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Anissa Abi-Dargham

Mark Slifstein, Anissa Abi-Dargham
No abstract text is available yet for this article.
April 15, 2018: Biological Psychiatry
Clifford M Cassidy, Peter D Balsam, Jodi J Weinstein, Rachel J Rosengard, Mark Slifstein, Nathaniel D Daw, Anissa Abi-Dargham, Guillermo Horga
Hallucinations, a cardinal feature of psychotic disorders such as schizophrenia, are known to depend on excessive striatal dopamine. However, an underlying cognitive mechanism linking dopamine dysregulation and the experience of hallucinatory percepts remains elusive. Bayesian models explain perception as an optimal combination of prior expectations and new sensory evidence, where perceptual distortions such as illusions and hallucinations may occur if prior expectations are afforded excessive weight. Such excessive weight of prior expectations, in turn, could stem from a gain-control process controlled by neuromodulators such as dopamine...
February 19, 2018: Current Biology: CB
Tiziano Colibazzi, Zhen Yang, Guillermo Horga, Yan Chao-Gan, Cheryl M Corcoran, Kristin Klahr, Gary Brucato, Ragy Girgis, Anissa Abi-Dargham, Michael P Milham, Bradley S Peterson
Background: Schizophrenia, a neurodevelopmental disorder, involves abnormalities in functional connectivity (FC) across distributed neural networks, which are thought to antedate the emergence of psychosis. In a cohort of adolescents and young adults at clinical high risk (CHR) for psychosis, we applied data-driven approaches to resting-state fMRI data so as to systematically characterize FC abnormalities during this period and determine whether these abnormalities are associated with psychosis risk and severity of psychotic symptoms...
November 2017: Biological Psychiatry: Cognitive Neuroscience and Neuroimaging
William A Carlezon, Anissa Abi-Dargham
No abstract text is available yet for this article.
June 2017: Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology
Mark Slifstein, Anissa Abi-Dargham
Molecular imaging with PET or SPECT has been an important research tool in psychiatry for as long as these modalities have been available. Here, we discuss two areas of neuroimaging relevant to current psychiatry research. The first is the use of imaging to study neurotransmission. We discuss the use of pharmacologic probes to induce changes in levels of neurotransmitters that can be inferred through their effects on outcome measures of imaging experiments, from their historical origins focusing on dopamine transmission through recent developments involving serotonin, GABA, and glutamate...
January 2017: Seminars in Nuclear Medicine
Anissa Abi-Dargham
No abstract text is available yet for this article.
January 1, 2017: Biological Psychiatry
Eugénie Lehembre-Shiah, Wei Leong, Gary Brucato, Anissa Abi-Dargham, Jeffrey A Lieberman, Guillermo Horga, Ragy R Girgis
No abstract text is available yet for this article.
January 1, 2017: JAMA Psychiatry
Anissa Abi-Dargham, Guillermo Horga
The field of medicine is moving toward the use of biomarkers for the optimization of individualized care. This is a particular challenge for the field of psychiatry, in which diagnosis is based on a descriptive collection of behaviors without the availability of any objective test to stratify patients. Neuroimaging techniques such as molecular imaging with positron-emission tomography (PET) or structural and functional magnetic resonance imaging (MRI) provide an opportunity to bring psychiatry from an era of subjective descriptive classification into objective and tangible brain-based measures...
November 2016: Nature Medicine
Ragy R Girgis, Mark Slifstein, Deepak D'Souza, Yih Lee, Antonia Periclou, Parviz Ghahramani, István Laszlovszky, Suresh Durgam, Nika Adham, Nabeel Nabulsi, Yiyun Huang, Richard E Carson, Béla Kiss, Margit Kapás, Anissa Abi-Dargham, Ashok Rakhit
RATIONALE: Second-generation antipsychotics occupy dopamine D2 receptors and act as antagonists or partial agonists at these receptors. While these drugs alleviate positive symptoms in patients with schizophrenia, they are less effective for treating cognitive deficits and negative symptoms. Dopamine D3 receptors are highly expressed in areas of the brain thought to play a role in the regulation of motivation and reward-related behavior. Consequently, the dopamine D3 receptor has become a target for treating negative symptoms in combination with D2 antagonism to treat positive symptoms in patients with schizophrenia...
