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Clinical correlation but no elevation of striatal dopamine synthesis capacity in two independent cohorts of medication-free individuals with schizophrenia. Mol Psychiatry 2022; 27:1241-1247. [PMID: 34789848 DOI: 10.1038/s41380-021-01337-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 09/03/2021] [Accepted: 10/01/2021] [Indexed: 11/08/2022]
Abstract
Dysregulation of dopamine systems has been considered a foundational driver of pathophysiological processes in schizophrenia, an illness characterized by diverse domains of symptomatology. Prior work observing elevated presynaptic dopamine synthesis capacity in some patient groups has not always identified consistent symptom correlates, and studies of affected individuals in medication-free states have been challenging to obtain. Here we report on two separate cohorts of individuals with schizophrenia spectrum illness who underwent blinded medication withdrawal and medication-free neuroimaging with [18F]-FDOPA PET to assess striatal dopamine synthesis capacity. Consistently in both cohorts, we found no significant differences between patient and matched, healthy comparison groups; however, we did identify and replicate robust inverse relationships between negative symptom severity and tracer-specific uptake widely throughout the striatum: [18F]-FDOPA specific uptake was lower in patients with a greater preponderance of negative symptoms. Complementary voxel-wise and region of interest analyses, both with and without partial volume correction, yielded consistent results. These data suggest that for some individuals, striatal hyperdopaminergia may not be a defining or enduring feature of primary psychotic illness. However, clinical differences across individuals may be significantly linked to variability in striatal dopaminergic tone. These findings call for further experimentation aimed at parsing the heterogeneity of dopaminergic systems function in schizophrenia.
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Buoli M, Caldiroli A, Altamura AC. Psychiatric Conditions in Parkinson Disease: A Comparison With Classical Psychiatric Disorders. J Geriatr Psychiatry Neurol 2016; 29:72-91. [PMID: 26377851 DOI: 10.1177/0891988715606233] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Psychiatric conditions often complicate the outcome of patients affected by Parkinson disease (PD), but they differ from classical psychiatric disorders in terms of underlying biological mechanisms, clinical presentation, and treatment response. The purpose of the present review is to illustrate the biological and clinical aspects of psychiatric conditions associated with PD, with particular reference to the differences with respect to classical psychiatric disorders. A careful search of articles on main databases was performed in order to obtain a comprehensive review about the main psychiatric conditions associated with PD. A manual selection of the articles was then performed in order to consider only those articles that concerned with the topic of the review. Psychiatric conditions in patients with PD present substantial differences with respect to classical psychiatric disorders. Their clinical presentation does not align with the symptom profiles represented by Diagnostic and Statistical Manual for Mental Disorders and International Classification of Diseases. Furthermore, psychiatry treatment guidelines are of poor help in managing psychiatric symptoms of patients with PD. Specific diagnostic tools and treatment guidelines are needed to allow early diagnosis and adequate treatment of psychiatric conditions in comorbidity with PD.
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Affiliation(s)
- Massimiliano Buoli
- Department of Psychiatry, University of Milan, Fondazione IRCCS Ca'Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Alice Caldiroli
- Department of Psychiatry, University of Milan, Fondazione IRCCS Ca'Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Alfredo Carlo Altamura
- Department of Psychiatry, University of Milan, Fondazione IRCCS Ca'Granda Ospedale Maggiore Policlinico, Milan, Italy
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3
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Relation between dopamine synthesis capacity and cell-level structure in human striatum: a multi-modal study with positron emission tomography and diffusion tensor imaging. PLoS One 2014; 9:e87886. [PMID: 24498218 PMCID: PMC3909269 DOI: 10.1371/journal.pone.0087886] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 01/04/2014] [Indexed: 12/02/2022] Open
Abstract
Positron emission tomography (PET) study has shown that dopamine synthesis capacity varied among healthy individuals. This interindividual difference might be due to a difference in the cell-level structure of presynaptic dopaminergic neurons, i.e., cellular density and/or number. In this study, the relations between the dopamine synthesis capacity measured by PET and the parameter estimates in diffusion tensor imaging (DTI) in striatal subregions were investigated in healthy human subjects. DTI and PET studies with carbon-11 labeled L-DOPA were performed in ten healthy subjects. Age-related changes in the above parameters were also considered. Fractional anisotropy showed a significant positive correlation with age in the posterior caudate. There was significant negative correlation between dopamine synthesis capacity and mean diffusivity in the posterior caudate and putamen. Assuming that mean diffusivity reflects the density of wide-spreading axonal terminals in the striatum, the result suggests that dopamine synthesis may be related to the density of dopaminergic neuronal fibers. It is evident that PET/DTI combined measurements can contribute to investigations of the pathophysiology of neuropsychiatric diseases involving malfunction of dopaminergic neurons.
