Author
Thomas Ernst
Other affiliations: Johns Hopkins University, Johns Hopkins University School of Medicine, University of Hawaii ...read more
Bio: Thomas Ernst is an academic researcher from University of Maryland, Baltimore. The author has contributed to research in topics: Population & Working memory. The author has an hindex of 20, co-authored 59 publications receiving 1934 citations. Previous affiliations of Thomas Ernst include Johns Hopkins University & Johns Hopkins University School of Medicine.
Papers published on a yearly basis
Papers
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University of California, San Diego1, McGill University2, Oregon Health & Science University3, Florida International University4, Yale University5, Washington University in St. Louis6, Virginia Commonwealth University7, University of Vermont8, University of Michigan9, Medical University of South Carolina10, National Institutes of Health11, SRI International12, University of Southern California13, McGovern Institute for Brain Research14, Harvard University15, Medical College of Wisconsin16, University of California, Irvine17, University of California, Los Angeles18, University of California, San Francisco19, University of Colorado Boulder20, University of Florida21, University of Maryland, Baltimore22, University of Massachusetts Boston23, University of Minnesota24, University of Pittsburgh25, University of Rochester26, University of Tennessee27, University of Utah28, University of Wisconsin–Milwaukee29, United States Department of Veterans Affairs30, Boston University31
TL;DR: The baseline neuroimaging processing and subject-level analysis methods used by the Adolescent Brain Cognitive Development Study are described to be a resource of unprecedented scale and depth for studying typical and atypical development.
431 citations
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University of California1, McGill University2, Oregon Health & Science University3, Florida International University4, Yale University5, University of Washington6, Virginia Commonwealth University7, University of Vermont8, University of Michigan9, Medical University of South Carolina10, National Institute on Drug Abuse11, SRI International12, Children's Hospital Los Angeles13, National Institutes of Health14, McGovern Institute for Brain Research15, Harvard University16, Medical College of Wisconsin17, University of Colorado Boulder18, University of Florida19, University of Maryland, Baltimore20, University of Massachusetts Amherst21, University of Minnesota22, University of Pittsburgh23, University of Rochester24, University of Tennessee25, University of Utah26, University of Wisconsin–Milwaukee27, Boston University28
TL;DR: The baseline neuroimaging processing and subject-level analysis methods used by the ABCD DAIC in the centralized processing and extraction of neuroanatomical and functional imaging phenotypes are described.
Abstract: The Adolescent Brain Cognitive Development (ABCD) Study is an ongoing, nationwide study of the effects of environmental influences on behavioral and brain development in adolescents. The ABCD Study is a collaborative effort, including a Coordinating Center, 21 data acquisition sites across the United States, and a Data Analysis and Informatics Center (DAIC). The main objective of the study is to recruit and assess over eleven thousand 9-10-year-olds and follow them over the course of 10 years to characterize normative brain and cognitive development, the many factors that influence brain development, and the effects of those factors on mental health and other outcomes. The study employs state-of-the-art multimodal brain imaging, cognitive and clinical assessments, bioassays, and careful assessment of substance use, environment, psychopathological symptoms, and social functioning. The data will provide a resource of unprecedented scale and depth for studying typical and atypical development. Here, we describe the baseline neuroimaging processing and subject-level analysis methods used by the ABCD DAIC in the centralized processing and extraction of neuroanatomical and functional imaging phenotypes. Neuroimaging processing and analyses include modality-specific corrections for distortions and motion, brain segmentation and cortical surface reconstruction derived from structural magnetic resonance imaging (sMRI), analysis of brain microstructure using diffusion MRI (dMRI), task-related analysis of functional MRI (fMRI), and functional connectivity analysis of resting-state fMRI.
276 citations
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TL;DR: The variability of the deactivated network across different cognitive tasks supports the hypothesis that global cerebral blood flow vary across different tasks, but not between different levels of task difficulty of the same task.
