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Sample records for dopamine functional mri

  1. Neurovascular coupling to D2/D3 dopamine receptor occupancy using simultaneous PET/functional MRI

    DEFF Research Database (Denmark)

    Sander, Christin Y; Hooker, Jacob M; Catana, Ciprian

    2013-01-01

    This study employed simultaneous neuroimaging with positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) to demonstrate the relationship between changes in receptor occupancy measured by PET and changes in brain activity inferred by fMRI. By administering the D2/D3...... dopamine receptor antagonist [(11)C]raclopride at varying specific activities to anesthetized nonhuman primates, we mapped associations between changes in receptor occupancy and hemodynamics [cerebral blood volume (CBV)] in the domains of space, time, and dose. Mass doses of raclopride above tracer levels...... caused increases in CBV and reductions in binding potential that were localized to the dopamine-rich striatum. Moreover, similar temporal profiles were observed for specific binding estimates and changes in CBV. Injection of graded raclopride mass doses revealed a monotonic coupling between neurovascular...

  2. Speech-induced striatal dopamine release is left lateralized and coupled to functional striatal circuits in healthy humans: A combined PET, fMRI and DTI study

    Science.gov (United States)

    Simonyan, Kristina; Herscovitch, Peter; Horwitz, Barry

    2013-01-01

    Considerable progress has been recently made in understanding the brain mechanisms underlying speech and language control. However, the neurochemical underpinnings of normal speech production remain largely unknown. We investigated the extent of striatal endogenous dopamine release and its influences on the organization of functional striatal speech networks during production of meaningful English sentences using a combination of positron emission tomography (PET) with the dopamine D2/D3 receptor radioligand [11C]raclopride and functional MRI (fMRI). In addition, we used diffusion tensor tractography (DTI) to examine the extent of dopaminergic modulatory influences on striatal structural network organization. We found that, during sentence production, endogenous dopamine was released in the ventromedial portion of the dorsal striatum, in its both associative and sensorimotor functional divisions. In the associative striatum, speech-induced dopamine release established a significant relationship with neural activity and influenced the left-hemispheric lateralization of striatal functional networks. In contrast, there were no significant effects of endogenous dopamine release on the lateralization of striatal structural networks. Our data provide the first evidence for endogenous dopamine release in the dorsal striatum during normal speaking and point to the possible mechanisms behind the modulatory influences of dopamine on the organization of functional brain circuits controlling normal human speech. PMID:23277111

  3. Beyond dopamine: functional MRI predictors of responsiveness to cognitive behaviour therapy for psychosis

    Directory of Open Access Journals (Sweden)

    Veena Kumari

    2010-02-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:Table Normal; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:Calibri,sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:Times New Roman; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Times New Roman; mso-bidi-theme-font:minor-bidi;} Despite the favourable effects of antipsychotics on positive symptoms of schizophrenia, many patients continue to suffer from distressing symptoms. Additional benefi ts of cognitive behavior therapy for psychosis (CBTp have been reported for approximately 50% of such patients. Given the role of left hemisphere-based language processes in responsiveness to CBT for depression, and language pathway abnormalities in psychosis, this study examined whether pre-therapy brain activity during a verbal monitoring task predicts CBTp responsiveness in schizophrenia. Fifty-two outpatients, stable on antipsychotics with at least one persistent distressing positive symptom and wishing to receive CBTp adjunctive to their treatment-as-usual, and 20 healthy participants underwent fMRI during monitoring of self- and externally-generated (normal and distorted speech. Subsequently, 26 patients received CBTp for 6-8 months adjunctive to their treatment-as-usual (CBTp + TAU, 20 completers, and 26 continued with their treatment-as-usual (TAU-alone, 18 completers. Symptoms were assessed (blindly at entry and follow-up. The CBTp + TAU and TAU-alone groups had comparable

  4. Dopamine

    International Nuclear Information System (INIS)

    Walters, L.

    1983-01-01

    Dopamine is an important neurotransmittor in the central nervous system. The physiological function of the peripheral dopamine receptors is unknown, but they are of therapeutic importance as dopamine is used to improve renal blood flow in shocked patients. There are 4 dopamine receptors. The classification of these dopamine receptors has been made possible by research with radiopharmaceuticals. Dopamine sensitive adenylate cyclase is an inherent part of the dopamine-1-receptor. Dopamine-1-receptors are stimulated by micromolar (physiological) concentrations of dopamine and inhibited by micromolar (supratherapeutic) concentrations of the antipsychotic drugs. The vascular effect of dopamine is mediated through the dopamine-1-receptors. Dopamine-2-receptors are responsible for the effect of dopamine at the mesolimbic, nigrostriatal and chemoreceptortrigger areas. It is activated by micromolar concentrations of dopamine and blocked by nanomolar (therapeutic) concentrations of the anti-psychotic drugs. Dopamine-3-receptors are activated by nanomolar concentrations of dopamine and inhibited by micromolar concentrations of the antipsychotic drugs. They occur on presynaptic nerve terminals and have a negative feedback effect on the liberation of dopamine, noradrenaline and serotonin. The dopamine-4-receptors are activated by nanomolar concentrations of dopamine. These are the only dopamine receptors that could be responsible for effects in the hypophysis as only nanomolar concentrations of dopamine occur there. These receptors are blocked by nanomolar concentrations of the antipsychotic drugs

  5. A receptor-based model for dopamine-induced fMRI signal

    Science.gov (United States)

    Mandeville, Joseph. B.; Sander, Christin Y. M.; Jenkins, Bruce G.; Hooker, Jacob M.; Catana, Ciprian; Vanduffel, Wim; Alpert, Nathaniel M.; Rosen, Bruce R.; Normandin, Marc D.

    2013-01-01

    This report describes a multi-receptor physiological model of the fMRI temporal response and signal magnitude evoked by drugs that elevate synaptic dopamine in basal ganglia. The model is formulated as a summation of dopamine’s effects at D1-like and D2-like receptor families, which produce functional excitation and inhibition, respectively, as measured by molecular indicators like adenylate cyclase or neuroimaging techniques like fMRI. Functional effects within the model are described in terms of relative changes in receptor occupancies scaled by receptor densities and neuro-vascular coupling constants. Using literature parameters, the model reconciles many discrepant observations and interpretations of pre-clinical data. Additionally, we present data showing that amphetamine stimulation produces fMRI inhibition at low doses and a biphasic response at higher doses in the basal ganglia of non-human primates (NHP), in agreement with model predictions based upon the respective levels of evoked dopamine. Because information about dopamine release is required to inform the fMRI model, we simultaneously acquired PET 11C-raclopride data in several studies to evaluate the relationship between raclopride displacement and assumptions about dopamine release. At high levels of dopamine release, results suggest that refinements of the model will be required to consistently describe the PET and fMRI data. Overall, the remarkable success of the model in describing a wide range of preclinical fMRI data indicate that this approach will be useful for guiding the design and analysis of basic science and clinical investigations and for interpreting the functional consequences of dopaminergic stimulation in normal subjects and in populations with dopaminergic neuroadaptations. PMID:23466936

  6. Quality assurance in functional MRI

    DEFF Research Database (Denmark)

    Liu, Thomas T; Glover, Gary H; Mueller, Bryon A

    2015-01-01

    Over the past 20 years, functional magnetic resonance imaging (fMRI) has ben- efited greatly from improvements in MRI hardware and software. At the same time, fMRI researchers have pushed the technical limits of MRI systems and greatly in- fluenced the development of state-of-the-art systems...... consistent data throughout the course of a study, and consistent stability across time and sites is needed to allow data from different time periods or acquisition sites to be optimally integrated....

  7. Functional MRI of the kidneys

    OpenAIRE

    Zhang, Jeff L.; Rusinek, Henry; Chandarana, Hersh; Lee, Vivian S.

    2013-01-01

    Renal function is characterized by different physiologic aspects, including perfusion, glomerular filtration, interstitial diffusion and tissue oxygenation. MRI shows great promise in assessing these renal tissue characteristics noninvasively. The last decade has witnessed a dramatic progress in MRI techniques for renal function assessment. This article briefly describes relevant renal anatomy and physiology, reviews the applications of functional MRI techniques for the diagnosis of renal dis...

  8. Diffusion, confusion and functional MRI

    International Nuclear Information System (INIS)

    Le Bihan, Denis

    2012-01-01

    Diffusion MRI has been introduced in 1985 and has had a very successful life on its own. While it has become a standard for imaging stroke and white matter disorders, the borders between diffusion MRI and the general field of fMRI have always remained fuzzy. First, diffusion MRI has been used to obtain images of brain function, based on the idea that diffusion MRI could also be made sensitive to blood flow, through the intra-voxel incoherent motion (IVIM) concept. Second, the IVIM concept helped better understand the contribution from different vasculature components to the BOLD fMRI signal. Third, it has been shown recently that a genuine fMRI signal can be obtained with diffusion MRI. This 'DfMRI' signal is notably different from the BOLD fMRI signal, especially for its much faster response to brain activation both at onset and offset, which points out to structural changes in the neural tissues, perhaps such as cell swelling, occurring in activated neural tissue. This short article reviews the major steps which have paved the way for this exciting development, underlying how technical progress with MRI equipment has each time been instrumental to expand the horizon of diffusion MRI toward the field of fMRI. (authors)

  9. Cross-hemispheric dopamine projections have functional significance

    Science.gov (United States)

    Fox, Megan E.; Mikhailova, Maria A.; Bass, Caroline E.; Takmakov, Pavel; Gainetdinov, Raul R.; Budygin, Evgeny A.; Wightman, R. Mark

    2016-01-01

    Dopamine signaling occurs on a subsecond timescale, and its dysregulation is implicated in pathologies ranging from drug addiction to Parkinson’s disease. Anatomic evidence suggests that some dopamine neurons have cross-hemispheric projections, but the significance of these projections is unknown. Here we report unprecedented interhemispheric communication in the midbrain dopamine system of awake and anesthetized rats. In the anesthetized rats, optogenetic and electrical stimulation of dopamine cells elicited physiologically relevant dopamine release in the contralateral striatum. Contralateral release differed between the dorsal and ventral striatum owing to differential regulation by D2-like receptors. In the freely moving animals, simultaneous bilateral measurements revealed that dopamine release synchronizes between hemispheres and intact, contralateral projections can release dopamine in the midbrain of 6-hydroxydopamine–lesioned rats. These experiments are the first, to our knowledge, to show cross-hemispheric synchronicity in dopamine signaling and support a functional role for contralateral projections. In addition, our data reveal that psychostimulants, such as amphetamine, promote the coupling of dopamine transients between hemispheres. PMID:27298371

  10. PCBs Alter Dopamine Mediated Function in Aging Workers

    Science.gov (United States)

    2011-01-01

    PCBs Alter Dopamine Mediated Function in Aging Workers 5a. CONTRACT NUMBER 5b. GRANT NUMBER DAMD17-02-1-0173 5c. PROGRAM ELEMENT...hypothesized that occupational exposure to polychlorinated biphenyls (PCBs) reduces dopamine (DA) terminal densities in the basal ganglia. We found...motor function in women compared to similarly aged men with similar bone lead levels. These latter findings are the first to demonstrate a sexual

  11. Clinical application of functional MRI

    International Nuclear Information System (INIS)

    Taniwaki, Takayuki

    2010-01-01

    Described is the present state of clinical application of fMRI in the preoperative assessment of brain tumors, and plasticity in and pathophysiology of central diseases. For the tumor resection, fMRI is useful for risk assessment of postoperative nerve dysfunction, for selection of the patient rather suitable for brain mapping at the invasive surgery than at the pre-operation and for guidance of the operation itself. Preoperative fMRI alone can neither distinguish the regions of the primary and secondary functions nor exhibit the relation between the tumor and white matter fibers but there are compensatory means for these drawbacks. Benefit of preoperative fMRI has not yet been based on the evidence on double blind trials. Combination of fMRI imaging and electroencephalography (EEG) finding has shown that, in generalized epilepsy, extensive and stimulated activation occurs in both frontal/occipital regions and in thalamus area, respectively, and that the concomitant lowered activities are conceivably the reflection of burst discharge in normal brain functions. Plasticity in the human brain has been demonstrated by fMRI in cerebral vascular diseases, multiple sclerosis and amyotrophic lateral sclerosis. Pathogenesis of Parkinson disease and depression has been better understood by fMRI investigations revealing regions with elevated and reduced activities. Studies of attention deficit hyperactivity disorder have shown similar change of activities with functional reductions of the right dorsolateral frontal anterior area and of dorsal frontal cingulate gyrus, together with stimulated wider regions to given tasks. As above, fMRI has greatly contributed to our understanding of diseases of central nervous system and is to be expected to expand wider in this field. (T.T.)

  12. Mandarin functional MRI Language paradigms

    OpenAIRE

    Ci, He; van Graan, Andre; Gonz?lvez, Gloria; Thompson, Pamela; Hill, Andrea; Duncan, John S.

    2016-01-01

    Abstract Objective The objective of this study was to implement convenient, fast, and accurate Mandarin task paradigms for functional MRI, and to locate the Chinese language functional areas in frontal and temporal lobes. Materials and Methods Nineteen healthy Chinese volunteers participated in this study, which utilized a block design with four language tasks: auditory naming (AN), picture naming (PN), verbal fluency?character (VFC), and verbal fluency?letter (VFL). All functional images wer...

  13. Plasma functionalized surface of commodity polymers for dopamine detection

    Energy Technology Data Exchange (ETDEWEB)

    Fabregat, Georgina [Departament d’Enginyeria Química, E.T.S. d’Enginyeria Industrial de Barcelona, Universitat Politècnica de Catalunya, Diagonal 647, 08028, Barcelona (Spain); Center for Research in Nano-Engineering, Universitat Politècnica de Catalunya, Campus Sud, Edifici C’, C/Pasqual i Vila s/n, Barcelona, E-08028 (Spain); Osorio, Joaquin [Departament d’Enginyeria Química, E.T.S. d’Enginyeria Industrial de Barcelona, Universitat Politècnica de Catalunya, Diagonal 647, 08028, Barcelona (Spain); Castedo, Alejandra [Center for Research in Nano-Engineering, Universitat Politècnica de Catalunya, Campus Sud, Edifici C’, C/Pasqual i Vila s/n, Barcelona, E-08028 (Spain); Institut de Tècniques Energètiques, E.T.S. d’Enginyeria Industrial de Barcelona, Universitat Politècnica de Catalunya, Diagonal 647, 08028, Barcelona (Spain); Armelin, Elaine [Departament d’Enginyeria Química, E.T.S. d’Enginyeria Industrial de Barcelona, Universitat Politècnica de Catalunya, Diagonal 647, 08028, Barcelona (Spain); Center for Research in Nano-Engineering, Universitat Politècnica de Catalunya, Campus Sud, Edifici C’, C/Pasqual i Vila s/n, Barcelona, E-08028 (Spain); and others

    2017-03-31

    Highlights: • Electrochemically inert polymers become electroactive after plasma functionalization. • Selective dopamine detection has been achieved functionalizing polymers with plasma. • Plasma-functionalized polymers are sensitive dopamine detectors. • XPS analyses reflect the transformation of inert polymers into electrosensors. - Abstract: We have fabricated potentially generalizable sensors based on polymeric-modified electrodes for the electrochemical detection of dopamine. Sensitive and selective sensors have been successfully obtained by applying a cold-plasma treatment during 1–2 min not only to conducting polymers but also to electrochemically inert polymers, such as polyethylene, polypropylene, polyvinylpyrrolidone, polycaprolactone and polystyrene. The effects of the plasma in the electrode surface activation, which is an essential requirement for the dopamine detection when inert polymers are used, have been investigated using X-ray photoelectron spectroscopy. Results indicate that exposure of polymer-modified electrodes to cold-plasma produces the formation of a large variety of reactive species adsorbed on the electrode surface, which catalyse the dopamine oxidation. With this technology, which is based on the application of a very simple physical functionalization, we have defined a paradox-based paradigm for the fabrication of electrochemical sensors by using inert and cheap plastics.

  14. Elevated Striatal Dopamine Function in Immigrants and Their Children: A Risk Mechanism for Psychosis

    OpenAIRE

    Egerton, A.; Howes, O. D.; Houle, S.; McKenzie, K.; Valmaggia, L. R.; Bagby, M. R.; Tseng, H-H; Bloomfield, M. A. P.; Kenk, M.; Bhattacharyya, S.; Suridjan, I.; Chaddock, C. A.; Winton-Brown, T. T.; Allen, P.; Rusjan, P.

    2017-01-01

    Migration is a major risk factor for schizophrenia but the neurochemical processes involved are unknown. One candidate mechanism is through elevations in striatal dopamine synthesis and release. The objective of this research was to determine whether striatal dopamine function is elevated in immigrants compared to nonimmigrants and the relationship with psychosis. Two complementary case–control studies of in vivo dopamine function (stress-induced dopamine release and dopamine synthesis capaci...

  15. Presence and function of dopamine transporter (DAT in stallion sperm: dopamine modulates sperm motility and acrosomal integrity.

    Directory of Open Access Journals (Sweden)

    Javier A Urra

    Full Text Available Dopamine is a catecholamine with multiple physiological functions, playing a key role in nervous system; however its participation in reproductive processes and sperm physiology is controversial. High dopamine concentrations have been reported in different portions of the feminine and masculine reproductive tract, although the role fulfilled by this catecholamine in reproductive physiology is as yet unknown. We have previously shown that dopamine type 2 receptor is functional in boar sperm, suggesting that dopamine acts as a physiological modulator of sperm viability, capacitation and motility. In the present study, using immunodetection methods, we revealed the presence of several proteins important for the dopamine uptake and signalling in mammalian sperm, specifically monoamine transporters as dopamine (DAT, serotonin (SERT and norepinephrine (NET transporters in equine sperm. We also demonstrated for the first time in equine sperm a functional dopamine transporter using 4-[4-(Dimethylaminostyryl]-N-methylpyridinium iodide (ASP(+, as substrate. In addition, we also showed that dopamine (1 mM treatment in vitro, does not affect sperm viability but decreases total and progressive sperm motility. This effect is reversed by blocking the dopamine transporter with the selective inhibitor vanoxerine (GBR12909 and non-selective inhibitors of dopamine reuptake such as nomifensine and bupropion. The effect of dopamine in sperm physiology was evaluated and we demonstrated that acrosome integrity and thyrosine phosphorylation in equine sperm is significantly reduced at high concentrations of this catecholamine. In summary, our results revealed the presence of monoamine transporter DAT, NET and SERT in equine sperm, and that the dopamine uptake by DAT can regulate sperm function, specifically acrosomal integrity and sperm motility.

  16. Diet-induced obesity: dopamine transporter function, impulsivity and motivation.

    Science.gov (United States)

    Narayanaswami, V; Thompson, A C; Cassis, L A; Bardo, M T; Dwoskin, L P

    2013-08-01

    A rat model of diet-induced obesity (DIO) was used to determine dopamine transporter (DAT) function, impulsivity and motivation as neurobehavioral outcomes and predictors of obesity. To evaluate neurobehavioral alterations following the development of DIO induced by an 8-week high-fat diet (HF) exposure, striatal D2-receptor density, DAT function and expression, extracellular dopamine concentrations, impulsivity, and motivation for high- and low-fat reinforcers were determined. To determine predictors of DIO, neurobehavioral antecedents including impulsivity, motivation for high-fat reinforcers, DAT function and extracellular dopamine were evaluated before the 8-week HF exposure. Striatal D2-receptor density was determined by in vitro kinetic analysis of [(3)H]raclopride binding. DAT function was determined using in vitro kinetic analysis of [(3)H]dopamine uptake, methamphetamine-evoked [(3)H]dopamine overflow and no-net flux in vivo microdialysis. DAT cell-surface expression was determined using biotinylation and western blotting. Impulsivity and food-motivated behavior were determined using a delay discounting task and progressive ratio schedule, respectively. Relative to obesity-resistant (OR) rats, obesity-prone (OP) rats exhibited 18% greater body weight following an 8-week HF-diet exposure, 42% lower striatal D2-receptor density, 30% lower total DAT expression, 40% lower in vitro and in vivo DAT function, 45% greater extracellular dopamine and twofold greater methamphetamine-evoked [(3)H]dopamine overflow. OP rats exhibited higher motivation for food, and surprisingly, were less impulsive relative to OR rats. Impulsivity, in vivo DAT function and extracellular dopamine concentration did not predict DIO. Importantly, motivation for high-fat reinforcers predicted the development of DIO. Human studies are limited by their ability to determine if impulsivity, motivation and DAT function are causes or consequences of DIO. The current animal model shows that

  17. Does human presynaptic striatal dopamine function predict social conformity?

    Science.gov (United States)

    Stokes, Paul R A; Benecke, Aaf; Puraite, Julita; Bloomfield, Michael A P; Shotbolt, Paul; Reeves, Suzanne J; Lingford-Hughes, Anne R; Howes, Oliver; Egerton, Alice

    2014-03-01

    Socially desirable responding (SDR) is a personality trait which reflects either a tendency to present oneself in an overly positive manner to others, consistent with social conformity (impression management (IM)), or the tendency to view one's own behaviour in an overly positive light (self-deceptive enhancement (SDE)). Neurochemical imaging studies report an inverse relationship between SDR and dorsal striatal dopamine D₂/₃ receptor availability. This may reflect an association between SDR and D₂/₃ receptor expression, synaptic dopamine levels or a combination of the two. In this study, we used a [¹⁸F]-DOPA positron emission tomography (PET) image database to investigate whether SDR is associated with presynaptic dopamine function. Striatal [¹⁸F]-DOPA uptake, (k(i)(cer), min⁻¹), was determined in two independent healthy participant cohorts (n=27 and 19), by Patlak analysis using a cerebellar reference region. SDR was assessed using the revised Eysenck Personality Questionnaire (EPQ-R) Lie scale, and IM and SDE were measured using the Paulhus Deception Scales. No significant associations were detected between Lie, SDE or IM scores and striatal [¹⁸F]-DOPA k(i)(cer). These results indicate that presynaptic striatal dopamine function is not associated with social conformity and suggests that social conformity may be associated with striatal D₂/₃ receptor expression rather than with synaptic dopamine levels.

  18. Developmental imaging genetics: linking dopamine function to adolescent behavior.

    Science.gov (United States)

    Padmanabhan, Aarthi; Luna, Beatriz

    2014-08-01

    Adolescence is a period of development characterized by numerous neurobiological changes that significantly influence behavior and brain function. Adolescence is of particular interest due to the alarming statistics indicating that mortality rates increase two to three-fold during this time compared to childhood, due largely to a peak in risk-taking behaviors resulting from increased impulsivity and sensation seeking. Furthermore, there exists large unexplained variability in these behaviors that are in part mediated by biological factors. Recent advances in molecular genetics and functional neuroimaging have provided a unique and exciting opportunity to non-invasively study the influence of genetic factors on brain function in humans. While genes do not code for specific behaviors, they do determine the structure and function of proteins that are essential to the neuronal processes that underlie behavior. Therefore, studying the interaction of genotype with measures of brain function over development could shed light on critical time points when biologically mediated individual differences in complex behaviors emerge. Here we review animal and human literature examining the neurobiological basis of adolescent development related to dopamine neurotransmission. Dopamine is of critical importance because of (1) its role in cognitive and affective behaviors, (2) its role in the pathogenesis of major psychopathology, and (3) the protracted development of dopamine signaling pathways over adolescence. We will then focus on current research examining the role of dopamine-related genes on brain function. We propose the use of imaging genetics to examine the influence of genetically mediated dopamine variability on brain function during adolescence, keeping in mind the limitations of this approach. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. The revised dopamine hypothesis of schizophrenia: evidence from pharmacological MRI studies with atypical antipsychotic medication

    NARCIS (Netherlands)

    da Silva Alves, Fabiana; Figee, Martijn; van Amelsvoort, Thérèse; Veltman, Dick; de Haan, Lieuwe

    2008-01-01

    The revised dopamine (DA) hypothesis states that clinical symptoms of schizophrenia are caused by an imbalance of the DA system. In this article, we aim to review evidence for this hypothesis by evaluating functional magnetic resonance imaging studies in schizophrenia. Because atypical drugs are

  20. Research progress of functional MRI in depression

    International Nuclear Information System (INIS)

    Xie Shenghui; Niu Guangming; Han Xiaodong; Qiao Pengfei

    2013-01-01

    The mood disorders of depression are associated with abnormalities of brain structure and function, and exploring their pathological mechanism has important significance for the choice of treatment and the curative effect evaluation. In recent years, the research of MRI on brain structure and function of depression has made great progress, especially in functional magnetic resonance imaging (fMRI). fMRI can detect the functional change in real time, and also can display the activity of brain and changes in the nerve pathways in patients with depression. This article summarizes the present research situation and progress of MRI in the diagnosis of depression. (authors)

  1. Functional MRI of the patellofemoral joint: comparison of ultrafast MRI, motion-triggered cine MRI and static MRI

    Energy Technology Data Exchange (ETDEWEB)

    Muhle, C. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany); Brossmann, J. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany); Melchert, U.H. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany); Schroeder, C. [Radiologische Abt., Universitaets-Kinderklinik, Christian-Albrechts-Universitaet, Kiel (Germany); Boer, R. de [Philips Medical Systems, Best (Netherlands); Spielmann, R.P. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany); Heller, M. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany)

    1995-12-31

    To evaluate the feasibility and usefulness of ultrafast MRI (u), patellar tracking from 30 of flexion to knee extension (0 ) was analysed and compared with motion-triggered cine MRI (m) and a static MRI technique (s). The different imaging methods were compared in respect of the patellofemoral relationship, the examination time and image quality. Eight healthy subjects and four patients (in total 18 joints) with patellar subluxation or luxation were examined. Significant differences between the static MRI series without quadriceps contraction and the functional MRI studies (motion-triggered cine MRI and ultrafast MRI) were found for the patellar tilt angle. In the dynamic joint studies there was no statistical difference of the regression coefficients between the motion-triggered cine MRI studies and the ultrafast MRI studies. The findings of the functional MRI studies compared with the static MRI images were significantly different for the lateralisation of the patella, expressed by the lateral patellar displacement and bisect offset. No significant differences in patellar lateralisation were found between motion-triggered cine MRI and ultrafast MRI. Ultrafast MRI was superior to motion-triggered cine MRI in terms of the reduction in imaging time and improvement of the image quality. (orig.)

  2. Functional MRI of the patellofemoral joint: comparison of ultrafast MRI, motion-triggered cine MRI and static MRI

    International Nuclear Information System (INIS)

    Muhle, C.; Brossmann, J.; Melchert, U.H.; Schroeder, C.; Boer, R. de; Spielmann, R.P.; Heller, M.

    1995-01-01

    To evaluate the feasibility and usefulness of ultrafast MRI (u), patellar tracking from 30 of flexion to knee extension (0 ) was analysed and compared with motion-triggered cine MRI (m) and a static MRI technique (s). The different imaging methods were compared in respect of the patellofemoral relationship, the examination time and image quality. Eight healthy subjects and four patients (in total 18 joints) with patellar subluxation or luxation were examined. Significant differences between the static MRI series without quadriceps contraction and the functional MRI studies (motion-triggered cine MRI and ultrafast MRI) were found for the patellar tilt angle. In the dynamic joint studies there was no statistical difference of the regression coefficients between the motion-triggered cine MRI studies and the ultrafast MRI studies. The findings of the functional MRI studies compared with the static MRI images were significantly different for the lateralisation of the patella, expressed by the lateral patellar displacement and bisect offset. No significant differences in patellar lateralisation were found between motion-triggered cine MRI and ultrafast MRI. Ultrafast MRI was superior to motion-triggered cine MRI in terms of the reduction in imaging time and improvement of the image quality. (orig.)

  3. Functional characterization of dopamine transporter in vivo using Drosophila melanogaster behavioral analysis.

    Directory of Open Access Journals (Sweden)

    Taro eUeno

    2014-09-01

    Full Text Available Dopamine mediates diverse functions such as motivation, reward, attention, learning/memory and sleep/arousal. Recent studies using model organisms including the fruit fly, have elucidated various physiological functions of dopamine, and identified specific neural circuits for these functions. Flies with mutations in the Drosophila dopamine transporter (dDAT gene show enhanced dopamine signaling, and short sleep and memory impairment phenotypes. However, understanding the mechanism by which dopamine signaling causes these phenotypes requires an understanding of the dynamics of dopamine release. Here we report the effects of dDAT expression on behavioral traits. We show that dDAT expression in a subset of dopaminergic neurons is sufficient for normal sleep. dDAT expression in other cell types such as Kenyon cells and glial cells can also rescue the short sleep phenotype of dDAT mutants. dDAT mutants also show a down-regulation of the D1-like dopamine receptor dDA1, and this phenotype is rescued when dDAT is expressed in the same cell types in which it rescues sleep. On the other hand, dDAT overexpression in mushroom bodies, which are the target of memory forming dopamine neurons, abolishes olfactory aversive memory. Our data demonstrate that expression of extrasynaptic dopamine transporters can rescue some aspects of dopamine signaling in dopamine transporter mutants. These results provide novel insights into regulatory systems that modulate dopamine signaling.

  4. Functional MRI of Multilingual Subjects

    International Nuclear Information System (INIS)

    Cho, Jae Min; Ryoo, Jae Wook; Choi, Dae Seob; Shin, Tae Beom; Chung, Sung Hoon; Kim, Ji Eun; Han, Heon; Kim, Sam Soo; Jeon, Yong Hwan

    2009-01-01

    To evaluate brain activation areas during the processing of languages in multilingual volunteers by functional MRI and to examine the differences between the mother and foreign languages. Nine multilingual (Korean, French, and English speaking) Korean individuals were enrolled in this study. Functional images were acquired during a lexical decision task (LDT) and picture naming task (PNT) in each of the Korean, French and English languages. The areas activated were analyzed topographically in each language and task, and compared between languages. Activation was noted in Broca's area, supramarginal gyrus, fusiform gyrus during the LDT. During the PNT, activation was noted in Broca's area, left prefrontal area, cerebellum, right extrastriated cortex. While Broca's area activation was observed for all languages during LDT, there was more activation in Broca's area and additional activation in the right prefrontal area with foreign languages. During the PNT, there was more activation in the left prefrontal area with foreign languages. Broca's area, which is known as a major language region, was activated by all languages and tasks. The brain activation areas were largely overlapping with the mother and foreign languages. However, there were wider areas of activation and additional different activation areas with foreign languages. These results suggest more cerebral effort during foreign language processing

  5. MRI in Optic Neuritis: Structure, Function, Interactions

    DEFF Research Database (Denmark)

    Fuglø, Dan

    2011-01-01

    resonance imaging (MRI), and the visual evoked potential (VEP) continues to show a delayed P100 indicating persistent demyelination. The explanation for this apparent discrepancy between structure and function could be due to either a redundancy in the visual pathways so that some degree of signal loss...... will have very few or no clinical symptoms, or it could be due to compensatory mechanisms in the visual pathway or the visual cortex. In order to understand the pathophysiology and recovery processes in ON it is essential to have sensitive methods to asses both structure and function. These methods...... are low. Functional MRI (fMRI) is a non-invasive technique that can measure brain activity with a high spatial resolution. Recently, technical and methodological advancements have made it feasible to record VEPs and fMRI simultaneously and the relationship between averaged VEPs and averaged fMRI signals...

  6. Adversity in childhood linked to elevated striatal dopamine function in adulthood

    OpenAIRE

    Egerton, A.; Valmaggia, L. R.; Howes, O. D.; Day, F.; Chaddock, C. A.; Allen, P.; Winton-Brown, T. T.; Bloomfield, M. A. P.; Bhattacharyya, S.; Chilcott, J.; Lappin, J. M.; Murray, R. M.; McGuire, P.

    2016-01-01

    Childhood adversity increases the risk of psychosis in adulthood. Theoretical and animal models suggest that this effect may be mediated by increased striatal dopamine neurotransmission. The primary objective of this study was to examine the relationship between adversity in childhood and striatal dopamine function in early adulthood. Secondary objectives were to compare exposure to childhood adversity and striatal dopamine function in young people at ultra high risk (UHR) of psychosis and he...

  7. Elevated Striatal Dopamine Function in Immigrants and Their Children: A Risk Mechanism for Psychosis.

    Science.gov (United States)

    Egerton, Alice; Howes, Oliver D; Houle, Sylvain; McKenzie, Kwame; Valmaggia, Lucia R; Bagby, Michael R; Tseng, Huai-Hsuan; Bloomfield, Michael A P; Kenk, Miran; Bhattacharyya, Sagnik; Suridjan, Ivonne; Chaddock, Chistopher A; Winton-Brown, Toby T; Allen, Paul; Rusjan, Pablo; Remington, Gary; Meyer-Lindenberg, Andreas; McGuire, Philip K; Mizrahi, Romina

    2017-03-01

    Migration is a major risk factor for schizophrenia but the neurochemical processes involved are unknown. One candidate mechanism is through elevations in striatal dopamine synthesis and release. The objective of this research was to determine whether striatal dopamine function is elevated in immigrants compared to nonimmigrants and the relationship with psychosis. Two complementary case-control studies of in vivo dopamine function (stress-induced dopamine release and dopamine synthesis capacity) in immigrants compared to nonimmigrants were performed in Canada and the United Kingdom. The Canadian dopamine release study included 25 immigrant and 31 nonmigrant Canadians. These groups included 23 clinical high risk (CHR) subjects, 9 antipsychotic naïve patients with schizophrenia, and 24 healthy volunteers. The UK dopamine synthesis study included 32 immigrants and 44 nonimmigrant British. These groups included 50 CHR subjects and 26 healthy volunteers. Both striatal stress-induced dopamine release and dopamine synthesis capacity were significantly elevated in immigrants compared to nonimmigrants, independent of clinical status. These data provide the first evidence that the effect of migration on the risk of developing psychosis may be mediated by an elevation in brain dopamine function. © The Author 2017. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center.

  8. Effects of age on reactive capacity and nigrostriatal dopamine function

    International Nuclear Information System (INIS)

    Gilliam, P.E.

    1984-01-01

    This investigation examined the effects of aging on reactive capacity (reaction time), and striatal dopamine function in the same animals. Twenty, 3 month old, and twenty, 24 month old, male Sprague-Dawley rats were trained in a reactive capacity test to quickly release a lever, in response to an auditory and visual stimulus, in order to avoid footshocks. The young animals were tested at 3, 6, and 9 months of age, while the Old animals were tested at 18, 21, and 24 months of age. Twenty-four hours after the last testing session the animals were sacrificed and their striata dissected for biochemical assays. A [ 3 H]-spiperone receptor binding assay was performed to determine the density and affinity of striatial D-2 receptors. It was hypothesized that the improvement in reactive capacity performance of the Old animals over days was due to their ability to compensate for their decrease in receptor density by an increase in the production and utilization of dopamine. Significant positive correlations were also found between reactive capacity performance and receptor density as well as between reactive capacity and the ratio of DOPAC + HVA/DA

  9. Multicentre structural and functional MRI

    OpenAIRE

    Gountouna, Viktoria-Eleni

    2014-01-01

    Neuroimaging techniques are likely to continue to improve our understanding of the brain in health and disease, but studies tend to be small, based in one imaging centre and of uncertain generalisability. Multicentre imaging studies therefore have great appeal but it is not yet clear under which circumstances data from different scanners can be combined. The successful harmonisation of multiple Magnetic Resonance Imaging (MRI) machines will increase study power, flexibility and...

  10. Imaging tools to study pharmacology: functional MRI on small rodents

    OpenAIRE

    Elisabeth eJonckers; Disha eShah; Julie eHamaide; Marleen eVerhoye; Annemie eVan Der Linden

    2015-01-01

    Functional Magnetic Resonance Imaging (fMRI) is an excellent tool to study the effect of pharmacological modulations on brain function in a non-invasive and longitudinal manner. We introduce several blood oxygenation level dependent (BOLD) fMRI techniques, including resting state (rsfMRI), stimulus-evoked (st-fMRI), and pharmacological MRI (phMRI). Respectively, these techniques permit the assessment of functional connectivity during rest as well as brain activation triggered by sensory stimu...

  11. Methodological principles for optimising functional MRI experiments

    International Nuclear Information System (INIS)

    Wuestenberg, T.; Giesel, F.L.; Strasburger, H.