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Agnati LF, Barlow P, Ghidoni R, Borroto-Escuela DO, Guidolin D, Fuxe K. Possible genetic and epigenetic links between human inner speech, schizophrenia and altruism. Brain Res 2012; 1476:38-57. [PMID: 22483963 DOI: 10.1016/j.brainres.2012.02.074] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Revised: 02/29/2012] [Accepted: 02/29/2012] [Indexed: 11/19/2022]
Abstract
Unique mental abilities have been crucial for evolutionary success of Homo sapiens and for the development of his complex social organization. However, these abilities have also become a target for mental disorders which often result in a reduced fitness and in conflicts between the individual and the conventions of society. To account for this evolutionary maladaptation, we advance a new concept: that of "mis-exaptation", derived from SJ Gould and E Vrba's concept of exaptation. Mis-exaptation is a characteristic which, although it may confer positive effects in one field of activity, may reach an inappropriate degree of specialisation to have deleterious effects in that or in another field thereby leading to a decrease in fitness of the individual. This paper considers "inner speech" as an exaptation. Although inner speech is usually a positive aid to learning and reasoning, it may also favour the emergence of mental disturbances, such as the auditory hallucinations which are characteristic of schizophrenia. There is, nevertheless, a possible evolutionary value in mis-exaptational inner speech; two traits associated with the mis-exapted state would be altruistic behaviour and heightened creativity, the latter being over-expressed in relatives of schizophrenic patients. A possible solution for the evolutionary-genetic paradox posed by altruism and schizophrenia arising from mis-exaptation will be suggested in the light of a cryptic genetic repertoire. A selection of illustrative examples of each of these mental states is presented as they appear in the pages of the European literature. This article is part of a Special Issue entitled: Brain Integration.
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Kuroda Y, Motohashi N, Ito H, Ito S, Takano A, Takahashi H, Nishikawa T, Suhara T. Chronic repetitive transcranial magnetic stimulation failed to change dopamine synthesis rate: preliminary L-[β-11C]DOPA positron emission tomography study in patients with depression. Psychiatry Clin Neurosci 2010; 64:659-62. [PMID: 21155169 DOI: 10.1111/j.1440-1819.2010.02152.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have examined the effects of repetitive transcranial magnetic stimulation (rTMS) on central dopaminergic function in patients with depression using positron emission tomography with L-[β-11C]DOPA, a ligand to assess the rate of endogenous dopamine synthesis. Eight patients were treated with 10-daily sessions of rTMS over the left dorsolateral prefrontal cortex. Positron emission tomography scanning was performed in each patient twice, before the first session and 1 day after the last session. Although four out of eight patients responded to rTMS, there were no changes in the striatal dopamine synthesis rate (k) following rTMS. These results suggest that chronic rTMS had a limited effect on the dopaminergic system.