Abstract: This parametric functional magnetic resonance imaging (fMRI) study investigates the balance of negative and positive fMRI signals in the brain. A set of visual attention (VA) and working memory (WM) tasks with graded levels of difficulty was used to deactivate separate but overlapping networks that include the frontal, temporal, occipital, and limbic lobes; regions commonly associated with auditory and emotional processing. Brain activation (% signal change and volume) was larger for VA tasks than for WM tasks, but deactivation was larger for WM tasks. Load-related increases of blood oxygenation level-dependent (BOLD) responses for different levels of task difficulty cross-correlated strongly in the deactivated network during VA but less so during WM. The variability of the deactivated network across different cognitive tasks supports the hypothesis that global cerebral blood flow vary across different tasks, but not between different levels of task difficulty of the same task. The task-dependent balance of activation and deactivation might allow maximization of resources for the activated network.
207 citations
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TL;DR: The greater activation in the active compared with abstinent marijuana users demonstrates a neuroadaptive state in the setting of active marijuana use, while the long-term chronic effect of marijuana on the altered brain network may be reversible with prolonged abstinence.
Abstract: Attention and memory deficits have been reported in heavy marijuana users, but these effects may be reversible after prolonged abstinence. It remains unclear whether the reversibility of these cognitive deficits indicates that chronic marijuana use does not alter cortical networks, or that such changes occur but the brain adapts to the drug-induced changes. Blood oxygenation-level dependent (BOLD) functional MRI (fMRI) was performed in 24 chronic marijuana users (12 abstinent and 12 active) and 19 age-, sex- and education-matched control subjects during a set of visual-attention tasks with graded levels of difficulty. Neuropsychological tests were also administered on each subject. The two marijuana user groups showed no significant difference in usage pattern (frequency or duration of use, age of first use, cumulative joints used, averaged >2000 joints) or estimated cumulative lifetime exposure of Δ-9-tetrahydrocannabinol (THC) (mean 168 ± 45 versus 244 ± 135 g). Despite similar task and cognitive test performance compared with control subjects, active and abstinent marijuana users showed decreased activation in the right prefrontal, medial and dorsal parietal, and medial cerebellar regions, but greater activation in various frontal, parietal and occipital brain regions during the visual-attention tasks (all with P ≤ 0.001, corrected, cluster level). However, the BOLD signals in the right frontal and medial cerebellar regions normalized with duration of abstinence in the abstinent users. Active marijuana users, with positive urine tests for THC, showed greater activation in the frontal and medial cerebellar regions than abstinent marijuana users and greater usage of the reserve network (regions with load effect), suggesting a neuroadaptive state. Both earlier age of first use and greater estimated cumulative dose of THC exposure were related to lower BOLD signals in the right prefrontal region and medial cerebellum. The altered BOLD activation pattern in the attention network and hypoactivation of the cerebellum suggest neuroadaptive processes or alteration of brain development in chronic marijuana users. These changes also may be related to marijuana-induced alteration in resting cerebral blood volume/flow or downregulation of cannabinoid (CB1) receptors. The greater activation in the active compared with abstinent marijuana users demonstrates a neuroadaptive state in the setting of active marijuana use, while the long-term chronic effect of marijuana on the altered brain network may be reversible with prolonged abstinence.
184 citations
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TL;DR: The results highlight the sensitivity to developmental effects and efficiency of this new computerized assessment battery for neurodevelopmental research and evidence for variable measurement sensitivity to cultural/socioeconomic factors.
Abstract: Objective
The NIH Toolbox Cognition Battery (NTCB) was designed to provide a brief, efficient computerized test of key neuropsychological functions appropriate for use in children as young as 3 years of age. This report describes the performance of a large group of typically developing children and adolescents and examines the impact of age and sociocultural variables on test performance.
156 citations
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TL;DR: An activation likelihood estimate (ALE) meta-analysis of neuroimaging studies reporting cerebellar activation in selected task categories provided support for an anterior sensorimotor vs. posterior cognitive/emotional dichotomy in the human cerebellum.
