, which support motivational systems and influence behavior. During adolescence, DA metabolism and striatal neurophysiology change significantly, and the striatum takes on greater functional significance in behavior. To date, research on the maturation of striatal motivational systems has been restricted to animal models, post mortem studies, and indirect neuroimaging evidence, limiting our ability to understand the neurobiological mechanisms of striatal development in humans. The parent grant identified increases in striatal function during reward processing in the adolescent period that were associated with indices of sensation seeking, as well as changes in brain networks suggesting a unique specialization in adolescence. We now propose to probe the neurobiological mechanisms underlying striatal changes in adolescence and how these affect brain systems and behavior. We will study 140 12- to 30-year-old healthy subjects in an accelerated longitudinal design using a molecular magnetic resonance (mMR) scanner that provides simultaneous magnetic resonance imaging (MRI) and positron emission tomography (PET) data. PET methods will quantify DA availability and release from young to middle adulthood, whereas complementary MRI measures of striatal neurophysiology will provide indices of reward-related neural activation in the striatum and indirect measures of DA processing via quantification of brain function and tissue iron (Aim 1). The effects of developmental changes in the striatum on brain systems will be characterized by linking striatal neurophysiology measures with functional and structural brain network connectivity (Aim 2). Neurobiological changes will be linked with behavioral measures of motivation, including a computational model of dopaminergic effects on reinforcement learning (Aim 3). This work will inform a model of the neurobiological processes underlying the transition from adolescence to adulthood that can clarify the development of psychopathology and increased risk-taking during this time.

Project Abstract/Summary This is the second renewal on a line of inquiry characterizing the neural basis of cognitive maturation through the adolescent period, a time of critical vulnerability to the emergence of major psychopathology (e.g., schizo- phrenia, mood disorders). Building on the findings from the first two grants using functional Magnetic Resonance Imaging, Diffusion Tensor Imaging, and Magnetoencephalography, indicating important specialization in cogni- tive brain systems during adolescence, we now propose to probe these underlying mechanisms. We aim to characterize changes in key neurotransmitters (NT): gamma-Aminobutyric acid (GABA), glutamate (Glu), and dopamine (DA), which animal and postmortem models show underlie circuit plasticity and undergo unique changes during the adolescent period. Specifically, changes in Glu/GABA processing, modulated by adolescent increases in DA, affect the excitatory/inhibitory (E/I) balance of cognitive brain systems, driving increases in the cortical signal-to-noise ratio (SNR) into adulthood supporting cognitive maturation. Our Central Hypothesis is that the relative changes of these NTs will increase the SNR of neural activity supporting the transition to adult level cognition. In Aim 1, we will use Magnetic Resonance Spectroscopy (MRS) at 7 Tesla to obtain measures of GABA and Glu as well as R2? indirect measures of dopamine (DA) longitudinally in vivo in 12-30 year olds. 7Tesla MRS provides critically greater sensitivity than 3Tesla affording significant increases in the accuracy of measures of GABA and Glu necessary for probing changes through adolescence, which have yet to be done. We hypothesize that we will observe decreases in measures of Glu and DA and increases in GABA resulting in decreases in the ratio of DA*Glu/GABA in prefrontal and subcortical regions. In Aim 2, we will inves- tigate the association between relative NT changes and systems level effects on known developmental changes in brain connectivity using resting state connectivity and measures of white matter integrity. We propose that NT systems changes will be associated with greater network integration and changes in the strength of corticosub- cortical connectivity through adolescence. Lastly, in Aim 3 we propose to characterize changes in SNR in the context of developmental improvements in higher-order executive function using a task that probes learning and working memory, functions that are known to show important improvements through adolescence. Together, these findings have relevance in elucidating the relative contributions of different NT systems to brain matura- tional processes providing novel insight into the neurobiological basis of normative neurocognitive development that is critical for identifying vulnerabilities for abnormal development that can lead to psychopathology.

ABSTRACT Adolescence is a period of marked cognitive development, reflected by improvements in the ability the effectively and consistently engage brain networks associated with cognitive control. However, while a wealth of behavioral and functional imaging studies have provided detailed insight into mean patterns of adolescent development, methodological challenges have limited our understanding of individual age-dependent trajectories. This has impeded the characterization of a template of ?typical? development, undermining our ability to link atypical development to the emergence of psychopathology. This difficulty arises due to cross-sectional and longitudinal studies with few follow-up assessments that track subjects over only a small window of their development, and is exacerbated by evolving technologies and research protocols that limit the ability to track true developmental change. Finally, the specificity of cognitive tasks used has led to disparate results, limiting our ability to understand development of cognitive control as a construct. We propose a novel analysis of an existing 10-year longitudinal data set that includes yearly task fMRI collected on a scanner with no hardware and minimal software upgrades, and behavioral assessments using a broad battery of cognitive tasks. The parent grant has produced a growing literature charting changes in task-related cognitive brain function and behavior, and related changes in white matter integrity. However, this study began prior to the establishment of resting state fMRI for characterizing functional brain networks, and thus this was not an aim, nor were continuous periods of rest included. Nevertheless, the study used a block design paradigm that allows for the assessment of resting state connectivity within ?off? periods, as previously described in the literature, which we demonstrate offers a viable means for assessing functional brain networks in developmental populations. In addition, an extensive cognitive assessment was gathered, and specific aspects of cognitive control (e.g., working memory, inhibitory control) have been extensively analyzed. However, recent approaches allow core mechanisms shared across cognitive tasks to be estimated as a ?domain-general cognitive control? component that can better characterize development of the overarching processes of cognitive control. We propose to mine this longitudinal data in an innovative manner not envisioned in the parent grant to characterize individual developmental trajectories of functional connectivity and their associations to a domain general component of cognitive control. We will identify connectivity patterns showing developmental change through adolescence associated with increases in domain-general measures of cognitive control. Finally, we will characterize individual age- dependent trajectories for both connectivity and behavior to identify variation in patterns of maturation, their early-adolescent predictors, and their relationship to adult outcomes. These results will inform the range of changes in adolescent brain architecture and how these are related to cognitive control normatively, which is critical for setting a template from which to understand aberrant maturation such as in psychopathology.