    2005-01-01

    Functional magnetic resonance imaging (fMRI) is one of the most common methods for localising neuronal activity in the brain. Even though the sensitivity of fMRI is comparatively low, the optimisation of certain experimental parameters allows obtaining reliable results. In this article, approaches for optimising the experimental design, imaging parameters and analytic strategies will be discussed. Clinical neuroscientists and interested physicians will receive practical rules of thumb for improving the efficiency of brain imaging experiments. (orig.) [de

  12. Test-retest measurements of dopamine D_1-type receptors using simultaneous PET/MRI imaging

    International Nuclear Information System (INIS)

    Kaller, Simon; Patt, Marianne; Becker, Georg-Alexander; Luthardt, Julia; Meyer, Philipp M.; Werner, Peter; Barthel, Henryk; Bresch, Anke; Sabri, Osama; Rullmann, Michael; Girbardt, Johanna; Fritz, Thomas H.; Hesse, Swen

    2017-01-01

    The role of dopamine D_1-type receptor (D_1R)-expressing neurons in the regulation of motivated behavior and reward prediction has not yet been fully established. As a prerequisite for future research assessing D_1-mediated neuronal network regulation using simultaneous PET/MRI and D_1R-selective ["1"1C]SCH23390, this study investigated the stability of central D_1R measurements between two independent PET/MRI sessions under baseline conditions. Thirteen healthy volunteers (7 female, age 33 ± 13 yrs) underwent 90-min emission scans, each after 90-s bolus injection of 486 ± 16 MBq ["1"1C]SCH23390, on two separate days within 2-4 weeks using a PET/MRI system. Parametric images of D_1R distribution volume ratio (DVR) and binding potential (BP_N_D) were generated by a multi-linear reference tissue model with two parameters and the cerebellar cortex as receptor-free reference region. Volume-of-interest (VOI) analysis was performed with manual VOIs drawn on consecutive transverse MRI slices for brain regions with high and low D_1R density. The DVR varied from 2.5 ± 0.3 to 2.9 ± 0.5 in regions with high D_1R density (e.g. the head of the caudate) and from 1.2 ± 0.1 to 1.6 ± 0.2 in regions with low D_1R density (e.g. the prefrontal cortex). The absolute variability of the DVR ranged from 2.4% ± 1.3% to 5.1% ± 5.3%, while Bland-Altman analyses revealed very low differences in mean DVR (e.g. 0.013 ± 0.17 for the nucleus accumbens). Intraclass correlation (one-way, random) indicated very high agreement (0.93 in average) for both DVR and BP_N_D values. Accordingly, the absolute variability of BP_N_D ranged from 7.0% ± 4.7% to 12.5% ± 10.6%; however, there were regions with very low D_1R content, such as the occipital cortex, with higher mean variability. The test-retest reliability of D_1R measurements in this study was very high. This was the case not only for D_1R-rich brain areas, but also for regions with low D_1R density. These results will provide a solid base

  13. Development of functional MRI in gastric cancer

    International Nuclear Information System (INIS)

    Zhang Lei; Shao Guoliang

    2013-01-01

    Gastric cancer is one of the most common malignant tumors in digestive tract functional MRI can represent the functional changes of the tumor. DWI not only provides a new way to diagnosis the gastric cancer, but also reflect the pathology changes of the tumor, which has great value to predict the therapeutic effect and prognosis of the tumor. MRS is the only method to test the chemical composition of tissues in live without injury, which has great value in the early diagnosis of gastric tumor and in the research of tumor mechanism. This review is mainly focused on the status and development of functional MRI in gastric cancer. (authors)

  14. Amphetamine Self-Administration Attenuates Dopamine D2 Autoreceptor Function

    Science.gov (United States)

    Calipari, Erin S; Sun, Haiguo; Eldeeb, Khalil; Luessen, Deborah J; Feng, Xin; Howlett, Allyn C; Jones, Sara R; Chen, Rong

    2014-01-01

    Dopamine D2 autoreceptors located on the midbrain dopaminergic neurons modulate dopamine (DA) neuron firing, DA release, and DA synthesis through a negative-feedback mechanism. Dysfunctional D2 autoreceptors following repeated drug exposure could lead to aberrant DA activity in the ventral tegmental area (VTA) and projection areas such as nucleus accumbens (NAcc), promoting drug-seeking and -taking behavior. Therefore, it is important to understand molecular mechanisms underlying drug-induced changes in D2 autoreceptors. Here, we reported that 5 days of amphetamine (AMPH) self-administration reduced the ability of D2 autoreceptors to inhibit DA release in the NAcc as determined by voltammetry. Using the antibody-capture [35S]GTPγS scintillation proximity assay, we demonstrated for the first time that midbrain D2/D3 receptors were preferentially coupled to Gαi2, whereas striatal D2/D3 receptors were coupled equally to Gαi2 and Gαo for signaling. Importantly, AMPH abolished the interaction between Gαi2 and D2/D3 receptors in the midbrain while leaving striatal D2/D3 receptors unchanged. The disruption of the coupling between D2/D3 receptors and Gαi2 by AMPH is at least partially explained by the enhanced RGS2 (regulator of G-protein signaling 2) activity resulting from an increased RGS2 trafficking to the membrane. AMPH had no effects on the midbrain expression and trafficking of other RGS proteins such as RGS4 and RGS8. Our data suggest that midbrain D2/D3 receptors are more susceptible to AMPH-induced alterations. Reduced D2 autoreceptor function could lead to enhanced DA signaling and ultimately addiction-related behavior. RGS2 may be a potential non-dopaminergic target for pharmacological intervention of dysfunctional DA transmission and drug addiction. PMID:24513972

  15. Functional variants of the dopamine receptor D2 gene modulate prefronto-striatal phenotypes in schizophrenia.

    Science.gov (United States)

    Bertolino, Alessandro; Fazio, Leonardo; Caforio, Grazia; Blasi, Giuseppe; Rampino, Antonio; Romano, Raffaella; Di Giorgio, Annabella; Taurisano, Paolo; Papp, Audrey; Pinsonneault, Julia; Wang, Danxin; Nardini, Marcello; Popolizio, Teresa; Sadee, Wolfgang

    2009-02-01

    Dopamine D2 receptor signalling is strongly implicated in the aetiology of schizophrenia. We have recently characterized the function of three DRD2 SNPs: rs12364283 in the promoter affecting total D2 mRNA expression; rs2283265 and rs1076560, respectively in introns 5 and 6, shifting mRNA splicing to two functionally distinct isoforms, the short form of D2 (D2S) and the long form (D2L). These two isoforms differentially contribute to dopamine signalling in prefrontal cortex and in striatum. We performed a case-control study to determine association of these variants and of their main haplotypes with several schizophrenia-related phenotypes. We demonstrate that the minor allele in the intronic variants is associated with reduced expression of %D2S of total mRNA in post-mortem prefrontal cortex, and with impaired working memory behavioural performance, both in patients and controls. However, the fMRI results show opposite effects in patients compared with controls: enhanced engagement of prefronto-striatal pathways in controls and reduced activity in patients. Moreover, the promoter variant is also associated with working memory activity in prefrontal cortex and striatum of patients, and less robustly with negative symptoms scores. Main haplotypes formed by the three DRD2 variants showed significant associations with these phenotypes consistent with those of the individual SNPs. Our results indicate that the three functional DRD2 variants modulate schizophrenia phenotypes possibly by modifying D2S/D2L ratios in the context of different total D2 density.

  16. Adversity in childhood linked to elevated striatal dopamine function in adulthood.

    Science.gov (United States)

    Egerton, Alice; Valmaggia, Lucia R; Howes, Oliver D; Day, Fern; Chaddock, Christopher A; Allen, Paul; Winton-Brown, Toby T; Bloomfield, Michael A P; Bhattacharyya, Sagnik; Chilcott, Jack; Lappin, Julia M; Murray, Robin M; McGuire, Philip

    2016-10-01

    Childhood adversity increases the risk of psychosis in adulthood. Theoretical and animal models suggest that this effect may be mediated by increased striatal dopamine neurotransmission. The primary objective of this study was to examine the relationship between adversity in childhood and striatal dopamine function in early adulthood. Secondary objectives were to compare exposure to childhood adversity and striatal dopamine function in young people at ultra high risk (UHR) of psychosis and healthy volunteers. Sixty-seven young adults, comprising 47 individuals at UHR for psychosis and 20 healthy volunteers were recruited from the same geographic area and were matched for age, gender and substance use. Presynaptic dopamine function in the associative striatum was assessed using 18F-DOPA positron emission tomography. Childhood adversity was assessed using the Childhood Experience of Care and Abuse questionnaire. Within the sample as a whole, both severe physical or sexual abuse (T63=2.92; P=0.005), and unstable family arrangements (T57=2.80; P=0.007) in childhood were associated with elevated dopamine function in the associative striatum in adulthood. Comparison of the UHR and volunteer subgroups revealed similar incidence of childhood adverse experiences, and there was no significant group difference in dopamine function. This study provides evidence that childhood adversity is linked to elevated striatal dopamine function in adulthood. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  17. Hypothermia-induced loss of endothelial barrier function is restored after dopamine pretreatment : Role of p42/p44 activation

    NARCIS (Netherlands)

    Brinkkoetter, Paul-Thomas; Beck, Grietje C.; Gottmann, Uwe; Loesel, Ralf; Schnetzke, Ulf; Rudic, Boris; Hanusch, Christine; Rafat, Neysan; Liu, Zhenzi; Weiss, Christel; Leuvinik, Henri G. D.; Ploeg, Rutger; Braun, Claude; Schnuelle, Peter; van der Woude, Fokko J.; Yard, Benito A.

    2006-01-01

    Background. Donor dopamine usage is associated with improved immediate graft function after renal transplantation. Although prolonged cold preservation results in an increased vascular permeability, the present study was conducted to examine in vitro and in vivo if dopamine Pretreatment influences

  18. Functional Connectome Analysis of Dopamine Neuron Glutamatergic Connections in Forebrain Regions.

    Science.gov (United States)

    Mingote, Susana; Chuhma, Nao; Kusnoor, Sheila V; Field, Bianca; Deutch, Ariel Y; Rayport, Stephen

    2015-12-09

    In the ventral tegmental area (VTA), a subpopulation of dopamine neurons express vesicular glutamate transporter 2 and make glutamatergic connections to nucleus accumbens (NAc) and olfactory tubercle (OT) neurons. However, their glutamatergic connections across the forebrain have not been explored systematically. To visualize dopamine neuron forebrain projections and to enable photostimulation of their axons independent of transmitter status, we virally transfected VTA neurons with channelrhodopsin-2 fused to enhanced yellow fluorescent protein (ChR2-EYFP) and used DAT(IREScre) mice to restrict expression to dopamine neurons. ChR2-EYFP-expressing neurons almost invariably stained for tyrosine hydroxylase, identifying them as dopaminergic. Dopamine neuron axons visualized by ChR2-EYFP fluorescence projected most densely to the striatum, moderately to the amygdala and entorhinal cortex (ERC), sparsely to prefrontal and cingulate cortices, and rarely to the hippocampus. Guided by ChR2-EYFP fluorescence, we recorded systematically from putative principal neurons in target areas and determined the incidence and strength of glutamatergic connections by activating all dopamine neuron terminals impinging on recorded neurons with wide-field photostimulation. This revealed strong glutamatergic connections in the NAc, OT, and ERC; moderate strength connections in the central amygdala; and weak connections in the cingulate cortex. No glutamatergic connections were found in the dorsal striatum, hippocampus, basolateral amygdala, or prefrontal cortex. These results indicate that VTA dopamine neurons elicit widespread, but regionally distinct, glutamatergic signals in the forebrain and begin to define the dopamine neuron excitatory functional connectome. Dopamine neurons are important for the control of motivated behavior and are involved in the pathophysiology of several major neuropsychiatric disorders. Recent studies have shown that some ventral midbrain dopamine neurons are

  19. Adaptive Analysis of Functional MRI Data

    International Nuclear Information System (INIS)

    Friman, Ola

    2003-01-01

    Functional Magnetic Resonance Imaging (fMRI) is a recently developed neuro-imaging technique with capacity to map neural activity with high spatial precision. To locate active brain areas, the method utilizes local blood oxygenation changes which are reflected as small intensity changes in a special type of MR images. The ability to non-invasively map brain functions provides new opportunities to unravel the mysteries and advance the understanding of the human brain, as well as to perform pre-surgical examinations in order to optimize surgical interventions. This dissertation introduces new approaches for the analysis of fMRI data. The detection of active brain areas is a challenging problem due to high noise levels and artifacts present in the data. A fundamental tool in the developed methods is Canonical Correlation Analysis (CCA). CCA is used in two novel ways. First as a method with the ability to fully exploit the spatio-temporal nature of fMRI data for detecting active brain areas. Established analysis approaches mainly focus on the temporal dimension of the data and they are for this reason commonly referred to as being mass-univariate. The new CCA detection method encompasses and generalizes the traditional mass-univariate methods and can in this terminology be viewed as a mass-multivariate approach. The concept of spatial basis functions is introduced as a spatial counterpart of the temporal basis functions already in use in fMRI analysis. The spatial basis functions implicitly perform an adaptive spatial filtering of the fMRI images, which significantly improves detection performance. It is also shown how prior information can be incorporated into the analysis by imposing constraints on the temporal and spatial models and a constrained version of CCA is devised to this end. A general Principal Component Analysis technique for generating and constraining temporal and spatial subspace models is proposed to be used in combination with the constrained CCA

  20. MRI to assess renal structure and function.

    Science.gov (United States)

    Artunc, Ferruh; Rossi, Cristina; Boss, Andreas

    2011-11-01

    In addition to excellent anatomical depiction, MRI techniques have expanded to study functional aspects of renal physiology, such as renal perfusion, glomerular filtration rate (GFR) or tissue oxygenation. This review will focus on current developments with an emphasis on clinical applicability. The method of GFR determination is largely heterogeneous and still has weaknesses. However, the technique of employing liver disappearance curves has been shown to be accurate in healthy persons and patients with chronic kidney disease. In potential kidney donors, complete evaluation of kidney anatomy and function can be accomplished in a single-stop investigation. Techniques without contrast media can be utilized to measure renal tissue oxygenation (blood oxygen level-dependent MRI) or perfusion (arterial spin labeling) and could aid in the diagnosis and treatment of ischemic renal diseases, such as renal artery stenosis. Diffusion imaging techniques may provide information on spatially restricted water diffusion and tumor cellularity. Functional MRI opens new horizons in studying renal physiology and pathophysiology in vivo. Although extensively utilized in research, labor-intensive postprocessing and lack of standardization currently limit the clinical applicability of functional MRI. Further studies are necessary to evaluate the clinical value of functional magnetic resonance techniques for early discovery and characterization of kidney disease.

  1. Extraction of temporal information in functional MRI

    Science.gov (United States)

    Singh, M.; Sungkarat, W.; Jeong, Jeong-Won; Zhou, Yongxia

    2002-10-01

    The temporal resolution of functional MRI (fMRI) is limited by the shape of the haemodynamic response function (hrf) and the vascular architecture underlying the activated regions. Typically, the temporal resolution of fMRI is on the order of 1 s. We have developed a new data processing approach to extract temporal information on a pixel-by-pixel basis at the level of 100 ms from fMRI data. Instead of correlating or fitting the time-course of each pixel to a single reference function, which is the common practice in fMRI, we correlate each pixel's time-course to a series of reference functions that are shifted with respect to each other by 100 ms. The reference function yielding the highest correlation coefficient for a pixel is then used as a time marker for that pixel. A Monte Carlo simulation and experimental study of this approach were performed to estimate the temporal resolution as a function of signal-to-noise ratio (SNR) in the time-course of a pixel. Assuming a known and stationary hrf, the simulation and experimental studies suggest a lower limit in the temporal resolution of approximately 100 ms at an SNR of 3. The multireference function approach was also applied to extract timing information from an event-related motor movement study where the subjects flexed a finger on cue. The event was repeated 19 times with the event's presentation staggered to yield an approximately 100-ms temporal sampling of the haemodynamic response over the entire presentation cycle. The timing differences among different regions of the brain activated by the motor task were clearly visualized and quantified by this method. The results suggest that it is possible to achieve a temporal resolution of /spl sim/200 ms in practice with this approach.

  2. Effects of dopamine on renal haemodynamics tubular function and sodium excretion in normal humans

    DEFF Research Database (Denmark)

    Olsen, Niels Vidiendal

    1998-01-01

    The renal functional changes following infusion of dopamine are well documented. The most pronounced effect is the increase in renal blood flow and a marked natriuretic response. Due to its specific renal effects, dopamine has become one of the most frequently used drugs in the treatment...... of critically ill patients with low cardiac output states and/or acute oliguric renal failure. Pharmacological effects of dopamine are dose dependent. Low doses of dopamine predominantly stimulate dopaminergic receptors, but with increasing doses actions secondary to stimulation of adrenergic beta(1) and alpha...... indirectly may dilate the vessels by inhibition of norepinephrine release. Consistent with previous results in animals, the present haemodynamic studies revealed that dopamine in normal subjects elicits a dose dependent biphasic effect on the mean arterial blood pressure. With 1 and 2 micrograms...

  3. Dopaminergic modulation of the human reward system: a placebo-controlled dopamine depletion fMRI study

    NARCIS (Netherlands)

    da Silva Alves, Fabiana; Schmitz, Nicole; Figee, Martijn; Abeling, Nico; Hasler, Gregor; van der Meer, Johan; Nederveen, Aart; de Haan, Lieuwe; Linszen, Don; van Amelsvoort, Therese

    2011-01-01

    Reward related behaviour is linked to dopaminergic neurotransmission. Our aim was to gain insight into dopaminergic involvement in the human reward system. Combining functional magnetic resonance imaging with dopaminergic depletion by α-methylparatyrosine we measured dopamine-related brain activity

  4. Methodology for functional MRI of simulated driving.

    Science.gov (United States)

    Kan, Karen; Schweizer, Tom A; Tam, Fred; Graham, Simon J

    2013-01-01

    The developed world faces major socioeconomic and medical challenges associated with motor vehicle accidents caused by risky driving. Functional magnetic resonance imaging (fMRI) of individuals using virtual reality driving simulators may provide an important research tool to assess driving safety, based on brain activity and behavior. A fMRI-compatible driving simulator was developed and evaluated in the context of straight driving, turning, and stopping in 16 young healthy adults. Robust maps of brain activity were obtained, including activation of the primary motor cortex, cerebellum, visual cortex, and parietal lobe, with limited head motion (driving is a feasible undertaking.

  5. Cerebral activity mapped by functional MRI

    International Nuclear Information System (INIS)

    Bruening, R.; Danek, A.; Wu, R.H.; Berchtenbreiter, C.; Reiser, M.

    1997-01-01

    Functional magnetic resonance imaging (fMRI) is a method to noninvasively measure the changes in cerebral activation during sensitive, cognitive or motor activity. fMRI detects activity by subtraction of states of activity and rest. During activity the signal is increased presumably due to a decrease of deoxyhemoglobin in the capillary and venous structures. Using a full field visual stimulation by flashlight goggles, a signal increase of 3% was detected in the primary visual cortex (V1). Different sequences and postprocessing algorythms will be discussed. Data from the primary cortical areas suggest a high reproducability of the experiments. Successfull experiments highly depend on cooperation of subjects. Despite success in experiments fMRI still has to be established for clinical purposes. (orig.) [de

  6. Dopamine-dependent changes in the functional connectivity between basal ganglia and cerebral cortex in humans

    NARCIS (Netherlands)

    Williams, D; Tijssen, M; van Bruggen, G; Bosch, A; Insola, A; Di Lazzaro, V; Mazzone, P; Oliviero, A; Quartarone, A; Speelman, H; Brown, P

    2002-01-01

    We test the hypothesis that interaction between the human basal ganglia and cerebral cortex involves activity in multiple functional circuits characterized by their frequency of oscillation, phase characteristics, dopamine dependency and topography. To this end we took recordings from

  7. COBRA: A prospective multimodal imaging study of dopamine, brain structure and function, and cognition.

    Science.gov (United States)

    Nevalainen, N; Riklund, K; Andersson, M; Axelsson, J; Ögren, M; Lövdén, M; Lindenberger, U; Bäckman, L; Nyberg, L

    2015-07-01

    Cognitive decline is a characteristic feature of normal human aging. Previous work has demonstrated marked interindividual variability in onset and rate of decline. Such variability has been linked to factors such as maintenance of functional and structural brain integrity, genetics, and lifestyle. Still, few, if any, studies have combined a longitudinal design with repeated multimodal imaging and a comprehensive assessment of cognition as well as genetic and lifestyle factors. The present paper introduces the Cognition, Brain, and Aging (COBRA) study, in which cognitive performance and brain structure and function are measured in a cohort of 181 older adults aged 64 to 68 years at baseline. Participants will be followed longitudinally over a 10-year period, resulting in a total of three equally spaced measurement occasions. The measurement protocol at each occasion comprises a comprehensive set of behavioral and imaging measures. Cognitive performance is evaluated via computerized testing of working memory, episodic memory, perceptual speed, motor speed, implicit sequence learning, and vocabulary. Brain imaging is performed using positron emission tomography with [(11)C]-raclopride to assess dopamine D2/D3 receptor availability. Structural magnetic resonance imaging (MRI) is used for assessment of white and gray-matter integrity and cerebrovascular perfusion, and functional MRI maps brain activation during rest and active task conditions. Lifestyle descriptives are collected, and blood samples are obtained and stored for future evaluation. Here, we present selected results from the baseline assessment along with a discussion of sample characteristics and methodological considerations that determined the design of the study. This article is part of a Special Issue entitled SI: Memory & Aging. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

  8. Functional Imaging: CT and MRI

    OpenAIRE

    van Beek, Edwin JR; Hoffman, Eric A

    2008-01-01

    Numerous imaging techniques permit evaluation of regional pulmonary function. Contrast-enhanced CT methods now allow assessment of vasculature and lung perfusion. Techniques using spirometric controlled MDCT allow for quantification of presence and distribution of parenchymal and airway pathology, Xenon gas can be employed to assess regional ventilation of the lungs and rapid bolus injections of iodinated contrast agent can provide quantitative measure of regional parenchymal perfusion. Advan...

  9. Surface functionalization of dopamine coated iron oxide nanoparticles for various surface functionalities

    Energy Technology Data Exchange (ETDEWEB)

    Sherwood, Jennifer; Xu, Yaolin; Lovas, Kira [Chemical and Biological Engineering, The University of Alabama, Tuscaloosa , AL 35487 (United States); Qin, Ying [Alabama Innovation and Mentoring of Entrepreneurs, The University of Alabama, Tuscaloosa, AL 35487 (United States); Bao, Yuping, E-mail: ybao@eng.ua.edu [Chemical and Biological Engineering, The University of Alabama, Tuscaloosa , AL 35487 (United States)

    2017-04-01

    We present effective conjugation of four small molecules (glutathione, cysteine, lysine, and Tris(hydroxymethyl)aminomethane) onto dopamine-coated iron oxide nanoparticles. Conjugation of these molecules could improve the surface functionality of nanoparticles for more neutral surface charge at physiological pH and potentially reduce non-specific adsorption of proteins to nanoparticles surfaces. The success of conjugation was evaluated with dynamic light scattering by measuring the surface charge changes and Fourier transform infrared spectroscopy for surface chemistry analysis. The stability of dopamine-coated nanoparticles and the ability of conjugated nanoparticles to reduce the formation of protein corona were evaluated by measuring the size and charge of the nanoparticles in biological medium. This facile conjugation method opens up possibilities for attaching various surface functionalities onto iron oxide nanoparticle surfaces for biomedical applications.

  10. Surface functionalization of dopamine coated iron oxide nanoparticles for various surface functionalities

    International Nuclear Information System (INIS)

    Sherwood, Jennifer; Xu, Yaolin; Lovas, Kira; Qin, Ying; Bao, Yuping

    2017-01-01

    We present effective conjugation of four small molecules (glutathione, cysteine, lysine, and Tris(hydroxymethyl)aminomethane) onto dopamine-coated iron oxide nanoparticles. Conjugation of these molecules could improve the surface functionality of nanoparticles for more neutral surface charge at physiological pH and potentially reduce non-specific adsorption of proteins to nanoparticles surfaces. The success of conjugation was evaluated with dynamic light scattering by measuring the surface charge changes and Fourier transform infrared spectroscopy for surface chemistry analysis. The stability of dopamine-coated nanoparticles and the ability of conjugated nanoparticles to reduce the formation of protein corona were evaluated by measuring the size and charge of the nanoparticles in biological medium. This facile conjugation method opens up possibilities for attaching various surface functionalities onto iron oxide nanoparticle surfaces for biomedical applications.

  11. Neuro-pharmacological functional MRI of epilepsy

    Energy Technology Data Exchange (ETDEWEB)

    Kiriyama, Hideki; Makabe, Tetsuo; Tomita, Susumu; Omoto, Takashi; Asari, Shoji [Okayama Univ. (Japan). School of Medicine; Aihara, Hiroshi; Kinugasa, Kazushi; Nishimoto, Akira; Ito, Takahiko

    2000-03-01

    We studied patients with epilepsy by neuro-pharmacological functional MRI technique using diazepam. Five normal volunteers and 7 patients with epilepsy were investigated. MRI was performed by a 1.5 T unit (SIGNA Horizon, GE) using the following parameters: TR/TE 5000 msec/80 msec, FA 90 deg, FOV 200 mm, matrix 128 x 128, slice thickness 7 mm. We performed MRI scanning over 5 minutes (2 minutes before and 3 minutes after injection of diazepam) for each 1 session; we scanned 3 sessions for each patient at intervals of 5 minutes. The diazepam was injected rapidly from the antecubital vein. The dose of diazepam was 0.05 mg/kg/injection (total dose was 0.15 mg/kg). The data were analyzed statistically using t-test. Signal change after administration of diazepam was less than 1 to 2% in healthy volunteers. By contrast, in patient with epilepsy, the signal change was almost 3%, which was significantly greater than that of the normal area (p=0.01). The neuro-pharmacological functional MRI technique using diazepam might be a useful method to identify epileptic foci. (author)

  12. Neuro-pharmacological functional MRI of epilepsy

    International Nuclear Information System (INIS)

    Kiriyama, Hideki; Makabe, Tetsuo; Tomita, Susumu; Omoto, Takashi; Asari, Shoji; Aihara, Hiroshi; Kinugasa, Kazushi; Nishimoto, Akira; Ito, Takahiko

    2000-01-01

    We studied patients with epilepsy by neuro-pharmacological functional MRI technique using diazepam. Five normal volunteers and 7 patients with epilepsy were investigated. MRI was performed by a 1.5 T unit (SIGNA Horizon, GE) using the following parameters: TR/TE 5000 msec/80 msec, FA 90 deg, FOV 200 mm, matrix 128 x 128, slice thickness 7 mm. We performed MRI scanning over 5 minutes (2 minutes before and 3 minutes after injection of diazepam) for each 1 session; we scanned 3 sessions for each patient at intervals of 5 minutes. The diazepam was injected rapidly from the antecubital vein. The dose of diazepam was 0.05 mg/kg/injection (total dose was 0.15 mg/kg). The data were analyzed statistically using t-test. Signal change after administration of diazepam was less than 1 to 2% in healthy volunteers. By contrast, in patient with epilepsy, the signal change was almost 3%, which was significantly greater than that of the normal area (p=0.01). The neuro-pharmacological functional MRI technique using diazepam might be a useful method to identify epileptic foci. (author)

  13. Clinical functional MRI. Persurgical functional neuroimaging. 2. ed.

    International Nuclear Information System (INIS)

    Stippich, Christoph

    2015-01-01

    The second, revised edition of this successful textbook provides an up-to-date description of the use of preoperative fMRI in patients with brain tumors and epilepsies. State of the art fMRI procedures are presented, with detailed consideration of practical aspects, imaging and data processing, normal and pathological findings, and diagnostic possibilities and limitations. Relevant information on brain physiology, functional neuroanatomy, imaging technique, and methodology is provided by recognized experts in these fields. Compared with the first edition, chapters have been updated to reflect the latest developments and in particular the current use of diffusion tensor imaging (DTI) and resting-state fMRI. Entirely new chapters are included on resting-state presurgical fMRI and the role of DTI and tractography in brain tumor surgery. Further chapters address multimodality functional neuroimaging, brain plasticity, and pitfalls, tips, and tricks.

  14. Clinical functional MRI. Persurgical functional neuroimaging. 2. ed.

    Energy Technology Data Exchange (ETDEWEB)

    Stippich, Christoph (ed.) [Univ. Hospitals Basel (Switzerland). Division of Diagnostic and Inventional Neuroradiology

    2015-06-01

    The second, revised edition of this successful textbook provides an up-to-date description of the use of preoperative fMRI in patients with brain tumors and epilepsies. State of the art fMRI procedures are presented, with detailed consideration of practical aspects, imaging and data processing, normal and pathological findings, and diagnostic possibilities and limitations. Relevant information on brain physiology, functional neuroanatomy, imaging technique, and methodology is provided by recognized experts in these fields. Compared with the first edition, chapters have been updated to reflect the latest developments and in particular the current use of diffusion tensor imaging (DTI) and resting-state fMRI. Entirely new chapters are included on resting-state presurgical fMRI and the role of DTI and tractography in brain tumor surgery. Further chapters address multimodality functional neuroimaging, brain plasticity, and pitfalls, tips, and tricks.

  15. Functional Proton MRI in Emphysematous Rats.

    Science.gov (United States)

    Bianchi, Andrea; Tibiletti, Marta; Kjørstad, Åsmund; Birk, Gerald; Schad, Lothar R; Stierstorfer, Birgit; Stiller, Detlef; Rasche, Volker

    2015-12-01

    To demonstrate the feasibility of proton magnetic resonance imaging (MRI) ventilation-related maps in rodents for the evaluation of lung function in the presence of pancreatic porcine elastase (PPE)-induced emphysema. Twelve rats were equally divided into 3 groups: group 1 (no administration of PPE); group 2 (PPE selectively only in the left lung); and group 3 (PPE administered in both lungs). Magnetic resonance imaging (MRI) and computed tomographic (CT) data were acquired at baseline, at 2 weeks and 4 weeks after administration, after which the animals were euthanized. The MRI protocol comprised a golden angle 2-dimensional ultrashort echo time MRI sequence [echo time, 0.343 millisecond (ms); repetition time, 120 ms; 12 slides with thickness, 1 mm; acquisition time, 30 minutes], from which inspiration and expiration images were reconstructed after the extraction of a self-gating signal. Inspiration images were registered to images at expiration, and expansion maps were created by calculating the specific difference in signal intensity. The lungs were segmented, and the mean specific expansion (MSE) calculated as an established surrogate for fractional ventilation. Computed tomographic data provided lung density (peak of the Hounsfield unit histogram, HU_P), whereas histology provided the mean linear intercept for each lung. Two weeks after administration, the control group had a mean MSE in both lungs corresponding to 96% of the baseline. Group 2 had 85% of the baseline, and group 3 had 57%. Considering the PPE-treated lungs alone, a significant reduction in MSE of 27% at 2 weeks and 40% at 4 weeks was found with respect to nontreated lungs. Significant correlations between HU_P and MSE were found at all time points (baseline: r = 0.606, P = 0.0017; 2 weeks: r = 0.837, P ≤ 0.0001; 4 weeks: r = 0.765, P Mean linear intercept values significantly correlated both with MRI MSE (r = -0.770, P The calculated ventilation-related maps showed a reduction of function in

  16. Pyrethroid pesticide-induced alterations in dopamine transporter function

    International Nuclear Information System (INIS)

    Elwan, Mohamed A.; Richardson, Jason R.; Guillot, Thomas S.; Caudle, W. Michael; Miller, Gary W.

    2006-01-01

    Parkinson's disease (PD) is a progressive neurodegenerative disease affecting the nigrostriatal dopaminergic pathway. Several epidemiological studies have demonstrated an association between pesticide exposure and the incidence of PD. Studies from our laboratory and others have demonstrated that certain pesticides increase levels of the dopamine transporter (DAT), an integral component of dopaminergic neurotransmission and a gateway for dopaminergic neurotoxins. Here, we report that repeated exposure (3 injections over 2 weeks) of mice to two commonly used pyrethroid pesticides, deltamethrin (3 mg/kg) and permethrin (0.8 mg/kg), increases DAT-mediated dopamine uptake by 31 and 28%, respectively. Using cells stably expressing DAT, we determined that exposure (10 min) to deltamethrin and permethrin (1 nM-100 μM) had no effect on DAT-mediated dopamine uptake. Extending exposures to both pesticides for 30 min (10 μM) or 24 h (1, 5, and 10 μM) resulted in significant decrease in dopamine uptake. This reduction was not the result of competitive inhibition, loss of DAT protein, or cytotoxicity. However, there was an increase in DNA fragmentation, an index of apoptosis, in cells exhibiting reduced uptake at 30 min and 24 h. These data suggest that up-regulation of DAT by in vivo pyrethroid exposure is an indirect effect and that longer-term exposure of cells results in apoptosis. Since DAT can greatly affect the vulnerability of dopamine neurons to neurotoxicants, up-regulation of DAT by deltamethrin and permethrin may increase the susceptibility of dopamine neurons to toxic insult, which may provide insight into the association between pesticide exposure and PD

  17. Application of functional MRI in breast diseases

    International Nuclear Information System (INIS)

    Feng Yun; Liu Shiyuan; Wang Chenguang; Tao Xiaofeng; Wang Jinlin; Wang Jian

    2007-01-01

    Objective: To investigate the value of functional MRI in the diagnosis and differential diagnosis of breast diseases. Methods: Sixty-five patients with 68 lesions were enrolled in this study. Conventional T 1 WI and T 2 WI scan, dynamic contrast enhanced MRI, diffusion weighted imaging and 1 H single voxel MR spectroscopy were performed consequently. All lesions were verified by pathology, including 4 cases of breast adenosis, 22 fibroadenomas, 2 chronic inflammations, 3 cysts, 33 infitrating ductal carcinomas, 1 intraductal carcinoma and 3 cystosarcoma phyllodes tumors. Morphological features, maximum enhancement ratio, time-intensity curve, apparent diffusion coefficient and Choline peak were analyzed. Results: The detection rates of T 1 WI and T 2 WI were 14.7% (n=10) and 51.5% (n=35). The sensitivity, specificity, accuracy of dynamic contrast enhanced MRI for the malignant tumor were 94. 6%, 71.4% and 76.5% respectively. Retrospective study showed that diffusion weighted imaging, with the b value from 800 s/mm 2 to 1000 s/mm 2 , could be used to differentiate various types of breast lesions. 1 H signal voxel spectroscopy had a sensitivity of 51.4%, specificity of 82.6%, and accuracy of 67.6% for the malignent. The sensitivity, specificity and accuracy could reach 97.3%, 90.0% and 92.6% respectively by combining conventional scan, dynamic contrast enhanced MRI and MR spectroscopy. Conclusion: Functional MRI, with high sensitivity, specificity and accuracy, can be used widely in the diagnosis of malignant breast lesions. (authors)

  18. Imaging of striatal dopamine transporters in rat brain with single pinhole SPECT and co-aligned MRI is highly reproducible

    International Nuclear Information System (INIS)

    Booij, Jan; Bruin, Kora de; Win, Maartje M.L. de; Lavini, Cristina Mphil; Heeten, Gerard J. den; Habraken, Jan

    2003-01-01

    A recently developed pinhole high-resolution SPECT system was used to measure striatal to non-specific binding ratios in rats (n = 9), after injection of the dopamine transporter ligand 123 I-FP-CIT, and to assess its test/retest reproducibility. For co-alignment purposes, the rat brain was imaged on a 1.5 Tesla clinical MRI scanner using a specially developed surface coil. The SPECT images showed clear striatal uptake. On the MR images, cerebral and extra-cerebral structures could be easily delineated. The mean striatal to non-specific [ 123 I]FP-CIT binding ratios of the test/retest studies were 1.7 ± 0.2 and 1.6 ± 0.2, respectively. The test/retest variability was approximately 9%. We conclude that the assessment of striatal [ 123 I]FP-CIT binding ratios in rats is highly reproducible

  19. A Genetic Toolkit for Dissecting Dopamine Circuit Function in Drosophila

    Directory of Open Access Journals (Sweden)

    Tingting Xie

    2018-04-01

    Full Text Available Summary: The neuromodulator dopamine (DA plays a key role in motor control, motivated behaviors, and higher-order cognitive processes. Dissecting how these DA neural networks tune the activity of local neural circuits to regulate behavior requires tools for manipulating small groups of DA neurons. To address this need, we assembled a genetic toolkit that allows for an exquisite level of control over the DA neural network in Drosophila. To further refine targeting of specific DA neurons, we also created reagents that allow for the conversion of any existing GAL4 line into Split GAL4 or GAL80 lines. We demonstrated how this toolkit can be used with recently developed computational methods to rapidly generate additional reagents for manipulating small subsets or individual DA neurons. Finally, we used the toolkit to reveal a dynamic interaction between a small subset of DA neurons and rearing conditions in a social space behavioral assay. : The rapid analysis of how dopaminergic circuits regulate behavior is limited by the genetic tools available to target and manipulate small numbers of these neurons. Xie et al. present genetic tools in Drosophila that allow rational targeting of sparse dopaminergic neuronal subsets and selective knockdown of dopamine signaling. Keywords: dopamine, genetics, behavior, neural circuits, neuromodulation, Drosophila

  20. Functional MRI for planning in neurosurgery

    International Nuclear Information System (INIS)

    Erb, M.; Saur, R.

    2007-01-01

    Beside structural images from CT and MR, functional data about localization of brain activations with different tasks becomes more and more important for presurgical planning. With this method, it's possible to depict mainly primary sensory and motoric areas, but also higher functions like speech and memory. To judge this information adequately, one has to be aware of the variability of activation pattern dependent on chosen threshold. Especially, the absence of such activation at a given location does not necessary mean that this area has no function. The reliability of a measurement strongly depends on efficiency of experimental design and cooperation of the patient. Therefore, short and easy tasks which can be performed in a block design should be preferred. Information about localization of functions determined by fMRI can mainly be used for presurgical planning. Intraoperative usage in the navigation system is problematic due to the brain shift. Therefore, intraoperative imaging together with dynamic adaptation using nonlinear deformation algorithms may improve the value of fMRI in the future. (orig.)

  1. Imaging tools to study pharmacology: functional MRI on small rodents

    Directory of Open Access Journals (Sweden)

    Elisabeth eJonckers

    2015-10-01

    Full Text Available Functional Magnetic Resonance Imaging (fMRI is an excellent tool to study the effect of pharmacological modulations on brain function in a non-invasive and longitudinal manner. We introduce several blood oxygenation level dependent (BOLD fMRI techniques, including resting state (rsfMRI, stimulus-evoked (st-fMRI, and pharmacological MRI (phMRI. Respectively, these techniques permit the assessment of functional connectivity during rest as well as brain activation triggered by sensory stimulation and/or a pharmacological challenge. The first part of this review describes the physiological basis of BOLD fMRI and the hemodynamic response on which the MRI contrast is based. Specific emphasis goes to possible effects of anaesthesia and the animal’s physiological conditions on neural activity and the hemodynamic response. The second part of this review describes applications of the aforementioned techniques in pharmacologically-induced, as well as in traumatic and transgenic disease models and illustrates how multiple fMRI methods can be applied successfully to evaluate different aspects of a specific disorder. For example, fMRI techniques can be used to pinpoint the neural substrate of a disease beyond previously defined hypothesis-driven regions-of-interest (ROIs. In addition, fMRI techniques allow one to dissect how specific modifications (e.g. treatment, lesion etc. modulate the functioning of specific brain areas (st-fMRI, phMRI and how functional connectivity (rsfMRI between several brain regions is affected, both in acute and extended time frames. Furthermore, fMRI techniques can be used to assess/explore the efficacy of novel treatments in depth, both in fundamental research as well as in preclinical settings. In conclusion, by describing several exemplary studies, we aim to highlight the advantages of functional MRI in exploring the acute and long-term effects of pharmacological substances and/or pathology on brain functioning along with

  2. Functional MRI experiments : acquisition, analysis and interpretation of data

    NARCIS (Netherlands)

    Ramsey, NF; Hoogduin, H; Jansma, JM

    2002-01-01

    Functional MRI is widely used to address basic and clinical neuroscience questions. In the key domains of fMRI experiments, i.e. acquisition, processing and analysis, and interpretation of data, developments are ongoing. The main issues are sensitivity for changes in fMRI signal that are associated

  3. Dopamine transporter polymorphism modulates oculomotor function and DAT1 mRNA expression in schizophrenia.

    Science.gov (United States)

    Wonodi, Ikwunga; Hong, L Elliot; Stine, O Colin; Mitchell, Braxton D; Elliott, Amie; Roberts, Rosalinda C; Conley, Robert R; McMahon, Robert P; Thaker, Gunvant K

    2009-03-05

    Smooth pursuit eye movement (SPEM) deficit is an established schizophrenia endophenotype with a similar neurocognitive construct to working memory. Frontal eye field (FEF) neurons controlling SPEM maintain firing when visual sensory information is removed, and their firing rates directly correlate with SPEM velocity. We previously demonstrated a paradoxical association between a functional polymorphism of dopamine signaling (COMT gene) and SPEM. Recent evidence implicates the dopamine transporter gene (DAT1) in modulating cortical dopamine and associated neurocognitive functions. We hypothesized that DAT1 10/10 genotype, which reduces dopamine transporter expression and increases extracellular dopamine, would affect SPEM. We examined the effects of DAT1 genotype on: Clinical diagnosis in the study sample (n = 418; 190 with schizophrenia), SPEM measures in a subgroup with completed oculomotor measures (n = 200; 87 schizophrenia), and DAT1 gene expression in FEF tissue obtained from postmortem brain samples (n = 32; 16 schizophrenia). DAT1 genotype was not associated with schizophrenia. DAT1 10/10 genotype was associated with better SPEM in healthy controls, intermediate SPEM in unaffected first-degree relatives of schizophrenia subjects, and worse SPEM in schizophrenia subjects. In the gene expression study, DAT1 10/10 genotype was associated with significantly reduced DAT1 mRNA transcript in FEF tissue from healthy control donors (P < 0.05), but higher expression in schizophrenia donors. Findings suggest regulatory effects of another gene(s) or etiological factor in schizophrenia, which modulate DAT1 gene function. 2008 Wiley-Liss, Inc.