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Affiliation(s)
- Yuko Kuroda
- Section of Psychiatry and Behavioral Science, Graduate School of Tokyo Medical and Dental University, Tokyo, Japan
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6
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Abstract
A dysregulation of the mesolimbic dopamine system in schizophrenia patients may lead to aberrant attribution of incentive salience and contribute to the emergence of psychopathological symptoms like delusions. The dopaminergic signal has been conceptualized to represent a prediction error that indicates the difference between received and predicted reward. The incentive salience hypothesis states that dopamine mediates the attribution of "incentive salience" to conditioned cues that predict reward. This hypothesis was initially applied in the context of drug addiction and then transferred to schizophrenic psychosis. It was hypothesized that increased firing (chaotic or stress associated) of dopaminergic neurons in the striatum of schizophrenia patients attributes incentive salience to otherwise irrelevant stimuli. Here, we review recent neuroimaging studies directly addressing this hypothesis. They suggest that neuronal functions associated with dopaminergic signaling, such as the attribution of salience to reward-predicting stimuli and the computation of prediction errors, are indeed altered in schizophrenia patients and that this impairment appears to contribute to delusion formation.
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Affiliation(s)
- Andreas Heinz
- Department of Psychiatry, Charité-Universitätsmedizin Berlin, Charité Campus Mitte, 10117 Berlin, Germany.
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Archer T, Beninger RJ, Palomo T, Kostrzewa RM. Epigenetics and biomarkers in the staging of neuropsychiatric disorders. Neurotox Res 2010; 18:347-66. [PMID: 20237880 DOI: 10.1007/s12640-010-9163-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Revised: 01/29/2010] [Accepted: 02/18/2010] [Indexed: 01/05/2023]
Abstract
Epigenetics, or alterations in the phenotype or gene expression due to mechanisms other than changes in the underlying DNA sequence, reflects the sensitivity and responsiveness of human and animal brains in constantly varying circumstances regulating gene expression profiles that define the biomarkers and present the ultimate phenotypical outcomes, such as cognition and emotion. Epigenetics is associated with functionally relevant alterations to the genome in such a fashion that under the particular conditions of early, adolescent, and adult life, environmental signals may activate intracellular pathways that remodel the "epigenome," triggering changes in gene expression and neural function. Thus, genetic influences in neuropsychiatric disorders that are subject to clinical staging, epigenetics in schizophrenia, epigenetic considerations in the expression of sensorimotor gating resulting from disease conditions, biomarkers of drug use and addiction, current notions on the role of dopamine in schizophrenia spectrum disorders, and the discrete interactions of biomarkers in persistent memory were to greater or lesser extents reflected upon. The relative contributions of endophenotypes and epistasis for mediating epigenetic phenomena and the outcomes as observed in the analysis of biomarkers appear to offer a multitude of interactive combinations to further complicate the labyrinthine machinations of diagnosis, intervention, and prognosis.
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Affiliation(s)
- Trevor Archer
- Department of Psychology, University of Gothenburg, Box 500, 405 30, Gothenburg, Sweden.
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Kumakura Y, Cumming P. PET studies of cerebral levodopa metabolism: a review of clinical findings and modeling approaches. Neuroscientist 2010; 15:635-50. [PMID: 19793723 DOI: 10.1177/1073858409338217] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
[(18)F]Fluoro-3,4-dihydroxyphenyl-L-alanine (FDOPA) was one of the first successful tracers for molecular imaging by positron emission tomography (PET), and has proven immensely valuable for studies of Parkinson's disease. Following intravenous FDOPA injection, the decarboxylated metabolite [(18)F] fluorodopamine is formed and trapped within terminals of the nigrostriatal dopamine neurons; reduction in the simple ratio between striatum and cerebellum is indicative of nigrostriatal degeneration. However, the kinetic analysis of dynamic FDOPA-PET recordings is formidably complex due to the entry into brain of the plasma metabolite O-methyl-FDOPA and due to the eventual washout of decarboxylated metabolites. Linear graphical analysis relative to a reference tissue input function is popular and convenient for routine clinical studies in which serial arterial blood samples are unavailable. This simplified approach has facilitated longitudinal studies in large patient cohorts. Linear graphical analysis relative to the metabolite-corrected arterial FDOPA input yields a more physiological index of FDOPA utilization, the net blood-brain clearance. Using a constrained compartmental model, FDOPA-PET recordings can be used to calculate the relative activity of the enzyme DOPA decarboxylase in living brain. We have extended this approach so as to obtain an index of steady-state trapping of [( 18)F]fluorodopamine in synaptic vesicles. Although simple methods of image analysis are sufficient for the purposes of routine clinical studies, the more complex approaches have revealed hidden aspects of brain dopamine in personality, healthy aging, and in the pathophysiologies of Parkinson's disease and schizophrenia.