October 2016: Psychopharmacology
Joshua L Roffman, Alexandra S Tanner, Hamdi Eryilmaz, Anais Rodriguez-Thompson, Noah J Silverstein, New Fei Ho, Adam Z Nitenson, Daniel B Chonde, Douglas N Greve, Anissa Abi-Dargham, Randy L Buckner, Dara S Manoach, Bruce R Rosen, Jacob M Hooker, Ciprian Catana
Local prefrontal dopamine signaling supports working memory by tuning pyramidal neurons to task-relevant stimuli. Enabled by simultaneous positron emission tomography-magnetic resonance imaging (PET-MRI), we determined whether neuromodulatory effects of dopamine scale to the level of cortical networks and coordinate their interplay during working memory. Among network territories, mean cortical D1 receptor densities differed substantially but were strongly interrelated, suggesting cross-network regulation. Indeed, mean cortical D1 density predicted working memory-emergent decoupling of the frontoparietal and default networks, which respectively manage task-related and internal stimuli...
June 2016: Science Advances
John H Krystal, Anissa Abi-Dargham, Schahram Akbarian, Amy F T Arnsten, Deanna M Barch, Carrie E Bearden, David L Braff, E Sherwood Brown, Edward T Bullmore, William A Carlezon, Cameron S Carter, Edwin H Cook, Zafiris Jeff Daskalakis, Ralph J DiLeone, Ronald S Duman, Anthony A Grace, Ahmad R Hariri, Paul J Harrison, Noboru Hiroi, Paul J Kenny, Joel E Kleinman, Andrew D Krystal, David A Lewis, Barbara K Lipska, Stephen R Marder, Graeme F Mason, Daniel H Mathalon, Colleen A McClung, Christopher J McDougle, Andrew M McIntosh, Francis J McMahon, Károly Mirnics, Lisa M Monteggia, Rajesh Narendran, Eric J Nestler, Alexander Neumeister, Michael C O'Donovan, Dost Öngür, Carmine M Pariante, Martin P Paulus, Godfrey Pearlson, Mary L Phillips, Daniel S Pine, Diego A Pizzagalli, Mikhail V Pletnikov, J Daniel Ragland, Judith L Rapoport, Kerry J Ressler, Scott J Russo, Gerard Sanacora, Akira Sawa, Alan F Schatzberg, Yavin Shaham, Simone G Shamay-Tsoory, Pamela Sklar, Matthew W State, Murray B Stein, Stephen M Strakowski, Stephan F Taylor, Gustavo Turecki, Bruce I Turetsky, Myrna M Weissman, Venetia Zachariou, Carlos A Zarate, Jon-Kar Zubieta
No abstract text is available yet for this article.
July 15, 2016: Biological Psychiatry
John H Krystal, Anissa Abi-Dargham, Deanna M Barch, Edward T Bullmore, Cameron S Carter, Daniel H Geschwind, Paul J Harrison, Eric J Nestler, Murray B Stein
No abstract text is available yet for this article.
July 1, 2016: Biological Psychiatry
Jodi J Weinstein, Muhammad O Chohan, Mark Slifstein, Lawrence S Kegeles, Holly Moore, Anissa Abi-Dargham
In light of the clinical evidence implicating dopamine in schizophrenia and the prominent hypotheses put forth regarding alterations in dopaminergic transmission in this disease, molecular imaging has been used to examine multiple aspects of the dopaminergic system. We review the imaging methods used and compare the findings across the different molecular targets. Findings have converged to suggest early dysregulation in the striatum, especially in the rostral caudate, manifesting as excess synthesis and release...
January 1, 2017: Biological Psychiatry
Corinde E Wiers, Ehsan Shokri-Kojori, Christopher T Wong, Anissa Abi-Dargham, Şükrü B Demiral, Dardo Tomasi, Gene-Jack Wang, Nora D Volkow
The extent to which cannabis is deleterious to the human brain is not well understood. Here, we test whether cannabis abusers (CA) have impaired frontal function and reactivity to dopaminergic signaling, which are fundamental to relapse in addiction. We measured brain glucose metabolism using PET and [(18)F]FDG both at baseline (placebo) and after challenge with methylphenidate (MP), a dopamine-enhancing drug, in 24 active CA (50% female) and 24 controls (HC; 50% female). Results show that (i) CA had lower baseline glucose metabolism than HC in frontal cortex including anterior cingulate, which was associated with negative emotionality...
