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Phan JA, Wong DF, Chang NHS, Kumakura Y, Bauer WR, Gjedde A. Transient equilibrium determination of dopamine D 2/D 3 receptor densities and affinities in brain. FRONTIERS IN NUCLEAR MEDICINE (LAUSANNE, SWITZERLAND) 2022; 2:1030387. [PMID: 36926525 PMCID: PMC10017089 DOI: 10.3389/fnume.2022.1030387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Long-term alteration of dopaminergic neurotransmission is known to modulate the D2/D3 receptor expression in the brain. The modulation can occur as a response to pathological processes or pharmacological intervention. The receptor density can be monitored by in vivo positron emission tomography (PET) of [11C] raclopride. To obtain accurate measurements of receptor-ligand interaction, it is essential to estimate binding parameters at true (if transient) equilibrium of bound and unbound ligand quantities. We designed this study as a comparison of two quantitative approaches to transient equilibrium, the TRansient EquilibriuM BoLus Estimation (TREMBLE) method and the Transient Equilibrium Model (TEM) method, to determine binding parameters at transient equilibrium with bolus injection of the radioligand. The data demonstrates that TREMBLE unlike TEM identified the time at which equilibrium existed. TREMBLE revealed that equilibrium prevailed at one or more times after bolus injection and identified differences of receptor density among regions such as putamen and caudate nucleus. We demonstrated that TREMBLE is a quantitative approach suitable for the study of pathophysiological conditions of certain types of neurotransmission the brain.
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Affiliation(s)
- Jenny-Ann Phan
- Department of Neurology, Gødstrup Hospital, Herning, Denmark
- NIDO - Centre for Research and Education, Gødstrup Hospital, Herning, Denmark
- Department of Neurology, Aarhus University, Aarhus, Denmark
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, Aarhus, Denmark
- Johns Hopkins Medical Institutions, Department of Radiology and Radiological Sciences, Division of Nuclear Medicine PET Center, Baltimore MD, United States
| | - Dean F. Wong
- Johns Hopkins Medical Institutions, Department of Radiology and Radiological Sciences, Division of Nuclear Medicine PET Center, Baltimore MD, United States
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, MO, United States
| | - Natalie H. S. Chang
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, Aarhus, Denmark
- Institute of Regional Health Research, University of Southern Denmark, Odense, Denmark
- Medical Spinal Research Unit, Spine Centre of Southern Denmark, University Hospital of Southern Denmark, Odense, Denmark
| | - Yoshitaka Kumakura
- Department of Diagnostic Radiology and Nuclear Medicine, Saitama Medical Center, Saitama Medical University, Moroyama, Japan
| | - William R. Bauer
- Translational Neuropsychiatry Unit, Department of Clinical Research, Aarhus University, Aarhus, Denmark
| | - Albert Gjedde
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, Aarhus, Denmark
- Johns Hopkins Medical Institutions, Department of Radiology and Radiological Sciences, Division of Nuclear Medicine PET Center, Baltimore MD, United States
- Translational Neuropsychiatry Unit, Department of Clinical Research, Aarhus University, Aarhus, Denmark
- Departments of Nuclear Medicine and Clinical Research, University of Southern Denmark and Odense University Hospital, Odense, Denmark
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
- Neuroscience Center, Tabriz University of Medical Sciences, Tabriz, Iran
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2
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Jepma M, Roy M, Ramlakhan K, van Velzen M, Dahan A. Different brain systems support learning from received and avoided pain during human pain-avoidance learning. eLife 2022; 11:74149. [PMID: 35731646 PMCID: PMC9217130 DOI: 10.7554/elife.74149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 06/07/2022] [Indexed: 12/14/2022] Open
Abstract
Both unexpected pain and unexpected pain absence can drive avoidance learning, but whether they do so via shared or separate neural and neurochemical systems is largely unknown. To address this issue, we combined an instrumental pain-avoidance learning task with computational modeling, functional magnetic resonance imaging (fMRI), and pharmacological manipulations of the dopaminergic (100 mg levodopa) and opioidergic (50 mg naltrexone) systems (N = 83). Computational modeling provided evidence that untreated participants learned more from received than avoided pain. Our dopamine and opioid manipulations negated this learning asymmetry by selectively increasing learning rates for avoided pain. Furthermore, our fMRI analyses revealed that pain prediction errors were encoded in subcortical and limbic brain regions, whereas no-pain prediction errors were encoded in frontal and parietal cortical regions. However, we found no effects of our pharmacological manipulations on the neural encoding of prediction errors. Together, our results suggest that human pain-avoidance learning is supported by separate threat- and safety-learning systems, and that dopamine and endogenous opioids specifically regulate learning from successfully avoided pain.