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Affiliation(s)
- Yoshitaka Kumakura
- Department of Nuclear Medicine, Graduate School of Medicine, University of Tokyo, and Research Center for Advanced Science and Technology, the University of Tokyo, Tokyo, Japan.
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Nikolaus S, Antke C, Müller HW. In vivo imaging of synaptic function in the central nervous system: II. Mental and affective disorders. Behav Brain Res 2009; 204:32-66. [DOI: 10.1016/j.bbr.2009.06.009] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Revised: 05/27/2009] [Accepted: 06/02/2009] [Indexed: 10/20/2022]
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10
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Razifar P, Engler H, Blomquist G, Ringheim A, Estrada S, Långström B, Bergström M. Principal component analysis with pre-normalization improves the signal-to-noise ratio and image quality in positron emission tomography studies of amyloid deposits in Alzheimer's disease. Phys Med Biol 2009; 54:3595-612. [DOI: 10.1088/0031-9155/54/11/021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Nozaki S, Kato M, Takano H, Ito H, Takahashi H, Arakawa R, Okumura M, Fujimura Y, Matsumoto R, Ota M, Takano A, Otsuka A, Yasuno F, Okubo Y, Kashima H, Suhara T. Regional dopamine synthesis in patients with schizophrenia using L-[beta-11C]DOPA PET. Schizophr Res 2009; 108:78-84. [PMID: 19056247 DOI: 10.1016/j.schres.2008.11.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Revised: 10/14/2008] [Accepted: 11/08/2008] [Indexed: 11/26/2022]
Abstract
The dopamine hypothesis has been the most widely known theory concerning schizophrenia. However, the exact mechanism including presynaptic dopaminergic activity and its relationship with symptom severity still remains to be revealed. We measured presynaptic dopamine synthesis using positron emission tomography (PET) with L-[beta-(11)C]DOPA in 18 patients with schizophrenia (14 drug-naive and 4 drug-free patients) and 20 control participants. Dopamine synthesis rates, expressed as k(i) values, were obtained using a graphical method, and the occipital cortex was used as reference region. Regions of interest were placed on the prefrontal cortex, temporal cortex, anterior cingulate, parahippocampus, thalamus, caudate nucleus, and putamen. Psychopathology was assessed with the Positive and Negative Symptom Scale (PANSS). We found significantly higher k(i) values in patients than in controls in the left caudate nucleus, but not in the other regions. The k(i) values in the thalamus exhibited a significant positive correlation with the PANSS total scores. Furthermore, a significant positive correlation was observed between the PANSS positive subscale scores and k(i) values in the right temporal cortex. Patients with schizophrenia showed higher dopamine synthesis in the left caudate nucleus, and dopaminergic transmission in the thalamus and right temporal cortex might be implicated in the expression of symptoms in schizophrenia.
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Affiliation(s)
- Shoko Nozaki
- Molecular Neuroimaging Group, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
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12
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Kalus P, Falkai P, Heinz A. [Structural and functional brain changes in schizophrenic disorders. Indications of early neuronal developmental disturbances?]. DER NERVENARZT 2008; 79:275-87. [PMID: 18264816 DOI: 10.1007/s00115-008-2414-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The neurodevelopmental hypothesis of schizophrenia, which was established 30 years ago and discussed controversially for a long time, postulates that pre- and perinatally acting cerebral noxae cause disturbances of corticogenesis in the developing neuronal fibre systems which are essential for later onset of the disease. During recent years the cerebral alterations of schizophrenic patients could be further characterized as area-, layer-, and cell type-specific changes in temporolimbic and frontal regions leading to specific abnormalities of intrinsic and extrinsic connectivity. Animal models allowed for realistic imitations of these structural lesions and for elucidating their functional consequences concerning transmitter systems and behaviour. With modern neuroimaging techniques microstructural changes and alterations in cerebral activation can be exactly demonstrated and related to the specific psychopathologic features of schizophrenia.