1,730 citations
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TL;DR: A meta-analytic summary of the neuroimaging literature on human emotion finds little evidence that discrete emotion categories can be consistently and specifically localized to distinct brain regions, and finds evidence that is consistent with a psychological constructionist approach to the mind.
Abstract: Researchers have wondered how the brain creates emotions since the early days of psychological science. With a surge of studies in affective neuroscience in recent decades, scientists are poised to answer this question. In this target article, we present a meta-analytic summary of the neuroimaging literature on human emotion. We compare the locationist approach (i.e., the hypothesis that discrete emotion categories consistently and specifically correspond to distinct brain regions) with the psychological constructionist approach (i.e., the hypothesis that discrete emotion categories are constructed of more general brain networks not specific to those categories) to better understand the brain basis of emotion. We review both locationist and psychological constructionist hypotheses of brain-emotion correspondence and report meta-analytic findings bearing on these hypotheses. Overall, we found little evidence that discrete emotion categories can be consistently and specifically localized to distinct brain regions. Instead, we found evidence that is consistent with a psychological constructionist approach to the mind: A set of interacting brain regions commonly involved in basic psychological operations of both an emotional and non-emotional nature are active during emotion experience and perception across a range of discrete emotion categories.
1,702 citations
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TL;DR: For instance, this paper found that brain activation in males is lateralized to the left inferior frontal gyrus regions; in females the pattern of activation is very different, engaging more diffuse neural systems that involve both the left and right inferior frontal cortex.
Abstract: A MUCH debated question is whether sex differences exist in the functional organization of the brain for language1–4. A long-held hypothesis posits that language functions are more likely to be highly lateralized in males and to be represented in both cerebral hemispheres in females5,6, but attempts to demonstrate this have been inconclusive7–17. Here we use echo-planar functional magnetic resonance imaging18–21 to study 38 right-handed subjects (19 males and 19 females) during orthographic (letter recognition), phonological (rhyme) and semantic (semantic category) tasks. During phonological tasks, brain activation in males is lateralized to the left inferior frontal gyrus regions; in females the pattern of activation is very different, engaging more diffuse neural systems that involve both the left and right inferior frontal gyrus. Our data provide clear evidence for a sex difference in the functional organization of the brain for language and indicate that these variations exist at the level of phonological processing.
1,247 citations
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TL;DR: Functional topography is considered to be a consequence of the differential arrangement of connections of the cerebellum with the spinal cord, brainstem, and cerebral hemispheres, reflecting cerebellar incorporation into the distributed neural circuits subserving movement, cognition, and emotion.
1,119 citations
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TL;DR: PVT results during extended periods of wakefulness reveal the presence of interacting circadian and homeostatic sleep drives and the interplay of “top‐down” and “bottom‐up” attention in producing the unstable and unpredictable patterns of behavior that are the hallmark of the sleep‐deprived state.
Abstract: Sleep deprivation severely compromises the ability of human beings to respond to stimuli in a timely fashion. These deficits have been attributed in large part to failures of vigilant attention, which many theorists believe forms the bedrock of the other more complex components of cognition. One of the leading paradigms used as an assay of vigilant attention is the psychomotor vigilance test (PVT), a high signal-load reaction-time test that is extremely sensitive to sleep deprivation. Over the last twenty years, four dominant findings have emerged from the use of this paradigm. First, sleep deprivation results in an overall slowing of responses. Second, sleep deprivation increases the propensity of individuals to lapse for lengthy periods (>500ms), as well as make errors of commission. Third, sleep deprivation enhances the time-on-task effect within each test bout. Finally, PVT results during extended periods of wakefulness reveal the presence of interacting circadian and homeostatic sleep drives. A theme that links these findings is the interplay of “top-down” and “bottom-up” attention in producing the unstable and unpredictable patterns of behavior that are the hallmark of the sleep-deprived state.
1,015 citations