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Affiliation(s)
- Marieke Jepma
- Department of Psychology, University of Amsterdam, Amsterdam, Netherlands.,Department of Psychology, Leiden University, Leiden, Netherlands.,Leiden Institute for Brain and Cognition, Leiden, Netherlands
| | - Mathieu Roy
- Department of Psychology, McGill University, Montreal, Canada.,Alan Edwards Centre for Research on Pain, McGill University, Montreal, Canada
| | - Kiran Ramlakhan
- Department of Psychology, Leiden University, Leiden, Netherlands.,Department of Research and Statistics, Municipality of Amsterdam, Amsterdam, Netherlands
| | - Monique van Velzen
- Department of Anesthesiology, Leiden University Medical Center, Leiden, Netherlands
| | - Albert Dahan
- Department of Anesthesiology, Leiden University Medical Center, Leiden, Netherlands
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3
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Esser R, Korn CW, Ganzer F, Haaker J. L-DOPA modulates activity in the vmPFC, nucleus accumbens, and VTA during threat extinction learning in humans. eLife 2021; 10:65280. [PMID: 34473055 PMCID: PMC8443250 DOI: 10.7554/elife.65280] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 09/01/2021] [Indexed: 12/26/2022] Open
Abstract
Learning to be safe is central for adaptive behaviour when threats are no longer present. Detecting the absence of an expected threat is key for threat extinction learning and an essential process for the behavioural treatment of anxiety-related disorders. One possible mechanism underlying extinction learning is a dopaminergic mismatch signal that encodes the absence of an expected threat. Here we show that such a dopamine-related pathway underlies extinction learning in humans. Dopaminergic enhancement via administration of L-DOPA (vs. Placebo) was associated with reduced retention of differential psychophysiological threat responses at later test, which was mediated by activity in the ventromedial prefrontal cortex that was specific to extinction learning. L-DOPA administration enhanced signals at the time-point of an expected, but omitted threat in extinction learning within the nucleus accumbens, which were functionally coupled with the ventral tegmental area and the amygdala. Computational modelling of threat expectancies further revealed prediction error encoding in nucleus accumbens that was reduced when L-DOPA was administered. Our results thereby provide evidence that extinction learning is influenced by L-DOPA and provide a mechanistic perspective to augment extinction learning by dopaminergic enhancement in humans.
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Affiliation(s)
- Roland Esser
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christoph W Korn
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Section Social Neuroscience, Department of General Psychiatry, Heidelberg, Germany
| | - Florian Ganzer
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,German Center for Addiction Research in Childhood and Adolescence, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jan Haaker
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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4
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Grimm O, Nägele M, Küpper-Tetzel L, de Greck M, Plichta M, Reif A. No effect of a dopaminergic modulation fMRI task by amisulpride and L-DOPA on reward anticipation in healthy volunteers. Psychopharmacology (Berl) 2021; 238:1333-1342. [PMID: 33140215 PMCID: PMC8062334 DOI: 10.1007/s00213-020-05693-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 10/23/2020] [Indexed: 01/02/2023]
Abstract
RATIONALE Dysregulation of dopaminergic neurotransmission, specifically altered reward processing assessed via the reward anticipation in the MID task, plays a central role in the etiopathogenesis of neuropsychiatric disorders. OBJECTIVES We hypothesized to find a difference in the activity level of the reward system (measured by the proxy reward anticipation) under drug administration versus placebo, in that amisulpride reduces, and L-DOPA enhances, its activity. METHODS We studied the influence of dopamine agonist L-DOPA and the antagonist amisulpride on the reward system using functional magnetic resonance imaging (fMRI) during a monetary incentive delay (MID) task in n = 45 healthy volunteers in a randomized, blinded, cross-over study. RESULTS The MID paradigm elicits strong activation in reward-dependent structures (such as ventral striatum, putamen, caudate, anterior insula) during reward anticipation. The placebo effect demonstrated the expected significant blood oxygen level-dependent activity in reward-dependent brain regions. Neither amisulpride nor L-DOPA led to significant changes in comparison with the placebo condition. This was true for whole-brain analysis as well as analysis of a pre-defined nucleus accumbens region-of-interest mask. CONCLUSION The present results cast doubt on the sensitivity of reward anticipation contrast in the MID task for assessing dopamine-specific changes in healthy volunteers by pharmaco-fMRI. While our task was not well-suited for detailed analysis of the outcome phase, we provide reasonable arguments that the lack of effect in the anticipation phase is not due to an inefficient task but points to unexpected behavior of the reward system during pharmacological challenge. Group differences of reward anticipation should therefore not be seen as simple representatives of dopaminergic states.