  4. Altered effect of dopamine transporter 3'UTR VNTR genotype on prefrontal and striatal function in schizophrenia.

    Science.gov (United States)

    Prata, Diana P; Mechelli, Andrea; Picchioni, Marco M; Fu, Cynthia H Y; Toulopoulou, Timothea; Bramon, Elvira; Walshe, Muriel; Murray, Robin M; Collier, David A; McGuire, Philip

    2009-11-01

    The dopamine transporter plays a key role in the regulation of central dopaminergic transmission, which modulates cognitive processing. Disrupted dopamine function and impaired executive processing are robust features of schizophrenia. To examine the effect of a polymorphism in the dopamine transporter gene (the variable number of tandem repeats in the 3' untranslated region) on brain function during executive processing in healthy volunteers and patients with schizophrenia. We hypothesized that this variation would have a different effect on prefrontal and striatal activation in schizophrenia, reflecting altered dopamine function. Case-control study. Psychiatric research center. Eighty-five subjects, comprising 44 healthy volunteers (18 who were 9-repeat carriers and 26 who were 10-repeat homozygotes) and 41 patients with DSM-IV schizophrenia (18 who were 9-repeat carriers and 23 who were 10-repeat homozygotes). Regional brain activation during word generation relative to repetition in an overt verbal fluency task measured by functional magnetic resonance imaging. Main effects of genotype and diagnosis on activation and their interaction were estimated with analysis of variance in SPM5. Irrespective of diagnosis, the 10-repeat allele was associated with greater activation than the 9-repeat allele in the left anterior insula and right caudate nucleus. Trends for the same effect in the right insula and for greater deactivation in the rostral anterior cingulate cortex were also detected. There were diagnosis x genotype interactions in the left middle frontal gyrus and left nucleus accumbens, where the 9-repeat allele was associated with greater activation than the 10-repeat allele in patients but not controls. Insular, cingulate, and striatal function during an executive task is normally modulated by variation in the dopamine transporter gene. Its effect on activation in the dorsolateral prefrontal cortex and ventral striatum is altered in patients with schizophrenia

  5. Aberrant dopamine D2-like receptor function in a rodent model of schizophrenia.

    Science.gov (United States)

    Perez, Stephanie M; Lodge, Daniel J

    2012-11-01

    Based on the observation that antipsychotic medications display antagonist properties at dopamine D2-like receptors, aberrant dopamine signaling has been proposed to underlie psychosis in patients with schizophrenia. Thus, it is not surprising that considerable research has been devoted to understanding the mechanisms involved in the antipsychotic action of these compounds. It is important to note that the majority of these studies have been performed in "normal" experimental animals. Given that these animals do not possess the aberrant neuronal information processing typically associated with schizophrenia, the aim of the current study was to examine the dopamine D2 receptor system in a rodent model of schizophrenia. Here, we demonstrate that methylazoxymethanol acetate (MAM)-treated rats display an enhanced effect of quinpirole on dopamine neuron activity and an aberrant locomotor response to D2-like receptor activation, suggesting changes in postsynaptic D2-like receptor function. To better understand the mechanisms underlying the enhanced response to D2-like ligands in MAM-treated rats, we examined the expression of D2, D3, and dopamine transporter mRNA in the nucleus accumbens and ventral tegmental area by quantitative reverse transcription-polymerase chain reaction. MAM-treated rats displayed a significant increase in dopamine D3 receptor mRNA expression in the nucleus accumbens with no significant changes in the expression of the D2 receptor. Taken together, these data demonstrate robust alterations in dopamine D2-like receptor function in a rodent model of schizophrenia and provide evidence that preclinical studies examining the mechanisms of antipsychotic drug action should be performed in animal models that mirror aspects of the abnormal neuronal transmission thought to underlie symptoms of schizophrenia.

  6. Functional MRI and CT biomarkers in oncology

    Energy Technology Data Exchange (ETDEWEB)

    Winfield, J.M. [Institute of Cancer Research and Royal Marsden NHS Foundation Trust, CRUK Imaging Centre at the Institute of Cancer Research, Sutton (United Kingdom); Institute of Cancer Research and Royal Marsden Hospital, MRI Unit, Sutton (United Kingdom); Payne, G.S.; DeSouza, N.M. [Institute of Cancer Research and Royal Marsden NHS Foundation Trust, CRUK Imaging Centre at the Institute of Cancer Research, Sutton (United Kingdom)

    2015-04-01

    Imaging biomarkers derived from MRI or CT describe functional properties of tumours and normal tissues. They are finding increasing numbers of applications in diagnosis, monitoring of response to treatment and assessment of progression or recurrence. Imaging biomarkers also provide scope for assessment of heterogeneity within and between lesions. A wide variety of functional parameters have been investigated for use as biomarkers in oncology. Some imaging techniques are used routinely in clinical applications while others are currently restricted to clinical trials or preclinical studies. Apparent diffusion coefficient, magnetization transfer ratio and native T{sub 1} relaxation time provide information about structure and organization of tissues. Vascular properties may be described using parameters derived from dynamic contrast-enhanced MRI, dynamic contrast-enhanced CT, transverse relaxation rate (R{sub 2}*), vessel size index and relative blood volume, while magnetic resonance spectroscopy may be used to probe the metabolic profile of tumours. This review describes the mechanisms of contrast underpinning each technique and the technical requirements for robust and reproducible imaging. The current status of each biomarker is described in terms of its validation, qualification and clinical applications, followed by a discussion of the current limitations and future perspectives. (orig.)

  7. Interactive Effects of Dopamine Baseline Levels and Cycle Phase on Executive Functions: The Role of Progesterone

    Directory of Open Access Journals (Sweden)

    Esmeralda Hidalgo-Lopez

    2017-07-01

    Full Text Available Estradiol and progesterone levels vary along the menstrual cycle and have multiple neuroactive effects, including on the dopaminergic system. Dopamine relates to executive functions in an “inverted U-shaped” manner and its levels are increased by estradiol. Accordingly, dopamine dependent changes in executive functions along the menstrual cycle have been previously studied in the pre-ovulatory phase, when estradiol levels peak. Specifically it has been demonstrated that working memory is enhanced during the pre-ovulatory phase in women with low dopamine baseline levels, but impaired in women with high dopamine baseline levels. However, the role of progesterone, which peaks in the luteal cycle phase, has not been taken into account previously. Therefore, the main goals of the present study were to extend these findings (i to the luteal cycle phase and (ii to other executive functions. Furthermore, the usefulness of the eye blink rate (EBR as an indicator of dopamine baseline levels in menstrual cycle research was explored. 36 naturally cycling women were tested during three cycle phases (menses–low sex hormones; pre-ovulatory–high estradiol; luteal–high progesterone and estradiol. During each session, women performed a verbal N-back task, as measure of working memory, and a single trial version of the Stroop task, as measure of response inhibition and cognitive flexibility. Hormone levels were assessed from saliva samples and spontaneous eye blink rate was recorded during menses. In the N-back task, women were faster during the luteal phase the higher their progesterone levels, irrespective of their dopamine baseline levels. In the Stroop task, we found a dopamine-cycle interaction, which was also driven by the luteal phase and progesterone levels. For women with higher EBR performance decreased during the luteal phase, whereas for women with lower EBR performance improved during the luteal phase. These findings suggest an important

  8. To see bruxism: a functional MRI study.

    Science.gov (United States)

    Yılmaz, S

    2015-01-01

    Since the pathophysiology of bruxism is not clearly understood, there exists no possible treatment. The aim of this study is to investigate the cerebral activation differences between healthy subjects and patients with bruxism on behalf of possible aetiological factors. 12 healthy subjects and 12 patients with bruxism, a total of 24 right-handed female subjects (aged 20-27 years) were examined using functional MRI during tooth-clenching and resting tasks. Imaging was performed with 3.0-T MRI scanner with a 32-channel head coil. Differences in regional brain activity between patients with bruxism and healthy subjects (control group) were observed with BrainVoyager QX 2.8 (Brain Innovation, Maastricht, Netherlands) statistical data analysis program. Activation maps were created using the general linear model: single study and multistudy multisubject for statistical group analysis. This protocol was approved by the ethics committee of medical faculty of Kirikkale University, Turkey (02/04), based on the guidelines set forth in the Declaration of Helsinki. The group analysis revealed a statistically significant increase in blood oxygenation level-dependent signal of three clusters in the control group (pbruxism. Our findings indicate that there was a decrease of cortical activation pattern in patients with bruxism in clenching tasks. This indicates decreased blood flow and activation in regional neuronal activity. Bruxism, as an oral motor disorder concerns dentistry, neurology and psychiatry. These results might improve the understanding and physiological handling of sleep bruxism.

  9. Endocannabinoid Signaling in Motivation, Reward, and Addiction: Influences on Mesocorticolimbic Dopamine Function.

    Science.gov (United States)

    Sagheddu, Claudia; Muntoni, Anna Lisa; Pistis, Marco; Melis, Miriam

    2015-01-01

    Evidence suggests that the endocannabinoid system has been conserved in the animal kingdom for 500 million years, and this system influences many critical behavioral processes including associative learning, reward signaling, goal-directed behavior, motor skill learning, and action-habit transformation. Additionally, the neurotransmitter dopamine has long been recognized to play a critical role in the processing of natural rewards, as well as of motivation that regulates approach and avoidance behavior. This motivational role of dopamine neurons is also based upon the evidence provided by several studies investigating disorders of dopamine pathways such as drug addiction and Parkinson's disease. From an evolutionary point of view, individuals engage in behaviors aimed at maximizing and minimizing positive and aversive consequences, respectively. Accordingly, those with the greatest fitness have a better potential to survival. Hence, deviations from fitness can be viewed as a part of the evolutionary process by means of natural selection. Given the long evolutionary history of both the endocannabinoid and dopaminergic systems, it is plausible that they must serve as fundamental and basic modulators of physiological functions and needs. Notably, endocannabinoids regulate dopamine neuronal activity and its influence on behavioral output. The goal of this chapter is to examine the endocannabinoid influence on dopamine signaling specifically related to (i) those behavioral processes that allow us to successfully adapt to ever-changing environments (i.e., reward signaling and motivational processes) and (ii) derangements from behavioral flexibility that underpin drug addiction. © 2015 Elsevier Inc. All rights reserved.

  10. Drug induced increases in CNS dopamine alter monocyte, macrophage and T cell functions: implications for HAND

    Science.gov (United States)

    Gaskill, Peter J.; Calderon, Tina M.; Coley, Jacqueline S.; Berman, Joan W.

    2013-01-01

    Central nervous system (CNS) complications resulting from HIV infection remain a major public health problem as individuals live longer due to the success of combined antiretroviral therapy (cART). As many as 70% of HIV infected people have HIV associated neurocognitive disorders (HAND). Many HIV infected individuals abuse drugs, such as cocaine, heroin or methamphetamine, that may be important cofactors in the development of HIV CNS disease. Despite different mechanisms of action, all drugs of abuse increase extracellular dopamine in the CNS. The effects of dopamine on HIV neuropathogenesis are not well understood, and drug induced increases in CNS dopamine may be a common mechanism by which different types of drugs of abuse impact the development of HAND. Monocytes and macrophages are central to HIV infection of the CNS and to HAND. While T cells have not been shown to be a major factor in HIV-associated neuropathogenesis, studies indicate that T cells may play a larger role in the development of HAND in HIV infected drug abusers. Drug induced increases in CNS dopamine may dysregulate functions of, or increase HIV infection in, monocytes, macrophages and T cells in the brain. Thus, characterizing the effects of dopamine on these cells is important for understanding the mechanisms that mediate the development of HAND in drug abusers. PMID:23456305

  11. Blink Rate in Boys with Fragile X Syndrome: Preliminary Evidence for Altered Dopamine Function

    Science.gov (United States)

    Roberts, J. E.; Symons, F. J.; Johnson, A.-M.; Hatton, D. D.; Boccia, M. L.

    2005-01-01

    Background: Dopamine, a neurotransmitter involved in motor and cognitive functioning, can be non-invasively measured via observation of spontaneous blink rates. Blink rates have been studied in a number of clinical conditions including schizophrenia, autism, Parkinsons, and attention deficit/hyperactivity disorder with results implicating either…

  12. Maternal separation affects dopamine transporter function in the Spontaneously Hypertensive Rat: An in vivo electrochemical study

    Directory of Open Access Journals (Sweden)

    Womersley Jacqueline S

    2011-12-01

    Full Text Available Abstract Background Attention-deficit/hyperactivity disorder (ADHD is a developmental disorder characterised by symptoms of inattention, impulsivity and hyperactivity. The spontaneously hypertensive rat (SHR is a well-characterised model of this disorder and has been shown to exhibit dopamine dysregulation, one of the hypothesised causes of ADHD. Since stress experienced in the early stages of life can have long-lasting effects on behaviour, it was considered that early life stress may alter development of the dopaminergic system and thereby contribute to the behavioural characteristics of SHR. It was hypothesized that maternal separation would alter dopamine regulation by the transporter (DAT in ways that distinguish SHR from control rat strains. Methods SHR and control Wistar-Kyoto (WKY rats were subjected to maternal separation for 3 hours per day from postnatal day 2 to 14. Rats were tested for separation-induced anxiety-like behaviour followed by in vivo chronoamperometry to determine whether changes had occurred in striatal clearance of dopamine by DAT. The rate of disappearance of ejected dopamine was used as a measure of DAT function. Results Consistent with a model for ADHD, SHR were more active than WKY in the open field. SHR entered the inner zone more frequently and covered a significantly greater distance than WKY. Maternal separation increased the time that WKY spent in the closed arms and latency to enter the open arms of the elevated plus maze, consistent with other rat strains. Of note is that, maternal separation failed to produce anxiety-like behaviour in SHR. Analysis of the chronoamperometric data revealed that there was no difference in DAT function in the striatum of non-separated SHR and WKY. Maternal separation decreased the rate of dopamine clearance (k-1 in SHR striatum. Consistent with this observation, the dopamine clearance time (T100 was increased in SHR. These results suggest that the chronic mild stress of

  13. Dopamine D(3) receptors contribute to methamphetamine-induced alterations in dopaminergic neuronal function: role of hyperthermia.

    Science.gov (United States)

    Baladi, Michelle G; Newman, Amy H; Nielsen, Shannon M; Hanson, Glen R; Fleckenstein, Annette E

    2014-06-05

    Methamphetamine administration causes long-term deficits to dopaminergic systems that, in humans, are thought to be associated with motor slowing and memory impairment. Methamphetamine interacts with the dopamine transporter (DAT) and increases extracellular concentrations of dopamine that, in turn, binds to a number of dopamine receptor subtypes. Although the relative contribution of each receptor subtype to the effects of methamphetamine is not fully known, non-selective dopamine D2/D3 receptor antagonists can attenuate methamphetamine-induced changes to dopamine systems. The present study extended these findings by testing the role of the dopamine D3 receptor subtype in mediating the long-term dopaminergic, and for comparison serotonergic, deficits caused by methamphetamine. Results indicate that the dopamine D3 receptor selective antagonist, PG01037, attenuated methamphetamine-induced decreases in striatal DAT, but not hippocampal serotonin (5HT) transporter (SERT), function, as assessed 7 days after treatment. However, PG01037 also attenuated methamphetamine-induced hyperthermia. When methamphetamine-induced hyperthermia was maintained by treating rats in a warm ambient environment, PG01037 failed to attenuate the effects of methamphetamine on DAT uptake. Furthermore, PG01037 did not attenuate methamphetamine-induced decreases in dopamine and 5HT content. Taken together, the present study demonstrates that dopamine D3 receptors mediate, in part, the long-term deficits in DAT function caused by methamphetamine, and that this effect likely involves an attenuation of methamphetamine-induced hyperthermia. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Dopamine D3 receptors contribute to methamphetamine-induced alterations in dopaminergic neuronal function: Role of hyperthermia

    Science.gov (United States)

    Baladi, Michelle G.; Newman, Amy H.; Nielsen, Shannon M.; Hanson, Glen R.; Fleckenstein, Annette E.

    2014-01-01

    Methamphetamine administration causes long-term deficits to dopaminergic systems that, in humans, are thought to be associated with motor slowing and memory impairment. Methamphetamine interacts with the dopamine transporter (DAT) and increases extracellular concentrations of dopamine that, in turn, binds to a number of dopamine receptor subtypes. Although the relative contribution of each receptor subtype to the effects of methamphetamine is not fully known, non-selective dopamine D2/D3 receptor antagonists can attenuate methamphetamine-induced changes to dopamine systems. The present study extended these findings by testing the role of the dopamine D3 receptor subtype in mediating the long-term dopaminergic, and for comparison serotonergic, deficits caused by methamphetamine. Results indicate that the dopamine D3 receptor selective antagonist, PG01037, attenuated methamphetamine-induced decreases in striatal DAT, but not hippocampal serotonin (5HT) transporter (SERT), function, as assessed 7 days after treatment. However, PG01037 also attenuated methamphetamine-induced hyperthermia. When methamphetamine-induced hyperthermia was maintained by treating rats in a warm ambient environment, PG01037 failed to attenuate the effects of methamphetamine on DAT uptake. Furthermore, PG01037 did not attenuate methamphetamine-induced decreases in dopamine and 5HT content. Taken together, the present study demonstrates that dopamine D3 receptors mediate, in part, the long-term deficits in DAT function caused by methamphetamine, and that this effect likely involves an attenuation of methamphetamine-induced hyperthermia. PMID:24685638

  15. IClinfMRI Software for Integrating Functional MRI Techniques in Presurgical Mapping and Clinical Studies.

    Science.gov (United States)

    Hsu, Ai-Ling; Hou, Ping; Johnson, Jason M; Wu, Changwei W; Noll, Kyle R; Prabhu, Sujit S; Ferguson, Sherise D; Kumar, Vinodh A; Schomer, Donald F; Hazle, John D; Chen, Jyh-Horng; Liu, Ho-Ling

    2018-01-01

    Task-evoked and resting-state (rs) functional magnetic resonance imaging (fMRI) techniques have been applied to the clinical management of neurological diseases, exemplified by presurgical localization of eloquent cortex, to assist neurosurgeons in maximizing resection while preserving brain functions. In addition, recent studies have recommended incorporating cerebrovascular reactivity (CVR) imaging into clinical fMRI to evaluate the risk of lesion-induced neurovascular uncoupling (NVU). Although each of these imaging techniques possesses its own advantage for presurgical mapping, a specialized clinical software that integrates the three complementary techniques and promptly outputs the analyzed results to radiology and surgical navigation systems in a clinical format is still lacking. We developed the Integrated fMRI for Clinical Research (IClinfMRI) software to facilitate these needs. Beyond the independent processing of task-fMRI, rs-fMRI, and CVR mapping, IClinfMRI encompasses three unique functions: (1) supporting the interactive rs-fMRI mapping while visualizing task-fMRI results (or results from published meta-analysis) as a guidance map, (2) indicating/visualizing the NVU potential on analyzed fMRI maps, and (3) exporting these advanced mapping results in a Digital Imaging and Communications in Medicine (DICOM) format that are ready to export to a picture archiving and communication system (PACS) and a surgical navigation system. In summary, IClinfMRI has the merits of efficiently translating and integrating state-of-the-art imaging techniques for presurgical functional mapping and clinical fMRI studies.

  16. Functional MRI in children: clinical and research applications

    International Nuclear Information System (INIS)

    Leach, James L.; Holland, Scott K.

    2010-01-01

    Functional MRI has become a critical research tool for evaluating brain function and developmental trajectories in children. Its clinical use in children is becoming more common. This presentation will review the basic underlying physiologic and technical aspects of fMRI, review research applications that have direct clinical relevance, and outline the current clinical uses of this technology. (orig.)

  17. Structural and Functional Effect of an Oscillating Electric Field on the Dopamine-D3 Receptor: A Molecular Dynamics Simulation Study.

    Directory of Open Access Journals (Sweden)

    Zohreh Fallah

    Full Text Available Dopamine as a neurotransmitter plays a critical role in the functioning of the central nervous system. The structure of D3 receptor as a member of class A G-protein coupled receptors (GPCRs has been reported. We used MD simulation to investigate the effect of an oscillating electric field, with frequencies in the range 0.6-800 GHz applied along the z-direction, on the dopamine-D3R complex. The simulations showed that at some frequencies, the application of an external oscillating electric field along the z-direction has a considerable effect on the dopamine-D3R. However, there is no enough evidence for prediction of changes in specific frequency, implying that there is no order in changes. Computing the correlation coefficient parameter showed that increasing the field frequency can weaken the interaction between dopamine and D3R and may decrease the Arg128{3.50}-Glu324{6.30} distance. Because of high stability of α helices along the z-direction, applying an oscillating electric field in this direction with an amplitude 10-time higher did not have a considerable effect. However, applying the oscillating field at the frequency of 0.6 GHz along other directions, such as X-Y and Y-Z planes, could change the energy between the dopamine and the D3R, and the number of internal hydrogen bonds of the protein. This can be due to the effect of the direction of the electric field vis-à-vis the ligands orientation and the interaction of the oscillating electric field with the dipole moment of the protein.

  18. Dopamine precursor depletion impairs structure and efficiency of resting state brain functional networks.

    Science.gov (United States)

    Carbonell, Felix; Nagano-Saito, Atsuko; Leyton, Marco; Cisek, Paul; Benkelfat, Chawki; He, Yong; Dagher, Alain

    2014-09-01

    Spatial patterns of functional connectivity derived from resting brain activity may be used to elucidate the topological properties of brain networks. Such networks are amenable to study using graph theory, which shows that they possess small world properties and can be used to differentiate healthy subjects and patient populations. Of particular interest is the possibility that some of these differences are related to alterations in the dopamine system. To investigate the role of dopamine in the topological organization of brain networks at rest, we tested the effects of reducing dopamine synthesis in 13 healthy subjects undergoing functional magnetic resonance imaging. All subjects were scanned twice, in a resting state, following ingestion of one of two amino acid drinks in a randomized, double-blind manner. One drink was a nutritionally balanced amino acid mixture, and the other was tyrosine and phenylalanine deficient. Functional connectivity between 90 cortical and subcortical regions was estimated for each individual subject under each dopaminergic condition. The lowered dopamine state caused the following network changes: reduced global and local efficiency of the whole brain network, reduced regional efficiency in limbic areas, reduced modularity of brain networks, and greater connection between the normally anti-correlated task-positive and default-mode networks. We conclude that dopamine plays a role in maintaining the efficient small-world properties and high modularity of functional brain networks, and in segregating the task-positive and default-mode networks. This article is part of the Special Issue Section entitled 'Neuroimaging in Neuropharmacology'. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Functional imaging of the kidneys with fast MRI techniques

    International Nuclear Information System (INIS)

    Prasad, Pottumarthi V.; Priatna, Agus

    1999-01-01

    Availability of faster and stronger gradient systems have given rise to a multitude of fast MRI data acquisition strategies which have tremendously increased the scope of MRI applications. These have led to the realization of long desired comprehensive approaches to evaluate anatomy and function using a single modality. In this work, we describe some of our own experiences with functional evaluation of the kidneys using MRI. Examples that suggest the feasibility of comprehensive approaches for evaluation of renal disease are also provided. We also introduce BOLD renal MRI, a method that may allow basic understanding of human renal physiology and pathophysiology in a way that has not been previously possible

  20. Functional MRI of Language Processing and Recovery

    NARCIS (Netherlands)

    C. Méndez Orellana (Carolina)

    2015-01-01

    markdownabstract__Abstract__ My thesis describe the utility of implementing fMRI to investigate how the language system is reorganized in brain damaged patients. Specifically for aphasia research fMRI allows to show how specific language treatment methods have the potential to enhance language

  1. Quantitation of global and regional left ventricular function by MRI

    NARCIS (Netherlands)

    van der Geest, RJ; Reiber, JHC; Reiber, JHC; VanDerWall, EE

    1998-01-01

    Magnetic resonance imaging (MRI) provides several imaging strategies for assessing left ventricular function. As a three-dimensional imaging technique, all measurements can be performed without relying on geometrical assumptions. Global and regional function parameters can be derived from

  2. Cholinergic modulation of mesolimbic dopamine function and reward.

    Science.gov (United States)

    Mark, Gregory P; Shabani, Shkelzen; Dobbs, Lauren K; Hansen, Stephen T

    2011-07-25

    The substantial health risk posed by obesity and compulsive drug use has compelled a serious research effort to identify the neurobiological substrates that underlie the development these pathological conditions. Despite substantial progress, an understanding of the neurochemical systems that mediate the motivational aspects of drug-seeking and craving remains incomplete. Important work from the laboratory of Bart Hoebel has provided key information on neurochemical systems that interact with dopamine (DA) as potentially important components in both the development of addiction and the expression of compulsive behaviors such as binge eating. One such modulatory system appears to be cholinergic pathways that interact with DA systems at all levels of the reward circuit. Cholinergic cells in the pons project to DA-rich cell body regions in the ventral tegmental area (VTA) and substantial nigra (SN) where they modulate the activity of dopaminergic neurons and reward processing. The DA terminal region of the nucleus accumbens (NAc) contains a small but particularly important group of cholinergic interneurons, which have extensive dendritic arbors that make synapses with a vast majority of NAc neurons and afferents. Together with acetylcholine (ACh) input onto DA cell bodies, cholinergic systems could serve a vital role in gating information flow concerning the motivational value of stimuli through the mesolimbic system. In this report we highlight evidence that CNS cholinergic systems play a pivotal role in behaviors that are motivated by both natural and drug rewards. We argue that the search for underlying neurochemical substrates of compulsive behaviors, as well as attempts to identify potential pharmacotherapeutic targets to combat them, must include a consideration of central cholinergic systems. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Amphetamine-induced dopamine release and neurocognitive function in treatment-naive adults with ADHD.

    Science.gov (United States)

    Cherkasova, Mariya V; Faridi, Nazlie; Casey, Kevin F; O'Driscoll, Gillian A; Hechtman, Lily; Joober, Ridha; Baker, Glen B; Palmer, Jennifer; Dagher, Alain; Leyton, Marco; Benkelfat, Chawki

    2014-05-01

    Converging evidence from clinical, preclinical, neuroimaging, and genetic research implicates dopamine neurotransmission in the pathophysiology of attention deficit hyperactivity disorder (ADHD). The in vivo neuroreceptor imaging evidence also suggests alterations in the dopamine system in ADHD; however, the nature and behavioral significance of those have not yet been established. Here, we investigated striatal dopaminergic function in ADHD using [(11)C]raclopride PET with a d-amphetamine challenge. We also examined the relationship of striatal dopamine responses to ADHD symptoms and neurocognitive function. A total of 15 treatment-free, noncomorbid adult males with ADHD (age: 29.87 ± 8.65) and 18 healthy male controls (age: 25.44 ± 6.77) underwent two PET scans: one following a lactose placebo and the other following d-amphetamine (0.3 mg/kg, p.o.), administered double blind and in random order counterbalanced across groups. In a separate session without a drug, participants performed a battery of neurocognitive tests. Relative to the healthy controls, the ADHD patients, as a group, showed greater d-amphetamine-induced decreases in striatal [(11)C]raclopride binding and performed more poorly on measures of response inhibition. Across groups, a greater magnitude of d-amphetamine-induced change in [(11)C]raclopride binding potential was associated with poorer performance on measures of response inhibition and ADHD symptoms. Our findings suggest an augmented striatal dopaminergic response in treatment-naive ADHD. Though in contrast to results of a previous study, this finding appears consistent with a model proposing exaggerated phasic dopamine release in ADHD. A susceptibility to increased phasic dopamine responsivity may contribute to such characteristics of ADHD as poor inhibition and impulsivity.

  4. Motor Function and Dopamine Release Measurements in Transgenic Huntington’s Disease Model Rats

    Science.gov (United States)

    Ortiz, Andrea N.; Osterhaus, Gregory L.; Lauderdale, Kelli; Mahoney, Luke; Fowler, Stephen C.; von Hörsten, Stephan; Riess, Olaf; Johnson, Michael A.

    2013-01-01

    Huntington’s disease (HD) is a fatal, genetic, neurodegenerative disorder characterized by deficits in motor and cognitive function. Here, we have quantitatively characterized motor deficiencies and dopamine release dynamics in transgenic HD model rats. Behavioral analyses were conducted using a newly-developed force-sensing runway and a previously-developed force-plate actometer. Gait disturbances were readily observed in transgenic HD rats at 12 to 15 months of age. Additionally, dopamine system challenge by ip injection of amphetamine also revealed that these rats were resistant to the expression of focused stereotypy compared to wild-type controls. Moreover, dopamine release, evoked by the application of single and multiple electrical stimulus pulses applied at different frequencies, and measured using fast-scan cyclic voltammetry at carbon-fiber microelectrodes, was diminished in transgenic HD rats compared to age-matched wild-type control rats. Collectively, these results underscore the potential contribution of dopamine release alterations to the expression of motor impairments in transgenic HD rats. PMID:22418060

  5. Test-retest measurements of dopamine D{sub 1}-type receptors using simultaneous PET/MRI imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kaller, Simon; Patt, Marianne; Becker, Georg-Alexander; Luthardt, Julia; Meyer, Philipp M.; Werner, Peter; Barthel, Henryk; Bresch, Anke; Sabri, Osama [University of Leipzig, Department of Nuclear Medicine, Leipzig (Germany); Rullmann, Michael [University of Leipzig, Department of Nuclear Medicine, Leipzig (Germany); Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig (Germany); Girbardt, Johanna [Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig (Germany); Fritz, Thomas H. [Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig (Germany); University of Gent, Institute for Psychoacoustics and Electronic Music (IPEM), Ghent (Belgium); Hesse, Swen [University of Leipzig, Department of Nuclear Medicine, Leipzig (Germany); Leipzig University Medical Centre, Integrated Research and Treatment Centre (IFB) Adiposity Diseases, Leipzig (Germany)

    2017-06-15

    The role of dopamine D{sub 1}-type receptor (D{sub 1}R)-expressing neurons in the regulation of motivated behavior and reward prediction has not yet been fully established. As a prerequisite for future research assessing D{sub 1}-mediated neuronal network regulation using simultaneous PET/MRI and D{sub 1}R-selective [{sup 11}C]SCH23390, this study investigated the stability of central D{sub 1}R measurements between two independent PET/MRI sessions under baseline conditions. Thirteen healthy volunteers (7 female, age 33 ± 13 yrs) underwent 90-min emission scans, each after 90-s bolus injection of 486 ± 16 MBq [{sup 11}C]SCH23390, on two separate days within 2-4 weeks using a PET/MRI system. Parametric images of D{sub 1}R distribution volume ratio (DVR) and binding potential (BP{sub ND}) were generated by a multi-linear reference tissue model with two parameters and the cerebellar cortex as receptor-free reference region. Volume-of-interest (VOI) analysis was performed with manual VOIs drawn on consecutive transverse MRI slices for brain regions with high and low D{sub 1}R density. The DVR varied from 2.5 ± 0.3 to 2.9 ± 0.5 in regions with high D{sub 1}R density (e.g. the head of the caudate) and from 1.2 ± 0.1 to 1.6 ± 0.2 in regions with low D{sub 1}R density (e.g. the prefrontal cortex). The absolute variability of the DVR ranged from 2.4% ± 1.3% to 5.1% ± 5.3%, while Bland-Altman analyses revealed very low differences in mean DVR (e.g. 0.013 ± 0.17 for the nucleus accumbens). Intraclass correlation (one-way, random) indicated very high agreement (0.93 in average) for both DVR and BP{sub ND} values. Accordingly, the absolute variability of BP{sub ND} ranged from 7.0% ± 4.7% to 12.5% ± 10.6%; however, there were regions with very low D{sub 1}R content, such as the occipital cortex, with higher mean variability. The test-retest reliability of D{sub 1}R measurements in this study was very high. This was the case not only for D{sub 1}R-rich brain areas, but

  6. Functional MRI language mapping in pre-surgical epilepsy patients ...

    African Journals Online (AJOL)

    Background. Functional magnetic resonance imaging (fMRI) is commonly applied to study the neural substrates of language in clinical research and for neurosurgical planning. fMRI language mapping is used to assess language lateralisation, or determine hemispheric dominance, and to localise regions of the brain ...

  7. Implantable microencapsulated dopamine (DA): prolonged functional release of DA in denervated striatal tissue.

    Science.gov (United States)

    McRae, A; Hjorth, S; Mason, D; Dillon, L; Tice, T

    1990-01-01

    Biodegradable controlled-release microcapsule systems made with the biocompatible biodegradable polyester excipient poly [DL-lactide-co-gly-colide] constitute an exciting new technology for drug delivery to the central nervous system (CNS). The present study describes functional observations indicating that implantation of dopamine (DA) microcapsules encapsulated within two different polymer excipients into denervated striatal tissue assures a prolonged release of the transmitter in vivo. This technology has a considerable potential for basic and possibly clinical research.

  8. Effects of Methylphenidate on Resting-State Functional Connectivity of the Mesocorticolimbic Dopamine Pathways in Cocaine Addiction

    Energy Technology Data Exchange (ETDEWEB)

    Konova, Anna B.; Moeller, Scott J.; Tomasi, Dardo; Volkow, Nora D.; Goldstein, Rita Z.

    2013-08-01

    Cocaine addiction is associated with altered resting-state functional connectivity among regions of the mesocorticolimbic dopamine pathways. Methylphenidate hydrochloride, an indirect dopamine agonist, normalizes task-related regional brain activity and associated behavior in cocaine users; however, the neural systems–level effects of methylphenidate in this population have not yet been described. To use resting-state functional magnetic resonance imaging to examine changes in mesocorticolimbic connectivity with methylphenidate and how connectivity of affected pathways relates to severity of cocaine addiction.

  9. Thinking and doing: the effects of dopamine and oxytocin genes and executive function on mothering behaviours.

    Science.gov (United States)

    Tombeau Cost, K; Unternaehrer, E; Plamondon, A; Steiner, M; Meaney, M; Atkinson, L; Kennedy, J L; Fleming, A S

    2017-02-01

    Animal and human studies suggest that initial expression of maternal behaviour depends on oxytocin and dopamine systems. However, the mechanism by which these systems affect parenting behaviours and the timing of these effects are not well understood. This article explores the role of mothers' executive function in mediating the relation between oxytocin and dopamine gene variants and maternal responsiveness at 48 months post-partum. Participants (n = 157) were mothers recruited in the Maternal Adversity, Vulnerability and Neurodevelopment Study, which assesses longitudinally two cohorts of mothers and children in Canada. We examined single nucleotide polymorphisms (SNPs) related to the dopamine and oxytocin systems (DRD1 rs686, DRD1 rs265976, OXTR rs237885 and OXTR rs2254298), assessed mothers' decision-making at 48 months using the Cambridge Neurological Automated Testing Battery (CANTAB) and evaluated maternal responsiveness from videotaped interactions during the Etch-A-Sketch co-operation task. Mediation analyses showed that OXTR rs2254298 A-carriers had an indirect effect on positive parenting which was mediated by mothers' performance on decision-making task (estimate = 0.115, P Dopamine SNPs were not associated with any measure of executive function or parenting (all P > 0.05). While oxytocin has previously been associated with only the early onset of maternal behaviour, we show that an OXTR polymorphism is involved in maternal behaviour at 48 months post-partum through mothers' executive function. This research highlights the importance of the oxytocin system to maternal parenting beyond infancy. © 2016 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

  10. Circadian perinatal photoperiod has enduring effects on retinal dopamine and visual function.

    Science.gov (United States)

    Jackson, Chad R; Capozzi, Megan; Dai, Heng; McMahon, Douglas G

    2014-03-26

    Visual system development depends on neural activity, driven by intrinsic and light-sensitive mechanisms. Here, we examined the effects on retinal function due to exposure to summer- and winter-like circadian light cycles during development and adulthood. Retinal light responses, visual behaviors, dopamine content, retinal morphology, and gene expression were assessed in mice reared in seasonal photoperiods consisting of light/dark cycles of 8:16, 16:8, and 12:12 h, respectively. Mice exposed to short, winter-like, light cycles showed enduring deficits in photopic retinal light responses and visual contrast sensitivity, but only transient changes were observed for scotopic measures. Dopamine levels were significantly lower in short photoperiod mice, and dopaminergic agonist treatment rescued the photopic light response deficits. Tyrosine hydroxylase and Early Growth Response factor-1 mRNA expression were reduced in short photoperiod retinas. Therefore, seasonal light cycles experienced during retinal development and maturation have lasting influence on retinal and visual function, likely through developmental programming of retinal dopamine.

  11. Functional recovery of supersensitive dopamine receptors after intrastriatal grafts of fetal substantia nigra

    International Nuclear Information System (INIS)

    Dawson, T.M.; Dawson, V.L.; Gage, F.H.; Fisher, L.J.; Hunt, M.A.; Wamsley, J.K.

    1991-01-01

    Interruption of the ascending dopamine neurons of the nigrostriatal pathway, by 6-hydroxydopamine (6-OHDA) lesion in rats, produced a significant loss of the dopamine transport complexes labeled with the phencyclidine derivative [3H]BTCP. This loss of dopamine innervation in the striatum was present at least 12 to 14 months after lesioning and was functionally manifested by ipsilateral rotation of the animals in response to amphetamine. In these same animals, in comparison to controls, there was a significant increase in the number (Bmax) of [3H]SCH 23390-labeled D-1 receptors in the striatum (36.7%) and the substantia nigra (35.1%) and a 54.4% increase in the number (Bmax) of [3H]sulpiride-labeled striatal D-2 receptors without an apparent change in affinity (Kd). Ten to twelve months after the transplantation of homologous fetal substantia nigra into the denervated striatum, there was a significant decrease in amphetamine-induced turning behavior. In these animals, there was an ingrowth of dopamine nerve terminals in the striatum as demonstrated by a return of [3H]BTCP binding. Accompanying this reinnervation was the normalization of D-1 and D-2 receptors to control values in the striatum as well as the return of D-1 receptors to prelesion densities in the substantia nigra. In a subgroup of transplanted rats, amphetamine continued to induce ipsilateral turning. In these animals both D-1 and D-2 receptors remained supersensitive. These results support the hypothesis that the functional recovery of transplanted animals is due, in part, to reinnervation of the striatum. In addition, long-term alterations in receptor density may be related to the behavioral deficits that are associated with the 6-OHDA-lesioned rat

  12. Functional MRI in human motor control studies and clinical applications

    International Nuclear Information System (INIS)

    Toma, Keiichiro

    2002-01-01

    Functional magnetic resonance imaging (fMRI) has been a useful tool for the noninvasive mapping of brain function associated with various motor and cognitive tasks. Because fMRI is based on the blood oxygenation level dependent (BOLD) effect, it does not directly record neural activity. With the fMRI technique, distinguishing BOLD signals creased by cortical projection neurons from those created by intracortical neurons appears to be difficult. Two major experimental designs are used in fMRI studies: block designs and event-related designs. Block-designed fMRI presupposes the steady state of regional cerebral blood flow and has been applied to examinations of brain activation caused by tasks requiring sustained or repetitive movements. By contrast, the more recently developed event-related fMRI with time resolution of a few seconds allows the mapping of brain activation associated with a single movement according to the transient aspects of the hemodynamic response. Increasing evidence suggests that multiple motor areas are engaged in a networked manner to execute various motor acts. In order to understand functional brain maps, it is important that one understands sequential and parallel organizations of anatomical connections between multiple motor areas. In fMRI studies of complex motor tasks, elementary parameters such as movement length, force, velocity, acceleration and frequency should be controlled, because inconsistency in those parameters may alter the extent and intensity of motor cortical activation, confounding interpretation of the findings obtained. In addition to initiation of movements, termination of movements plays an important role in the successful achievement of complex movements. Brain areas exclusively related to the termination of movements have been, for the first time, uncovered with an event-related fMRI technique. We propose the application of fMRI to the elucidation of the pathophysiology of movement disorders, particularly dystonia

  13. Functional MRI in human motor control studies and clinical applications

    Energy Technology Data Exchange (ETDEWEB)

    Toma, Keiichiro [Kyoto Univ. (Japan). Graduate School of Medicine; Nakai, Toshiharu [Inst. of Biomedical Research and Innovation, Kobe (Japan)

    2002-07-01

    Functional magnetic resonance imaging (fMRI) has been a useful tool for the noninvasive mapping of brain function associated with various motor and cognitive tasks. Because fMRI is based on the blood oxygenation level dependent (BOLD) effect, it does not directly record neural activity. With the fMRI technique, distinguishing BOLD signals creased by cortical projection neurons from those created by intracortical neurons appears to be difficult. Two major experimental designs are used in fMRI studies: block designs and event-related designs. Block-designed fMRI presupposes the steady state of regional cerebral blood flow and has been applied to examinations of brain activation caused by tasks requiring sustained or repetitive movements. By contrast, the more recently developed event-related fMRI with time resolution of a few seconds allows the mapping of brain activation associated with a single movement according to the transient aspects of the hemodynamic response. Increasing evidence suggests that multiple motor areas are engaged in a networked manner to execute various motor acts. In order to understand functional brain maps, it is important that one understands sequential and parallel organizations of anatomical connections between multiple motor areas. In fMRI studies of complex motor tasks, elementary parameters such as movement length, force, velocity, acceleration and frequency should be controlled, because inconsistency in those parameters may alter the extent and intensity of motor cortical activation, confounding interpretation of the findings obtained. In addition to initiation of movements, termination of movements plays an important role in the successful achievement of complex movements. Brain areas exclusively related to the termination of movements have been, for the first time, uncovered with an event-related fMRI technique. We propose the application of fMRI to the elucidation of the pathophysiology of movement disorders, particularly dystonia

  14. The pathophysiological functions mediated by D-1 dopamine receptors

    International Nuclear Information System (INIS)

    Goldstein, M.; Kuga, S.; Meller, E.; SHimizu, Y.