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Affiliation(s)
- P Kalus
- Psychiatrische Universitätsklinik der Charité im St. Hedwig Krankenhaus, Grosse Hamburger Strasse 5-11, 10115 Berlin.
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Kumakura Y, Cumming P, Vernaleken I, Buchholz HG, Siessmeier T, Heinz A, Kienast T, Bartenstein P, Gründer G. Elevated [18F]fluorodopamine turnover in brain of patients with schizophrenia: an [18F]fluorodopa/positron emission tomography study. J Neurosci 2007; 27:8080-7. [PMID: 17652599 PMCID: PMC6672729 DOI: 10.1523/jneurosci.0805-07.2007] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Previous positron emission tomography (PET) studies with levodopa analogs have revealed a modestly increased capacity for dopamine synthesis in the striatum of patients with schizophrenia compared with healthy age-matched control subjects. We hypothesized that not just the synthesis but also the turnover of radiolabeled dopamine is elevated in patients. To test the hypothesis, we reanalyzed 2-h-long [18F]fluorodopa (FDOPA)/PET recordings from eight unmedicated patients with schizophrenia and 15 healthy age-matched control subjects, using new methods for the quantification of [18F]fluorodopamine steady-state kinetics. The fractional rate constant for the catabolism and elimination of [18F]fluorodopamine was elevated nearly twofold in striatum, the largest biochemical difference in brain of schizophrenics yet reported. The magnitude of the intrinsic blood-brain FDOPA clearance with correction for this loss of [18F]fluorodopamine metabolites was increased by 20% in caudate and putamen and by 50% in amygdala and midbrain of the patients. However, the magnitude of the steady-state storage of FDOPA and its decarboxylated metabolites (V(d)) was reduced by one-third in the caudate nucleus and amygdala of the schizophrenic group. Thus, reduced steady-state storage of [18F]fluorodopamine occurs in the midst of accelerated synthesis in brain of untreated patients. Positive scores of the positive and negative syndrome scale correlated inversely with the magnitude of V(d) in amygdala, suggesting an association between positive symptoms and impaired steady-state storage of FDOPA metabolites in that structure.
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Affiliation(s)
- Yoshitaka Kumakura
- Centre for Functionally Integrative Neuroscience, Aarhus University, DK-8000 Aarhus C, Denmark.
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Forssberg H, Fernell E, Waters S, Waters N, Tedroff J. Altered pattern of brain dopamine synthesis in male adolescents with attention deficit hyperactivity disorder. Behav Brain Funct 2006; 2:40. [PMID: 17144907 PMCID: PMC1698925 DOI: 10.1186/1744-9081-2-40] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2006] [Accepted: 12/04/2006] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Limited data from positron emission tomography (PET) studies of subjects with attention-deficit/hyperactivity disorder (ADHD) indicate alterations in brain dopamine neurotransmission. However, these studies have used conventional univariate approaches that are less sensitive to detect complex interactions that may exist between different brain dopamine pathways and individual symptoms of ADHD. We aimed to investigate these potential interactions in adolescents with ADHD. METHODS We used a 3D PET scan to measure utilization of native L-[11C]-DOPA to map dopamine presynaptic function in various cortical, striatal and midbrain regions in a group of 8 male adolescents with ADHD and 6 age matched controls. To evaluate the interactions between the studied brain regions, multivariate statistical methods were used. RESULTS Abnormal dopaminergic function was found in multiple brain regions of patients with ADHD. A main finding was lower L-[11C]-DOPA utilization in adolescent with ADHD as compared to control subjects, especially in subcortical regions. This pattern of dopaminergic activity was correlated specifically with symptoms of inattention. CONCLUSION Dopamine signalling in the brain plays an important modulatory role in a variety of motor and cognitive functions. We have identified region-specific functional abnormalities in dopaminergic function, which may help better account for the symptoms of ADHD.