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Affiliation(s)
- Oliver Grimm
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital, Goethe University Frankfurt am Main, Frankfurt, Germany.
| | - Magdalena Nägele
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital, Goethe University Frankfurt am Main, Frankfurt, Germany
| | - Lea Küpper-Tetzel
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital, Goethe University Frankfurt am Main, Frankfurt, Germany
| | - Moritz de Greck
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital, Goethe University Frankfurt am Main, Frankfurt, Germany
| | - Michael Plichta
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital, Goethe University Frankfurt am Main, Frankfurt, Germany
| | - Andreas Reif
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital, Goethe University Frankfurt am Main, Frankfurt, Germany
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Chakroun K, Mathar D, Wiehler A, Ganzer F, Peters J. Dopaminergic modulation of the exploration/exploitation trade-off in human decision-making. eLife 2020; 9:e51260. [PMID: 32484779 PMCID: PMC7266623 DOI: 10.7554/elife.51260] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 05/01/2020] [Indexed: 01/15/2023] Open
Abstract
Involvement of dopamine in regulating exploration during decision-making has long been hypothesized, but direct causal evidence in humans is still lacking. Here, we use a combination of computational modeling, pharmacological intervention and functional magnetic resonance imaging to address this issue. Thirty-one healthy male participants performed a restless four-armed bandit task in a within-subjects design under three drug conditions: 150 mg of the dopamine precursor L-dopa, 2 mg of the D2 receptor antagonist haloperidol, and placebo. Choices were best explained by an extension of an established Bayesian learning model accounting for perseveration, directed exploration and random exploration. Modeling revealed attenuated directed exploration under L-dopa, while neural signatures of exploration, exploitation and prediction error were unaffected. Instead, L-dopa attenuated neural representations of overall uncertainty in insula and dorsal anterior cingulate cortex. Our results highlight the computational role of these regions in exploration and suggest that dopamine modulates how this circuit tracks accumulating uncertainty during decision-making.