    1986-01-01

    This chapter describes some behavioral responses which might be mediated by D 1 and D 2 DA receptors, and the authors discuss their clinical relevance. It was of considerable interest to determine whether a selective D 1 DA antagonist, such as SCH 23390, will induce catalepsy and whether this behavior is mediated by D 1 , or by both D 1 and D 2 DA receptors. Rats were used in the experiments. The authors examined whether the addition of the S 2 antagonist ketanserin affects the displacement of 3 H-Spi by SCH 23390. Induction of self-mutilating biting (SMB) behavior in monkeys with unilateral ventromedial tegmental (VMT) lesions by DA agonists and its prevention by DA antagonists is examined. The authors also discuss the possible relationships between abnormal guanine nucleotide metabolism and dopaminergic neuronal function through the implications in LeschNyhan syndrome and in some mental disorders

  15. Dopamine D2 receptor function is compromised in the brain of the methionine sulfoxide reductase A knockout mouse

    OpenAIRE

    Oien, Derek B.; Ortiz, Andrea N.; Rittel, Alexander G.; Dobrowsky, Rick T.; Johnson, Michael A.; Levant, Beth; Fowler, Stephen C.; Moskovitz, Jackob

    2010-01-01

    Previous research suggests that brain oxidative stress and altered rodent locomotor behavior are linked. We observed bio-behavioral changes in methionine sulfoxide reductase A knockout mice associated with abnormal dopamine signaling. Compromised ability of these knockout mice to reduce methionine sulfoxide enhances accumulation of sulfoxides in proteins. We examined the dopamine D2-receptor function and expression, which has an atypical arrangement and quantity of methionine residues. Indeed...

  16. Missense dopamine transporter mutations associate with adult parkinsonism and ADHD

    DEFF Research Database (Denmark)

    Hansen, Freja H; Skjørringe, Tina; Yasmeen, Saiqa

    2014-01-01

    experiments suggested that the disrupted function of the DAT-Asp421Asn mutant is the result of compromised sodium binding, in agreement with Asp421 coordinating sodium at the second sodium site. For DAT-Asp421Asn, substrate efflux experiments revealed a constitutive, anomalous efflux of dopamine......Parkinsonism and attention deficit hyperactivity disorder (ADHD) are widespread brain disorders that involve disturbances of dopaminergic signaling. The sodium-coupled dopamine transporter (DAT) controls dopamine homeostasis, but its contribution to disease remains poorly understood. Here, we......-deoxy-glucose-PET/MRI (FDG-PET/MRI) scan, the patient suffered from progressive dopaminergic neurodegeneration. In heterologous cells, both DAT variants exhibited markedly reduced dopamine uptake capacity but preserved membrane targeting, consistent with impaired catalytic activity. Computational simulations and uptake...

  17. Brain activation studies with PET and functional MRI

    Energy Technology Data Exchange (ETDEWEB)

    Yonekura, Yoshiharu [Fukui Medical Univ., Matsuoka (Japan). Biomedical Imaging Research Center; Sadato, Norihiro [Okazaki National Research Inst., Aichi (Japan). National Inst. for Physiological Sciences

    2002-01-01

    Application of PET and functional MRI in brain activation studies is reviewed. 3D-PET images obtained repeatedly after intravenous injection of about 370 MBq of H{sub 2}{sup 15}O can detect a faint blood flow change in the brain. Functional MRI can also detect the blood flow change in the brain due to blood oxygen level-dependent effect. Echo-planar imaging is popular in MRI with 1.5 or 3 T. Images are analyzed by statistical parametric mapping with correction of cerebral regions, anatomical normalization and statistics. PET data give the blood flow change by the H{sub 2}{sup 15}O incorporation into the brain and MRI data, by the scarce tissue oxygen consumption despite the change. Actual images during the cognition task-performance and of frequent artifacts are given. PET is suitable for studies of brain functions like sensibility and emotion and functional MRI, like cortex functions and clinical practices in identification of functional regions prior to surgery and evaluation of functional recovery of damaged brain. (K.H.)

  18. Brain activation studies with PET and functional MRI

    International Nuclear Information System (INIS)

    Yonekura, Yoshiharu; Sadato, Norihiro

    2002-01-01

    Application of PET and functional MRI in brain activation studies is reviewed. 3D-PET images obtained repeatedly after intravenous injection of about 370 MBq of H 2 15 O can detect a faint blood flow change in the brain. Functional MRI can also detect the blood flow change in the brain due to blood oxygen level-dependent effect. Echo-planar imaging is popular in MRI with 1.5 or 3 T. Images are analyzed by statistical parametric mapping with correction of cerebral regions, anatomical normalization and statistics. PET data give the blood flow change by the H 2 15 O incorporation into the brain and MRI data, by the scarce tissue oxygen consumption despite the change. Actual images during the cognition task-performance and of frequent artifacts are given. PET is suitable for studies of brain functions like sensibility and emotion and functional MRI, like cortex functions and clinical practices in identification of functional regions prior to surgery and evaluation of functional recovery of damaged brain. (K.H.)

  19. Functional imaging of the kidneys with fast MRI techniques

    International Nuclear Information System (INIS)

    Prasad, P.V.; Priatna, A.

    1999-01-01

    Availability of faster and stronger gradient systems have given rise to a multitude of fast MRI data acquisition strategies which have tremendously increased the scope of MRI applications. These have led to the realization of long desired comprehensive approaches to evaluate anatomy and function using a single modality. In this work, we describe some of our own experiences with functional evaluation of the kidneys using MRI. Examples that suggest the feasibility of comprehensive approaches for evaluation of renal disease are also provided. We also introduce BOLD renal MRI, a method that may allow basic understanding of human renal physiology and pathophysiology in a way that has not been previously possible. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  20. Functional imaging of the kidneys with fast MRI techniques

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, P.V.; Priatna, A. [AN-234, MRI Research, Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Ave., Boston, MA (United States)

    1999-02-01

    Availability of faster and stronger gradient systems have given rise to a multitude of fast MRI data acquisition strategies which have tremendously increased the scope of MRI applications. These have led to the realization of long desired comprehensive approaches to evaluate anatomy and function using a single modality. In this work, we describe some of our own experiences with functional evaluation of the kidneys using MRI. Examples that suggest the feasibility of comprehensive approaches for evaluation of renal disease are also provided. We also introduce BOLD renal MRI, a method that may allow basic understanding of human renal physiology and pathophysiology in a way that has not been previously possible. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  1. Methodological Improvements in Combining TMS and Functional MRI

    OpenAIRE

    Moisa, Marius

    2011-01-01

    Since 1997, when Bohning and colleagues demonstrated for the first time the feasibility of interleaving transcranial magnetic stimulation (TMS) with blood oxygenation level dependency functional magnetic resonance imaging (BOLD fMRI), this combination became a very promising techniques to study brain connectivity. However, the implementation of a reliable setup for interleaved TMS/fMRI is still technically challenging. In this thesis, I intended to further explore and develop methodological i...

  2. Gd-DTPA-Dopamine-Bisphytanyl Amphiphile: Synthesis, Characterisation and Relaxation Parameters of the Nanoassemblies and Their Potential as MRI Contrast Agents.

    Science.gov (United States)

    Gupta, Abhishek; Willis, Scott A; Waddington, Lynne J; Stait-Gardner, Tim; de Campo, Liliana; Hwang, Dennis W; Kirby, Nigel; Price, William S; Moghaddam, Minoo J

    2015-09-28

    Here, a new amphiphilic magnetic resonance imaging (MRI) contrast agent, a Gd(III)-chelated diethylenetriaminepentaacetic acid conjugated to two branched alkyl chains via a dopamine spacer, Gd-DTPA-dopamine-bisphytanyl (Gd-DTPA-Dop-Phy), which is readily capable of self-assembling into liposomal nanoassemblies upon dispersion in an aqueous solution, is reported. In vitro relaxivities of the dispersions were found to be much higher than Magnevist, a commercially available contrast agent, at 0.47 T but comparable at 9.40 T. Analysis of variable temperature (17)O NMR transverse relaxation measurements revealed the water exchange of the nanoassemblies to be faster than that previously reported for paramagnetic liposomes. Molecular reorientation dynamics were probed by (1)H NMRD profiles using a classical inner and outer sphere relaxation model and a Lipari-Szabo "model-free" approach. High payloads of Gd(III) ions in the liposomal nanoassemblies made solely from the Gd-DTPA-Dop-Phy amphiphiles, in combination with slow molecular reorientation and fast water exchange makes this novel amphiphile a suitable candidate to be investigated as an advanced MRI contrast agent. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Clinical application of functional MRI for chronic epilepsy

    International Nuclear Information System (INIS)

    Woermann, F.G.; Labudda, K.

    2010-01-01

    Functional magnetic resonance imaging (fMRI) is frequently used in the presurgical diagnostic procedure of epilepsy patients, in particular for lateralization of speech and memory and for localization of the primary motor cortex to delineate the epileptogenic lesion from eloquent brain areas. fMRI is one of the non-invasive procedures in the presurgical diagnostic process, together with medical history, seizure semiology, neurological examination, interictal and ictal EEG, structural MRI, video EEG monitoring and neuropsychology. This diagnostic sequence leads either to the decision for or against elective epilepsy surgery or to the decision to proceed with invasive diagnostic techniques (Wada test, intra-operative or extra-operative cortical stimulation). It is difficult to evaluate the contribution of the fMRI test in isolation to the validity of the entire diagnostic sequence. Complications such as memory loss and aphasia in temporal lobe resections or paresis after frontal lobe resections are rare and rarely of disastrous extent. This further complicates the evaluation of the clinical relevance of fMRI as a predictive tool. In this article studies which investigated the concordance between fMRI and other diagnostic gold standards will be presented as well as the association between presurgical fMRI and postsurgical morbidity. (orig.) [de

  4. Joint brain connectivity estimation from diffusion and functional MRI data

    Science.gov (United States)

    Chu, Shu-Hsien; Lenglet, Christophe; Parhi, Keshab K.

    2015-03-01

    Estimating brain wiring patterns is critical to better understand the brain organization and function. Anatomical brain connectivity models axonal pathways, while the functional brain connectivity characterizes the statistical dependencies and correlation between the activities of various brain regions. The synchronization of brain activity can be inferred through the variation of blood-oxygen-level dependent (BOLD) signal from functional MRI (fMRI) and the neural connections can be estimated using tractography from diffusion MRI (dMRI). Functional connections between brain regions are supported by anatomical connections, and the synchronization of brain activities arises through sharing of information in the form of electro-chemical signals on axon pathways. Jointly modeling fMRI and dMRI data may improve the accuracy in constructing anatomical connectivity as well as functional connectivity. Such an approach may lead to novel multimodal biomarkers potentially able to better capture functional and anatomical connectivity variations. We present a novel brain network model which jointly models the dMRI and fMRI data to improve the anatomical connectivity estimation and extract the anatomical subnetworks associated with specific functional modes by constraining the anatomical connections as structural supports to the functional connections. The key idea is similar to a multi-commodity flow optimization problem that minimizes the cost or maximizes the efficiency for flow configuration and simultaneously fulfills the supply-demand constraint for each commodity. In the proposed network, the nodes represent the grey matter (GM) regions providing brain functionality, and the links represent white matter (WM) fiber bundles connecting those regions and delivering information. The commodities can be thought of as the information corresponding to brain activity patterns as obtained for instance by independent component analysis (ICA) of fMRI data. The concept of information

  5. Validating excised rodent lungs for functional hyperpolarized xenon-129 MRI.

    Directory of Open Access Journals (Sweden)

    David M L Lilburn

    Full Text Available Ex vivo rodent lung models are explored for physiological measurements of respiratory function with hyperpolarized (hp (129Xe MRI. It is shown that excised lung models allow for simplification of the technical challenges involved and provide valuable physiological insights that are not feasible using in vivo MRI protocols. A custom designed breathing apparatus enables MR images of gas distribution on increasing ventilation volumes of actively inhaled hp (129Xe. Straightforward hp (129Xe MRI protocols provide residual lung volume (RV data and permit for spatially resolved tracking of small hp (129Xe probe volumes during the inhalation cycle. Hp (129Xe MRI of lung function in the excised organ demonstrates the persistence of post mortem airway responsiveness to intravenous methacholine challenges. The presented methodology enables physiology of lung function in health and disease without additional regulatory approval requirements and reduces the technical and logistical challenges with hp gas MRI experiments. The post mortem lung functional data can augment histological measurements and should be of interest for drug development studies.

  6. Human brain functional MRI and DTI visualization with virtual reality.

    Science.gov (United States)

    Chen, Bin; Moreland, John; Zhang, Jingyu

    2011-12-01

    Magnetic resonance diffusion tensor imaging (DTI) and functional MRI (fMRI) are two active research areas in neuroimaging. DTI is sensitive to the anisotropic diffusion of water exerted by its macromolecular environment and has been shown useful in characterizing structures of ordered tissues such as the brain white matter, myocardium, and cartilage. The diffusion tensor provides two new types of information of water diffusion: the magnitude and the spatial orientation of water diffusivity inside the tissue. This information has been used for white matter fiber tracking to review physical neuronal pathways inside the brain. Functional MRI measures brain activations using the hemodynamic response. The statistically derived activation map corresponds to human brain functional activities caused by neuronal activities. The combination of these two methods provides a new way to understand human brain from the anatomical neuronal fiber connectivity to functional activities between different brain regions. In this study, virtual reality (VR) based MR DTI and fMRI visualization with high resolution anatomical image segmentation and registration, ROI definition and neuronal white matter fiber tractography visualization and fMRI activation map integration is proposed. Rationale and methods for producing and distributing stereoscopic videos are also discussed.

  7. Functional MRI in awake unrestrained dogs.

    Directory of Open Access Journals (Sweden)

    Gregory S Berns

    Full Text Available Because of dogs' prolonged evolution with humans, many of the canine cognitive skills are thought to represent a selection of traits that make dogs particularly sensitive to human cues. But how does the dog mind actually work? To develop a methodology to answer this question, we trained two dogs to remain motionless for the duration required to collect quality fMRI images by using positive reinforcement without sedation or physical restraints. The task was designed to determine which brain circuits differentially respond to human hand signals denoting the presence or absence of a food reward. Head motion within trials was less than 1 mm. Consistent with prior reinforcement learning literature, we observed caudate activation in both dogs in response to the hand signal denoting reward versus no-reward.

  8. Development and function of the midbrain dopamine system: what we know and what we need to

    OpenAIRE

    Bissonette, G. B.; Roesch, M. R.

    2015-01-01

    The past two decades have seen an explosion in our understanding of the origin and development of the midbrain dopamine system. Much of this work has been focused on the aspects of dopamine neuron development related to the onset of movement disorders such as Parkinson’s disease, with the intent of hopefully delaying, preventing or fixing symptoms. While midbrain dopamine degeneration is a major focus for treatment and research, many other human disorders are impacted by abnormal dopamine, in...

  9. Functional MRI: Genesis, State of the art and the Sequel

    International Nuclear Information System (INIS)

    Bharath, Rose Dawn

    2014-01-01

    The last 25 years have seen functional magnetic resonance imaging (fMRI) grow from an interesting experimental imaging technique in the hands of some to a primary investigation of choice in the localization and lateralization of brain function prior to surgery. Developments in the field of computational neurosciences have transformed fMRI analysis from classical subtractive type analysis to dynamic casual modeling, and now to graph theory analysis. This has widened the scope of fMRI, and is therefore finding applications in understanding neural correlates of diseases like autism and Alzheimer's disease, prognostication of diseases like traumatic brain injury, and has the potential to direct therapy. It is unfortunately true that this widened ambit has not received the clinical attention it deserves, probably because fMRI is susceptible to artifacts from skull base and blood products and has reduced sensitivity in patients with vascular malformations, or because a change in medical practice usually lags behind the technological and scientific developments that make it possible. This review focuses on the developmental chronology of fMRI image analysis in the last 25 years with highlights on major milestones like developments in the field of paradigms, analysis methods, resting state fMRI, and functional connectivity. To make the statistical images of brain at work more colorful, the article starts with genesis of fMRI and ends with the hope of a promising bright future. Many inputs for this article are obtained from a series of 103 review articles edited by Bandettini et al., compiling personal experiences of pioneers in this field. Interested readers are encouraged to refer to these for a more complete overview.

  10. A surface acoustic wave sensor functionalized with a polypyrrole molecularly imprinted polymer for selective dopamine detection.

    Science.gov (United States)

    Maouche, Naima; Ktari, Nadia; Bakas, Idriss; Fourati, Najla; Zerrouki, Chouki; Seydou, Mahamadou; Maurel, François; Chehimi, Mohammed Mehdi

    2015-11-01

    A surface acoustic wave sensor operating at 104 MHz and functionalized with a polypyrrole molecularly imprinted polymer has been designed for selective detection of dopamine (DA). Optimization of pyrrole/DA ratio, polymerization and immersion times permitted to obtain a highly selective sensor, which has a sensitivity of 0.55°/mM (≈ 550 Hz/mM) and a detection limit of ≈ 10 nM. Morphology and related roughness parameters of molecularly imprinted polymer surfaces, before and after extraction of DA, as well as that of the non imprinted polymer were characterized by atomic force microscopy. The developed chemosensor selectively recognized dopamine over the structurally similar compound 4-hydroxyphenethylamine (referred as tyramine), or ascorbic acid,which co-exists with DA in body fluids at a much higher concentration. Selectivity tests were also carried out with dihydroxybenzene, for which an unexpected phase variation of order of 75% of the DA one was observed. Quantum chemical calculations, based on the density functional theory, were carried out to determine the nature of interactions between each analyte and the PPy matrix and the DA imprinted PPy polypyrrole sensing layer in order to account for the important phase variation observed during dihydroxybenzene injection. Copyright © 2015 John Wiley & Sons, Ltd.

  11. Research progress of BOLD-functional MRI of hepatic encephalopathy

    International Nuclear Information System (INIS)

    Ni Ling; Zhang Longjiang; Lu Guangming

    2013-01-01

    Hepatic encephalopathy (HE), characterized by a wide spectrum of clinical manifestations, ranging from behavior abnormality, conscious disorder and even coma, is a consequence of liver dysfunction in both acute and chronic hepatic diseases. Minimal hepatic encephalopathy (MHE) refers to a subgroup of cirrhotic patients without clinical overt hepatic encephalopathy symptoms hut with abnormalities in neuro -cognitive functions. HE/MHE can have a far-reaching impact on quality of life and prognosis. The exact neuropathology mechanism was still unclear. Recently, functional MRI (fMRI) has been increasingly applied for investigating the neuro-pathophysiological mechanism of HE. This paper will review the fMRI research applied on uncovering the neuropathology mechanism of HE. (authors)

  12. Iron oxide magnetic nanoparticles with versatile surface functions based on dopamine anchors

    Science.gov (United States)

    Mazur, Mykola; Barras, Alexandre; Kuncser, Victor; Galatanu, Andrei; Zaitzev, Vladimir; Turcheniuk, Kostiantyn V.; Woisel, Patrice; Lyskawa, Joel; Laure, William; Siriwardena, Aloysius; Boukherroub, Rabah; Szunerits, Sabine

    2013-03-01

    The synthesis of multifunctional magnetic nanoparticles (MF-MPs) is one of the most active research areas in advanced materials as their multifunctional surfaces allow conjugation of biological and chemical molecules, thus making it possible to achieve target-specific diagnostic in parallel to therapeutics. We report here a simple strategy to integrate in a one-step reaction several reactive sites onto the particles. The preparation of MF-MPs is based on their simultaneous modification with differently functionalized dopamine derivatives using simple solution chemistry. The formed MF-MPs show comparable magnetic properties to those of naked nanoparticles with almost unaltered particle size of around 25 nm. The different termini, amine, azide and maleimide functions, enable further functionalization of MF-MPs by the grafting-on approach. Michael addition, Cu(i) catalyzed « click » chemistry and amidation reactions are performed on the MF-MPs integrating subsequently 6-(ferrocenyl)-hexanethiol, horseradish peroxidase (HRP) and mannose.

  13. Adrenal phaeochromocytoma: correlation of MRI appearances with histology and function

    International Nuclear Information System (INIS)

    Jacques, Audrey E.T.; Sahdev, Anju; Sandrasagara, Madrika; Rockall, Andrea G.; Reznek, Rodney H.; Goldstein, Rick; Chew, Shern; Berney, Daniel

    2008-01-01

    The purpose of this study was to describe the range of appearances of adrenal phaeochromocytomas on T2-weighted MRI, correlate appearances with histopathology, and quantify the incidence of the previously described hyperintense appearance. The appearance and MR characteristics of 44 phaeochromocytomas were reviewed retrospectively. T2-weighted appearances were grouped: (1) 'classical', homogeneous, high signal intensity, isointense to CSF; (2) homogeneous, isointense or minimally hyperintense to spleen, hypointense to CSF; (3) heterogeneous, marbled appearance; (4) heterogeneous, multiple high signal intensity pockets. All 44 adrenal phaeochromocytomas were well circumscribed, 1.2-15 cm in maximum diameter, with no visual or quantitative signal loss on chemical shift imaging. On T2-weighted MRI 5/44 (11%) had group 1 appearance; 15/44 (34%) group 2, 7/44 (16%) group 3; and 17/44 (39%) group 4. Homogeneous group 1 and 2 lesions were smaller (mean 4.5 cm) than heterogeneous group 3 and 4 lesions (mean 6.3 cm). Increasing MRI heterogeneity correlated pathologically with increasing amounts of haemorrhage, necrosis and fibrosis. No MRI features were predictive of malignancy. Non-functioning phaeochromocytomas were larger than functioning lesions. No size difference was seen between syndrome and sporadic lesions. In this large series we report a wide range of appearances of adrenal phaeochromocytomas on T2-weighted MRI. The previously described classical hyperintense phaeochromocytoma is relatively uncommon. (orig.)

  14. Combination of behaviorally sub-effective doses of glutamate NMDA and dopamine D1 receptor antagonists impairs executive function.

    Science.gov (United States)

    Desai, Sagar J; Allman, Brian L; Rajakumar, Nagalingam

    2017-04-14

    Impairment of executive function is a core feature of schizophrenia. Preclinical studies indicate that injections of either N-methyl d-aspartate (NMDA) or dopamine D 1 receptor blockers impair executive function. Despite the prevailing notion based on postmortem findings in schizophrenia that cortical areas have marked suppression of glutamate and dopamine, recent in vivo imaging studies suggest that abnormalities of these neurotransmitters in living patients may be quite subtle. Thus, we hypothesized that modest impairments in both glutamate and dopamine function can act synergistically to cause executive dysfunction. In the present study, we investigated the effect of combined administration of "behaviorally sub-effective" doses of NMDA and dopamine D 1 receptor antagonists on executive function. An operant conditioning-based set-shifting task was used to assess behavioral flexibility in rats that were systemically injected with NMDA and dopamine D 1 receptor antagonists individually or in combination prior to task performance. Separate injections of the NMDA receptor antagonist, MK-801, and the dopamine D 1 receptor antagonist, SCH 23390, at low doses did not impair set-shifting; however, the combined administration of these same behaviorally sub-effective doses of the antagonists significantly impaired the performance during set-shifting without affecting learning, retrieval of the memory of the initial rule, latency of responses or the number of omissions. The combined treatment also produced an increased number of perseverative errors. Our results indicate that NMDA and D 1 receptor blockade act synergistically to cause behavioral inflexibility, and as such, subtle abnormalities in glutamatergic and dopaminergic systems may act cooperatively to cause deficits in executive function. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Functional MRI (fMRI) on lesions in and around the motor and the eloquent cortices

    International Nuclear Information System (INIS)

    Hara, Yoshie; Nakamura, Mitsugu; Tamura, Shogo; Tamaki, Norihiko; Kitamura, Junji

    1999-01-01

    From the view point of neurosurgeons, to aim the preoperative localized diagnosis on the motor and the eloquent cortices and postoperative preservation of neurological functions, fMRI was carried for patients with lesions in and around the motor and the eloquent cortices. Even in cases of mechanical oppression or brain edema, the motor and the eloquent cortices are localized on cerebral gyri. In perioperative period, identification and preserving the motor and the eloquent cortices are important for keeping brain function. Twenty six preoperative cases and 3 normal healthy subjects were observed. Exercise enhanced fMRI was performed on 3 normal healthy subjects, fMRI with motor stimulation in 24 cases and fMRI with speech stimulation in 4 cases. The signal intensity increased in all cases responsing to both stimulations. But the signal intensity in 8 cases decreased in some regions by motor stimulation and 1 case by speech stimulation. The decrease of signal intensity in this study seems to be a clinically important finding and it will be required to examine the significance in future. (K.H.)

  16. Muscle MRI and functional outcome measures in Becker muscular dystrophy.

    Science.gov (United States)

    Barp, Andrea; Bello, Luca; Caumo, Luca; Campadello, Paola; Semplicini, Claudio; Lazzarotto, Annalisa; Sorarù, Gianni; Calore, Chiara; Rampado, Alessandro; Motta, Raffaella; Stramare, Roberto; Pegoraro, Elena

    2017-11-22

    Becker muscular dystrophy (BMD) is a neuromuscular disorder allelic to Duchenne muscular dystrophy (DMD), caused by in-frame mutations in the dystrophin gene, and characterized by a clinical progression that is both milder and more heterogeneous than DMD. Muscle magnetic resonance imaging (MRI) has been proposed as biomarker of disease progression in dystrophinopathies. Correlation with clinically meaningful outcome measures such as North Star Ambulatory Assessment (NSAA) and 6 minute walk test (6MWT) is paramount for biomarker qualification. In this study, 51 molecularly confirmed BMD patients (aged 7-69 years) underwent muscle MRI and were evaluated with functional measures (NSAA and 6MWT) at the time of the MRI, and subsequently after one year. We confirmed a pattern of fatty substitution involving mainly the hip extensors and most thigh muscles. Severity of muscle fatty substitution was significantly correlated with specific DMD mutations: in particular, patients with an isolated deletion of exon 48, or deletions bordering exon 51, showed milder involvement. Fat infiltration scores correlated with baseline functional measures, and predicted changes after 1 year. We conclude that in BMD, skeletal muscle MRI not only strongly correlates with motor function, but also helps in predicting functional deterioration within a 12-month time frame.

  17. An Introduction to Normalization and Calibration Methods in Functional MRI

    Science.gov (United States)

    Liu, Thomas T.; Glover, Gary H.; Mueller, Bryon A.; Greve, Douglas N.; Brown, Gregory G.

    2013-01-01

    In functional magnetic resonance imaging (fMRI), the blood oxygenation level dependent (BOLD) signal is often interpreted as a measure of neural activity. However, because the BOLD signal reflects the complex interplay of neural, vascular, and metabolic processes, such an interpretation is not always valid. There is growing evidence that changes…

  18. Functional MRI of human hypothalamic responses following glucose ingestion

    NARCIS (Netherlands)

    Smeets, P.A.M.; Graaf, C. de; Stafleu, A.; Osch, M.J.P. van; Grond, J. van der

    2005-01-01

    The hypothalamus is intimately involved in the regulation of food intake, integrating multiple neural and hormonal signals. Several hypothalamic nuclei contain glucose-sensitive neurons, which play a crucial role in energy homeostasis. Although a few functional magnetic resonance imaging (fMRI)

  19. Methamphetamine Increases Locomotion and Dopamine Transporter Activity in Dopamine D5 Receptor-Deficient Mice

    OpenAIRE

    Hayashizaki, Seiji; Hirai, Shinobu; Ito, Yumi; Honda, Yoshiko; Arime, Yosefu; Sora, Ichiro; Okado, Haruo; Kodama, Tohru; Takada, Masahiko

    2013-01-01

    Dopamine regulates the psychomotor stimulant activities of amphetamine-like substances in the brain. The effects of dopamine are mediated through five known dopamine receptor subtypes in mammals. The functional relevance of D5 dopamine receptors in the central nervous system is not well understood. To determine the functional relevance of D5 dopamine receptors, we created D5 dopamine receptor-deficient mice and then used these mice to assess the roles of D5 dopamine receptors in the behaviora...

  20. Dopamine D2-like receptors (DRD2 and DRD4) in chickens: Tissue distribution, functional analysis, and their involvement in dopamine inhibition of pituitary prolactin expression.

    Science.gov (United States)

    Lv, Can; Mo, Chunheng; Liu, Haikun; Wu, Chao; Li, Zhengyang; Li, Juan; Wang, Yajun

    2018-04-20

    Dopamine (DA) D2-like (and D1-like) receptors are suggested to mediate the dopamine actions in the anterior pituitary and/or CNS of birds. However, the information regarding the structure, functionality, and expression of avian D2-like receptors have not been fully characterized. In this study, we cloned two D2-like receptors (cDRD2, cDRD4) from chicken brain using RACE PCR. The cloned cDRD4 is a 378-amino acid receptor, which shows 57% amino acid (a.a.) identity with mouse DRD4. As in mammals, two cDRD2 isoforms, cDRD2L (long isoform, 437 a.a.) and cDRD2S (short isoform, 408 a.a.), which differ in their third intracellular loop, were identified in chickens. Using cell-based luciferase reporter assays or Western blot, we demonstrated that cDRD4, cDRD2L and cDRD2S could be activated by dopamine and quinpirole (a D2-like receptor agonist) dose-dependently, and their activation inhibits cAMP signaling pathway and stimulates MAPK/ERK signaling cascade, indicating that they are functional receptors capable of mediating dopamine actions. Quantitative real-time PCR revealed that cDRD2 and cDRD4 are widely expressed in chicken tissues with abundant expression noted in anterior pituitary, and their expressions are likely controlled by their promoters near exon 1, as demonstrated by dual-luciferase reporter assays in DF-1 cells. In accordance with cDRD2/cDRD4 expression in the pituitary, DA or quinpirole could partially inhibit vasoactive intestinal peptide-induced prolactin expression in cultured chick pituitary cells. Together, our data proves the functionality of DRD2 and DRD4 in birds and aids to uncover the conserved roles of DA/D2-like receptor system in vertebrates, such as its action on the pituitary. Copyright © 2018. Published by Elsevier B.V.

  1. Cortical language activation in aphasia: a functional MRI study

    International Nuclear Information System (INIS)

    Xu Xiaojun; Zhang Minming; Shang Desheng; Wang Qidong; Luo Benyan

    2004-01-01

    Objective: To investigate the differences of the underlying neural basis of language processing between normal subjects and aphasics, and to study the feasibility for functional magnetic resonance imaging (fMRI) in examining the cortical language activation in clinical aphasics. Methods: fMRI was used to map language network in 6 normal subjects and 3 patients with aphasia who were in the stage of recovery from acute stroke. The participants performed word generation task during fMRI scanning, which measured the signal changes associated with regional neural activity induced by the task. These signal changes were processed to statistically generate the activation map that represented the language area. Results: In normal subjects, a distributed language network was activated. Activations were present in the frontal, temporal, parietal and occipital regions in normal group. In the patient group, however, no activation was showed in the left inferior frontal gyrus whether or not the patient had lesion in the left frontal lobe. Two patients showed activations in some right hemisphere regions where no activation appeared in normal subjects. Conclusion: The remote effect of focal lesion and functional redistribution or reorganization was found in aphasic patients. fMRI was useful in evaluating the language function in aphasic patients. (authors)

  2. Nature or Nurture? Determining the Heritability of Human Striatal Dopamine Function: an [18F]-DOPA PET Study

    Science.gov (United States)

    Stokes, Paul R A; Shotbolt, Paul; Mehta, Mitul A; Turkheimer, Eric; Benecke, Aaf; Copeland, Caroline; Turkheimer, Federico E; Lingford-Hughes, Anne R; Howes, Oliver D

    2013-01-01

    Striatal dopamine function is important for normal personality, cognitive processes and behavior, and abnormalities are linked to a number of neuropsychiatric disorders. However, no studies have examined the relative influence of genetic inheritance and environmental factors in determining striatal dopamine function. Using [18F]-DOPA positron emission tomography (PET), we sought to determine the heritability of presynaptic striatal dopamine function by comparing variability in uptake values in same sex monozygotic (MZ) twins to dizygotic (DZ) twins. Nine MZ and 10 DZ twin pairs underwent high-resolution [18F]-DOPA PET to assess presynaptic striatal dopamine function. Uptake values for the overall striatum and functional striatal subdivisions were determined by a Patlak analysis using a cerebellar reference region. Heritability, shared environmental effects and non-shared individual-specific effects were estimated using a region of interest (ROI) analysis and a confirmatory parametric analysis. Overall striatal heritability estimates from the ROI and parametric analyses were 0.44 and 0.33, respectively. We found a distinction between striatal heritability in the functional subdivisions, with the greatest heritability estimates occurring in the sensorimotor striatum and the greatest effect of individual-specific environmental factors in the limbic striatum. Our results indicate that variation in overall presynaptic striatal dopamine function is determined by a combination of genetic factors and individual-specific environmental factors, with familial environmental effects having no effect. These findings underline the importance of individual-specific environmental factors for striatal dopaminergic function, particularly in the limbic striatum, with implications for understanding neuropsychiatric disorders such as schizophrenia and addictions. PMID:23093224

  3. Single cocaine exposure does not alter striatal pre-synaptic dopamine function in mice: an [18 F]-FDOPA PET study.

    Science.gov (United States)

    Bonsall, David R; Kokkinou, Michelle; Veronese, Mattia; Coello, Christopher; Wells, Lisa A; Howes, Oliver D

    2017-12-01

    Cocaine is a recreational drug of abuse that binds to the dopamine transporter, preventing reuptake of dopamine into pre-synaptic terminals. The increased presence of synaptic dopamine results in stimulation of both pre- and post-synaptic dopamine receptors, considered an important mechanism by which cocaine elicits its reinforcing properties. However, the effects of acute cocaine administration on pre-synaptic dopamine function remain unclear. Non-invasive imaging techniques such as positron emission tomography have revealed impaired pre-synaptic dopamine function in chronic cocaine users. Similar impairments have been seen in animal studies, with microdialysis experiments indicating decreased basal dopamine release. Here we use micro positron emission tomography imaging techniques in mice to measure dopamine synthesis capacity and determine the effect of acute cocaine administration of pre-synaptic dopamine function. We show that a dose of 20 mg/kg cocaine is sufficient to elicit hyperlocomotor activity, peaking 15-20 min post treatment (p dopamine synthesis capacity in the striatum was not significantly altered by acute cocaine treatment (KiCer: 0.0097 per min vs. 0.0112 per min in vehicle controls, p > 0.05). Furthermore, expression levels of two key enzymes related to dopamine synthesis, tyrosine hydroxylase and aromatic l-amino acid decarboxylase, within the striatum of scanned mice were not significantly affected by acute cocaine pre-treatment (p > 0.05). Our findings suggest that while the regulation of dopamine synthesis and release in the striatum have been shown to change with chronic cocaine use, leading to a reduced basal tone, these adaptations to pre-synaptic dopaminergic neurons are not initiated following a single exposure to the drug. © 2017 International Society for Neurochemistry.

  4. Limonene inhibits methamphetamine-induced locomotor activity via regulation of 5-HT neuronal function and dopamine release.

    Science.gov (United States)

    Yun, Jaesuk

    2014-05-15

    Methamphetamine is a psychomotor stimulant that produces hyperlocomotion in rodents. Limonene (a cyclic terpene from citrus essential oils) has been reported to induce sedative effects. In this study, we demonstrated that limonene administration significantly inhibited serotonin (5-hydroxytryptamine, 5-HT)-induced head twitch response in mice. In rats, pretreatment with limonene decreased hyperlocomotion induced by methamphetamine injection. In addition, limonene reversed the increase in dopamine levels in the nucleus accumbens of rats given methamphetamine. These results suggest that limonene may inhibit stimulant-induced behavioral changes via regulating dopamine levels and 5-HT receptor function. Copyright © 2013 Elsevier GmbH. All rights reserved.

  5. Increased Motor Activity During REM Sleep Is Linked with Dopamine Function in Idiopathic REM Sleep Behavior Disorder and Parkinson Disease

    DEFF Research Database (Denmark)

    Zoetmulder, Marielle; Nikolic, Miki; Biernat, Heidi B

    2016-01-01

    STUDY OBJECTIVES: Rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia characterized by impaired motor inhibition during REM sleep, and dream-enacting behavior. RBD is especially associated with α-synucleinopathies, such as Parkinson disease (PD). Follow-up studies have shown......-FP-CIT uptake in the putamen. In PD patients, EMG-activity was correlated to anti-Parkinson medication. CONCLUSIONS: Our results support the hypothesis that increased EMG-activity during REM sleep is at least partly linked to the nigrostriatal dopamine system in iRBD, and with dopamine function in PD....... the relation between this system and electromyographic (EMG) activity during sleep. The objective of this study was to investigate the relationship between the nigrostriatal dopamine system and muscle activity during sleep in iRBD and PD. METHODS: 10 iRBD patients, 10 PD patients with PD, 10 PD patients...

  6. Increased Motor Activity During REM Sleep Is Linked with Dopamine Function in Idiopathic REM Sleep Behaviour Disorder and Parkinson Disease

    DEFF Research Database (Denmark)

    Zoetmulder, Marielle; Nikolic, Miki; Biernat, Heidi

    2016-01-01

    STUDY OBJECTIVES: Rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia characterized by impaired motor inhibition during REM sleep, and dream-enacting behavior. RBD is especially associated with α-synucleinopathies, such as Parkinson disease (PD). Follow-up studies have shown...... in the putamen. In PD patients, EMG-activity was correlated to anti-Parkinson medication. CONCLUSIONS: Our results support the hypothesis that increased EMG-activity during REM sleep is at least partly linked to the nigrostriatal dopamine system in iRBD, and with dopamine function in PD....... the relation between this system and electromyographic (EMG) activity during sleep. The objective of this study was to investigate the relationship between the nigrostriatal dopamine system and muscle activity during sleep in iRBD and PD. METHODS: 10 iRBD patients, 10 PD patients with PD, 10 PD patients...