Abstract Adolescent Brain Cognitive Development (ABCD) is the largest long-term study of brain development and child health in the United States. The ABCD Research Consortium consists of 21 research sites across the country, a Coordinating Center, and a Data Analysis and Informatics Resource Center. In its first five years, under RFA-DA-15-015, ABCD enrolled a diverse sample of 11,878 9-10 year olds from across the consortium, and will track their biological and behavioral development through adolescence into young adulthood. All participants received a comprehensive baseline assessment, including state-of-the-art brain imaging, neuropsychological testing, bioassays, careful assessment of substance use, mental health, physical health, and culture and environment. A similar detailed assessment recurs every 2 years. Interim in-person annual interviews and mid-year telephone or mobile app assessments provide refined temporal resolution of developmental changes and life events that occur over time with minimal burden to participating youth and parents. Intensive efforts are made to keep the vast majority of participants involved with the study through adolescence and beyond, and retention rates thus far are very high. Neuroimaging has expanded our understanding of brain development from childhood into adulthood. Using this and other cutting-edge technologies, ABCD can determine how different kinds of youth experiences (such as sports, school involvement, extracurricular activities, videogames, social media, unhealthy sleep patterns, and vaping) interact with each other and with a child?s changing biology to affect brain development and social, behavioral, academic, health, and other outcomes. Data, securely and privately shared with the scientific community, will enable investigators to: (1) describe individual developmental pathways in terms of neural, cognitive, emotional, and academic functioning, and influencing factors; (2) develop national standards of healthy brain development; (3) investigate the roles and interaction of genes and the environment on development; (4) examine how physical activity, sleep, screen time, sports injuries (including traumatic brain injuries), and other experiences influence brain development; (5) determine and replicate factors that influence mental health from childhood to young adulthood; (6) characterize relationships between mental health and substance use; and (7) specify how use of substances such as cannabis, alcohol, tobacco, and caffeine affects developmental outcomes, and how neural, cognitive, emotional, and environmental factors influence the risk for adolescent substance use.

PROJECT SUMMARY/ABSTRACT While the rate of neonatal abstinence syndrome has reached a staggering 6.5 per 1,000 births nationwide, the short- and long-term effects of in-utero opioid exposure are far from clear. We lack fundamental knowledge of neurotypical neonatal development and struggle to disentangle the effect of opioid exposure from other protective and risk factors impacting infant health. The fetal stage of brain development is a critical period when foundational aspects of brain structure and function are being established. In addition, postnatal brain development and specialization are shaped by environmental experiences thus allowing maturation to be influenced by lifestyle factors associated with opioid use. This Phase I project will plan for a large scale, multi- site research study to prospectively examine human brain, cognitive, behavioral, social, and emotional development beginning prenatally through childhood. The University of Pittsburgh is one of four linked sites including Oregon Health and Sciences University, New York University and the University of Vermont that will address key challenges critical to the success of the planned Phase II study. Aim 1 will develop, implement and evaluate innovative recruitment and retention strategies for high-risk populations through a longitudinal survey of 150 pregnant women per site (n=600 across sites), half of whom are opioid using. Aim 2 will implement a multi-site, standardized, longitudinal research protocol by enrolling 20 pregnant women per site (n=80 across sites), half of whom are opioid using. This prospective longitudinal study will collect fetal and neonatal multimodal MRI, biospecimens, and maternal psychosocial and health assessments. Aim 3 will evaluate data acquisition, processing, and statistical considerations to maximize data quality, usability, and integration across sites. We will test the efficacy of (A) real-time motion monitoring/quality assessment for improving overall data quality and (B) time-savings versus MRI quality using new acceleration sequence protocols. This approach will inform and set a strong foundation for a comprehensive and effective Phase II research plan. The University of Pittsburgh site is led by a highly productive, NIH-funded investigative team with multidisciplinary expertise in substance use (Krans, Bogen), pregnancy (Krans), and fetal, neonatal, and pediatric neuroimaging (Luna, Panigrahy). Specifically, our team has established study protocols that yield excellent recruitment (~76%) and retention (~74%) rates among opioid using pregnant women, has substantial experience with imaging the immature brain (fetal/neonatal) and is a leader in developmental cognitive neuroscience using multimodal imaging to investigate neural mechanisms underlying neurocognitive development through adolescence. We will leverage our on-going, NIH-funded, multi-center neuroimaging studies to provide imaging harmonization techniques and assist with the development of structural fetal brain and placental imaging pipeline for all linked sites to assistant with development of Phase II protocol. Further, we will pilot innovative studies of age-related Iron deposition and quantitative fetal MR spectroscopy.