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Affiliation(s)
- Karima Chakroun
- Department of Systems Neuroscience, University Medical Center Hamburg-EppendorfHamburgGermany
| | - David Mathar
- Department of Psychology, Biological Psychology, University of CologneCologneGermany
| | - Antonius Wiehler
- Department of Systems Neuroscience, University Medical Center Hamburg-EppendorfHamburgGermany
- Institut du Cerveau et de la Moelle épinière - ICM, Centre de NeuroImagerie de Recherche - CENIR, Sorbonne Universités, Groupe Hospitalier Pitié-SalpêtrièreParisFrance
| | - Florian Ganzer
- German Center for Addiction Research in Childhood and Adolescence, University Medical Center Hamburg-EppendorfHamburgGermany
| | - Jan Peters
- Department of Systems Neuroscience, University Medical Center Hamburg-EppendorfHamburgGermany
- Department of Psychology, Biological Psychology, University of CologneCologneGermany
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Effects of daily L-dopa administration on learning and brain structure in older adults undergoing cognitive training: a randomised clinical trial. Sci Rep 2020; 10:5227. [PMID: 32251360 PMCID: PMC7090037 DOI: 10.1038/s41598-020-62172-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Accepted: 03/04/2020] [Indexed: 11/08/2022] Open
Abstract
Cognitive aging creates major individual and societal burden, motivating search for treatment and preventive care strategies. Behavioural interventions can improve cognitive performance in older age, but effects are small. Basic research has implicated dopaminergic signalling in plasticity. We investigated whether supplementation with the dopamine-precursor L-dopa improves effects of cognitive training on performance. Sixty-three participants for this randomised, parallel-group, double-blind, placebo-controlled trial were recruited via newspaper advertisements. Inclusion criteria were: age of 65–75 years, Mini-Mental State Examination score >25, absence of serious medical conditions. Eligible subjects were randomly allocated to either receive 100/25 mg L-dopa/benserazide (n = 32) or placebo (n = 31) prior to each of twenty cognitive training sessions administered during a four-week period. Participants and staff were blinded to group assignment. Primary outcomes were latent variables of spatial and verbal fluid intelligence. Compared to the placebo group, subjects receiving L-dopa improved less in spatial intelligence (−0.267 SDs; 95%CI [−0.498, −0.036]; p = 0.024). Change in verbal intelligence did not significantly differ between the groups (−0.081 SDs, 95%CI [−0.242, 0.080]; p = 0.323). Subjects receiving L-dopa also progressed slower through the training and the groups displayed differential volumetric changes in the midbrain. No statistically significant differences were found for the secondary cognitive outcomes. Adverse events occurred for 10 (31%) and 7 (23%) participants in the active and control groups, correspondingly. The results speak against early pharmacological interventions in older healthy adults to improve broader cognitive functions by targeting the dopaminergic system and provide no support for learning-enhancing properties of L-dopa supplements in the healthy elderly. The findings warrant closer investigation about the cognitive effects of early dopamine-replacement therapy in neurological disorders. This trial was preregistered at the European Clinical Trial Registry, EudraCT#2016-000891-54 (2016-10-05).
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Maturation of the human striatal dopamine system revealed by PET and quantitative MRI. Nat Commun 2020; 11:846. [PMID: 32051403 PMCID: PMC7015913 DOI: 10.1038/s41467-020-14693-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Accepted: 01/28/2020] [Indexed: 01/18/2023] Open
Abstract
The development of the striatum dopamine (DA) system through human adolescence, a time of increased sensation seeking and vulnerability to the emergence of psychopathology, has been difficult to study due to pediatric restrictions on direct in vivo assessments of DA. Here, we applied neuroimaging in a longitudinal sample of n = 146 participants aged 12–30. R2′, an MR measure of tissue iron which co-localizes with DA vesicles and is necessary for DA synthesis, was assessed across the sample. In the 18–30 year-olds (n = 79) we also performed PET using [11C]dihydrotetrabenazine (DTBZ), a measure of presynaptic vesicular DA storage, and [11C]raclopride (RAC), an indicator of D2/D3 receptor availability. We observed decreases in D2/D3 receptor availability with age, while presynaptic vesicular DA storage (as measured by DTBZ), which was significantly associated with R2′ (standardized coefficient = 0.29, 95% CI = [0.11, 0.48]), was developmentally stable by age 18. Our results provide new evidence for maturational specialization of the striatal DA system through adolescence. How the human dopamine system changes during adolescence is still unclear. Here, the authors combine PET and quantitative MRI measures to show that dopamine D2/D3 receptor availability decreases with age while presynaptic dopamine vesicular storage was developmentally stable by age 18
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8
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Spagnolo PA, Kimes A, Schwandt ML, Shokri-Kojori E, Thada S, Phillips KA, Diazgranados N, Preston KL, Herscovitch P, Tomasi D, Ramchandani VA, Heilig M. Striatal Dopamine Release in Response to Morphine: A [ 11C]Raclopride Positron Emission Tomography Study in Healthy Men. Biol Psychiatry 2019; 86:356-364. [PMID: 31097294 PMCID: PMC6699765 DOI: 10.1016/j.biopsych.2019.03.965] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 02/04/2019] [Accepted: 03/05/2019] [Indexed: 11/19/2022]