  7. Development and function of the midbrain dopamine system: what we know and what we need to.

    Science.gov (United States)

    Bissonette, G B; Roesch, M R

    2016-01-01

    The past two decades have seen an explosion in our understanding of the origin and development of the midbrain dopamine system. Much of this work has been focused on the aspects of dopamine neuron development related to the onset of movement disorders such as Parkinson's disease, with the intent of hopefully delaying, preventing or fixing symptoms. While midbrain dopamine degeneration is a major focus for treatment and research, many other human disorders are impacted by abnormal dopamine, including drug addiction, autism and schizophrenia. Understanding dopamine neuron ontogeny and how dopamine connections and circuitry develops may provide us with key insights into potentially important avenues of research for other dopamine-related disorders. This review will provide a brief overview of the major molecular and genetic players throughout the development of midbrain dopamine neurons and what we know about the behavioral- and disease-related implications associated with perturbations to midbrain dopamine neuron development. We intend to combine the knowledge of two broad fields of neuroscience, both developmental and behavioral, with the intent on fostering greater discussion between branches of neuroscience in the service of addressing complex cognitive questions from a developmental perspective and identifying important gaps in our knowledge for future study. © 2015 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

  8. Microwave-assisted deposition of silver nanoparticles on bamboo pulp fabric through dopamine functionalization

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Linghui [College of Light Industry, Textile and Food Engineering, Sichuan University, No.24 South Section 1, Yihuan Road, Chengdu (China); Guo, Ronghui, E-mail: ronghuiguo214@126.com [College of Light Industry, Textile and Food Engineering, Sichuan University, No.24 South Section 1, Yihuan Road, Chengdu (China); Lan, Jianwu [College of Light Industry, Textile and Food Engineering, Sichuan University, No.24 South Section 1, Yihuan Road, Chengdu (China); Jiang, Shouxiang [Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China); Lin, Shaojian [Institute for Technical and Macromolecular Chemistry, University of Hamburg Bundesstrasse 45, D-20146 Hamburg (Germany)

    2016-11-15

    Highlights: • Silver nanoparticles were synthesized on bamboo pulp fabric using dopamine as an adhesive and reducing agent under microwave radiation. • Silver coated bamboo pulp fabric modified with dopamine has good UV protection and hydrophobic property. • Silver nanoparticles can be strongly fixed on dopamine modified bamboo pulp fabric. - Abstract: Silver nanoparticles were synthesized on bamboo pulp fabric with dopamine as the adhesive and reducing agent under microwave radiation. The silver nanoparticle coated bamboo pulp fabrics were characterized by X-ray photoelectron spectroscopy, scanning electron microscope and X-ray diffraction. Ultraviolet (UV) protection, color and water contact angles of the silver nanoparticle coated bamboo pulp fabrics were evaluated. In addition, the influences of concentrations of dopamine and treatment time on color strength (K/S values) of the silver nanoparticle coated fabric were investigated. Fastness to washing was employed to evaluate the adhesive strength between the silver coating and the bamboo pulp fabric modified with dopamine. The results show that the dopamine modified bamboo pulp fabric is evenly covered with silver nanoparticles. The silver nanoparticle coated bamboo pulp fabric modified with dopamine shows the excellent UV protection with an ultraviolet protection factor of 157.75 and the hydrophobicity with a water contact angle of 132.4°. In addition, the adhesive strength between the silver nanoparticles and bamboo pulp fabric is significantly improved. Silver nanoparticles coating on bamboo pulp fabric modified with dopamine is environmentally friendly, easy to carry out and highly efficient.

  9. A targeted drug delivery system based on dopamine functionalized nano graphene oxide

    Science.gov (United States)

    Masoudipour, Elham; Kashanian, Soheila; Maleki, Nasim

    2017-01-01

    The cellular targeting property of a biocompatible drug delivery system can widely increase the therapeutic effect against various diseases. Here, we report a dopamine conjugated nano graphene oxide (DA-nGO) carrier for cellular delivery of the anticancer drug, Methotrexate (MTX) into DA receptor positive human breast adenocarcinoma cell line. The material was characterized using scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy and UV-vis spectroscopy. Furthermore, the antineoplastic action of MTX loaded DA-nGO against DA receptor positive and negative cell lines were explored. The results presented in this article demonstrated that the application of DA functionalized GO as a targeting drug carrier can improve the drug delivery efficacy for DA receptor positive cancer cell lines and promise future designing of carrier conjugates based on it.

  10. Combination of functional MRI with SAS and MRA

    Energy Technology Data Exchange (ETDEWEB)

    Sumida, Masayuki; Takeshita, Shinichirou; Kutsuna, Munenori; Akimitsu, Tomohide; Arita, Kazunori; Kurisu, Kaoru [Hiroshima Univ. (Japan). School of Medicine

    1999-02-01

    For presurgical diagnosis of brain surface, combination of functional MRI (fMRI) with the MR angiography was examined. This method could visualize brain bay, convolution and vein as index of surface. Five normal adults (male, mean age: 28-year-old) and 7 patients with brain tumor on the main locus to surface (male: 4, female: 3, mean age: 52.3-year-old) were studied. fMRI was performed by SPGR method (TR 70, TE 40, flip angle 60, one slice, thickness 10 mm, FOV 20 cm, matrix 128 x 128). The brain surface was visualized by SAS (surface anatomy scanning). SAS was performed by FSE method (TR 6000, TE 200, echo train 16, thickness 20 mm, slice 3, NEX 2). Cortical veins near superior sagittal sinus were visualized by MRA with 2D-TOF method (TR 50, TE 20, flip angle 60, thickness 2 mm, slice 28, NEX 1). These images were superimposed and functional image of peripheral sensorimotor region was evaluated anatomically. In normal adults, high signal was visualized at another side of near sensorimotor region at 8 of 10 sides. All high signal area of fMRI agreed with cortical vein near sensorimotor region that was visualized by MRA. In patients with brain tumor, signal was visualized at another side of sensorimotor region of tumor without 2 cases with palsy. In another side of tumor, signal of fMRI was visualized in 5 of 7 cases. The tumor was visualized as opposite low signal field in SAS. Locational relation between tumor and brain surface and brain function was visualized distinctly by combination of MRA, SAS and MRA. This method could become useful for presurgical diagnosis. (K.H.)

  11. Norepinephrine versus dopamine and their interaction in modulating synaptic function in the prefrontal cortex.

    Science.gov (United States)

    Xing, Bo; Li, Yan-Chun; Gao, Wen-Jun

    2016-06-15

    Among the neuromodulators that regulate prefrontal cortical circuit function, the catecholamine transmitters norepinephrine (NE) and dopamine (DA) stand out as powerful players in working memory and attention. Perturbation of either NE or DA signaling is implicated in the pathogenesis of several neuropsychiatric disorders, including attention deficit hyperactivity disorder (ADHD), post-traumatic stress disorder (PTSD), schizophrenia, and drug addiction. Although the precise mechanisms employed by NE and DA to cooperatively control prefrontal functions are not fully understood, emerging research indicates that both transmitters regulate electrical and biochemical aspects of neuronal function by modulating convergent ionic and synaptic signaling in the prefrontal cortex (PFC). This review summarizes previous studies that investigated the effects of both NE and DA on excitatory and inhibitory transmissions in the prefrontal cortical circuitry. Specifically, we focus on the functional interaction between NE and DA in prefrontal cortical local circuitry, synaptic integration, signaling pathways, and receptor properties. Although it is clear that both NE and DA innervate the PFC extensively and modulate synaptic function by activating distinctly different receptor subtypes and signaling pathways, it remains unclear how these two systems coordinate their actions to optimize PFC function for appropriate behavior. Throughout this review, we provide perspectives and highlight several critical topics for future studies. This article is part of a Special Issue entitled SI: Noradrenergic System. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Functional MRI and neurophysiological aspects of obesity

    International Nuclear Information System (INIS)

    Sztrokay, A.; Reiser, M.; Meindl, T.; Gutyrchik, E.

    2011-01-01

    Functional magnetic resonance imaging studies have revealed that metabolic signals and food stimuli activate the mesocorticolimbic neural network involved in processing the reward system. Activation is influenced by obesity and hunger and many recent brain imaging studies have detected that food and drug stimuli activate many of the same reward circuits. These findings have implications for obesity prevention and therapy. Educational efforts need to be directed towards those at increased risk of becoming obese and the food industry has to be involved in providing and promoting healthier food options. Given that visual food stimuli are potent triggers of desire, seductive advertising of high calorie foods directed towards children should be curtailed. The application of non-invasive brain imaging methodologies to the study of hedonic and homeostatic eating behavior represents a novel and important experimental approach. Further advances in imaging technology and improved experimental designs will provide new and important insights into human ingestive behavior that may lead to new developments in behavioral and pharmacological therapies. (orig.) [de

  13. Imaging of dopamine transporters with 99Tcm-TRODAT-1, rCBF and MRI in animal model of parkinson disease

    International Nuclear Information System (INIS)

    Deng Haoyu; Wang Wei; Li Xinhui; Yu Xiaoping

    2001-01-01

    Objective: To study the relationship between radioactivity distribution and changes of regional cerebral blood flow (rCBF) and tissue structure in the striatum of Parkinson disease (PD) model monkeys with 99 Tc m - TRODAT-1 and to estimate the value of imaging with 99 Tc m -TRODAT-1 in early diagnosis of PD. Methods: 99 Tc m -TRODAT-1 and rCBF imaging were performed on five monkeys before and after being made into a single side PD model. Two of the 5 PD model monkeys also received MRI. Results: In 99 Tc m -TRODAT-1 imaging the radioactivity ratio of striatum to cerebellum (S/C) in the normal monkeys was 1.48 at 180 min after injection of the imaging agent, the ratio of radioactivity in PD model monkeys in their destroyed striatum to that in cerebellum and in normal side striatum were 0.96 and 1.43, respectively. There was no difference in rCBF perfusion between normal and destroyed striatum of the PD model monkeys and between striatum tissue in two hemispheres of the normal monkeys either. The destruction of the tissue structure was not detected in PD model monkeys with MRI. Conclusions: 90 Tc m -TRODAT-1 can specifically bind dopamine transporters (DAT), sensitively display DAT uptake decrease ahead of the structural damage and cerebral blood flow perfusion decrease in PD model monkeys. It could become a useful imaging modality for the early diagnosis of PD

  14. Dopamine-Related Disruption of Functional Topography of Striatal Connections in Unmedicated Patients With Schizophrenia.

    Science.gov (United States)

    Horga, Guillermo; Cassidy, Clifford M; Xu, Xiaoyan; Moore, Holly; Slifstein, Mark; Van Snellenberg, Jared X; Abi-Dargham, Anissa

    2016-08-01

    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. To examine whether the pattern of brain connectivity across striatal subregions is abnormal in unmedicated patients with schizophrenia and whether this abnormality relates to psychotic symptoms and extrastriatal dopaminergic transmission. In this multimodal, case-control study, we obtained resting-state functional magnetic resonance imaging data from 18 unmedicated patients with schizophrenia and 24 matched healthy controls from the New York State Psychiatric Institute. A subset of these (12 and 17, respectively) underwent positron emission tomography with the dopamine D2 receptor radiotracer carbon 11-labeled FLB457 before and after amphetamine administration. Data were acquired between June 16, 2011, and February 25, 2014. Data analysis was performed from September 1, 2014, to January 11, 2016. Group differences in the striatal connectivity pattern (assessed via multivariable logistic regression) across striatal subregions, the association between the multivariate striatal connectivity pattern and extrastriatal baseline D2 receptor binding potential and its change after amphetamine administration, and the association between the multivariate connectivity pattern and the severity of positive symptoms evaluated with the Positive and Negative Syndrome Scale. Of the patients with schizophrenia (mean [SEM] age, 35.6 [11.8] years), 9 (50%) were male and 9

  15. Inaudible functional MRI using a truly mute gradient echo sequence

    International Nuclear Information System (INIS)

    Marcar, V.L.; Girard, F.; Rinkel, Y.; Schneider, J.F.; Martin, E.

    2002-01-01

    We performed functional MRI experiments using a mute version of a gradient echo sequence on adult volunteers using either a simple visual stimulus (flicker goggles: 4 subjects) or an auditory stimulus (music: 4 subjects). Because the mute sequence delivers fewer images per unit time than a fast echo planar imaging (EPI) sequence, we explored our data using a parametric ANOVA test and a non-parametric Wilcoxon-Mann-Whitney test in addition to performing a cross-correlation analysis. All three methods were in close agreement regarding the location of the BOLD contrast signal change. We demonstrated that, using appropriate statistical analysis, functional MRI using an MR sequence that is acoustically inaudible to the subject is feasible. Furthermore compared with the ''silent'' event-related procedures involving an EPI protocol, our mGE protocol compares favourably with respect to experiment time and the BOLD signal. (orig.)

  16. Inaudible functional MRI using a truly mute gradient echo sequence

    Energy Technology Data Exchange (ETDEWEB)

    Marcar, V.L. [University of Zurich, Department of Psychology, Neuropsychology, Treichlerstrasse 10, 8032 Zurich (Switzerland); Girard, F. [GE Medical Systems SA, 283, rue de la Miniere B.P. 34, 78533 Buc Cedex (France); Rinkel, Y.; Schneider, J.F.; Martin, E. [University Children' s Hospital, Neuroradiology and Magnetic Resonance, Department of Diagnostic Imaging, Steinwiesstrasse 75, 8032 Zurich (Switzerland)

    2002-11-01

    We performed functional MRI experiments using a mute version of a gradient echo sequence on adult volunteers using either a simple visual stimulus (flicker goggles: 4 subjects) or an auditory stimulus (music: 4 subjects). Because the mute sequence delivers fewer images per unit time than a fast echo planar imaging (EPI) sequence, we explored our data using a parametric ANOVA test and a non-parametric Wilcoxon-Mann-Whitney test in addition to performing a cross-correlation analysis. All three methods were in close agreement regarding the location of the BOLD contrast signal change. We demonstrated that, using appropriate statistical analysis, functional MRI using an MR sequence that is acoustically inaudible to the subject is feasible. Furthermore compared with the ''silent'' event-related procedures involving an EPI protocol, our mGE protocol compares favourably with respect to experiment time and the BOLD signal. (orig.)

  17. Evaluation of various somatosensory stimulations for functional MRI

    International Nuclear Information System (INIS)

    Hara, Kazushi; Nakasato, Nobukazu; Mizoi, Kazuo; Yoshimoto, Takashi; Shimizu, Hiroaki.

    1997-01-01

    The aim of this functional magnetic resonance imaging (fMRI) study was to test detectability of activated area using various somatosensory stimulations. The following stimulations were performed in normal volunteers: regular or irregular electrical median nerve stimulation (n=5, each), tactile stimulation to the palm and fingers (n=8), pain stimulation to the index finger (n=5) or to the palm and fingers (n=5). fMRI was acquired with a spoiled gradient echo sequence at 1.5 T. Detectability of activated area was the highest when the pain stimulation was applied to the palm and fingers (80%). A successful rate for the tactile stimulation was 25%, and the other stimulations failed to demonstrate any activation. When successful, the highest signal activation on fMRI was seen on a sulcus, which presumably arose from a vein. The sulcus was defined as the central sulcus by somatosensory evoked field using a median nerve stimulation. Our study indicates that the pain stimulation to the palm and fingers may be a choice for the sensory fMRI. (author)

  18. Donor dopamine treatment in brain dead rats is associated with an improvement in renal function early after transplantation and a reduction in renal inflammation

    NARCIS (Netherlands)

    Hoeger, Simone; Reisenbuechler, Anke; Gottmann, Uwe; Doyon, Fabian; Braun, Claude; Kaya, Ziya; Seelen, Marc A.; van Son, Willem J.; Waldherr, Ruediger; Schnuelle, Peter; Yard, Benito A.

    Brain death (BD) is associated with tissue inflammation. As dopamine treatment of BD donor rats reduces renal monocyte infiltration, we tested if this treatment affects renal function and inflammation in recipients. BD was induced in F344 rats and was maintained for 6 h in all experiments. Dopamine

  19. Multigenerational effects of adolescent morphine exposure on dopamine D2 receptor function.

    Science.gov (United States)

    Byrnes, John J; Johnson, Nicole L; Carini, Lindsay M; Byrnes, Elizabeth M

    2013-05-01

    The use and misuse of prescription opiates in adolescent populations, and in particular, adolescent female populations, has increased dramatically in the past two decades. Given the significant role that opioids play in neuroendocrine function, exposure to opiates during this critical developmental period could have significant consequences for the female, as well as her offspring. In the current set of studies, we utilized the female rat to model the transgenerational impact of adolescent opiate exposure. We examined locomotor sensitization in response to the dopamine D2/D3 receptor agonist quinpirole in the adult male progeny (F1 and F2 generations) of females exposed to morphine during adolescence. All females were drug-free for at least 3 weeks prior to conception, eliminating the possibility of direct fetal exposure to morphine. Both F1 and F2 progeny of morphine-exposed females demonstrated attenuated locomotor sensitization following repeated quinpirole administration. These behavioral effects were coupled with increased quinpirole-induced corticosterone secretion and upregulated kappa opioid receptor and dopamine D2 receptor (D2R) gene expression within the nucleus accumbens. These results suggest significant modifications in response to repeated D2R activation in the progeny of females exposed to opiates during adolescence. Given the significant role that the D2R plays in psychopathology, adolescent opiate exposure could shift the vulnerability of future offspring to psychological disorders, including addiction. Moreover, that effects are also observed in the F2 generation suggests that adolescent opiate exposure can trigger transgenerational epigenetic modifications impacting systems critical for motivated behavior.

  20. Dopamine modulates risk-taking as a function of baseline sensation-seeking trait.

    Science.gov (United States)

    Norbury, Agnes; Manohar, Sanjay; Rogers, Robert D; Husain, Masud

    2013-08-07

    Trait sensation-seeking, defined as a need for varied, complex, and intense sensations, represents a relatively underexplored hedonic drive in human behavioral neuroscience research. It is related to increased risk for a range of behaviors including substance use, gambling, and risky sexual practice. Individual differences in self-reported sensation-seeking have been linked to brain dopamine function, particularly at D2-like receptors, but so far no causal evidence exists for a role of dopamine in sensation-seeking behavior in humans. Here, we investigated the effects of the selective D2/D3 agonist cabergoline on performance of a probabilistic risky choice task in healthy humans using a sensitive within-subject, placebo-controlled design. Cabergoline significantly influenced the way participants combined different explicit signals regarding probability and loss when choosing between response options associated with uncertain outcomes. Importantly, these effects were strongly dependent on baseline sensation-seeking score. Overall, cabergoline increased sensitivity of choice to information about probability of winning; while decreasing discrimination according to magnitude of potential losses associated with different options. The largest effects of the drug were observed in participants with lower sensation-seeking scores. These findings provide evidence that risk-taking behavior in humans can be directly manipulated by a dopaminergic drug, but that the effectiveness of such a manipulation depends on baseline differences in sensation-seeking trait. This emphasizes the importance of considering individual differences when investigating manipulation of risky decision-making, and may have relevance for the development of pharmacotherapies for disorders involving excessive risk-taking in humans, such as pathological gambling.

  1. Comparative studies of brain activation with MEG and functional MRI

    International Nuclear Information System (INIS)

    George, J.S.; Aine, C.J.; Sanders, J.A.; Lewine, J.D.; Caprihan, A.

    1993-01-01

    The past two years have witnessed the emergence of MRI as a functional imaging methodology. Initial demonstrations involved the injection of a paramagnetic contrast agent and required ultrafast echo planar imaging capability to adequately resolve the passage of the injected bolus. By measuring the local reduction in image intensity due to magnetic susceptibility, it was possible to calculate blood volume, which changes as a function of neural activation. Later developments have exploited endogenous contrast mechanisms to monitor changes in blood volume or in venous blood oxygen content. Recently, we and others have demonstrated that it is possible to make such measurements in a clinical imager, suggesting that the large installed base of such machines might be utilized for functional imaging. Although it is likely that functional MRI (fMRI) will subsume some of the clinical and basic neuroscience applications now touted for MEG, it is also clear that these techniques offer different largely complementary, capabilities. At the very least, it is useful to compare and cross-validate the activation maps produced by these techniques. Such studies will be valuable as a check on results of neuromagnetic distributed current reconstructions and will allow better characterization of the relationship between neurophysiological activation and associated hemodynamic changes. A more exciting prospect is the development of analyses that combine information from the two modalities to produce a better description of underlying neural activity than is possible with either technique in isolation. In this paper we describe some results from initial comparative studies and outline several techniques that can be used to treat MEG and fMRI data within a unified computational framework

  2. Functional MRI in Patients with Intracranial Lesions near Language Areas.

    Science.gov (United States)

    Hakyemez, B; Erdogan, C; Yildirim, N; Bora, I; Bekar, A; Parlak, M

    2006-06-30

    We aimed to depict Broca's area and Wernicke's area by word generation and sentence formation paradigms in patients with various intracranial lesions adjacent to language areas using functional MRI technique and to evaluate the ability of functional MRI to lateralize the hemispheric dominance for language. Twenty-three right-handed patients were included in this study. Lesions were classified as low-grade glioma (n=8), high-grade glioma (n=9), metastasis (n=1), meningioma (n=1), arteriovenous malformation (n=2) and mesial temporal sclerosis (n=2). We performed blood-oxygenated-level-dependant functional MRI using a 1.5-T unit. Word generation and sentence formation tasks were used to activate language areas. Language areas were defined as Brodmann 44, 45 (Broca's area) and Brodmann 22 area (Wernicke's area). Laterality index was used to show the dominant hemisphere. Two poorly cooperative patients showed no activation and were excluded from the study. Broca's area was localized in 21 patients (100 %). Wernicke's area, on the other hand, could only be localized in eight of the 21 patients (38 %).The left hemisphere was dominant in 86% of patients while atypical language lateralization (right or bilateral) was demonstrated in 14% of the patients. Bilateral activation areas were shown in 10% of those patients while right cerebral hemisphere was dominant in 4% of the patients. Word generation and sentence formation tasks are especially helpful in localizing Broca's area. Wernicke's area could also be demonstrated in some of the cases. Functional MRI can be used as an important and useful means of demonstrating language areas in patients with lesions adjacent to those areas and depicting the hemispheric dominance.

  3. Individual differences in impulsive action and dopamine transporter function in rat orbitofrontal cortex.

    Science.gov (United States)

    Yates, J R; Darna, M; Beckmann, J S; Dwoskin, L P; Bardo, M T

    2016-01-28

    Impulsivity, which can be subdivided into impulsive action and impulsive choice, is implicated as a factor underlying drug abuse vulnerability. Although previous research has shown that dopamine (DA) systems in prefrontal cortex are involved in impulsivity and substance abuse, it is not known if inherent variation in DA transporter (DAT) function contributes to impulsivity. The current study determined if individual differences in either impulsive action or impulsive choice are related to DAT function in orbitofrontal (OFC) and/or medial prefrontal cortex (mPFC). Rats were first tested both for impulsive action in a cued go/no-go task and for impulsive choice in a delay-discounting task. Following behavioral evaluation, in vitro [(3)H]DA uptake assays were performed in OFC and mPFC isolated from individual rats. Vmax in OFC, but not mPFC, was correlated with performance in the cued go/no-go task, with decreased OFC DAT function being associated with high impulsive action. In contrast, Vmax in OFC and mPFC was not correlated with performance in the delay-discounting task. The current results demonstrate that impulsive behavior in cued go/no-go performance is associated with decreased DAT function in OFC, suggesting that hyperdopaminergic tone in this prefrontal subregion mediates, at least in part, increased impulsive action. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  4. High temporal resolution functional MRI using parallel echo volumar imaging

    International Nuclear Information System (INIS)

    Rabrait, C.; Ciuciu, P.; Ribes, A.; Poupon, C.; Dehaine-Lambertz, G.; LeBihan, D.; Lethimonnier, F.; Le Roux, P.; Dehaine-Lambertz, G.

    2008-01-01

    Purpose: To combine parallel imaging with 3D single-shot acquisition (echo volumar imaging, EVI) in order to acquire high temporal resolution volumar functional MRI (fMRI) data. Materials and Methods: An improved EVI sequence was associated with parallel acquisition and field of view reduction in order to acquire a large brain volume in 200 msec. Temporal stability and functional sensitivity were increased through optimization of all imaging parameters and Tikhonov regularization of parallel reconstruction. Two human volunteers were scanned with parallel EVI in a 1.5 T whole-body MR system, while submitted to a slow event-related auditory paradigm. Results: Thanks to parallel acquisition, the EVI volumes display a low level of geometric distortions and signal losses. After removal of low-frequency drifts and physiological artifacts,activations were detected in the temporal lobes of both volunteers and voxel-wise hemodynamic response functions (HRF) could be computed. On these HRF different habituation behaviors in response to sentence repetition could be identified. Conclusion: This work demonstrates the feasibility of high temporal resolution 3D fMRI with parallel EVI. Combined with advanced estimation tools,this acquisition method should prove useful to measure neural activity timing differences or study the nonlinearities and non-stationarities of the BOLD response. (authors)

  5. Elaboration de plateformes biomimétiques à base de dopamine pour la fonctionnalisation du titane Elaboration of biomimetic dopamine platforms for the functionalization of titanium surfaces

    Directory of Open Access Journals (Sweden)

    Laure William

    2013-11-01

    Full Text Available L'étude concerne la fonctionnalisation de surfaces à base de titane à partir d'une ancre chimique biomimétique modifiable chimiquement, la dopamine, dans le but de concevoir des biomatériaux utilisables en tant que dispositifs implantables. Deux approches différentes de greffage par la stratégie «graft to» sont proposées. La première consiste en la synthèse et l'immobilisation sur les surfaces de titane de polymères parfaitement définis et stimulables fonctionnalisés par un motif catéchol en extrémité de chaîne. La seconde propose de modifier préalablement la surface par une ancre chimique spécifique intégrant un motif catéchol d'une part et un motif furane ou maléimide d'autre part permettant d'engager sur demande une réaction réversible de cycloaddition de type Diels Alder (DA avec une large gamme de molécules ou polymères fonctionnalisés par l'entité complémentaire. The aim of this study concerns the functionalization of titanium surfaces by using versatile dopamine based on biomimetic anchors. This general concept was exploited to design new biomaterials which might be used as medical implants. In this context, two different grafting strategies based onto the “grafting to” approach were developed. The first one consisted on the synthesis and the immobilization of well-defined catechol end-functionalized polymers onto titanium surfaces. The second strategy was based on the functionalization of titanium surfaces by using dopamine derivates containing, on the one hand, a catechol unit for surface attachment and, on the other hand, a furan or a maleimide moiety able to react, on demand, through reversible Diels Alder (DA reaction.

  6. Donor Preconditioning After the Onset of Brain Death With Dopamine Derivate n-Octanoyl Dopamine Improves Early Posttransplant Graft Function in the Rat.

    Science.gov (United States)

    Li, S; Korkmaz-Icöz, S; Radovits, T; Ruppert, M; Spindler, R; Loganathan, S; Hegedűs, P; Brlecic, P; Theisinger, B; Theisinger, S; Höger, S; Brune, M; Lasitschka, F; Karck, M; Yard, B; Szabó, G

    2017-07-01

    Heart transplantation is the therapy of choice for end-stage heart failure. However, hemodynamic instability, which has been demonstrated in brain-dead donors (BDD), could also affect the posttransplant graft function. We tested the hypothesis that treatment of the BDD with the dopamine derivate n-octanoyl-dopamine (NOD) improves donor cardiac and graft function after transplantation. Donor rats were given a continuous intravenous infusion of either NOD (0.882 mg/kg/h, BDD+NOD, n = 6) or a physiological saline vehicle (BDD, n = 9) for 5 h after the induction of brain death by inflation of a subdural balloon catheter. Controls were sham-operated (n = 9). In BDD, decreased left-ventricular contractility (ejection fraction; maximum rate of rise of left-ventricular pressure; preload recruitable stroke work), relaxation (maximum rate of fall of left-ventricular pressure; Tau), and increased end-diastolic stiffness were significantly improved after the NOD treatment. Following the transplantation, the NOD-treatment of BDD improved impaired systolic function and ventricular relaxation. Additionally, after transplantation increased interleukin-6, tumor necrosis factor TNF-α, NF-kappaB-p65, and nuclear factor (NF)-kappaB-p105 gene expression, and increased caspase-3, TNF-α and NF-kappaB protein expression could be significantly downregulated by the NOD treatment compared to BDD. BDD postconditioning with NOD through downregulation of the pro-apoptotic factor caspase-3, pro-inflammatory cytokines, and NF-kappaB may protect the heart against the myocardial injuries associated with brain death and ischemia/reperfusion. © 2017 The American Society of Transplantation and the American Society of Transplant Surgeons.

  7. Acquisition and analysis strategies in functional MRI at high fields

    International Nuclear Information System (INIS)

    Windischberger, C.

    2001-08-01

    Functional magnetic resonance imaging represents a non-invasive technique to examine neuronal activity in the brain. It applies radio waves to excite nuclear spins, using the emitted signal during relaxation for image generation. Signal modulations from local blood flow and oxygenation level changes caused by neuronal activity are the basis for calculating functional brain maps with high spatial resolution. The present work discusses concepts for improving the spatial and temporal resolution, as well as sophisticated analysis approaches. Besides an exhaustive description of image reconstruction algorithms, computational simulations on echo-shifting in echo-planar imaging are presented and effects on spatial resolution are quantified. The results demonstrate that echo-shifting causes only minimal resolution losses for high signal-to-noise data, but leads to severe resolution degradation (up to 30 %) in images with low signal-to-noise ratios. After an overview of the mechanisms that cause fMRI signal changes subsequent to neuronal activity, explorative analysis algorithms like Fuzzy Cluster Analysis, as well as parametric approaches are described and discussed. In the context of fMRI artifacts, effects of respiratory motion are examined. For the first time, well-defined breathing patterns are used to quantify the influences on fMRI signal intensity. Also, the variability of fMRI activation in a mental rotation paradigm are investigated, using single-trial analysis. Such, intra-subject activation consistency was determined successfully. Finally, in a second study on mental rotation explorative data analysis was applied to retrieve neuro-functional hypotheses. (author)

  8. Correlation between the availability of dopamine transporter and olfactory function in healthy subjects

    International Nuclear Information System (INIS)

    Pak, Kyoungjune; Kim, Keunyoung; Kim, In Joo; Lee, Myung Jun; Lee, Jae Meen; Kim, Bum Soo; Kim, Seong-Jang

    2018-01-01

    Olfactory dysfunction in Parkinson's disease is usually prodromal to other symptoms. In this study, we aimed to explore the association of olfactory function with the availabilities of striatal dopamine transporter (DAT) in healthy subjects. Data used in the preparation of this article were obtained from Parkinson's Progression Markers Initiative database (www.ppmi-info.org/data). The study population consisted of healthy controls with screening 123 I-FP-CIT single photon emission tomography (SPECT). University of Pennsylvania Smell Identification Test (UPSIT) was assessed to evaluate the olfactory function. Totally, 181 healthy subjects (117 male, 64 female) with 123 I-FP-CIT SPECT data were included in this study. Specific binding ratios (SBRs) of the caudate nucleus (rho = -0.4217, p < 0.0001), putamen (rho = -0.2292, p = 0.0019), and striatum (rho=-0.3425, p < 0.0001) showed a reduction with ageing. SBRs of the caudate nucleus, putamen, and striatum were positively correlated with UPSIT (rho = 0.3716, p < 0.0001; rho = 0.3655, p < 0.0001; rho = 0.3880, p < 0.0001). After controlling for age by partial correlation, SBRs of the caudate nucleus, putamen, and striatum showed an influence on UPSIT (rho = 0.3288, p < 0.0001; rho = 0.3374, p < 0.0001; rho = 0.3511, p < 0.0001). Olfactory function is associated with the availability of striatal DAT independent of age in healthy subjects. (orig.)

  9. Functional MRI studies in children with attention deficit hyperactivity disorder

    International Nuclear Information System (INIS)

    Zhang Lei; Jin Zhen; Zeng Yawei; Wang Yan; Zang Yufeng

    2004-01-01

    Objective: To investigate the brain activation map during Go-NoGo tasks in children with attention deficit hyperactivity disorder (ADHD) and matched controls using functional MRI. Methods: Block designed BOLD functional MRI scan covering the whole brain was performed on 10 boys having ADHD and 11 healthy boys. The 2 groups were matched by age, sex, and handedness. Executing advanced inhibitory Go-NoGo tasks served as stimuli for all subjects. The fMRI data was analyzed by SPM99 (Statistical Parametric Mapping) software with statistic t-test to generate the activation map. Results: (1) The normal children showed significant activations in left thalamus and right cingulate gyrus and fewer activations in right middle frontal gyrus during stimulate controlled Go task, but the children with ADHD showed less activations in left thalamus. (2) In response controlled Go task, the normal children showed activations in right insula, cingulate gyrus and left frontal gyrus, while the ADHD children showed lower power of response in the right middle frontal gyrus.(3) In NoGo task, right middle frontal gyrus was the dominant activated regions, and left anterior cingulate, left middle frontal gyrus and right thalamus also had some activations in normal children, while the activations of right prefrontal decreased and the thalamus increased in ADHD boys. Conclusion: In children with ADHD, some dysfunctional brain areas, mainly the prefrontal lobe and anterior cingulate gyrus were found. Thalamus was also involved according to the brain activation map

  10. Functional MRI studies in children with attention deficit hyperactivity disorder

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Zhang; Zhen, Jin; Yawei, Zeng; Yan, Wang [fMRI Center, Lab of Cognition Science and Learning, National Education Ministry and Department of Radiology, 306 Hospital of PLA, Beijing (China); Yufeng, Zang

    2004-06-01

    Objective: To investigate the brain activation map during Go-NoGo tasks in children with attention deficit hyperactivity disorder (ADHD) and matched controls using functional MRI. Methods: Block designed BOLD functional MRI scan covering the whole brain was performed on 10 boys having ADHD and 11 healthy boys. The 2 groups were matched by age, sex, and handedness. Executing advanced inhibitory Go-NoGo tasks served as stimuli for all subjects. The fMRI data was analyzed by SPM99 (Statistical Parametric Mapping) software with statistic t-test to generate the activation map. Results: (1) The normal children showed significant activations in left thalamus and right cingulate gyrus and fewer activations in right middle frontal gyrus during stimulate controlled Go task, but the children with ADHD showed less activations in left thalamus. (2) In response controlled Go task, the normal children showed activations in right insula, cingulate gyrus and left frontal gyrus, while the ADHD children showed lower power of response in the right middle frontal gyrus.(3) In NoGo task, right middle frontal gyrus was the dominant activated regions, and left anterior cingulate, left middle frontal gyrus and right thalamus also had some activations in normal children, while the activations of right prefrontal decreased and the thalamus increased in ADHD boys. Conclusion: In children with ADHD, some dysfunctional brain areas, mainly the prefrontal lobe and anterior cingulate gyrus were found. Thalamus was also involved according to the brain activation map.

  11. Preparation and characterization of silver nanoparticles immobilized on multi-walled carbon nanotubes by poly(dopamine) functionalization

    International Nuclear Information System (INIS)

    Jiang Yi; Lu Yonglai; Zhang Liqun; Liu Li; Dai Yajie; Wang Wencai

    2012-01-01

    Multi-walled carbon nanotubes (MWNTs) functionalized with poly(dopamine) (PDA) were found to cause the immobilization of silver nanoparticles on the surface. The PDA functional layer not only improved the dispersion of MWNTs in aqueous solution, but also was used as a platform for subsequent silver nanoparticle immobilization. The surface morphology of the functionalized MWNTs was observed by high-resolution transmission electron microscopy. The results showed that PDA layers with controlled thickness on the nanometer scale were formed on MWNT surfaces by in situ spontaneous oxidative polymerization of dopamine, and that high-density of homogeneously dispersed spherical silver nanoparticles with sizes of 3–4 nm were immobilized on their outer surface. The space between spherical silver nanoparticles is less than 10 nm. Both X-ray photoelectron spectroscopy and X-ray diffraction results showed that the Ag nanoparticles on the surface of hybrids exist in the zero valent state.

  12. Practical Introduction to Cerebral Functional Magnetic Resonance (fMRI)

    International Nuclear Information System (INIS)

    Delgado, Jorge Andres; Rascovsky Simon; Sanz, Alexander; Castrillon, Juan Gabriel

    2008-01-01

    Magnetic resonance (MR ) imaging holds a privileged position within neuroimaging techniques owing to its high anatomic detail and its capacity to study many physiological processes. The appearance of functional magnetic resonance (fMR I) brings more relevance to MR , turning it into a powerful tool with the ability to group, in a single exam, high-resolution anatomy and cerebral function. In this article we describe the principles and some advantages of fMRI compared to other neuro functional imaging modalities. In addition, we present the site wide and analysis requisites for the performance and post-processing of the most common neuro functional experiments in clinical practice. We also include neuro functional images obtained at Instituto de Alta Tecnologia Medica of Antioquia (IATM ) on a healthy volunteer group and two pathological cases. Lastly, we mention some of the practical indications of this technique which is still in an intense development, research and validation phase.

  13. HIV Infection Is Associated with Impaired Striatal Function during Inhibition with Normal Cortical Functioning on Functional MRI

    NARCIS (Netherlands)

    du Plessis, Stéfan; Vink, Matthijs; Joska, John A; Koutsilieri, Eleni; Bagadia, Asif; Stein, Dan J; Emsley, Robin

    2015-01-01

    The aim of the present study was to investigate the effect of HIV infection on cortical and subcortical regions of the frontal-striatal system involved in the inhibition of voluntary movement. Functional MRI (fMRI) studies suggest that human immunodeficiency virus (HIV) infection is associated with

  14. Incidental MRI Findings in Patients with Impaired Cognitive Function

    International Nuclear Information System (INIS)

    Hwang, Yoon Joon

    2013-01-01

    This study aims to evaluate the incidental findings on brain MRI of patients with cognitive function impairments. We analyzed magnetic resonance (MR) findings of 236 patients with decreased cognitive function. MR protocols include conventional T2 weighted axial images, fluid attenuated inversion recovery axial images, T1 weighted coronal 3-dimensional magnetization-prepared rapid acquisition of gradient echo and diffusion tensor images. We retrospectively evaluated the signal changes that suggest acute/subacute infarction and space occupying lesions which show mass effect. Incidental MR findings were seen in 16 patients. Nine patients (3.8%) showed increased signal intensity on trace map of diffusion tensor images suggesting acute/subacute infarctions. Space occupying lesions were detected in 7 patients, and 3 lesions (1.27%) had mass effect and edema and were considered clinically significant lesions that diminish cognitive functions. Several incidental MR findings were detected in patients with decreased cognitive function, and the incidence of aucte/subacute infarctions were higher. Proper evaluations of MRI in patients with impaired cognitive functions will be helpful in early detection and management of ischemic lesions and space occupying lesions.