September 2016: Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology
Guillermo Horga, Clifford M Cassidy, Xiaoyan Xu, Holly Moore, Mark Slifstein, Jared X Van Snellenberg, Anissa Abi-Dargham
IMPORTANCE: Despite the well-established role of striatal dopamine in psychosis, current views generally agree that cortical dysfunction is likely necessary for the emergence of psychotic symptoms. The topographic organization of striatal-cortical connections is central to gating and integration of higher-order information, so a disruption of such topography via dysregulated dopamine could lead to cortical dysfunction in schizophrenia. However, this hypothesis remains to be tested using multivariate methods ascertaining the global pattern of striatal connectivity and without the confounding effects of antidopaminergic medication...
August 1, 2016: JAMA Psychiatry
Jenna M Reinen, Jared X Van Snellenberg, Guillermo Horga, Anissa Abi-Dargham, Nathaniel D Daw, Daphna Shohamy
BACKGROUND: Recent findings demonstrate that patients with schizophrenia are worse at learning to predict rewards than losses, suggesting that motivational context modulates learning in this disease. However, these findings derive from studies in patients treated with antipsychotic medications, D2 receptor antagonists that may interfere with the neural systems that underlie motivation and learning. Thus, it remains unknown how motivational context affects learning in schizophrenia, separate from the effects of medication...
November 2016: Schizophrenia Bulletin
Clifford M Cassidy, Jared X Van Snellenberg, Caridad Benavides, Mark Slifstein, Zhishun Wang, Holly Moore, Anissa Abi-Dargham, Guillermo Horga
UNLABELLED: Connectivity between brain networks may adapt flexibly to cognitive demand, a process that could underlie adaptive behaviors and cognitive deficits, such as those observed in neuropsychiatric conditions like schizophrenia. Dopamine signaling is critical for working memory but its influence on internetwork connectivity is relatively unknown. We addressed these questions in healthy humans using functional magnetic resonance imaging (during ann-back working-memory task) and positron emission tomography using the radiotracer [(11)C]FLB457 before and after amphetamine to measure the capacity for dopamine release in extrastriatal brain regions...
April 13, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Jared X Van Snellenberg, Ragy R Girgis, Guillermo Horga, Elsmarieke van de Giessen, Mark Slifstein, Najate Ojeil, Jodi J Weinstein, Holly Moore, Jeffrey A Lieberman, Daphna Shohamy, Edward E Smith, Anissa Abi-Dargham
BACKGROUND: The neural correlates of working memory (WM) impairment in schizophrenia remain a key puzzle in understanding the cognitive deficits and dysfunction of dorsolateral prefrontal cortex observed in this disorder. We sought to determine whether patients with schizophrenia exhibit an alteration in the inverted-U relationship between WM load and activation that we recently observed in healthy individuals and whether this could account for WM deficits in this population. METHODS: Medicated (n = 30) and unmedicated (n = 21) patients with schizophrenia and healthy control subjects (n = 45) performed the self-ordered WM task during functional magnetic resonance imaging...
October 15, 2016: Biological Psychiatry
Ragy R Girgis, Jared X Van Snellenberg, Andrew Glass, Lawrence S Kegeles, Judy L Thompson, Melanie Wall, Raymond Y Cho, Cameron S Carter, Mark Slifstein, Anissa Abi-Dargham, Jeffrey A Lieberman
BACKGROUND: Evidence from preclinical and human studies indicates the presence of reduced dopamine-1 receptor (D1R) signaling in the cortex, where D1Rs predominate, in patients with schizophrenia (SCZ), which may contribute to their cognitive deficits. Furthermore, studies in nonhuman primates (NHP) have suggested that intermittent administration of low doses of D1R agonists produce long-lasting reversals in cognitive deficits. The purpose of this trial was to test whether a similar design, involving subacute intermittent administration of low doses of a full, selective agonist at D1Rs, DAR-0100A, would improve cognitive deficits in SCZ...
May 2016: Journal of Psychopharmacology
Tiziano Colibazzi, Guillermo Horga, Zhishun Wang, Yuankai Huo, Cheryl Corcoran, Kristin Klahr, Gary Brucato, Ragy Girgis, Kelly Gill, Anissa Abi-Dargham, Bradley S Peterson
Cognitive control, a set of functions that develop throughout adolescence, is important in the pathogenesis of psychotic disorders. Whether cognitive control has a role in conferring vulnerability for the development of psychotic illness is still unknown. The aim of this study was to investigate the neural systems supporting cognitive control in individuals deemed to be potentially prodromal for psychotic illness. We recruited 56 participants at clinical high-risk (CHR) for psychosis based on the Structured Interview for Psychosis-Risk Syndromes (SIPS) and 49 healthy controls...
April 2016: Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology
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