Abstract
BACKGROUND Preclinical and human positron emission tomography studies have produced inconsistent results regarding the effects of opioids on mesolimbic dopamine (DA). Here, we quantify striatal DA release (measured by [11C]raclopride displacement) in response to an intravenous infusion of morphine, and its relationship with morphine-induced subjective effects, in healthy, nondependent opioid-experienced participants. METHODS Fifteen healthy male participants were initially included. Sessions were on separate days. On session 1, participants received intravenous morphine (10 mg/70 kg) in the clinic to ensure tolerability. Participants without adverse reactions (n = 10) then received intravenous morphine and placebo (saline) sessions, in counterbalanced order, while undergoing [11C]raclopride positron emission tomography scans. Subjective and physiological responses were assessed. Region-of-interest and voxelwise image analyses were used to assess changes in [11C]raclopride nondisplaceable binding potential. RESULTS Morphine produced marked subjective and physiological effects and induced a significant decrease in [11C]raclopride nondisplaceable binding potential, particularly in the nucleus accumbens and globus pallidus, where the change in [11C]raclopride nondisplaceable binding potential was approximately 9%. However, the subjective effects of morphine did not show a simple pattern of correlation with DA release. CONCLUSIONS This is, to our knowledge, the first study providing in vivo human evidence that DA transmission in the ventral striatum is affected by morphine. Further studies are required to fully delineate the DA contribution to the reinforcing effects of opioids.
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Affiliation(s)
- Primavera A Spagnolo
- Human Motor Control Section, National Institute on Neurological Disorders and Stroke, National Instutes of Health, Bethesda, Maryland
| | - Alane Kimes
- Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland
| | - Melanie L Schwandt
- Office of the Clinical Director, National Institute on Alcohol Abuse and Alcoholism, National Instutes of Health, Bethesda, Maryland
| | - Ehsan Shokri-Kojori
- Laboratory of Neuroimaging, National Institute on Alcohol Abuse and Alcoholism, National Instutes of Health, Bethesda, Maryland
| | - Shantalaxmi Thada
- Positron Emission Tomography Department, Clinical Center, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland
| | - Karran A Phillips
- Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland
| | - Nancy Diazgranados
- Office of the Clinical Director, National Institute on Alcohol Abuse and Alcoholism, National Instutes of Health, Bethesda, Maryland
| | - Kenzie L Preston
- Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland
| | - Peter Herscovitch
- Positron Emission Tomography Department, Clinical Center, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland
| | - Dardo Tomasi
- Laboratory of Neuroimaging, National Institute on Alcohol Abuse and Alcoholism, National Instutes of Health, Bethesda, Maryland
| | - Vijay A Ramchandani
- Section on Human Psychopharmacology, National Institute on Alcohol Abuse and Alcoholism, National Instutes of Health, Bethesda, Maryland.
| | - Markus Heilig
- Center for Social and Affective Neuroscience, Linköping University, Linköping, Sweden.
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Maia TV, Conceição VA. Dopaminergic Disturbances in Tourette Syndrome: An Integrative Account. Biol Psychiatry 2018; 84:332-344. [PMID: 29656800 DOI: 10.1016/j.biopsych.2018.02.1172] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 02/04/2018] [Accepted: 02/25/2018] [Indexed: 12/28/2022]
Abstract
Tourette syndrome (TS) is thought to involve dopaminergic disturbances, but the nature of those disturbances remains controversial. Existing hypotheses suggest that TS involves 1) supersensitive dopamine receptors, 2) overactive dopamine transporters that cause low tonic but high phasic dopamine, 3) presynaptic dysfunction in dopamine neurons, or 4) dopaminergic hyperinnervation. We review evidence that contradicts the first two hypotheses; we also note that the last two hypotheses have traditionally been considered too narrowly, explaining only small subsets of findings. We review all studies that have used positron emission tomography and single-photon emission computerized tomography to investigate the dopaminergic system in TS. The seemingly diverse findings from those studies have typically been interpreted as pointing to distinct mechanisms, as evidenced by the various hypotheses concerning the nature of dopaminergic disturbances in TS. We show, however, that the hyperinnervation hypothesis provides a simple, parsimonious explanation for all such seemingly diverse findings. Dopaminergic hyperinnervation likely causes increased tonic and phasic dopamine. We have previously shown, using a computational model of the role of dopamine in basal ganglia, that increased tonic dopamine and increased phasic dopamine likely increase the propensities to express and learn tics, respectively. There is therefore a plausible mechanistic link between dopaminergic hyperinnervation and TS via increased tonic and phasic dopamine. To further bolster this argument, we review evidence showing that all medications that are effective for TS reduce signaling by tonic dopamine, phasic dopamine, or both.