  15. Quantitative evaluation of the reticuloendothelial system function with dynamic MRI.

    Directory of Open Access Journals (Sweden)

    Ting Liu

    Full Text Available To evaluate the reticuloendothelial system (RES function by real-time imaging blood clearance as well as hepatic uptake of superparamagnetic iron oxide nanoparticle (SPIO using dynamic magnetic resonance imaging (MRI with two-compartment pharmacokinetic modeling.Kinetics of blood clearance and hepatic accumulation were recorded in young adult male 01b74 athymic nude mice by dynamic T2* weighted MRI after the injection of different doses of SPIO nanoparticles (0.5, 3 or 10 mg Fe/kg. Association parameter, Kin, dissociation parameter, Kout, and elimination constant, Ke, derived from dynamic data with two-compartment model, were used to describe active binding to Kupffer cells and extrahepatic clearance. The clodrosome and liposome were utilized to deplete macrophages and block the RES function to evaluate the capability of the kinetic parameters for investigation of macrophage function and density.The two-compartment model provided a good description for all data and showed a low sum squared residual for all mice (0.27±0.03. A lower Kin, a lower Kout and a lower Ke were found after clodrosome treatment, whereas a lower Kin, a higher Kout and a lower Ke were observed after liposome treatment in comparison to saline treatment (P<0.005.Dynamic SPIO-enhanced MR imaging with two-compartment modeling can provide information on RES function on both a cell number and receptor function level.

  16. Elucidating the impact of neurofibromatosis-1 germline mutations on neurofibromin function and dopamine-based learning.

    Science.gov (United States)

    Anastasaki, Corina; Woo, Albert S; Messiaen, Ludwine M; Gutmann, David H

    2015-06-15

    Neurofibromatosis type 1 (NF1) is a common autosomal dominant neurologic condition characterized by significant clinical heterogeneity, ranging from malignant cancers to cognitive deficits. Recent studies have begun to reveal rare genotype-phenotype correlations, suggesting that the specific germline NF1 gene mutation may be one factor underlying disease heterogeneity. The purpose of this study was to define the impact of the germline NF1 gene mutation on brain neurofibromin function relevant to learning. Herein, we employ human NF1-patient primary skin fibroblasts, induced pluripotent stem cells and derivative neural progenitor cells (NPCs) to demonstrate that NF1 germline mutations have dramatic effects on neurofibromin expression. Moreover, while all NF1-patient NPCs exhibit increased RAS activation and reduced cyclic AMP generation, there was a neurofibromin dose-dependent reduction in dopamine (DA) levels. Additionally, we leveraged two complementary Nf1 genetically-engineered mouse strains in which hippocampal-based learning and memory is DA-dependent to establish that neuronal DA levels and signaling as well as mouse spatial learning are controlled in an Nf1 gene dose-dependent manner. Collectively, this is the first demonstration that different germline NF1 gene mutations differentially dictate neurofibromin function in the brain. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. Spontaneous eye blink rate as predictor of dopamine-related cognitive function-A review.

    Science.gov (United States)

    Jongkees, Bryant J; Colzato, Lorenza S

    2016-12-01

    An extensive body of research suggests the spontaneous eye blink rate (EBR) is a non-invasive indirect marker of central dopamine (DA) function, with higher EBR predicting higher DA function. In the present review we provide a comprehensive overview of this literature. We broadly divide the available research in studies that aim to disentangle the dopaminergic underpinnings of EBR, investigate its utility in diagnosis of DA-related disorders and responsivity to drug treatment, and, lastly, investigate EBR as predictor of individual differences in DA-related cognitive performance. We conclude (i) EBR can reflect both DA receptor subtype D1 and D2 activity, although baseline EBR might be most strongly related to the latter, (ii) EBR can predict hypo- and hyperdopaminergic activity as well as normalization of this activity following treatment, and (iii) EBR can reliably predict individual differences in performance on many cognitive tasks, in particular those related to reward-driven behavior and cognitive flexibility. In sum, this review establishes EBR as a useful predictor of DA in a wide variety of contexts. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Au nanoparticles on tryptophan-functionalized graphene for sensitive detection of dopamine

    International Nuclear Information System (INIS)

    Lian, Qianwen; Luo, Ai; An, Zhenzhen; Li, Zhuang; Guo, Yongyang; Zhang, Dongxia; Xue, Zhonghua; Zhou, Xibin; Lu, Xiaoquan

    2015-01-01

    Graphical abstract: - Highlights: • A novel AuNPs/Trp-GR composite was fabricated by directly electrochemical deposition. • The composite exhibited excellent electrocatalytic activity towards DA. • The proposed method was applied to real samples. - Abstract: A novel and uniform gold nanoparticles/tryptophan-functionalized graphene nanocomposite (AuNPs/Trp-GR) has been successfully fabricated by directly electrochemical depositing gold onto the surface of tryptophan-functionalized graphene (Trp-GR). The nanostructure of AuNPs/Trp-GR was characterized by using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). It was demonstrated that Au nanoparticles were well dispersed on the surface of Trp-GR which might attribute to the more binding sites provided by Trp-GR for the formation of Au nanoparticles. The electrocatalytic activity of the AuNPs/Trp-GR towards the dopamine (DA) was systematically investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under optimum conditions, a wide and valuable linear range (0.5–411 μM), a low detection limit (0.056 μM, S/N = 3), good repeatability and stability were obtained for the determination of DA. Furthermore, the modified electrode was successfully applied to real samples analysis

  19. Au nanoparticles on tryptophan-functionalized graphene for sensitive detection of dopamine

    Energy Technology Data Exchange (ETDEWEB)

    Lian, Qianwen; Luo, Ai; An, Zhenzhen; Li, Zhuang; Guo, Yongyang; Zhang, Dongxia [Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Geography and Environment Science, Northwest Normal University, 730070, Lanzhou (China); Xue, Zhonghua [College of Chemistry and Chemical Engineering, Northwest Normal University, 730070, Lanzhou (China); Zhou, Xibin, E-mail: zhouxb@nwnu.edu.cn [Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Geography and Environment Science, Northwest Normal University, 730070, Lanzhou (China); Lu, Xiaoquan, E-mail: Luxq@nwnu.edu.cn [College of Chemistry and Chemical Engineering, Northwest Normal University, 730070, Lanzhou (China)

    2015-09-15

    Graphical abstract: - Highlights: • A novel AuNPs/Trp-GR composite was fabricated by directly electrochemical deposition. • The composite exhibited excellent electrocatalytic activity towards DA. • The proposed method was applied to real samples. - Abstract: A novel and uniform gold nanoparticles/tryptophan-functionalized graphene nanocomposite (AuNPs/Trp-GR) has been successfully fabricated by directly electrochemical depositing gold onto the surface of tryptophan-functionalized graphene (Trp-GR). The nanostructure of AuNPs/Trp-GR was characterized by using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). It was demonstrated that Au nanoparticles were well dispersed on the surface of Trp-GR which might attribute to the more binding sites provided by Trp-GR for the formation of Au nanoparticles. The electrocatalytic activity of the AuNPs/Trp-GR towards the dopamine (DA) was systematically investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under optimum conditions, a wide and valuable linear range (0.5–411 μM), a low detection limit (0.056 μM, S/N = 3), good repeatability and stability were obtained for the determination of DA. Furthermore, the modified electrode was successfully applied to real samples analysis.

  20. Effects of Smoking Cessation on Presynaptic Dopamine Function of Addicted Male Smokers

    DEFF Research Database (Denmark)

    Rademacher, Lena; Prinz, Susanne; Winz, Oliver

    2016-01-01

    BACKGROUND: There is evidence of abnormal cerebral dopamine transmission in nicotine-dependent smokers, but it is unclear whether dopaminergic abnormalities are due to acute nicotine abuse or whether they persist with abstinence. We addressed this question by conducting longitudinal positron...... then underwent cessation treatment, and successful abstainers were re-examined by FDOPA-PET after 3 months of abstinence (n = 15). Uptake of FDOPA was analyzed using a steady-state model yielding estimates of the dopamine synthesis capacity (K); the turnover of tracer dopamine formed in living brain (kloss......); and the tracer distribution volume (Vd), which is an index of dopamine storage capacity. RESULTS: Compared with nonsmokers, K was 15% to 20% lower in the caudate nuclei of consuming smokers. Intraindividual comparisons of consumption and long-term abstinence revealed significant increases in K in the right...

  1. Functionally distinct dopamine signals in nucleus accumbens core and shell in the freely moving rat

    DEFF Research Database (Denmark)

    Dreyer, Jakob K.; Vander Weele, Caitlin M.; Lovic, Vedran

    2016-01-01

    Dynamic signaling of mesolimbic dopamine (DA) neurons has been implicated in reward learning, drug abuse, and motivation. However, this system is complex because firing patterns of these neurons are heterogeneous; subpopulations receive distinct synaptic inputs, and project to anatomically...

  2. Functional MRI in schizophrenia. Diagnostics and therapy monitoring of cognitive deficits of schizophrenic patients by functional MRI

    International Nuclear Information System (INIS)

    Furtner, J.; Prayer, D.; Sachs, G.

    2010-01-01

    Cognitive impairments are core psychopathological components of the symptomatic of schizophrenic patients. These dysfunctions are generally related to attention, executive functions and memory. This report provides information on the importance of using functional magnetic resonance imaging (fMRI) for the diagnostics and therapy monitoring of the different subtypes of cognitive dysfunctions. Furthermore, it describes the typical differences in the activation of individual brain regions between schizophrenic patients and healthy control persons. This information should be helpful in identifying the deficit profile of each patient and create an individual therapy plan. (orig.) [de

  3. Effects of milrinone and epinephrine or dopamine on biventricular function and hemodynamics in right heart failure after pulmonary regurgitation.

    Science.gov (United States)

    Hyldebrandt, Janus Adler; Agger, Peter; Sivén, Eleonora; Wemmelund, Kristian Borup; Heiberg, Johan; Frederiksen, Christian Alcaraz; Ravn, Hanne Berg

    2015-09-01

    Right ventricular failure (RVF) secondary to pulmonary regurgitation (PR) impairs right ventricular (RV) function and interrupts the interventricular relationship. There are few recommendations for the medical management of severe RVF after prolonged PR. PR was induced in 16 Danish landrace pigs by plication of the pulmonary valve leaflets. Twenty-three pigs served as controls. At reexamination the effect of milrinone, epinephrine, and dopamine was evaluated using biventricular conductance and pulmonary catheters. Seventy-nine days after PR was induced, RV end-diastolic volume index (EDVI) had increased by 33% (P = 0.006) and there was a severe decrease in the load-independent measurement of contractility (PRSW) (-58%; P = 0.003). Lower cardiac index (CI) (-28%; P Milrinone improved RV-PRSW and CI and maintained systemic pressure while reducing central venous pressure (CVP). Epinephrine and dopamine further improved biventricular PRSW and CI equally in a dose-dependent manner. Systemic and pulmonary pressures were higher in the dopamine-treated animals compared with epinephrine-treated animals. None of the treatments improved stroke volume index (SVI) despite increases in contractility. Strong correlation was detected between SVI and LV-EDVI, but not SVI and biventricular contractility. In RVF due to PR, milrinone significantly improved CI, SvO2, and CVP and increased contractility in the RV. Epinephrine and dopamine had equal inotropic effect, but a greater vasopressor effect was observed for dopamine. SV was unchanged due to inability of both treatments to increase LV-EDVI. Copyright © 2015 the American Physiological Society.

  4. Renal rescue of dopamine D2 receptor function reverses renal injury and high blood pressure

    Science.gov (United States)

    Konkalmatt, Prasad R.; Asico, Laureano D.; Zhang, Yanrong; Yang, Yu; Drachenberg, Cinthia; Zheng, Xiaoxu; Han, Fei; Jose, Pedro A.; Armando, Ines

    2016-01-01

    Dopamine D2 receptor (DRD2) deficiency increases renal inflammation and blood pressure in mice. We show here that long-term renal-selective silencing of Drd2 using siRNA increases renal expression of proinflammatory and profibrotic factors and blood pressure in mice. To determine the effects of renal-selective rescue of Drd2 expression in mice, the renal expression of DRD2 was first silenced using siRNA and 14 days later rescued by retrograde renal infusion of adeno-associated virus (AAV) vector with DRD2. Renal Drd2 siRNA treatment decreased the renal expression of DRD2 protein by 55%, and DRD2 AAV treatment increased the renal expression of DRD2 protein by 7.5- to 10-fold. Renal-selective DRD2 rescue reduced the expression of proinflammatory factors and kidney injury, preserved renal function, and normalized systolic and diastolic blood pressure. These results demonstrate that the deleterious effects of renal-selective Drd2 silencing on renal function and blood pressure were rescued by renal-selective overexpression of DRD2. Moreover, the deleterious effects of 45-minute bilateral ischemia/reperfusion on renal function and blood pressure in mice were ameliorated by a renal-selective increase in DRD2 expression by the retrograde ureteral infusion of DRD2 AAV immediately after the induction of ischemia/reperfusion injury. Thus, 14 days after ischemia/reperfusion injury, the renal expression of profibrotic factors, serum creatinine, and blood pressure were lower in mice infused with DRD2 AAV than in those infused with control AAV. These results indicate an important role of renal DRD2 in limiting renal injury and preserving normal renal function and blood pressure. PMID:27358912

  5. Evaluation of pulmonary arterial morphology and function in cyanotic congenital heart disease by MRI and cine MRI

    International Nuclear Information System (INIS)

    Hashimoto, Ikuo; Tsubata, Shinichi; Miyazaki, Ayumi; Ichida, Fukiko; Okada, Toshio; Murakami, Arata; Futatsuya, Ryuusuke; Nakajima, Kenshuu; Nakajima, Akio

    1993-01-01

    Pulmonary arterial anatomy was evaluated by magnetic resonance imaging (MRI), angiography and two-dimensional echocardiography in 20 patients with cyanotic heart disease associated with decreased pulmonary blood flow. Excellent correlation between MRI and angiographic estimates of pulmonary artery diameter was obtained (main pulmonary artery, r=0.87; right pulmonary artery, r=0.96; left pulmonary artery, r=0.95). However, echocardiography could not describe peripheral pulmonary arteries obviously, especially left pulmonary artery. In the assessment of peripheral pulmonary stenosis or obstruction, cine MRI was superior to echocardiography. We conclude that MRI and cine MRI will play an important role in the serial evaluation of pulmonary arterial morphology and function in patients with cyanotic congenital heart disease before and after surgical repair. (author)

  6. Evaluation of pulmonary arterial morphology and function in cyanotic congenital heart disease by MRI and cine MRI

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, Ikuo; Tsubata, Shinichi; Miyazaki, Ayumi; Ichida, Fukiko; Okada, Toshio; Murakami, Arata; Futatsuya, Ryuusuke; Nakajima, Kenshuu; Nakajima, Akio [Toyama Medical and Pharmaceutical Univ. (Japan)

    1993-01-01

    Pulmonary arterial anatomy was evaluated by magnetic resonance imaging (MRI), angiography and two-dimensional echocardiography in 20 patients with cyanotic heart disease associated with decreased pulmonary blood flow. Excellent correlation between MRI and angiographic estimates of pulmonary artery diameter was obtained (main pulmonary artery, r=0.87; right pulmonary artery, r=0.96; left pulmonary artery, r=0.95). However, echocardiography could not describe peripheral pulmonary arteries obviously, especially left pulmonary artery. In the assessment of peripheral pulmonary stenosis or obstruction, cine MRI was superior to echocardiography. We conclude that MRI and cine MRI will play an important role in the serial evaluation of pulmonary arterial morphology and function in patients with cyanotic congenital heart disease before and after surgical repair. (author).

  7. The power of using functional fMRI on small rodents to study brain pharmacology and disease

    OpenAIRE

    Jonckers, Elisabeth; Shah, Disha; Hamaide, Julie; Verhoye, Marleen; Van der Linden, Annemie

    2015-01-01

    Abstract: Functional magnetic resonance imaging (fMRI) is an excellent tool to study the effect of pharmacological modulations on brain function in a non-invasive and longitudinal manner. We introduce several blood oxygenation level dependent (BOLD) fMRI techniques, including resting state (rsfMRI), stimulus-evoked (st-fMRI), and pharmacological MRI (phMRI). Respectively, these techniques permit the assessment of functional connectivity during rest as well as brain activation triggered by sen...

  8. Functionalized Ergot-alkaloids as potential dopamine D3 receptor agonists for treatment of schizophrenia

    Science.gov (United States)

    Ivanova, Bojidarka; Spiteller, Michael

    2012-12-01

    The relationship between the molecular structure and physical properties of functionalized naturally occurred Ergot-alkaloids as potential dopamine D3 receptor agonists is presented. The molecular modeling of the ergoline-skeleton is based on the comprehensive theoretical study of the binding affinity of the isolated chemicals towards the active sites of the D3 sub-type receptor (D3R) loops. The studied proton accepting ability under physiological conditions allows classifying four types of monocationics, characterizing with the different binding modes to D3R involving selected amino acid residues to the active sites. These results marked the pharmaceutical potential and clinical usage of the reported compounds as antipsychotic drugs for Schizophrenia treatment, since they allowed evaluating the highlights of the different hypothesizes of the biochemical causes the illness. The applied complex approach for theoretical and experimental elucidation, including quantum chemistry method, electrospray ionization (ESI) and matrix assisted laser desorption/ionization (MALDI) mass spectrometric (MS) methods, nuclear magnetic resonance and vibrational IR and Raman spectroscopy on the isolated fifteen novel derivatives (1)-(15) and their different protonated forms (1a)-(15a) evidenced a strong dependence of molecular conformation, physical properties and binding affinity. Thus, the semi-synthetic functionalization of the naturally occurred products (NPs), provided significant possibilities to further molecular drugs-design and development of novel derivatives with wanted biological function, using the established profile of selected classes/families of NPs. The work described chiefly the non-linear (NL) approach for the interpretation of the mass chromatograms on the performed hybrid high performance liquid chromatography (HPLC) tandem MS/MS and MS/MS/MS experiments, discussing the merits and great diversity of instrumentation flexibility, thus achieving fundamental

  9. Dopamine in the medial amygdala network mediates human bonding.

    Science.gov (United States)

    Atzil, Shir; Touroutoglou, Alexandra; Rudy, Tali; Salcedo, Stephanie; Feldman, Ruth; Hooker, Jacob M; Dickerson, Bradford C; Catana, Ciprian; Barrett, Lisa Feldman

    2017-02-28

    Research in humans and nonhuman animals indicates that social affiliation, and particularly maternal bonding, depends on reward circuitry. Although numerous mechanistic studies in rodents demonstrated that maternal bonding depends on striatal dopamine transmission, the neurochemistry supporting maternal behavior in humans has not been described so far. In this study, we tested the role of central dopamine in human bonding. We applied a combined functional MRI-PET scanner to simultaneously probe mothers' dopamine responses to their infants and the connectivity between the nucleus accumbens (NAcc), the amygdala, and the medial prefrontal cortex (mPFC), which form an intrinsic network (referred to as the "medial amygdala network") that supports social functioning. We also measured the mothers' behavioral synchrony with their infants and plasma oxytocin. The results of this study suggest that synchronous maternal behavior is associated with increased dopamine responses to the mother's infant and stronger intrinsic connectivity within the medial amygdala network. Moreover, stronger network connectivity is associated with increased dopamine responses within the network and decreased plasma oxytocin. Together, these data indicate that dopamine is involved in human bonding. Compared with other mammals, humans have an unusually complex social life. The complexity of human bonding cannot be fully captured in nonhuman animal models, particularly in pathological bonding, such as that in autistic spectrum disorder or postpartum depression. Thus, investigations of the neurochemistry of social bonding in humans, for which this study provides initial evidence, are warranted.

  10. Reduced striatal dopamine DA D2 receptor function in dominant-negative GSK-3 transgenic mice.

    Science.gov (United States)

    Gomez-Sintes, Raquel; Bortolozzi, Analia; Artigas, Francesc; Lucas, José J

    2014-09-01

    Glycogen synthase kinase-3 (GSK-3) is a serine/threonine kinase with constitutive activity involved in cellular architecture, gene expression, cell proliferation, fate decision and apoptosis, among others. GSK-3 expression is particularly high in brain where it may be involved in neurological and psychiatric disorders such as Alzheimer׳s disease, bipolar disorder and major depression. A link with schizophrenia is suggested by the antipsychotic drug-induced GSK-3 regulation and by the involvement of the Akt/GSK-3 pathway in dopaminergic neurotransmission. Taking advantage of the previous development of dominant negative GSK-3 transgenic mice (Tg) showing a selective reduction of GSK-3 activity in forebrain neurons but not in dopaminergic neurons, we explored the relationship between GSK-3 and dopaminergic neurotransmission in vivo. In microdialysis experiments, local quinpirole (DA D2-R agonist) in dorsal striatum reduced dopamine (DA) release significantly less in Tg mice than in wild-type (WT) mice. However, local SKF-81297 (selective DA D1-R agonist) in dorsal striatum reduced DA release equally in both control and Tg mice indicating a comparable function of DA D1-R in the direct striato-nigral pathway. Likewise, systemic quinpirole administration - acting preferentially on presynaptic DA D2- autoreceptors to modulate DA release-reduced striatal DA release similarly in both control and Tg mice. Quinpirole reduced locomotor activity and induced c-fos expression in globus pallidus (both striatal DA D2-R-mediated effects) significantly more in WT than in Tg mice. Taking together, the present results show that dominant negative GSK-3 transgenic mice show reduced DA D2-R-mediated function in striatum and further support a link between dopaminergic neurotransmission and GSK-3 activity. Copyright © 2014 Elsevier B.V. and ECNP. All rights reserved.

  11. Tunable fabrication of hierarchical hybrids via the incorporation of poly(dopamine) functional interlayer

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ting; Zhao, Xin; Zhang, Junxian; Dong, Jie; Zhang, Qinghua, E-mail: qhzhang@dhu.edu.cn

    2016-04-30

    Highlights: • PS/PDA with well-defined core/shell structures was prepared in aqueous solution. • Au NPs were coated on PS/PDA by in-situ reduction and self-assembly approach. • PS/PDA/Au had homogeneous and dense Au coatings with different shape. • Hierarchical spheres exhibited a well-defined core/shell structure maintaining the spherical morphology. - Abstract: Two kinds of ternary hybrids were prepared by anchoring different shapes and loadings of Au nanoparticles (NPs) on poly(dopamine) (PDA) functionalized polystyrene (PS) microspheres with two different strategies, i.e., in situ reduction and self-assembly approach. PDA coatings were firstly introduced to functionalize the hydrophobic PS surface with sufficient amino and hydroxyl groups, which enhanced the interaction between Au NPs and the polymer spheres. Thus, Au NPs could be easily immobilized onto the surface of the PDA/PS microspheres, and the hierarchical composite microspheres exhibited a well-defined core/shell structure without sacrificing the spherical PS morphology. PS/PDA/Au-R and PS/PDA/Au-A microspheres fabricated by in situ reduction and self-assembly approach showed different distinct Au nano-shell morphology with the corresponding optical, catalytic and electrochemical properties. Field emission scanning electron microscopy and transmission electronic microscopy verified these hierarchical structures with the ultrathin PDA film incorporating between the inner PS core and the outer Au NPs shell. X-ray diffraction and X-ray photoelectron spectroscopy confirmed the presence of PDA and Au layer on the surface of the composite particles. These green and facile methods with mild experimental conditions can extend to fabricate other polymer or inorganic substrates coated by various noble metals.

  12. Dissociable roles of dopamine and serotonin transporter function in a rat model of negative urgency.

    Science.gov (United States)

    Yates, Justin R; Darna, Mahesh; Gipson, Cassandra D; Dwoskin, Linda P; Bardo, Michael T

    2015-09-15

    Negative urgency is a facet of impulsivity that reflects mood-based rash action and is associated with various maladaptive behaviors in humans. However, the underlying neural mechanisms of negative urgency are not fully understood. Several brain regions within the mesocorticolimbic pathway, as well as the neurotransmitters dopamine (DA) and serotonin (5-HT), have been implicated in impulsivity. Extracellular DA and 5-HT concentrations are regulated by DA transporters (DAT) and 5-HT transporters (SERT); thus, these transporters may be important molecular mechanisms underlying individual differences in negative urgency. The current study employed a reward omission task to model negative urgency in rats. During reward trials, a cue light signaled the non-contingent delivery of one sucrose pellet; immediately following the non-contingent reward, rats responded on a lever to earn sucrose pellets (operant phase). Omission trials were similar to reward trials, except that non-contingent sucrose was omitted following the cue light prior to the operant phase. As expected, contingent responding was higher following omission of expected reward than following delivery of expected reward, thus reflecting negative urgency. Upon completion of behavioral training, Vmax and Km were obtained from kinetic analysis of [(3)H]DA and [(3)H]5-HT uptake using synaptosomes prepared from nucleus accumbens (NAc), dorsal striatum (Str), medial prefrontal cortex (mPFC), and orbitofrontal cortex (OFC) isolated from individual rats. Vmax for DAT in NAc and for SERT in OFC were positively correlated with negative urgency scores. The current findings suggest that mood-based impulsivity (negative urgency) is associated with enhanced DAT function in NAc and SERT function in OFC. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. A novel passive paradigm for functional magnetic resonance imaging (fMRI) to localize brain functions

    International Nuclear Information System (INIS)

    Gasser, T.; Sandalcioglu, I.E.; Skwarek, V.; Gizewski, E.; Stolke, D.; Hans, V.

    2003-01-01

    The design of a shielded stimulation-device for electrical stimulation of peripheral nerves in the MRI-environment as passive fMRI-paradigm is content of this study. Especially the technical aspects and selection criteria of the stimulation-parameters are discussed. The clinical value for neurosurgical patients is outlined by supplying data from clinical studies, evaluating this novel paradigm. Thus neurosurgeons are supplied with superior information about functional anatomy, therefore being able to preserve functionally relevant brain-structures. (orig.) [de

  14. MRI

    DEFF Research Database (Denmark)

    Schroeter, Aileen; Rudin, Markus; Gianolio, Eliana

    2017-01-01

    This chapter discusses principles of nuclear magnetic resonance (NMR) and MRI followed by a survey on the major classes of MRI contrast agents (CA), their modes of action, and some of the most significative applications. The two more established classes of MRI-CA are represented by paramagnetic...... been attained that markedly increase the number and typology of systems with CEST properties. Currently much attention is also devoted to hyperpolarized molecules that display a sensitivity enhancement sufficient for their direct exploitation for the formation of the MR image. A real breakthrough...

  15. Endogenous versus exogenous lithium clearance for evaluation of dopamine-induced changes in renal tubular function

    DEFF Research Database (Denmark)

    Olsen, Niels Vidiendal; Fogh-Andersen, N; Strandgaard, S

    1996-01-01

    1. The present randomized, double-blind cross-over study compared endogenous and exogenous lithium clearance (CLi) for estimation of the effect of dopamine on tubular sodium reabsorption. Twelve normal, salt-repleted male subjects were investigated on three different occasions with either placebo...... or 450 mg or 600 mg of lithium given in random order at 22.00 hours. After an overnight fast, renal clearance studies were performed during a 1 h baseline period and subsequently during the second hour of an infusion of 3 micrograms min-1 kg-1 of dopamine. 2. Baseline values of endogenous CLi.......3-31.0)% (P lithium increased the baseline sodium clearance (CNa), but glomerular filtration rate and urine flow rate remained unchanged. 3. Dopamine increased CNa to similar values on the three study days. CLi increased to 40.9 (35.5-46.5) ml/min (endogenous lithium, P

  16. MRI

    Science.gov (United States)

    ... the room. Pins, hairpins, metal zippers, and similar metallic items can distort the images. Removable dental work ... an MRI can cause heart pacemakers and other implants not to work as well. The magnets can ...

  17. Nigrostriatal proteasome inhibition impairs dopamine neurotransmission and motor function in minipigs

    DEFF Research Database (Denmark)

    Lillethorup, Thea Pinholt; Glud, Andreas Nørgaard; Alstrup, Aage Kristian Olsen

    2018-01-01

    weeks after the unilateral administration of 100 μg lactacystin into the MFB. Compared to their baseline values, minipigs injected with lactacystin showed on average a 36% decrease in ipsilateral striatal binding potential corresponding to impaired presynaptic dopamine terminals. Behaviourally, minipigs....... In conclusion, direct injection of lactacystin into the MFB of minipigs provides a model of PD with reduced dopamine neurotransmission, TH-positive neuron reduction, microglial activation and behavioural deficits. This large animal model could be useful in studies of symptomatic and neuroprotective therapies...

  18. Controllable Synthesis of Functional Hollow Carbon Nanostructures with Dopamine As Precursor for Supercapacitors.

    Science.gov (United States)

    Liu, Chao; Wang, Jing; Li, Jiansheng; Luo, Rui; Shen, Jinyou; Sun, Xiuyun; Han, Weiqing; Wang, Lianjun

    2015-08-26

    N-doped hollow carbon spheres (N-HCSs) are promising candidates as electrode material for supercapacitor application. In this work, we report a facile one-step synthesis of discrete and highly dispersible N-HCSs with dopamine (DA) as a carbon precursor and TEOS as a structure-assistant agent in a mixture containing water, ethanol, and ammonia. The architectures of resultant N-HCSs, including yolk-shell hollow carbon spheres (YS-HCSs), single-shell hollow carbon spheres (SS-HCSs), and double-shells hollow carbon spheres (DS-HCSs), can be efficiently controlled through the adjustment of the amount of ammonia. To explain the relation and formation mechanism of these hollow carbon structures, the samples during the different synthetic steps, including polymer/silica spheres, carbon/silica spheres and silica spheres by combustion in air, were characterized by TEM. Electrochemical measurements performed on YS-HCSs, SS-HCSs, and DS-HCSs showed high capacitance with 215, 280, and 381 F g(-1), respectively. Moreover, all the nitrogen-doped hollow carbon nanospheres showed a good cycling stability 97.0% capacitive retention after 3000 cycles. Notably, the highest capacitance of DS-HCSs up to 381 F g(-1) is higher than the capacitance reported so far for many carbon-based materials, which may be attributed to the high surface area, hollow structure, nitrogen functionalization, and double-shell architecture. These kinds of N-doped hollow-structured carbon spheres may show promising prospects as advanced energy storage materials and catalyst supports.

  19. Simultaneous determination of ascorbic acid, dopamine and uric acid based on tryptophan functionalized graphene

    International Nuclear Information System (INIS)

    Lian, Qianwen; He, Zhifang; He, Qian; Luo, Ai; Yan, Kaiwang; Zhang, Dongxia; Lu, Xiaoquan; Zhou, Xibin

    2014-01-01

    Highlights: • Trp-GR was synthesized by utilizing a facile ultrasonic method. • The material as prepared had well dispersivity in water and better conductivity than pure GR. • Trp-GR/GCE showed excellent potential for the determination of AA, DA and UA. • The proposed method was applied for the analysis of AA, DA and UA in real samples. - Abstract: A new type of tryptophan-functionalized graphene nanocomposite (Trp-GR) was synthesized by utilizing a facile ultrasonic method via π–π conjugate action between graphene (GR) and tryptophan (Trp) molecule. The material as prepared had well dispersivity in water and better conductivity than pure GR. The surface morphology of Trp-GR was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The electrochemical behaviors of ascorbic acid (AA), dopamine (DA), and uric acid (UA) were investigated by cyclic voltammetry (CV) on the surface of Trp-GR. The separation of the oxidation peak potentials for AA–DA, DA–UA and UA–AA was about 182 mV, 125 mV and 307 mV, which allowed simultaneously determining AA, DA, and UA. Differential pulse voltammetery (DPV) was used for the determination of AA, DA, and UA in their mixture. Under optimum conditions, the linear response ranges for the determination of AA, DA, and UA were 0.2–12.9 mM, 0.5–110 μM, and 10–1000 μM, with the detection limits (S/N = 3) of 10.09 μM, 0.29 μM and 1.24 μM, respectively. Furthermore, the modified electrode was investigated for real sample analysis

  20. Simultaneous determination of ascorbic acid, dopamine and uric acid based on tryptophan functionalized graphene

    Energy Technology Data Exchange (ETDEWEB)

    Lian, Qianwen; He, Zhifang; He, Qian; Luo, Ai; Yan, Kaiwang; Zhang, Dongxia [Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province, College of Geography and Environment Science, Northwest Normal University, Lanzhou, 730070 (China); Lu, Xiaoquan, E-mail: Luxq@nwnu.edu.cn [Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou, 730070 (China); Zhou, Xibin, E-mail: zhouxb@nwnu.edu.cn [Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province, College of Geography and Environment Science, Northwest Normal University, Lanzhou, 730070 (China)

    2014-05-01

    Highlights: • Trp-GR was synthesized by utilizing a facile ultrasonic method. • The material as prepared had well dispersivity in water and better conductivity than pure GR. • Trp-GR/GCE showed excellent potential for the determination of AA, DA and UA. • The proposed method was applied for the analysis of AA, DA and UA in real samples. - Abstract: A new type of tryptophan-functionalized graphene nanocomposite (Trp-GR) was synthesized by utilizing a facile ultrasonic method via π–π conjugate action between graphene (GR) and tryptophan (Trp) molecule. The material as prepared had well dispersivity in water and better conductivity than pure GR. The surface morphology of Trp-GR was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The electrochemical behaviors of ascorbic acid (AA), dopamine (DA), and uric acid (UA) were investigated by cyclic voltammetry (CV) on the surface of Trp-GR. The separation of the oxidation peak potentials for AA–DA, DA–UA and UA–AA was about 182 mV, 125 mV and 307 mV, which allowed simultaneously determining AA, DA, and UA. Differential pulse voltammetery (DPV) was used for the determination of AA, DA, and UA in their mixture. Under optimum conditions, the linear response ranges for the determination of AA, DA, and UA were 0.2–12.9 mM, 0.5–110 μM, and 10–1000 μM, with the detection limits (S/N = 3) of 10.09 μM, 0.29 μM and 1.24 μM, respectively. Furthermore, the modified electrode was investigated for real sample analysis.

  1. Function-specific and Enhanced Brain Structural Connectivity Mapping via Joint Modeling of Diffusion and Functional MRI.

    Science.gov (United States)

    Chu, Shu-Hsien; Parhi, Keshab K; Lenglet, Christophe

    2018-03-16

    A joint structural-functional brain network model is presented, which enables the discovery of function-specific brain circuits, and recovers structural connections that are under-estimated by diffusion MRI (dMRI). Incorporating information from functional MRI (fMRI) into diffusion MRI to estimate brain circuits is a challenging task. Usually, seed regions for tractography are selected from fMRI activation maps to extract the white matter pathways of interest. The proposed method jointly analyzes whole brain dMRI and fMRI data, allowing the estimation of complete function-specific structural networks instead of interactively investigating the connectivity of individual cortical/sub-cortical areas. Additionally, tractography techniques are prone to limitations, which can result in erroneous pathways. The proposed framework explicitly models the interactions between structural and functional connectivity measures thereby improving anatomical circuit estimation. Results on Human Connectome Project (HCP) data demonstrate the benefits of the approach by successfully identifying function-specific anatomical circuits, such as the language and resting-state networks. In contrast to correlation-based or independent component analysis (ICA) functional connectivity mapping, detailed anatomical connectivity patterns are revealed for each functional module. Results on a phantom (Fibercup) also indicate improvements in structural connectivity mapping by rejecting false-positive connections with insufficient support from fMRI, and enhancing under-estimated connectivity with strong functional correlation.

  2. Synthesis of palladium@gold nanoalloys/nitrogen and sulphur-functionalized multiple graphene aerogel for electrochemical detection of dopamine

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ruiyi; Yang, Tingting [School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122 (China); Li, Zaijun, E-mail: zaijunli@jiangnan.edu.cn [School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122 (China); Key Laboratory of Food Colloids and Biotechnology, Ministry of Education, Wuxi 214122 (China); Gu, Zhiguo; Wang, Guangli; Liu, Junkang [School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122 (China)

    2017-02-15

    Integration of noble metal nanomaterials on graphene nanosheets potentially paves one way to improve their electronic, chemical and electrochemical properties. The study reported synthesis of palladium@gold nanoalloys/nitrogen and sulphur-functionalized multiple graphene aerogel composite (Pd@Au/N,S-MGA). The as-prepared composite offers a well-defined three-dimensional architecture with rich of mesopores. The Pd@Au nanoalloys were dispersed on the graphene framework networks and their active sites were fully exposed. The unique structure achieves to ultra high electron/ion conductivity, electrocatalytic activity and structural stability. The sensor based on the Pd@Au/N,S-MGA creates ultrasensitive electrochemical response towards dopamine due to significantly electrochemical synergy between Pd, Au and N,S-MGA. Its differential pulse voltammetric signal linearly increases with the increase of dopamine concentration in the range from 1.0 × 10{sup −9} M to 4.0 × 10{sup −5} M with the detection limit of 3.6 × 10{sup −10} M (S/N = 3). The analytical method provides the advantage of sensitivity, reproducibility, rapidity and long-term stability. It has been successfully applied in the detection of trace dopamine in biological samples. The study also opens a window on the electronic properties of graphene aerogel and metal nanomaterials as well their nanohybrids to meet needs of further applications as nanoelectronics in diagnosis, bioanalysis and catalysis. - Graphical abstract: We reported a new palladium@gold nanoalloys/nitrogen and sulphur-functionalized multiple graphene aerogel. The sensor based on the nanohybrid exhibits ultrahigh sensitivity, reproducibility and stability to electrochemical detection of dopamine. - Highlights: • We reported Pd@A/nitrogen and sulphur-functionalized multiple graphene aerogel. • The nanohybrid offers unique three-dimensional architecture with rich of mesopores. • The architecture achieve to ultrahigh

  3. Synthesis of palladium@gold nanoalloys/nitrogen and sulphur-functionalized multiple graphene aerogel for electrochemical detection of dopamine

    International Nuclear Information System (INIS)

    Li, Ruiyi; Yang, Tingting; Li, Zaijun; Gu, Zhiguo; Wang, Guangli; Liu, Junkang

    2017-01-01

    Integration of noble metal nanomaterials on graphene nanosheets potentially paves one way to improve their electronic, chemical and electrochemical properties. The study reported synthesis of palladium@gold nanoalloys/nitrogen and sulphur-functionalized multiple graphene aerogel composite (Pd@Au/N,S-MGA). The as-prepared composite offers a well-defined three-dimensional architecture with rich of mesopores. The Pd@Au nanoalloys were dispersed on the graphene framework networks and their active sites were fully exposed. The unique structure achieves to ultra high electron/ion conductivity, electrocatalytic activity and structural stability. The sensor based on the Pd@Au/N,S-MGA creates ultrasensitive electrochemical response towards dopamine due to significantly electrochemical synergy between Pd, Au and N,S-MGA. Its differential pulse voltammetric signal linearly increases with the increase of dopamine concentration in the range from 1.0 × 10"−"9 M to 4.0 × 10"−"5 M with the detection limit of 3.6 × 10"−"1"0 M (S/N = 3). The analytical method provides the advantage of sensitivity, reproducibility, rapidity and long-term stability. It has been successfully applied in the detection of trace dopamine in biological samples. The study also opens a window on the electronic properties of graphene aerogel and metal nanomaterials as well their nanohybrids to meet needs of further applications as nanoelectronics in diagnosis, bioanalysis and catalysis. - Graphical abstract: We reported a new palladium@gold nanoalloys/nitrogen and sulphur-functionalized multiple graphene aerogel. The sensor based on the nanohybrid exhibits ultrahigh sensitivity, reproducibility and stability to electrochemical detection of dopamine. - Highlights: • We reported Pd@A/nitrogen and sulphur-functionalized multiple graphene aerogel. • The nanohybrid offers unique three-dimensional architecture with rich of mesopores. • The architecture achieve to ultrahigh electron

  4. Functional MRI in pre-surgical planning: case study and cautionary ...

    African Journals Online (AJOL)

    Background. Since its inception almost 20 years ago, functional magnetic resonance imaging (fMRI) has greatly advanced our knowledge of human brain function. Although the clinical applications of fMRI are still limited, there have recently been encouraging advances for its use in pre-operative functional cortical mapping ...