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Affiliation(s)
- Hans Forssberg
- Neuropediatrics, Department of Women and Child Health, Karolinska Institutet, Stockholm, Sweden
| | - Elisabeth Fernell
- Neuropediatrics, Department of Women and Child Health, Karolinska Institutet, Stockholm, Sweden
| | - Susanna Waters
- Carlsson Research AB, Arvid Wallgrens backe 20, 413 46, Göteborg, Sweden
| | - Nicholas Waters
- Carlsson Research AB, Arvid Wallgrens backe 20, 413 46, Göteborg, Sweden
| | - Joakim Tedroff
- Carlsson Research AB, Arvid Wallgrens backe 20, 413 46, Göteborg, Sweden
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Razifar P, Axelsson J, Schneider H, Långström B, Bengtsson E, Bergström M. A new application of pre-normalized principal component analysis for improvement of image quality and clinical diagnosis in human brain PET studies—Clinical brain studies using [11C]-GR205171, [11C]-l-deuterium-deprenyl, [11C]-5-Hydroxy-l-Tryptophan, [11C]-l-DOPA and Pittsburgh Compound-B. Neuroimage 2006; 33:588-98. [PMID: 16934493 DOI: 10.1016/j.neuroimage.2006.05.060] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2005] [Revised: 05/11/2006] [Accepted: 05/23/2006] [Indexed: 10/24/2022] Open
Abstract
Principal component analysis (PCA) is one of the most applied multivariate image analysis tool on dynamic Positron Emission Tomography (PET). Independent of used reconstruction methodologies, PET images contain correlation in-between pixels, correlations in-between frame and errors caused by the reconstruction algorithm including different corrections, which can affect the performance of the PCA. In this study, we have investigated a new approach of application of PCA on pre-normalized, dynamic human PET images. A range of different tracers have been used for this purpose to explore the performance of the new method as a way to improve detection and visualization of significant changes in tracer kinetics and to enhance the discrimination between pathological and healthy regions in the brain. We compare the new results with the results obtained using other methods. Images generated using the new approach contain more detailed anatomical information with higher quality, precision and visualization, compared with images generated using other methods.
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Affiliation(s)
- Pasha Razifar
- Uppsala University, Centre for Image Analysis, Lägerhyddsv. 3, SE-752 37 Uppsala, Sweden
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Ota M, Yasuno F, Ito H, Seki C, Nozaki S, Asada T, Suhara T. Age-related decline of dopamine synthesis in the living human brain measured by positron emission tomography with L-[beta-11C]DOPA. Life Sci 2006; 79:730-6. [PMID: 16580023 DOI: 10.1016/j.lfs.2006.02.017] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2005] [Revised: 02/08/2006] [Accepted: 02/15/2006] [Indexed: 01/25/2023]
Abstract
Loss of dopamine synthesis in the striatum with normal human aging has been observed in the postmortem brain. To investigate whether there is age-associated change in dopamine synthesis in the extrastriatal brain regions similar to that in the striatum, positron emission tomography studies with (11)C-labelled l-DOPA were performed on 21 normal healthy male subjects (age range 20-67 years). Decline in the tissue fraction of gray matter per region of interest was also investigated. The overall uptake rate constant for each region of interest was quantified by the Patlak plot method using the occipital cortex as reference region. Regions of interest were set on the dorsolateral prefrontal cortex, lateral temporal cortex, medial temporal cortex, occipital cortex, parietal cortex, anterior cingulate, thalamus, midbrain, caudate nucleus, and putamen. Test-retest analysis indicated good reproducibility of the overall uptake rate constant. Significant age-related declines of dopamine synthesis were observed in the striatum and extrastriatal regions except midbrain. The decline in the overall uptake rate constant was more prominent than in the tissue fraction of gray matter. These results indicate that the previously demonstrated age-related decline in striatal dopamine synthesis extends to several extrastriatal regions in normal human brain.
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Affiliation(s)
- Miho Ota
- Clinical Neuroimaging Section, Department of Molecular Neuroimaging, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
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