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Affiliation(s)
- Tiago V Maia
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.
| | - Vasco A Conceição
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
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Abstract
Dopamine D3 receptors have key roles in behavioral reward, addiction, Parkinson's disease, and schizophrenia, and there is interest in studying their role in these disorders using PET. However, current PET radiotracers for studying D3 receptors in humans all bind to both D2 and D3 due to similarities between the two receptors. Selective D2 and D3 radioligands would aid investigation of the differences between D2 and D3 circuitry in the central nervous system. While there are currently in vitro measures of ligand D3/D2 selectivity, there is a need for an in vivo PET measure of D3/D2 selectivity. This review discusses current PET imaging of dopamine D2/D3 receptors and proposes methodology for quantitating in vivo selectivity of probes for PET imaging of dopamine D3 receptors.
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Affiliation(s)
- Robert K Doot
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Jacob G Dubroff
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kyle J Labban
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Robert H Mach
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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The “highs and lows” of the human brain on dopaminergics: Evidence from neuropharmacology. Neurosci Biobehav Rev 2017. [DOI: 10.1016/j.neubiorev.2017.06.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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12
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Polyanska L, Critchley HD, Rae CL. Centrality of prefrontal and motor preparation cortices to Tourette Syndrome revealed by meta-analysis of task-based neuroimaging studies. NEUROIMAGE-CLINICAL 2017; 16:257-267. [PMID: 28831377 PMCID: PMC5554925 DOI: 10.1016/j.nicl.2017.08.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 08/01/2017] [Accepted: 08/02/2017] [Indexed: 01/31/2023]
Abstract
Tourette Syndrome (TS) is a neurodevelopmental condition characterized by chronic multiple tics, which are experienced as compulsive and 'unwilled'. Patients with TS can differ markedly in the frequency, severity, and bodily distribution of tics. Moreover, there are high comorbidity rates with attention deficit hyperactivity disorder (ADHD), obsessive compulsive disorder (OCD), anxiety disorders, and depression. This complex clinical profile may account for apparent variability of findings across neuroimaging studies that connect neural function to cognitive and motor behavior in TS. Here we crystalized information from neuroimaging regarding the functional circuitry of TS, and furthermore, tested specifically for neural determinants of tic severity, by applying activation likelihood estimation (ALE) meta-analyses to neuroimaging (activation) studies of TS. Fourteen task-based studies (13 fMRI and one H2O-PET) met rigorous inclusion criteria. These studies, encompassing 25 experiments and 651 participants, tested for differences between TS participants and healthy controls across cognitive, motor, perceptual and somatosensory domains. Relative to controls, TS participants showed distributed differences in the activation of prefrontal (inferior, middle, and superior frontal gyri), anterior cingulate, and motor preparation cortices (lateral premotor cortex and supplementary motor area; SMA). Differences also extended into sensory (somatosensory cortex and the lingual gyrus; V4); and temporo-parietal association cortices (posterior superior temporal sulcus, supramarginal gyrus, and retrosplenial cortex). Within TS participants, tic severity (reported using the Yale Global Tic Severity Scale; YGTSS) selectively correlated with engagement of SMA, precentral gyrus, and middle frontal gyrus across tasks. The dispersed involvement of multiple cortical regions with differences in functional reactivity may account for heterogeneity in the symptomatic expression of TS and its comorbidities. More specifically for tics and tic severity, the findings reinforce previously proposed contributions of premotor and lateral prefrontal cortices to tic expression.