  5. Resting state functional MRI in Parkinson's disease: the impact of deep brain stimulation on 'effective' connectivity.

    Science.gov (United States)

    Kahan, Joshua; Urner, Maren; Moran, Rosalyn; Flandin, Guillaume; Marreiros, Andre; Mancini, Laura; White, Mark; Thornton, John; Yousry, Tarek; Zrinzo, Ludvic; Hariz, Marwan; Limousin, Patricia; Friston, Karl; Foltynie, Tom

    2014-04-01

    Depleted of dopamine, the dynamics of the parkinsonian brain impact on both 'action' and 'resting' motor behaviour. Deep brain stimulation has become an established means of managing these symptoms, although its mechanisms of action remain unclear. Non-invasive characterizations of induced brain responses, and the effective connectivity underlying them, generally appeals to dynamic causal modelling of neuroimaging data. When the brain is at rest, however, this sort of characterization has been limited to correlations (functional connectivity). In this work, we model the 'effective' connectivity underlying low frequency blood oxygen level-dependent fluctuations in the resting Parkinsonian motor network-disclosing the distributed effects of deep brain stimulation on cortico-subcortical connections. Specifically, we show that subthalamic nucleus deep brain stimulation modulates all the major components of the motor cortico-striato-thalamo-cortical loop, including the cortico-striatal, thalamo-cortical, direct and indirect basal ganglia pathways, and the hyperdirect subthalamic nucleus projections. The strength of effective subthalamic nucleus afferents and efferents were reduced by stimulation, whereas cortico-striatal, thalamo-cortical and direct pathways were strengthened. Remarkably, regression analysis revealed that the hyperdirect, direct, and basal ganglia afferents to the subthalamic nucleus predicted clinical status and therapeutic response to deep brain stimulation; however, suppression of the sensitivity of the subthalamic nucleus to its hyperdirect afferents by deep brain stimulation may subvert the clinical efficacy of deep brain stimulation. Our findings highlight the distributed effects of stimulation on the resting motor network and provide a framework for analysing effective connectivity in resting state functional MRI with strong a priori hypotheses.

  6. Visual functions in phenylketonuria-evaluating the dopamine and long-chain polyunsaturated fatty acids depletion hypotheses.

    Science.gov (United States)

    Gramer, Gwendolyn; Förl, Birgit; Springer, Christina; Weimer, Petra; Haege, Gisela; Mackensen, Friederike; Müller, Edith; Völcker, Hans Eberhard; Hoffmann, Georg Friedrich; Lindner, Martin; Krastel, Hermann; Burgard, Peter

    2013-01-01

    In phenylketonuria presymptomatic treatment following newborn screening prevents severe mental and physical impairment. The reasons for subtle impairments of cerebral functions despite early treatment remain unclear. We assessed a broad spectrum of visual functions in early-treated patients with phenylketonuria and evaluated two hypotheses-the dopamine and the long-chain polyunsaturated fatty acids (LCPUFAs) depletion hypotheses. Contrast sensitivity, colour vision, electroretinography, frequency doubling technology campimetry (FDT), and their relation with blood phenylalanine and docosahexaenoic acid levels were assessed in 36 patients with phenylketonuria and 18 age-matched healthy controls. Contrast sensitivity was significantly lower and total error scores in colour vision significantly higher in patients than controls. Electroretinography results differed significantly between patients and controls. We found a trend for the effect of phenylalanine-levels on contrast sensitivity and a significant effect on colour vision/FDT results. Docosahexaenoic acid levels in erythrocytes were not associated with visual functions. This is the first evaluation of visual functions in phenylketonuria using a comprehensive ophthalmological test battery. We found no evidence supporting the long-chain polyunsaturated fatty acids depletion hypothesis. However, the effect of phenylalanine-levels on visual functions suggests that imbalance between phenylalanine and tyrosine may affect retinal dopamine levels in phenylketonuria. This is supported by the similar patterns of visual functions in patients with phenylketonuria observed in our study and patients with Parkinson's disease. Copyright © 2012 Elsevier Inc. All rights reserved.

  7. Dopamine and glucose, obesity and Reward Deficiency Syndrome

    Directory of Open Access Journals (Sweden)

    Kenneth eBlum

    2014-09-01

    Full Text Available Obesity and many well described eating disorders are accurately considered a global epidemic. The consequences of Reward Deficiency Syndrome, a genetic and epigenetic phenomena that involves the interactions of powerful neurotransmitters, are impairments of brain reward circuitry, hypodopaminergic function and abnormal craving behavior. Numerous sound neurochemical and genetic studies provide strong evidence that food addiction is similar to psychoactive drug addiction. Important facts which could translate to potential therapeutic targets espoused in this review include: 1 brain dopamine (DA production and use is stimulated by consumption of alcohol in large quantities or carbohydrates bingeing; 2 in the mesolimbic system the enkephalinergic neurons are in close proximity, to glucose receptors; 3 highly concentrated glucose activates the calcium channel to stimulate dopamine release from P12 cells; 4 blood glucose and cerebrospinal fluid concentrations of homovanillic acid, the dopamine metabolite, are significantly correlated and 5 2-deoxyglucose the glucose analogue, in pharmacological doses associates with enhanced dopamine turnover and causes acute glucoprivation. Evidence from animal studies and human fMRI support the hypothesis that multiple, but similar brain circuits are disrupted in obesity and drug dependence and DA-modulated reward circuits are involved in pathologic eating behaviors. Treatment for addiction to glucose and drugs alike, based on a consensus of neuroscience research, should incorporate dopamine agonist therapy, in contrast to current theories and practices that use dopamine antagonists. Until now, powerful dopamine-D2 agonists have failed clinically, due to chronic down regulation of D2 receptors instead, consideration of novel less powerful D2 agonists that up-regulate D2 receptors seems prudent. We encourage new strategies targeted at improving DA function in the treatment and prevention of obesity a subtype of

  8. Functional MRI studies of human vision on a clinical imager

    International Nuclear Information System (INIS)

    George, J.S.; Lewine, J.D.; Aine, C.J.; van Hulsteyn, D.; Wood, C.C.; Sanders, J.; Maclin, E.; Belliveau, J.W.; Caprihan, A.

    1992-01-01

    During the past decade, Magnetic Resonance Imaging (MRI) has become the method of choice for imaging the anatomy of the human brain. Recently, Belliveau and colleagues have reported the use of echo planar magnetic resonance imaging (EPI) to image patterns of neural activity. Here, we report functional MR imaging in response to visual stimulation without the use of contrast agents, and without the extensive hardware modifications required for EPI. Regions of activity were observed near the expected locations of V1, V2 and possibly V3 and another active region was observed near the parietal-occipital sulcus on the superior surface of the cerebrum. These locations are consistent with sources observed in neuromagnetic studies of the human visual response

  9. Brain serotonin and dopamine transporter bindings in adults with high-functioning autism.

    Science.gov (United States)

    Nakamura, Kazuhiko; Sekine, Yoshimoto; Ouchi, Yasuomi; Tsujii, Masatsugu; Yoshikawa, Etsuji; Futatsubashi, Masami; Tsuchiya, Kenji J; Sugihara, Genichi; Iwata, Yasuhide; Suzuki, Katsuaki; Matsuzaki, Hideo; Suda, Shiro; Sugiyama, Toshiro; Takei, Nori; Mori, Norio

    2010-01-01

    Autism is a neurodevelopmental disorder that is characterized by repetitive and/or obsessive interests and behavior and by deficits in sociability and communication. Although its neurobiological underpinnings are postulated to lie in abnormalities of the serotoninergic and dopaminergic systems, the details remain unknown. To determine the occurrence of changes in the binding of serotonin and dopamine transporters, which are highly selective markers for their respective neuronal systems. Using positron emission tomography, we measured the binding of brain serotonin and dopamine transporters in each individual with the radioligands carbon 11 ((11)C)-labeled trans-1,2,3,5,6,10-beta-hexahydro-6-[4-(methylthio)phenyl]pyrrolo-[2,1-a]isoquinoline ([(11)C](+)McN-5652) and 2beta-carbomethoxy-3-beta-(4-fluorophenyl)tropane ([(11)C]WIN-35,428), respectively. Statistical parametric mapping was used for between-subject analysis and within-subject correlation analysis with respect to clinical variables. Participants recruited from the community. Twenty men (age range, 18-26 years; mean [SD] IQ, 99.3 [18.1]) with autism and 20 age- and IQ-matched control subjects. Serotonin transporter binding was significantly lower throughout the brain in autistic individuals compared with controls (P dopamine transporter binding was significantly higher in the orbitofrontal cortex of the autistic group (P dopamine transporter binding was significantly inversely correlated with serotonin transporter binding (r = -0.61; P = .004). The brains of autistic individuals have abnormalities in both serotonin transporter and dopamine transporter binding. The present findings indicate that the gross abnormalities in these neurotransmitter systems may underpin the neurophysiologic mechanism of autism. Our sample was not characteristic or representative of a typical sample of adults with autism in the community.

  10. Functional mapping of the sensorimotor cortex: combined use of magnetoencephalography, functional MRI, and motor evoked potentials

    International Nuclear Information System (INIS)

    Morioka, T.; Fujii, K.; Fukui, M.; Mizushima, A.; Matsumoto, S.; Hasuo, K.; Yamamoto, T.; Tobimatsu, S.

    1995-01-01

    Combined use of magnetoencephalography (MEG), functional magnetic resonance imaging (f-MRI), and motor evoked potentials (MEPs) was carried out on one patient in an attempt to localise precisely a structural lesion to the central sulcus. A small cyst in the right frontoparietal region was thought to be the cause of generalised seizures in an otherwise asymptomatic woman. First the primary sensory cortex was identified with magnetic source imaging (MSI) of somatosensory evoked magnetic fields using MEG and MRI. Second, the motor area of the hand was identified using f-MRI during handsqueezing. Then transcranial magnetic stimulation localised the hand motor area on the scalp, which was mapped onto the MRI. There was a good agreement between MSI, f-MRI and MEP as to the location of the sensorimotor cortex and its relationship to the lesion. Multimodality mapping techniques may thus prove useful in the precise localisation of cortical lesions, and in the preoperative determination of the best treatment for peri-rolandic lesions. (orig.)

  11. Functional mapping of the sensorimotor cortex: combined use of magnetoencephalography, functional MRI, and motor evoked potentials

    Energy Technology Data Exchange (ETDEWEB)

    Morioka, T. [Dept. of Neurosurgery, Neurological Inst., Kyshu Univ., Fukuoka (Japan); Fujii, K. [Dept. of Neurosurgery, Neurological Inst., Kyshu Univ., Fukuoka (Japan); Fukui, M. [Dept. of Neurosurgery, Neurological Inst., Kyshu Univ., Fukuoka (Japan); Mizushima, A. [Dept. of Radiology, Kyushu Univ. Fukuoka (Japan); Matsumoto, S. [Dept. of Radiology, Kyushu Univ. Fukuoka (Japan); Hasuo, K. [Dept. of Radiology, Kyushu Univ. Fukuoka (Japan); Yamamoto, T. [Dept. of Otolaryngology, Kyushu Univ. Fukuoka (Japan); Tobimatsu, S. [Dept. of Clinical Neurophysiology, Neurological Inst., Kyushu Univ., Fukuoka (Japan)

    1995-10-01

    Combined use of magnetoencephalography (MEG), functional magnetic resonance imaging (f-MRI), and motor evoked potentials (MEPs) was carried out on one patient in an attempt to localise precisely a structural lesion to the central sulcus. A small cyst in the right frontoparietal region was thought to be the cause of generalised seizures in an otherwise asymptomatic woman. First the primary sensory cortex was identified with magnetic source imaging (MSI) of somatosensory evoked magnetic fields using MEG and MRI. Second, the motor area of the hand was identified using f-MRI during handsqueezing. Then transcranial magnetic stimulation localised the hand motor area on the scalp, which was mapped onto the MRI. There was a good agreement between MSI, f-MRI and MEP as to the location of the sensorimotor cortex and its relationship to the lesion. Multimodality mapping techniques may thus prove useful in the precise localisation of cortical lesions, and in the preoperative determination of the best treatment for peri-rolandic lesions. (orig.)

  12. Dynamic interaction between fetal adversity and a genetic score reflecting dopamine function on developmental outcomes at 36 months.

    Directory of Open Access Journals (Sweden)

    Adrianne R Bischoff

    Full Text Available Fetal adversity, evidenced by poor fetal growth for instance, is associated with increased risk for several diseases later in life. Classical cut-offs to characterize small (SGA and large for gestational age (LGA newborns are used to define long term vulnerability. We aimed at exploring the possible dynamism of different birth weight cut-offs in defining vulnerability in developmental outcomes (through the Bayley Scales of Infant and Toddler Development, using the example of a gene vs. fetal adversity interaction considering gene choices based on functional relevance to the studied outcome.36-month-old children from an established prospective birth cohort (Maternal Adversity, Vulnerability, and Neurodevelopment were classified according to birth weight ratio (BWR (SGA ≤0.85, LGA >1.15, exploring a wide range of other cut-offs and genotyped for polymorphisms associated with dopamine signaling (TaqIA-A1 allele, DRD2-141C Ins/Ins, DRD4 7-repeat, DAT1-10- repeat, Met/Met-COMT, composing a score based on the described function, in which hypofunctional variants received lower scores.There were 251 children (123 girls and 128 boys. Using the classic cut-offs (0.85 and 1.15, there were no statistically significant interactions between the neonatal groups and the dopamine genetic score. However, when changing the cut-offs, it is possible to see ranges of BWR that could be associated with vulnerability to poorer development according to the variation in the dopamine function.The classic birth weight cut-offs to define SGA and LGA newborns should be seen with caution, as depending on the outcome in question, the protocols for long-term follow up could be either too inclusive-therefore most costly, or unable to screen true vulnerabilities-and therefore ineffective to establish early interventions and primary prevention.

  13. “Awake” intraoperative functional MRI (ai-fMRI) for mapping the eloquent cortex: Is it possible in awake craniotomy?☆

    Science.gov (United States)

    Lu, Jun-Feng; Zhang, Han; Wu, Jin-Song; Yao, Cheng-Jun; Zhuang, Dong-Xiao; Qiu, Tian-Ming; Jia, Wen-Bin; Mao, Ying; Zhou, Liang-Fu

    2012-01-01

    As a promising noninvasive imaging technique, functional MRI (fMRI) has been extensively adopted as a functional localization procedure for surgical planning. However, the information provided by preoperative fMRI (pre-fMRI) is hampered by the brain deformation that is secondary to surgical procedures. Therefore, intraoperative fMRI (i-fMRI) becomes a potential alternative that can compensate for brain shifts by updating the functional localization information during craniotomy. However, previous i-fMRI studies required that patients be under general anesthesia, preventing the wider application of such a technique as the patients cannot perform tasks unless they are awake. In this study, we propose a new technique that combines awake surgery and i-fMRI, named “awake” i-fMRI (ai-fMRI). We introduced ai-fMRI to the real-time localization of sensorimotor areas during awake craniotomy in seven patients. The results showed that ai-fMRI could successfully detect activations in the bilateral primary sensorimotor areas and supplementary motor areas for all patients, indicating the feasibility of this technique in eloquent area localization. The reliability of ai-fMRI was further validated using intraoperative stimulation mapping (ISM) in two of the seven patients. Comparisons between the pre-fMRI-derived localization result and the ai-fMRI derived result showed that the former was subject to a heavy brain shift and led to incorrect localization, while the latter solved that problem. Additionally, the approaches for the acquisition and processing of the ai-fMRI data were fully illustrated and described. Some practical issues on employing ai-fMRI in awake craniotomy were systemically discussed, and guidelines were provided. PMID:24179766

  14. Multiparametric MRI in the assessment of response of rectal cancer to neoadjuvant chemoradiotherapy: A comparison of morphological, volumetric and functional MRI parameters

    International Nuclear Information System (INIS)

    Hoetker, Andreas M.; Tarlinton, Lisa; Gollub, Marc J.; Mazaheri, Yousef; Woo, Kaitlin M.; Goenen, Mithat; Saltz, Leonard B.; Goodman, Karyn A.; Garcia-Aguilar, Julio

    2016-01-01

    To compare morphological and functional MRI metrics and determine which ones perform best in assessing response to neoadjuvant chemoradiotherapy (CRT) in rectal cancer. This retrospective study included 24 uniformly-treated patients with biopsy-proven rectal adenocarcinoma who underwent MRI, including diffusion-weighted (DW) and dynamic contrast-enhanced (DCE) sequences, before and after completion of CRT. On all MRI exams, two experienced readers independently measured longest and perpendicular tumour diameters, tumour volume, tumour regression grade (TRG) and tumour signal intensity ratio on T2-weighted imaging, as well as tumour volume and apparent diffusion coefficient on DW-MRI and tumour volume and transfer constant K"t"r"a"n"s on DCE-MRI. These metrics were correlated with histopathological percent tumour regression in the resected specimen (%TR). Inter-reader agreement was assessed using the concordance correlation coefficient (CCC). For both readers, post-treatment DW-MRI and DCE-MRI volumetric tumour assessments were significantly associated with %TR; DCE-MRI volumetry showed better inter-reader agreement (CCC=0.700) than DW-MRI volumetry (CCC=0.292). For one reader, mrTRG, post-treatment T2 tumour volumetry and assessments of volume change made with T2, DW-MRI and DCE-MRI were also significantly associated with %TR. Tumour volumetry on post-treatment DCE-MRI and DW-MRI correlated well with %TR, with DCE-MRI volumetry demonstrating better inter-reader agreement. (orig.)

  15. Multiparametric MRI in the assessment of response of rectal cancer to neoadjuvant chemoradiotherapy: A comparison of morphological, volumetric and functional MRI parameters

    Energy Technology Data Exchange (ETDEWEB)

    Hoetker, Andreas M. [Memorial Sloan Kettering Cancer Center, Department of Radiology, New York, NY (United States); Universitaetsmedizin Mainz, Department of Diagnostic and Interventional Radiology, Mainz (Germany); Tarlinton, Lisa; Gollub, Marc J. [Memorial Sloan Kettering Cancer Center, Department of Radiology, New York, NY (United States); Mazaheri, Yousef [Memorial Sloan Kettering Cancer Center, Department of Medical Physics, New York, NY (United States); Woo, Kaitlin M.; Goenen, Mithat [Memorial Sloan Kettering Cancer Center, Department of Epidemiology and Biostatistics, New York, NY (United States); Saltz, Leonard B. [Memorial Sloan Kettering Cancer Center, Department of Medicine, Gastrointestinal Oncology Service, New York, NY (United States); Goodman, Karyn A. [Memorial Sloan Kettering Cancer Center, Department of Radiation Oncology, New York, NY (United States); Garcia-Aguilar, Julio [Memorial Sloan Kettering Cancer Center, Department of Surgery, New York, NY (United States)

    2016-12-15

    To compare morphological and functional MRI metrics and determine which ones perform best in assessing response to neoadjuvant chemoradiotherapy (CRT) in rectal cancer. This retrospective study included 24 uniformly-treated patients with biopsy-proven rectal adenocarcinoma who underwent MRI, including diffusion-weighted (DW) and dynamic contrast-enhanced (DCE) sequences, before and after completion of CRT. On all MRI exams, two experienced readers independently measured longest and perpendicular tumour diameters, tumour volume, tumour regression grade (TRG) and tumour signal intensity ratio on T2-weighted imaging, as well as tumour volume and apparent diffusion coefficient on DW-MRI and tumour volume and transfer constant K{sup trans} on DCE-MRI. These metrics were correlated with histopathological percent tumour regression in the resected specimen (%TR). Inter-reader agreement was assessed using the concordance correlation coefficient (CCC). For both readers, post-treatment DW-MRI and DCE-MRI volumetric tumour assessments were significantly associated with %TR; DCE-MRI volumetry showed better inter-reader agreement (CCC=0.700) than DW-MRI volumetry (CCC=0.292). For one reader, mrTRG, post-treatment T2 tumour volumetry and assessments of volume change made with T2, DW-MRI and DCE-MRI were also significantly associated with %TR. Tumour volumetry on post-treatment DCE-MRI and DW-MRI correlated well with %TR, with DCE-MRI volumetry demonstrating better inter-reader agreement. (orig.)

  16. Divergent effects of norepinephrine, dopamine and substance P on the activation, differentiation and effector functions of human cytotoxic T lymphocytes

    Directory of Open Access Journals (Sweden)

    Niggemann Bernd

    2009-12-01

    Full Text Available Abstract Background Neurotransmitters are important regulators of the immune system, with very distinct and varying effects on different leukocyte subsets. So far little is known about the impact of signals mediated by neurotransmitters on the function of CD8+ T lymphocytes. Therefore, we investigated the influence of norepinephrine, dopamine and substance P on the key tasks of CD8+ T lymphocytes: activation, migration, extravasation and cytotoxicity. Results The activation of naïve CD8+ T lymphocytes by CD3/CD28 cross-linking was inhibited by norepinephrine and dopamine, which was caused by a downregulation of interleukin (IL-2 expression via Erk1/2 and NF-κB inhibition. Furthermore, all of the investigated neurotransmitters increased the spontaneous migratory activity of naïve CD8+ T lymphocytes with dopamine being the strongest inducer. In contrast, activated CD8+ T lymphocytes showed a reduced migratory activity in the presence of norepinephrine and substance P. With regard to extravasation we found norepinephrine to induce adhesion of activated CD8+ T cells: norepinephrine increased the interleukin-8 release from endothelium, which in turn had effect on the activated CXCR1+ CD8+ T cells. At last, release of cytotoxic granules from activated cells in response to CD3 cross-linking was not influenced by any of the investigated neurotransmitters, as we have analyzed by measuring the β-hexosamidase release. Conclusion Neurotransmitters are specific modulators of CD8+ T lymphocytes not by inducing any new functions, but by fine-tuning their key tasks. The effect can be either stimulatory or suppressive depending on the activation status of the cells.

  17. Functional MRI of music emotion processing in frontotemporal dementia.

    Science.gov (United States)

    Agustus, Jennifer L; Mahoney, Colin J; Downey, Laura E; Omar, Rohani; Cohen, Miriam; White, Mark J; Scott, Sophie K; Mancini, Laura; Warren, Jason D

    2015-03-01

    Frontotemporal dementia is an important neurodegenerative disorder of younger life led by profound emotional and social dysfunction. Here we used fMRI to assess brain mechanisms of music emotion processing in a cohort of patients with frontotemporal dementia (n = 15) in relation to healthy age-matched individuals (n = 11). In a passive-listening paradigm, we manipulated levels of emotion processing in simple arpeggio chords (mode versus dissonance) and emotion modality (music versus human emotional vocalizations). A complex profile of disease-associated functional alterations was identified with separable signatures of musical mode, emotion level, and emotion modality within a common, distributed brain network, including posterior and anterior superior temporal and inferior frontal cortices and dorsal brainstem effector nuclei. Separable functional signatures were identified post-hoc in patients with and without abnormal craving for music (musicophilia): a model for specific abnormal emotional behaviors in frontotemporal dementia. Our findings indicate the potential of music to delineate neural mechanisms of altered emotion processing in dementias, with implications for future disease tracking and therapeutic strategies. © 2014 The Authors. Annals of the New York Academy of Sciences published by Wiley Periodicals Inc. on behalf of The New York Academy of Sciences.

  18. Intrinsic network activity in tinnitus investigated using functional MRI

    Science.gov (United States)

    Leaver, Amber M.; Turesky, Ted K.; Seydell-Greenwald, Anna; Morgan, Susan; Kim, Hung J.; Rauschecker, Josef P.

    2016-01-01

    Tinnitus is an increasingly common disorder in which patients experience phantom auditory sensations, usually ringing or buzzing in the ear. Tinnitus pathophysiology has been repeatedly shown to involve both auditory and non-auditory brain structures, making network-level studies of tinnitus critical. In this magnetic resonance imaging (MRI) study, we used two resting-state functional connectivity (RSFC) approaches to better understand functional network disturbances in tinnitus. First, we demonstrated tinnitus-related reductions in RSFC between specific brain regions and resting-state networks (RSNs), defined by independent components analysis (ICA) and chosen for their overlap with structures known to be affected in tinnitus. Then, we restricted ICA to data from tinnitus patients, and identified one RSN not apparent in control data. This tinnitus RSN included auditory-sensory regions like inferior colliculus and medial Heschl’s gyrus, as well as classically non-auditory regions like the mediodorsal nucleus of the thalamus, striatum, lateral prefrontal and orbitofrontal cortex. Notably, patients’ reported tinnitus loudness was positively correlated with RSFC between the mediodorsal nucleus and the tinnitus RSN, indicating that this network may underlie the auditory-sensory experience of tinnitus. These data support the idea that tinnitus involves network dysfunction, and further stress the importance of communication between auditory-sensory and fronto-striatal circuits in tinnitus pathophysiology. PMID:27091485

  19. Study of acupuncture point Liv 3 with functional MRI

    International Nuclear Information System (INIS)

    Wang Wei; Li Kuncheng; Hao Jing; Yang Yanhui; Shan Baoci; Yan Bin; Li Ke; Xu Jianyang

    2006-01-01

    Objective: To investigate the mechanism of acupuncture point Liv3 (Taichong) and possible post-effect of acupuncture by using functional magnetic resonance imaging (fMRI) Methods: Eighteen healthy right-handed volunteers participated in the experiment. The experiment used single block design, including rest state, stimulation state and post effect state (PE). Everyone only received acupuncture at one of the two stimulations, that was: true acupuncture (TA) at right Liv3 or sham acupoint (SA) near Liv3, in which 10 subjects participated in TA and other 8 subjects in SA. The fMRI data were obtained from scanning the whole brain and were analyzed using SPM99. Significant changes of stimulation state or post effect state compared to rest state were accessed using t-statistics. The t-ratios were used to form the statistical parametric maps which showed brain activation areas by acupuncture above P< 0.001. In order to remove the effects of other non-acupuncture factors, we used the mask function to exclude the areas activated by SA from the areas activated by TA. Results: The brain activation areas during TA for 10 subjects exclusive by SA for 8 subjects were showed on bilateral cerebella(t value is 10.06 and 9.82, respectively), prefrontal lobe (PF), superior parietal lobule (SPL, t value is 4.36 and 4.53, respectively) and inferior parietal lobule (IPL, t value is 3.94 and 4.95, respectively), occipital lobe, parahippocampal gyms, insula( t value is 3.82 and 5.51, respectively), thalamus, lentiform nucleus (t value is 3.24 and 4.40, respectively), contralateral temporal pole, anterior cingnlate cortex (ACC), and posterior cingulate cortex (PGC, all of P<0.01). The PE of TA for 10 subjects exclusive by 'PE' of SA for 8 subjects activated bilateral cerebella, PF, SPL, IPL, occipital lobe, lentiform nucleus, parahippocampal gyrus, ipsilateral tempoaral pole, hippocampus, insula, thalamus, contralateral head of nucleus caudate, corpus callosum, ACC, and PCC. Conclusion

  20. MRI with intrathecal MRI gadolinium contrast medium administration: a possible method to assess glymphatic function in human brain

    International Nuclear Information System (INIS)

    Eide, Per Kristian; Ringstad, Geir

    2015-01-01

    Recently, the “glymphatic system” of the brain has been discovered in rodents, which is a paravascular, transparenchymal route for clearance of excess brain metabolites and distribution of compounds in the cerebrospinal fluid. It has already been demonstrated that intrathecally administered gadolinium (Gd) contrast medium distributes along this route in rats, but so far not in humans. A 27-year-old woman underwent magnetic resonance imaging (MRI) with intrathecal administration of gadobutrol, which distributed throughout her entire brain after 1 and 4.5 h. MRI with intrathecal Gd may become a tool to study glymphatic function in the human brain

  1. MRI with intrathecal MRI gadolinium contrast medium administration: a possible method to assess glymphatic function in human brain.

    Science.gov (United States)

    Eide, Per Kristian; Ringstad, Geir

    2015-11-01

    Recently, the "glymphatic system" of the brain has been discovered in rodents, which is a paravascular, transparenchymal route for clearance of excess brain metabolites and distribution of compounds in the cerebrospinal fluid. It has already been demonstrated that intrathecally administered gadolinium (Gd) contrast medium distributes along this route in rats, but so far not in humans. A 27-year-old woman underwent magnetic resonance imaging (MRI) with intrathecal administration of gadobutrol, which distributed throughout her entire brain after 1 and 4.5 h. MRI with intrathecal Gd may become a tool to study glymphatic function in the human brain.

  2. Comparison of left ventricular function assessment between echocardiography and MRI in Duchenne muscular dystrophy

    Energy Technology Data Exchange (ETDEWEB)

    Buddhe, Sujatha; Lewin, Mark; Olson, Aaron; Soriano, Brian D. [University of Washington School of Medicine and Seattle Children' s Hospital, Division of Cardiology, Department of Pediatrics, Seattle, WA (United States); Ferguson, Mark [University of Washington School of Medicine and Seattle Children' s Hospital, Department of Radiology, Seattle, WA (United States)

    2016-09-15

    Cardiomyopathy in Duchenne muscular dystrophy (DMD) is associated with death in approximately 40% of patients. Echocardiography is routinely used to assess left ventricular (LV) function; however, it has limitations in these patients. We compared echocardiographic measures of cardiac function assessment to cardiac MRI. We included children and young adults with DMD who had MRI performed between January 2010 and July 2015. We measured echocardiographic and MRI parameters of function assessment, including strain. Presence of late gadolinium enhancement (LGE) was assessed by MRI. Subjects were divided into two groups based on MRI left ventricular ejection fraction (LVEF): group I, LVEF ≥55% and group II, LVEF <55%. We included 41 studies in 33 subjects, with 25 in group I and 16 in group II. Mean age of subjects was 13.6 ± 2.8 years and mean duration between echocardiogram and MRI was 7.6 ± 4.1 months. Only 8 of 16 (50%) patients in group II had diminished function on echocardiogram. Echocardiographic images were suboptimal in 16 subjects (39%). Overall, echocardiographic parameters had weak correlation with MRI-derived ejection fraction percentage. MRI-derived myocardial strain assessment has better correlation with MRI ejection fraction as compared to echocardiography-derived strain parameters. Echocardiography-based ventricular functional assessment has weak correlation with MRI parameters in children and young adults with Duchenne muscular dystrophy. While this correlation improves in the subset of subjects with adequate echocardiographic image quality, it remains modest and potentially suboptimal for clinical management. Accordingly, we conclude that MRI should be performed routinely and early in children with DMD, not only for LGE imaging but also for functional assessment. (orig.)

  3. Comparison of left ventricular function assessment between echocardiography and MRI in Duchenne muscular dystrophy

    International Nuclear Information System (INIS)

    Buddhe, Sujatha; Lewin, Mark; Olson, Aaron; Soriano, Brian D.; Ferguson, Mark

    2016-01-01

    Cardiomyopathy in Duchenne muscular dystrophy (DMD) is associated with death in approximately 40% of patients. Echocardiography is routinely used to assess left ventricular (LV) function; however, it has limitations in these patients. We compared echocardiographic measures of cardiac function assessment to cardiac MRI. We included children and young adults with DMD who had MRI performed between January 2010 and July 2015. We measured echocardiographic and MRI parameters of function assessment, including strain. Presence of late gadolinium enhancement (LGE) was assessed by MRI. Subjects were divided into two groups based on MRI left ventricular ejection fraction (LVEF): group I, LVEF ≥55% and group II, LVEF <55%. We included 41 studies in 33 subjects, with 25 in group I and 16 in group II. Mean age of subjects was 13.6 ± 2.8 years and mean duration between echocardiogram and MRI was 7.6 ± 4.1 months. Only 8 of 16 (50%) patients in group II had diminished function on echocardiogram. Echocardiographic images were suboptimal in 16 subjects (39%). Overall, echocardiographic parameters had weak correlation with MRI-derived ejection fraction percentage. MRI-derived myocardial strain assessment has better correlation with MRI ejection fraction as compared to echocardiography-derived strain parameters. Echocardiography-based ventricular functional assessment has weak correlation with MRI parameters in children and young adults with Duchenne muscular dystrophy. While this correlation improves in the subset of subjects with adequate echocardiographic image quality, it remains modest and potentially suboptimal for clinical management. Accordingly, we conclude that MRI should be performed routinely and early in children with DMD, not only for LGE imaging but also for functional assessment. (orig.)

  4. Functional versus Nonfunctional Rehabilitation in Chronic Ischemic Stroke: Evidences from a Randomized Functional MRI Study

    Directory of Open Access Journals (Sweden)

    Maristela C. X. Pelicioni

    2016-01-01

    Full Text Available Motor rehabilitation of stroke survivors may include functional and/or nonfunctional strategy. The present study aimed to compare the effect of these two rehabilitation strategies by means of clinical scales and functional Magnetic Resonance Imaging (fMRI. Twelve hemiparetic chronic stroke patients were selected. Patients were randomly assigned a nonfunctional (NFS or functional (FS rehabilitation scheme. Clinical scales (Fugl-Meyer, ARA test, and modified Barthel and fMRI were applied at four moments: before rehabilitation (P1 and immediately after (P2, 1 month after (P3, and three months after (P4 the end of rehabilitation. The NFS group improved significantly and exclusively their Fugl-Meyer scores at P2, P3, and P4, when compared to P1. On the other hand, the FS group increased significantly in Fugl-Meyer at P2, when compared to P1, and also in their ARA and Barthel scores. fMRI inspection at the individual level revealed that both rehabilitation schemes most often led to decreased activation sparseness, decreased activity of contralesional M1, increased asymmetry of M1 activity to the ipsilesional side, decreased perilesional activity, and decreased SMA activity. Increased M1 asymmetry with rehabilitation was also confirmed by Lateralization Indexes. Our clinical analysis revealed subtle differences between FS and NFS.

  5. Chronotype Modulates Language Processing-Related Cerebral Activity during Functional MRI (fMRI.

    Directory of Open Access Journals (Sweden)

    Jessica Rosenberg

    Full Text Available Based on individual daily physiological cycles, humans can be classified as early (EC, late (LC and intermediate (IC chronotypes. Recent studies have verified that chronotype-specificity relates to performance on cognitive tasks: participants perform more efficiently when tested in the chronotype-specific optimal time of day than when tested in their non-optimal time. Surprisingly, imaging studies focussing on the underlying neural mechanisms of potential chronotype-specificities are sparse. Moreover, chronotype-specific alterations of language-related semantic processing have been neglected so far.16 male, healthy ECs, 16 ICs and 16 LCs participated in a fast event-related functional Magnetic Resonance Imaging (fMRI paradigm probing semantic priming. Subjects read two subsequently presented words (prime, target and were requested to determine whether the target word was an existing word or a non-word. Subjects were tested during their individual evening hours when homeostatic sleep pressure and circadian alertness levels are high to ensure equal entrainment.Chronotype-specificity is associated with task-performance and brain activation. First, ECs exhibited slower reaction times than LCs. Second, ECs showed attenuated BOLD responses in several language-related brain areas, e.g. in the left postcentral gyrus, left and right precentral gyrus and in the right superior frontal gyrus. Additionally, increased BOLD responses were revealed for LCs as compared to ICs in task-related areas, e.g. in the right inferior parietal lobule and in the right postcentral gyrus.These findings reveal that even basic language processes are associated with chronotype-specific neuronal mechanisms. Consequently, results might change the way we schedule patient evaluations and/or healthy subjects in e.g. experimental research and adding "chronotype" as a statistical covariate.

  6. Measuring Memory Reactivation With Functional MRI: Implications for Psychological Theory.

    Science.gov (United States)

    Levy, Benjamin J; Wagner, Anthony D

    2013-01-01

    Environmental cues often remind us of earlier experiences by triggering the reactivation of memories of events past. Recent evidence suggests that memory reactivation can be observed using functional MRI and that distributed pattern analyses can even provide evidence of reactivation on individual trials. The ability to measure memory reactivation offers unique and powerful leverage on theoretical issues of long-standing interest in cognitive psychology, providing a means to address questions that have proven difficult to answer with behavioral data alone. In this article, we consider three instances. First, reactivation measures can indicate whether memory-based inferences (i.e., generalization) arise through the encoding of integrated cross-event representations or through the flexible expression of separable event memories. Second, online measures of memory reactivation may inform theories of forgetting by providing information about when competing memories are reactivated during competitive retrieval situations. Finally, neural reactivation may provide a window onto the role of replay in memory consolidation. The ability to track memory reactivation, including at the individual trial level, provides unique leverage that is not afforded by behavioral measures and thus promises to shed light on such varied topics as generalization, integration, forgetting, and consolidation. © The Author(s) 2013.

  7. The Neural Basis of Typewriting: A Functional MRI Study.

    Science.gov (United States)

    Higashiyama, Yuichi; Takeda, Katsuhiko; Someya, Yoshiaki; Kuroiwa, Yoshiyuki; Tanaka, Fumiaki

    2015-01-01

    To investigate the neural substrate of typewriting Japanese words and to detect the difference between the neural substrate of typewriting and handwriting, we conducted a functional magnetic resonance imaging (fMRI) study in 16 healthy volunteers. All subjects were skillful touch typists and performed five tasks: a typing task, a writing task, a reading task, and two control tasks. Three brain regions were activated during both the typing and the writing tasks: the left superior parietal lobule, the left supramarginal gyrus, and the left premotor cortex close to Exner's area. Although typing and writing involved common brain regions, direct comparison between the typing and the writing task revealed greater left posteromedial intraparietal cortex activation in the typing task. In addition, activity in the left premotor cortex was more rostral in the typing task than in the writing task. These findings suggest that, although the brain circuits involved in Japanese typewriting are almost the same as those involved in handwriting, there are brain regions that are specific for typewriting.

  8. The Neural Basis of Typewriting: A Functional MRI Study.

    Directory of Open Access Journals (Sweden)

    Yuichi Higashiyama

    Full Text Available To investigate the neural substrate of typewriting Japanese words and to detect the difference between the neural substrate of typewriting and handwriting, we conducted a functional magnetic resonance imaging (fMRI study in 16 healthy volunteers. All subjects were skillful touch typists and performed five tasks: a typing task, a writing task, a reading task, and two control tasks. Three brain regions were activated during both the typing and the writing tasks: the left superior parietal lobule, the left supramarginal gyrus, and the left premotor cortex close to Exner's area. Although typing and writing involved common brain regions, direct comparison between the typing and the writing task revealed greater left posteromedial intraparietal cortex activation in the typing task. In addition, activity in the left premotor cortex was more rostral in the typing task than in the writing task. These findings suggest that, although the brain circuits involved in Japanese typewriting are almost the same as those involved in handwriting, there are brain regions that are specific for typewriting.

  9. Partially Adaptive STAP Algorithm Approaches to functional MRI

    Science.gov (United States)

    Huang, Lejian; Thompson, Elizabeth A.; Schmithorst, Vincent; Holland, Scott K.; Talavage, Thomas M.