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Affiliation(s)
- Liliana Polyanska
- Sackler Centre for Consciousness Science, University of Sussex, Falmer BN1 9RY, UK.,Department of Neuroscience, Brighton & Sussex Medical School, Falmer BN1 9RY, UK.,Department of Education and Psychology, Freie Universität Berlin, Habelschwerdter Allee 45, 14195 Berlin, Germany
| | - Hugo D Critchley
- Sackler Centre for Consciousness Science, University of Sussex, Falmer BN1 9RY, UK.,Department of Neuroscience, Brighton & Sussex Medical School, Falmer BN1 9RY, UK
| | - Charlotte L Rae
- Sackler Centre for Consciousness Science, University of Sussex, Falmer BN1 9RY, UK.,Department of Neuroscience, Brighton & Sussex Medical School, Falmer BN1 9RY, UK
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Siddiqi SH, Creech ML, Black KJ. Orthostatic stability with intravenous levodopa. PeerJ 2015; 3:e1198. [PMID: 26336641 PMCID: PMC4556150 DOI: 10.7717/peerj.1198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 07/29/2015] [Indexed: 11/20/2022] Open
Abstract
Intravenous levodopa has been used in a multitude of research studies due to its more predictable pharmacokinetics compared to the oral form, which is used frequently as a treatment for Parkinson's disease (PD). Levodopa is the precursor for dopamine, and intravenous dopamine would strongly affect vascular tone, but peripheral decarboxylase inhibitors are intended to block such effects. Pulse and blood pressure, with orthostatic changes, were recorded before and after intravenous levodopa or placebo-after oral carbidopa-in 13 adults with a chronic tic disorder and 16 tic-free adult control subjects. Levodopa caused no statistically or clinically significant changes in blood pressure or pulse. These data add to previous data that support the safety of i.v. levodopa when given with adequate peripheral inhibition of DOPA decarboxylase.
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Affiliation(s)
- Shan H Siddiqi
- Department of Psychiatry, Washington University School of Medicine , St. Louis, MO , USA
| | - Mary L Creech
- Department of Neurology, Washington University School of Medicine , St. Louis, MO , USA
| | - Kevin J Black
- Department of Psychiatry, Washington University School of Medicine , St. Louis, MO , USA ; Department of Neurology, Washington University School of Medicine , St. Louis, MO , USA ; Department of Radiology, Anatomy & Neurobiology, and Division of Biology and Biomedical Sciences, Washington University School of Medicine , St. Louis, MO , USA
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Greene DJ, Schlaggar BL, Black KJ. Neuroimaging in Tourette Syndrome: Research Highlights From 2014-2015. CURRENT DEVELOPMENTAL DISORDERS REPORTS 2015; 2:300-308. [PMID: 26543796 DOI: 10.1007/s40474-015-0062-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Tourette Syndrome (ts) is a developmental neuropsychiatric disorder of the central nervous system defined by the presence of chronic tics. While investigations of the underlying brain mechanisms have provided valuable information, a complete understanding of the pathophysiology of ts remains elusive. Neuroimaging methods provide remarkable tools for examining the human brain, and have been used to study brain structure and function in ts. In this article, we review ts neuroimaging studies published in 2014-2015. We highlight a number of noteworthy studies due to their innovative methods and interesting findings. Yet, we note that many of the recent studies share common concerns, specifically susceptibility to motion artifacts and modest sample sizes. Thus, we encourage future work to carefully address potential methodological confounds and to study larger samples to increase the potential for replicable results.
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Affiliation(s)
- Deanna J Greene
- Department of Psychiatry, Washington University School of Medicine ; Department of Radiology, Washington University School of Medicine
| | - Bradley L Schlaggar
- Department of Psychiatry, Washington University School of Medicine ; Department of Radiology, Washington University School of Medicine ; Department of Neurology, Washington University School of Medicine ; Department of Anatomy & Neurobiology, Washington University School of Medicine ; Department of Pediatrics, Washington University School of Medicine
| | - Kevin J Black
- Department of Psychiatry, Washington University School of Medicine ; Department of Radiology, Washington University School of Medicine ; Department of Neurology, Washington University School of Medicine ; Department of Anatomy & Neurobiology, Washington University School of Medicine
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