    2010-01-01

    In this work, the architectures of three partially adaptive STAP algorithms are introduced, one of which is explored in detail, that reduce dimensionality and improve tractability over fully adaptive STAP when used in construction of brain activation maps in fMRI. Computer simulations incorporating actual MRI noise and human data analysis indicate that element space partially adaptive STAP can attain close to the performance of fully adaptive STAP while significantly decreasing processing time and maximum memory requirements, and thus demonstrates potential in fMRI analysis. PMID:19272913

  10. Functional responses of pre- and postsynaptic dopamine D2 receptors in rat brain striatum

    OpenAIRE

    Ma, Guofen

    2014-01-01

    El sistema dopaminèrgic has estat molt estudiat en els darrers anys, principalment degut a la seva implicació en diverses patologies com la malaltia de Parkinson, la esquizofrènia o la síndrome de Tourette, així com també en l'abús de drogues. S'han descrit cinc subtipus de receptors per la dopamina (DA), tots els quals pertanyen a la família de receptors acoblats a proteïnes G (GPCRs). D'aquests cinc subtipus, els receptors D2 son la diana principal dels antipsicòtics (antagonistes) i també ...

  11. Genetic reduction of mitochondrial complex I function does not lead to loss of dopamine neurons in vivo.

    Science.gov (United States)

    Kim, Hyung-Wook; Choi, Won-Seok; Sorscher, Noah; Park, Hyung Joon; Tronche, François; Palmiter, Richard D; Xia, Zhengui

    2015-09-01

    Inhibition of mitochondrial complex I activity is hypothesized to be one of the major mechanisms responsible for dopaminergic neuron death in Parkinson's disease. However, loss of complex I activity by systemic deletion of the Ndufs4 gene, one of the subunits comprising complex I, does not cause dopaminergic neuron death in culture. Here, we generated mice with conditional Ndufs4 knockout in dopaminergic neurons (Ndufs4 conditional knockout mice [cKO]) to examine the effect of complex I inhibition on dopaminergic neuron function and survival during aging and on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treatment in vivo. Ndufs4 cKO mice did not show enhanced dopaminergic neuron loss in the substantia nigra pars compacta or dopamine-dependent motor deficits over the 24-month life span. These mice were just as susceptible to MPTP as control mice. However, compared with control mice, Ndufs4 cKO mice exhibited an age-dependent reduction of dopamine in the striatum and increased α-synuclein phosphorylation in dopaminergic neurons of the substantia nigra pars compacta. We also used an inducible Ndufs4 knockout mouse strain (Ndufs4 inducible knockout) in which Ndufs4 is conditionally deleted in all cells in adult to examine the effect of adult onset, complex I inhibition on MPTP sensitivity of dopaminergic neurons. The Ndufs4 inducible knockout mice exhibited similar sensitivity to MPTP as control littermates. These data suggest that mitochondrial complex I inhibition in dopaminergic neurons does contribute to dopamine loss and the development of α-synuclein pathology. However, it is not sufficient to cause cell-autonomous dopaminergic neuron death during the normal life span of mice. Furthermore, mitochondrial complex I inhibition does not underlie MPTP toxicity in vivo in either cell autonomous or nonautonomous manner. These results provide strong evidence that inhibition of mitochondrial complex I activity is not sufficient to cause dopaminergic neuron

  12. Dopamine D4 Receptor Gene Associated with the Frontal-Striatal-Cerebellar Loop in Children with ADHD: A Resting-State fMRI Study.

    Science.gov (United States)

    Qian, Andan; Wang, Xin; Liu, Huiru; Tao, Jiejie; Zhou, Jiejie; Ye, Qiong; Li, Jiance; Yang, Chuang; Cheng, Jingliang; Zhao, Ke; Wang, Meihao

    2018-03-21

    Attention deficit hyperactivity disorder (ADHD) is a common childhood neuropsychiatric disorder that has been linked to the dopaminergic system. This study aimed to investigate the effects of regulation of the dopamine D4 receptor (DRD4) on functional brain activity during the resting state in ADHD children using the methods of regional homogeneity (ReHo) and functional connectivity (FC). Resting-state functional magnetic resonance imaging data were analyzed in 49 children with ADHD. All participants were classified as either carriers of the DRD4 4-repeat/4-repeat (4R/4R) allele (n = 30) or the DRD4 2-repeat (2R) allele (n = 19). The results showed that participants with the DRD4 2R allele had decreased ReHo bilaterally in the posterior lobes of the cerebellum, while ReHo was increased in the left angular gyrus. Compared with participants carrying the DRD4 4R/4R allele, those with the DRD4 2R allele showed decreased FC to the left angular gyrus in the left striatum, right inferior frontal gyrus, and bilateral lobes of the cerebellum. The increased FC regions included the left superior frontal gyrus, medial frontal gyrus, and rectus gyrus. These data suggest that the DRD4 polymorphisms are associated with localized brain activity and specific functional connections, including abnormality in the frontal-striatal-cerebellar loop. Our study not only enhances the understanding of the correlation between the cerebellar lobes and ADHD, but also provides an imaging basis for explaining the neural mechanisms underlying ADHD in children.

  13. High frame rate retrospectively triggered Cine MRI for assessment of murine diastolic function

    NARCIS (Netherlands)

    Coolen, Bram F.; Abdurrachim, Desiree; Motaal, Abdallah G.; Nicolay, Klaas; Prompers, Jeanine J.; Strijkers, Gustav J.

    2013-01-01

    To assess left ventricular (LV) diastolic function in mice with Cine MRI, a high frame rate (>60 frames per cardiac cycle) is required. For conventional electrocardiography-triggered Cine MRI, the frame rate is inversely proportional to the pulse repetition time (TR). However, TR cannot be lowered

  14. Assessment of muscle function using hybrid PET/MRI

    DEFF Research Database (Denmark)

    Haddock, Bryan; Holm, Søren; Poulsen, Jákup M.

    2017-01-01

    -FDG while activating the quadriceps of one leg with repeated knee extension exercises followed by hand-grip exercises for one arm. Immediately following the exercises, the subjects were scanned simultaneously with 18F-FDG PET/MRI and muscle groups were evaluated for increases in 18F-FDG uptake and MRI T2......Purpose: The aim of this study was to determine the relationship between relative glucose uptake and MRI T2 changes in skeletal muscles following resistance exercise using simultaneous PET/MRI scans. Methods: Ten young healthy recreationally active men (age 21 – 28 years) were injected with 18F...... values. Results: A significant linear correlation between 18F-FDG uptake and changes in muscle T2 (R2 = 0.71) was found. for both small and large muscles and in voxel to voxel comparisons. Despite large intersubject differences in muscle recruitment, the linear correlation between 18F-FDG uptake...

  15. Partially Adaptive STAP Algorithm Approaches to functional MRI

    OpenAIRE

    Huang, Lejian; Thompson, Elizabeth A.; Schmithorst, Vincent; Holland, Scott K.; Talavage, Thomas M.

    2008-01-01

    In this work, the architectures of three partially adaptive STAP algorithms are introduced, one of which is explored in detail, that reduce dimensionality and improve tractability over fully adaptive STAP when used in construction of brain activation maps in fMRI. Computer simulations incorporating actual MRI noise and human data analysis indicate that element space partially adaptive STAP can attain close to the performance of fully adaptive STAP while significantly decreasing processing tim...

  16. Normal pancreatic exocrine function does not exclude MRI/MRCP chronic pancreatitis findings.

    Science.gov (United States)

    Alkaade, Samer; Cem Balci, Numan; Momtahen, Amir Javad; Burton, Frank

    2008-09-01

    Abnormal pancreatic function tests have been reported to precede the imaging findings of chronic pancreatitis. Magnetic resonance imaging (MRI) with magnetic resonance cholangiopancreatography (MRCP) is increasingly accepted as the primary imaging modality for the detection of structural changes of early mild chronic pancreatitis. The aim of this study was to evaluate MRI/MRCP findings in patients with symptoms consistent with chronic pancreatitis who have normal Secretin Endoscopic Pancreatic Function test. A retrospective study of 32 patients referred for evaluation of chronic abdominal pain consistent with chronic pancreatitis and reported normal standard abdominal imaging (ultrasound, computed tomography, or MRI). All patients underwent Secretin Endoscopic Pancreatic Function testing and pancreatic MRI/MRCP at our institution. We reviewed the MRI/MRCP images in patients who had normal Secretin Endoscopic Pancreatic Function testing. MRI/MRCP images were assessed for pancreatic duct morphology, gland size, parenchymal signal and morphology, and arterial contrast enhancement. Of the 32 patients, 23 had normal Secretin Endoscopic Pancreatic Function testing, and 8 of them had mild to marked spectrum of abnormal MRI/MRCP findings that were predominantly focal. Frequencies of the findings were as follows: pancreatic duct stricture (n=3), pancreatic duct dilatation (n=3), side branch ectasia (n=4), atrophy (n=5), decreased arterial enhancement (n=5), decreased parenchymal signal (n=1), and cavity formation (n=1). The remaining15 patients had normal pancreatic structure on MRI/MRCP. Normal pancreatic function testing cannot exclude abnormal MRI/MRCP especially focal findings of chronic pancreatitis. Further studies needed to verify significance of these findings and establish MRI/MRCP imaging criteria for the diagnosis of chronic pancreatitis.

  17. Activated and deactivated functional brain areas in the Deqi state: A functional MRI study.

    Science.gov (United States)

    Huang, Yong; Zeng, Tongjun; Zhang, Guifeng; Li, Ganlong; Lu, Na; Lai, Xinsheng; Lu, Yangjia; Chen, Jiarong

    2012-10-25

    We compared the activities of functional regions of the brain in the Deqi versus non-Deqi state, as reported by physicians and subjects during acupuncture. Twelve healthy volunteers received sham and true needling at the Waiguan (TE5) acupoint. Real-time cerebral functional MRI showed that compared with non-sensation after sham needling, true needling activated Brodmann areas 3, 6, 8, 9, 10, 11, 13, 20, 21, 37, 39, 40, 43, and 47, the head of the caudate nucleus, the parahippocampal gyrus, thalamus and red nucleus. True needling also deactivated Brodmann areas 1, 2, 3, 4, 5, 6, 7, 9, 10, 18, 24, 31, 40 and 46.

  18. Nigrostriatal proteasome inhibition impairs dopamine neurotransmission and motor function in minipigs.

    Science.gov (United States)

    Lillethorup, Thea P; Glud, Andreas N; Alstrup, Aage K O; Mikkelsen, Trine W; Nielsen, Erik H; Zaer, Hamed; Doudet, Doris J; Brooks, David J; Sørensen, Jens Christian H; Orlowski, Dariusz; Landau, Anne M

    2018-05-01

    Parkinson's disease (PD) is characterized by degeneration of dopaminergic neurons in the substantia nigra leading to slowness and stiffness of limb movement with rest tremor. Using ubiquitin proteasome system inhibitors, rodent models have shown nigrostriatal degeneration and motor impairment. We translated this model to the Göttingen minipig by administering lactacystin into the medial forebrain bundle (MFB). Minipigs underwent positron emission tomography (PET) imaging with (+)-α-[ 11 C]dihydrotetrabenazine ([ 11 C]DTBZ), a marker of vesicular monoamine transporter 2 availability, at baseline and three weeks after the unilateral administration of 100 μg lactacystin into the MFB. Compared to their baseline values, minipigs injected with lactacystin showed on average a 36% decrease in ipsilateral striatal binding potential corresponding to impaired presynaptic dopamine terminals. Behaviourally, minipigs displayed asymmetrical motor disability with spontaneous rotations in one of the animals. Immunoreactivity for tyrosine hydroxylase (TH) and HLA-DR-positive microglia confirmed asymmetrical reduction in nigral TH-positive neurons with an inflammatory response in the lactacystin-injected minipigs. In conclusion, direct injection of lactacystin into the MFB of minipigs provides a model of PD with reduced dopamine neurotransmission, TH-positive neuron reduction, microglial activation and behavioural deficits. This large animal model could be useful in studies of symptomatic and neuroprotective therapies with translatability to human PD. Copyright © 2018 Elsevier Inc. All rights reserved.

  19. Effects of Field-Map Distortion Correction on Resting State Functional Connectivity MRI

    Directory of Open Access Journals (Sweden)

    Hiroki Togo

    2017-12-01

    Full Text Available Magnetic field inhomogeneities cause geometric distortions of echo planar images used for functional magnetic resonance imaging (fMRI. To reduce this problem, distortion correction (DC with field map is widely used for both task and resting-state fMRI (rs-fMRI. Although DC with field map has been reported to improve the quality of task fMRI, little is known about its effects on rs-fMRI. Here, we tested the influence of field-map DC on rs-fMRI results using two rs-fMRI datasets derived from 40 healthy subjects: one with DC (DC+ and the other without correction (DC−. Independent component analysis followed by the dual regression approach was used for evaluation of resting-state functional connectivity networks (RSN. We also obtained the ratio of low-frequency to high-frequency signal power (0.01–0.1 Hz and above 0.1 Hz, respectively; LFHF ratio to assess the quality of rs-fMRI signals. For comparison of RSN between DC+ and DC− datasets, the default mode network showed more robust functional connectivity in the DC+ dataset than the DC− dataset. Basal ganglia RSN showed some decreases in functional connectivity primarily in white matter, indicating imperfect registration/normalization without DC. Supplementary seed-based and simulation analyses supported the utility of DC. Furthermore, we found a higher LFHF ratio after field map correction in the anterior cingulate cortex, posterior cingulate cortex, ventral striatum, and cerebellum. In conclusion, field map DC improved detection of functional connectivity derived from low-frequency rs-fMRI signals. We encourage researchers to include a DC step in the preprocessing pipeline of rs-fMRI analysis.

  20. Dopamine and anorexia nervosa.

    Science.gov (United States)

    Södersten, P; Bergh, C; Leon, M; Zandian, M

    2016-01-01

    We have suggested that reduced food intake increases the risk for anorexia nervosa by engaging mesolimbic dopamine neurons, thereby initially rewarding dieting. Recent fMRI studies have confirmed that dopamine neurons are activated in anorexia nervosa, but it is not clear whether this response is due to the disorder or to its resulting nutritional deficit. When the body senses the shortage of nutrients, it rapidly shifts behavior toward foraging for food as a normal physiological response and the mesolimbic dopamine neurons may be involved in that process. On the other hand, the altered dopamine status of anorexics has been suggested to result from a brain abnormality that underlies their complex emotional disorder. We suggest that the outcomes of the treatments that emerge from that perspective remain poor because they target the mental symptoms that are actually the consequences of the food deprivation that accompanies anorexia. On the other hand, a method that normalizes the disordered eating behavior of anorexics results in much better physiological, behavioral, and emotional outcomes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Measurement and imaging of brain function using MRI, MEG, and TMS

    International Nuclear Information System (INIS)

    Iramina, Keiji

    2008-01-01

    This paper reviews functional imaging techniques in neuroscience such as magnetic resonance imaging (MRI) functional MRI (fMRI), magnetoencephalogray (MEG), and transcranial magnetic stimulation (TMS). fMRI and MEG allow the neuronal activity of the brain to be measured non-invasively. MEG detects an electrical activity as neuronal activity, while, fMRI detects a hemodynamic response as neuronal activity. TMS is the application of a brief magnetic pulse or a train of pulses to the skull, which results in the induction of a local electric current in the underlying surface of the brain, thereby producing a localized axonal depolarization. As a non-invasive and effective method to make reversible lesions in the human brain, TMS has a long and successful history. All of these techniques have major potential for applications in the neuroscience and medicine. (author)

  2. Brain functional BOLD perturbation modelling for forward fMRI and inverse mapping

    Science.gov (United States)

    Robinson, Jennifer; Calhoun, Vince

    2018-01-01

    Purpose To computationally separate dynamic brain functional BOLD responses from static background in a brain functional activity for forward fMRI signal analysis and inverse mapping. Methods A brain functional activity is represented in terms of magnetic source by a perturbation model: χ = χ0 +δχ, with δχ for BOLD magnetic perturbations and χ0 for background. A brain fMRI experiment produces a timeseries of complex-valued images (T2* images), whereby we extract the BOLD phase signals (denoted by δP) by a complex division. By solving an inverse problem, we reconstruct the BOLD δχ dataset from the δP dataset, and the brain χ distribution from a (unwrapped) T2* phase image. Given a 4D dataset of task BOLD fMRI, we implement brain functional mapping by temporal correlation analysis. Results Through a high-field (7T) and high-resolution (0.5mm in plane) task fMRI experiment, we demonstrated in detail the BOLD perturbation model for fMRI phase signal separation (P + δP) and reconstructing intrinsic brain magnetic source (χ and δχ). We also provided to a low-field (3T) and low-resolution (2mm) task fMRI experiment in support of single-subject fMRI study. Our experiments show that the δχ-depicted functional map reveals bidirectional BOLD χ perturbations during the task performance. Conclusions The BOLD perturbation model allows us to separate fMRI phase signal (by complex division) and to perform inverse mapping for pure BOLD δχ reconstruction for intrinsic functional χ mapping. The full brain χ reconstruction (from unwrapped fMRI phase) provides a new brain tissue image that allows to scrutinize the brain tissue idiosyncrasy for the pure BOLD δχ response through an automatic function/structure co-localization. PMID:29351339

  3. Brain functional BOLD perturbation modelling for forward fMRI and inverse mapping.

    Science.gov (United States)

    Chen, Zikuan; Robinson, Jennifer; Calhoun, Vince

    2018-01-01

    To computationally separate dynamic brain functional BOLD responses from static background in a brain functional activity for forward fMRI signal analysis and inverse mapping. A brain functional activity is represented in terms of magnetic source by a perturbation model: χ = χ0 +δχ, with δχ for BOLD magnetic perturbations and χ0 for background. A brain fMRI experiment produces a timeseries of complex-valued images (T2* images), whereby we extract the BOLD phase signals (denoted by δP) by a complex division. By solving an inverse problem, we reconstruct the BOLD δχ dataset from the δP dataset, and the brain χ distribution from a (unwrapped) T2* phase image. Given a 4D dataset of task BOLD fMRI, we implement brain functional mapping by temporal correlation analysis. Through a high-field (7T) and high-resolution (0.5mm in plane) task fMRI experiment, we demonstrated in detail the BOLD perturbation model for fMRI phase signal separation (P + δP) and reconstructing intrinsic brain magnetic source (χ and δχ). We also provided to a low-field (3T) and low-resolution (2mm) task fMRI experiment in support of single-subject fMRI study. Our experiments show that the δχ-depicted functional map reveals bidirectional BOLD χ perturbations during the task performance. The BOLD perturbation model allows us to separate fMRI phase signal (by complex division) and to perform inverse mapping for pure BOLD δχ reconstruction for intrinsic functional χ mapping. The full brain χ reconstruction (from unwrapped fMRI phase) provides a new brain tissue image that allows to scrutinize the brain tissue idiosyncrasy for the pure BOLD δχ response through an automatic function/structure co-localization.

  4. Structural and functional MRI in children with renal disease. First experience

    Energy Technology Data Exchange (ETDEWEB)

    Joergensen, Bettina; Froekiaer, Joergen [Aarhus Univ. Hospital (Denmark). Inst. of Clinical Medicine; Karstoft, Kristian; Pedersen, Michael [Aarhus Univ. Hospital (Denmark). Inst. of Clinical Medicine; Aarhus Univ. Hospital (Denmark). MR Research Centre; Joergensen, Troels Munch [Aarhus Univ. Hospital (Denmark). Dept. of Urology; Rittig, Soeren [Aarhus Univ. Hospital (Denmark). Dept. of Paediatrics

    2010-07-01

    This MRI study demonstrates our first clinical experiences with structural and functional evaluation in children with renal dysfunction, and communicates our experience with quantitative measurements of renal function compared to reference values found employing radionucleotides. We included renal impaired children who were recruited for clinical radioisotopic GFR measurements (n=8). MRI was performed 2 hours after Cr-EDTA measurements and was conducted using a protocol involving both anatomical/structural sequences and a dynamic contrast-enhanced sequence. Data obtained with the dynamic MRI sequence were processed using the graphical Patlak approach to obtain estimates of GFR. We were able to characterize the intrarenal configuration (cortex, medulla, pelvicalyceal arrangement) in all cases. Functional analyses of dynamic contrast-enhanced MRI revealed an overall underestimation of GFR measured by MRI compared to Cr-EDTPA measures (range: -2% to -43%). We advocate the use of MRI as a single-modality approach in the structural and functional evaluation of impaired kidneys in children, and concurrently, we presented a clinically available strategy for estimations of renal cortical volume and single kidney function. However, the use of MRI contrast agents have recently become controversial in renal patients due to the risk of NSF. (orig.)

  5. Hyperpolarized 129Xe MRI: A viable functional lung imaging modality?

    International Nuclear Information System (INIS)

    Patz, Samuel; Hersman, F. William; Muradian, Iga; Hrovat, Mirko I.; Ruset, Iulian C.; Ketel, Stephen; Jacobson, Francine; Topulos, George P.; Hatabu, Hiroto; Butler, James P.

    2007-01-01

    The majority of researchers investigating hyperpolarized gas MRI as a candidate functional lung imaging modality have used 3 He as their imaging agent of choice rather than 129 Xe. This preference has been predominantly due to, 3 He providing stronger signals due to higher levels of polarization and higher gyromagnetic ratio, as well as its being easily available to more researchers due to availability of polarizers (USA) or ease of gas transport (Europe). Most researchers agree, however, that hyperpolarized 129 Xe will ultimately emerge as the imaging agent of choice due to its unlimited supply in nature and its falling cost. Our recent polarizer technology delivers vast improvements in hyperpolarized 129 Xe output. Using this polarizer, we have demonstrated the unique property of xenon to measure alveolar surface area noninvasively. In this article, we describe our human protocols and their safety, and our results for the measurement of the partial pressure of pulmonary oxygen (pO 2 ) by observation of 129 Xe signal decay. We note that the measurement of pO 2 by observation of 129 Xe signal decay is more complex than that for 3 He because of an additional signal loss mechanism due to interphase diffusion of 129 Xe from alveolar gas spaces to septal tissue. This results in measurements of an equivalent pO 2 that accounts for both traditional T 1 decay from pO 2 and that from interphase diffusion. We also provide an update on new technological advancements that form the foundation for an improved compact design polarizer as well as improvements that provide another order-of-magnitude scale-up in xenon polarizer output

  6. Functional MRI study of cerebral cortical activation during volitional swallowing

    International Nuclear Information System (INIS)

    Wakasa, Toru; Aiga, Hideki; Yanagi, Yoshinobu; Kawai, Noriko; Sugimoto, Tomosada; Kuboki, Takuo; Kishi, Kanji

    2002-01-01

    The purpose of this study was to investigate the somatotropic distribution and lateralization of motor and sensory cortical activity during swallowing in healthy adult human subjects using functional MR imaging. Nine healthy right-handed adult volunteers (6 men, 3 women; ages 22-38) were examined. Their cortical activities were evoked by having them swallow, five times, a small bolus of water (3 ml) supplied through a plastic catheter. As a positive control, the subjects performed five repetitions of right-handed grasping tasks. Blood oxygenation level-dependent images were obtained using a 1.5 Tesla MR system (Magnetom Vision, Siemens Germany; repetition time/echo time (TR/TE)=0.96/0.66, flip angle (FA)=90 deg). T1 weighted anatomical images were obtained for the same slices in each subject. Cerebral activity was observed most notably in the primary motor cortex and primary somatosensory cortex, followed by the premotor cortex, anterior cingulate cortex, frontal operculum, and insula. The hand-grasping task activated relatively superior parts of the primary motor and somatosensory cortices. The swallowing task, on the other hand, activated the inferior parts of the pre- and postcentral gyri. The hand-grasping activation of motor and sensory cortices was localized absolutely on the contralateral side, whereas swallowing activated the motor cortex either bilaterally or unilaterally. Swallowing activated the sensory cortex almost always bilaterally. This study suggested that fMRI could be used to identify the specific areas of cortical activation caused by various tasks, and to differentiate the locations of cortical activation between tasks. (author)

  7. Functional MRI study of cerebral cortical activation during volitional swallowing

    Energy Technology Data Exchange (ETDEWEB)

    Wakasa, Toru; Aiga, Hideki; Yanagi, Yoshinobu; Kawai, Noriko; Sugimoto, Tomosada; Kuboki, Takuo; Kishi, Kanji [Okayama Univ. (Japan). Graduate School of Medicine and Dentistry

    2002-12-01

    The purpose of this study was to investigate the somatotropic distribution and lateralization of motor and sensory cortical activity during swallowing in healthy adult human subjects using functional MR imaging. Nine healthy right-handed adult volunteers (6 men, 3 women; ages 22-38) were examined. Their cortical activities were evoked by having them swallow, five times, a small bolus of water (3 ml) supplied through a plastic catheter. As a positive control, the subjects performed five repetitions of right-handed grasping tasks. Blood oxygenation level-dependent images were obtained using a 1.5 Tesla MR system (Magnetom Vision, Siemens Germany; repetition time/echo time (TR/TE)=0.96/0.66, flip angle (FA)=90 deg). T1 weighted anatomical images were obtained for the same slices in each subject. Cerebral activity was observed most notably in the primary motor cortex and primary somatosensory cortex, followed by the premotor cortex, anterior cingulate cortex, frontal operculum, and insula. The hand-grasping task activated relatively superior parts of the primary motor and somatosensory cortices. The swallowing task, on the other hand, activated the inferior parts of the pre- and postcentral gyri. The hand-grasping activation of motor and sensory cortices was localized absolutely on the contralateral side, whereas swallowing activated the motor cortex either bilaterally or unilaterally. Swallowing activated the sensory cortex almost always bilaterally. This study suggested that fMRI could be used to identify the specific areas of cortical activation caused by various tasks, and to differentiate the locations of cortical activation between tasks. (author)

  8. Real-time functional MR imaging (fMRI) for presurgical evaluation of paediatric epilepsy

    Energy Technology Data Exchange (ETDEWEB)

    Kesavadas, Chandrasekharan; Thomas, Bejoy; Kumar Gupta, Arun [Sree Chitra Tirunal Institute for Medical Sciences and Technology, Department of Imaging Sciences and Interventional Radiology, Trivandrum (India); Sujesh, Sreedharan [Sree Chitra Tirunal Institute for Medical Sciences and Technology, Biomedical Technology Wing, Trivandrum (India); Ashalata, Radhakrishnan; Radhakrishnan, Kurupath [Sree Chitra Tirunal Institute for Medical Sciences and Technology, Department of Neurology, Trivandrum (India); Abraham, Mathew [Sree Chitra Tirunal Institute for Medical Sciences and Technology, Department of Neurosurgery, Trivandrum (India)

    2007-10-15

    The role of fMRI in the presurgical evaluation of children with intractable epilepsy is being increasingly recognized. Real-time fMRI allows the clinician to visualize functional brain activation in real time. Since there is no off-line data analysis as in conventional fMRI, the overall time for the procedure is reduced, making it clinically feasible in a busy clinical sitting. (1) To study the accuracy of real-time fMRI in comparison to conventional fMRI with off-line processing; (2) to determine its effectiveness in mapping the eloquent cortex and language lateralization in comparison to invasive procedures such as intraoperative cortical stimulation and Wada testing; and (3) to evaluate the role of fMRI in presurgical decision making in children with epilepsy. A total of 23 patients (age range 6-18 years) underwent fMRI with sensorimotor, visual and language paradigms. Data processing was done in real time using in-line BOLD. The results of real-time fMRI matched those of off-line processing done using the well-accepted standard technique of statistical parametric mapping (SPM) in all the initial ten patients in whom the two techniques were compared. Coregistration of the fMRI data on a 3-D FLAIR sequence rather than a T1-weighted image gave better information regarding the relationship of the lesion to the area of activation. The results of intraoperative cortical stimulation and fMRI matched in six out of six patients, while the Wada test and fMRI had similar results in four out of five patients in whom these techniques were performed. In the majority of patients in this series the technique influenced patient management. Real-time fMRI is an easily performed and reliable technique in the presurgical workup of children with epilepsy. (orig.)

  9. Real-time functional MR imaging (fMRI) for presurgical evaluation of paediatric epilepsy

    International Nuclear Information System (INIS)

    Kesavadas, Chandrasekharan; Thomas, Bejoy; Kumar Gupta, Arun; Sujesh, Sreedharan; Ashalata, Radhakrishnan; Radhakrishnan, Kurupath; Abraham, Mathew

    2007-01-01

    The role of fMRI in the presurgical evaluation of children with intractable epilepsy is being increasingly recognized. Real-time fMRI allows the clinician to visualize functional brain activation in real time. Since there is no off-line data analysis as in conventional fMRI, the overall time for the procedure is reduced, making it clinically feasible in a busy clinical sitting. (1) To study the accuracy of real-time fMRI in comparison to conventional fMRI with off-line processing; (2) to determine its effectiveness in mapping the eloquent cortex and language lateralization in comparison to invasive procedures such as intraoperative cortical stimulation and Wada testing; and (3) to evaluate the role of fMRI in presurgical decision making in children with epilepsy. A total of 23 patients (age range 6-18 years) underwent fMRI with sensorimotor, visual and language paradigms. Data processing was done in real time using in-line BOLD. The results of real-time fMRI matched those of off-line processing done using the well-accepted standard technique of statistical parametric mapping (SPM) in all the initial ten patients in whom the two techniques were compared. Coregistration of the fMRI data on a 3-D FLAIR sequence rather than a T1-weighted image gave better information regarding the relationship of the lesion to the area of activation. The results of intraoperative cortical stimulation and fMRI matched in six out of six patients, while the Wada test and fMRI had similar results in four out of five patients in whom these techniques were performed. In the majority of patients in this series the technique influenced patient management. Real-time fMRI is an easily performed and reliable technique in the presurgical workup of children with epilepsy. (orig.)

  10. Akinetic Crisis in Parkinson's Disease Is Associated with a Severe Loss of Striatal Dopamine Transporter Function: A Report of Two Cases

    Directory of Open Access Journals (Sweden)

    Valtteri Kaasinen

    2014-11-01

    Full Text Available Akinetic crisis or acute akinesia is a life-threatening complication of Parkinson's disease (PD with unknown pathophysiological mechanisms. Clinically, it resembles the neuroleptic malignant syndrome, and dopaminergic drugs are transiently ineffective in the acute phase of the condition. There are no published dopaminergic functional imaging studies on PD patients with akinetic crisis. Here we report 2 advanced PD patients with akinetic crisis who were scanned with SPECT using brain dopamine transporter ligand [123I]FP-CIT. The first patient was additionally scanned before the condition developed, and the second patient was scanned after recovery. Striatal dopamine transporter binding was lower during than before the crisis, and both patients showed a nearly complete loss of dopamine transporter binding during the crisis. Serial imaging showed that the uptake remained negligible despite an improvement in motor function after recovery. Akinetic crisis in PD appears to be associated with a particularly severe loss of presynaptic striatal dopamine function that does not improve after recovery. Apart from presynaptic dopaminergic function, other dopaminergic or nondopaminergic mechanisms are involved in the clinical improvement of motor functions after akinetic crisis in PD.

  11. Value of functional MRI in evaluation of patients with suspected prostate cancer

    Directory of Open Access Journals (Sweden)

    Mostafa Mohamed Mostafa Elian

    2015-12-01

    Conclusion: Functional MRI provided a highly sensitive method in diagnosing and localizing prostate cancer. Being noninvasive, highly sensitive with wider spectrum in nearby pelvic organs assessment in one imaging session, it may totally replace TRUS-guided biopsy.

  12. Functional connectivity analysis of the brain network using resting-state fMRI

    International Nuclear Information System (INIS)

    Hayashi, Toshihiro

    2011-01-01

    Spatial patterns of spontaneous fluctuations in blood oxygenation level-dependent (BOLD) signals reflect the underlying neural architecture. The study of the brain network based on these self-organized patterns is termed resting-state functional MRI (fMRI). This review article aims at briefly reviewing a basic concept of this technology and discussing its implications for neuropsychological studies. First, the technical aspects of resting-state fMRI, including signal sources, physiological artifacts, image acquisition, and analytical methods such as seed-based correlation analysis and independent component analysis, are explained, followed by a discussion on the major resting-state networks, including the default mode network. In addition, the structure-function correlation studied using diffuse tensor imaging and resting-state fMRI is briefly discussed. Second, I have discussed the reservations and potential pitfalls of 2 major imaging methods: voxel-based lesion-symptom mapping and task fMRI. Problems encountered with voxel-based lesion-symptom mapping can be overcome by using resting-state fMRI and evaluating undamaged brain networks in patients. Regarding task fMRI in patients, I have also emphasized the importance of evaluating the baseline brain activity because the amplitude of activation in BOLD fMRI is hard to interpret as the same baseline cannot be assumed for both patient and normal groups. (author)

  13. Comparison of post-surgical MRI presentation of the pituitary gland and its hormonal function.

    Science.gov (United States)

    Bladowska, Joanna; Sokolska, Violetta; Sozański, Tomasz; Bednarek-Tupikowska, Grażyna; Sąsiadek, Marek

    2010-01-01

    Post-surgical evaluation of the pituitary gland in MRI is difficult because of a change of anatomical conditions. It depends also on numerous other factors, including: size and expansion of a tumour before surgery, type of surgical access, quality and volume of filling material used and time of its resorption.The aim of the study was to compare MR image of the pituitary gland after surgery with clinical findings and to establish a correlation between MRI presentation of spared pituitary and its hormonal function. 124 patients after resection of pituitary adenomas - 409 MRI results in total - were studied. With a 1.5-T unit, T1-weighted sagittal and coronal, enhanced and unenhanced images were obtained. The pituitary gland seemed to be normal in MRI in 11 patients, 8 of them had completely regular pituitary function but in 3 of them we noticed a partial hypopituitarism. In 99 patients only a part of the pituitary gland was recognised, 53 of them had hypopituitarism but 46 of them were endocrinologically healthy. 14 patients seemed to have no persistent pituitary gland in MRI, in comparison to hormonal studies: there was panhypopituitarism in 6 and hypopituitarism in 8 cases. MRI presentation of post - surgical pituitary gland doesn't necessarily correlate with its hormonal function - there was a significant statistical difference. Some patients with partial pituitary seems normal hormonal function. In some cases the pituitary seem normal in MRI but these patients have hormonal disorders and need substitution therapy.

  14. Comparison of post-surgical MRI presentation of the pituitary gland and its hormonal function

    International Nuclear Information System (INIS)

    Bladowska, J.; Sokolska, V.; Sasiadek, M.; Sozanski, T.; Bednarek-Tupikowska, G.

    2010-01-01

    Background: Post-surgical evaluation of the pituitary gland in MRI is difficult because of a change of anatomical conditions. It depends also on numerous other factors, including: size and expansion of a tumour before surgery, type of surgical access, quality and volume of filling material used and time of its resorption.The aim of the study was to compare MR image of the pituitary gland after surgery with clinical findings and to establish a correlation between MRI presentation of spared pituitary and its hormonal function. Material/Methods: 124 patients after resection of pituitary adenomas - 409 MRI results in total - were studied. With a 1.5-T unit, T1-weighted sagittal and coronal, enhanced and unenhanced images were obtained. Results: The pituitary gland seemed to be normal in MRI in 11 patients, 8 of them had completely regular pituitary function but in 3 of them we noticed a partial hypopituitarism. In 99 patients only a part of the pituitary gland was recognised, 53 of them had hypopituitarism but 46 of them were endocrinologically healthy. 14 patients seemed to have no persistent pituitary gland in MRI, in comparison to hormonal studies: there was panhypopituitarism in 6 and hypopituitarism in 8 cases. Conclusions: MRI presentation of post - surgical pituitary gland doesn't necessarily correlate with its hormonal function - there was a significant statistical difference. Some patients with partial pituitary seems normal hormonal function. In some cases the pituitary seem normal in MRI but these patients have hormonal disorders and need substitution therapy. (authors)

  15. Physiological and technical limitations of functional magnetic resonance imaging (fMRI) - consequences for clinical use

    International Nuclear Information System (INIS)

    Wuestenberg, T.; Jordan, K.; Giesel, F.L.; Villringer, A.

    2003-01-01

    Functional magnetic resonance imaging (fMRI) is the most common noninvasive technique in functional neuroanatomy. The capabilities and limitations of the method will be discussed based on a short review of the current knowledge about the neurovascular relationship. The focus of this article is on current methodical and technical problems regarding fMRI-based detection and localization of neuronal activity. Main error sources and their influence on the reliability and validity of fMRI-methods are presented. Appropriate solution strategies will be proposed and evaluated. Finally, the clinical relevance of MR-based diagnostic methods are discussed. (orig.) [de

  16. Successful function of autologous iPSC-derived dopamine neurons following transplantation in a non-human primate model of Parkinson's disease

    DEFF Research Database (Denmark)

    Hallett, Penelope J; Deleidi, Michela; Astradsson, Arnar

    2015-01-01

    that unilateral engraftment of CM-iPSCs could provide a gradual onset of functional motor improvement contralateral to the side of dopamine neuron transplantation, and increased motor activity, without a need for immunosuppression. Postmortem analyses demonstrated robust survival of midbrain-like dopaminergic......Autologous transplantation of patient-specific induced pluripotent stem cell (iPSC)-derived neurons is a potential clinical approach for treatment of neurological disease. Preclinical demonstration of long-term efficacy, feasibility, and safety of iPSC-derived dopamine neurons in non-human primate...... models will be an important step in clinical development of cell therapy. Here, we analyzed cynomolgus monkey (CM) iPSC-derived midbrain dopamine neurons for up to 2 years following autologous transplantation in a Parkinson's disease (PD) model. In one animal, with the most successful protocol, we found...

  17. Preparation of alanine and tyrosine functionalized graphene oxide nanoflakes and their modified carbon paste electrodes for the determination of dopamine

    International Nuclear Information System (INIS)

    Kumar, Mohan; Swamy, B.E. Kumara; Asif, M.H. Mohammed; Viswanath, C.C.

    2017-01-01

    Highlights: • The prepared graphene oxide was functionalized by alanine and tyrosine. • The prepared materials were used for sensor for dopamine. • The functionalized graphene oxide modified carbon paste electrodes shows good sensitivity, stability and repeatability. - Abstract: Herein, established the synthesis of graphene oxide (GO) by Hummers Method with addition of KMnO_4 followed by thermal heating at 80 °C. The obtained GO was further functionalized by alanine and tyrosine. The prepared GO, alanine functionalized GO nanoflakes (AGONF) and tyrosine functionalized GO nanoflakes (TGONF) were characterized by spectroscopic technique using energy-dispersive spectroscopy (EDS), quantitatively by scanning electron microscopy (SEM) and structural studies along with interlayer distance verified through X-ray diffraction technique. Afterwards, the prepared AGONF and TGONF were used as the modifier for the carbon paste electrode (CPE). The electrochemical behavior of the AGONF and TGONF modified carbon paste electrodes (MCPEs) towards dopamine (DA) in phosphate buffer solution (PBS) were examined by cyclic voltammetric (CV) technique and the obtained consequences showed good electrocatalytic activity of MCPEs by increasing the redox peak current with a lower potential difference compared to the bare CPE (BCPE). The AGONF and TGONF MCPEs were further used for the optimization studies. From the pH studies, it was found that the equal number of proton and electron transfer reaction involved in both the modified electrodes. The scan rate studies demonstrate the adsorption controlled electrode process at AGONF MCPE and diffusion controlled at TGONF MCPE. The oxidation peak current increased linearly with two concentration interval of DA at a range of 2–7 μM and 10–30 μM in presence of PBS (pH 7.4) at MCPEs and the limit of detection (LOD) were found to be 0.84 μM and 0.96 μM for first interval DA concentration range (2–7 μM) at AGONF and TGONF MCPE. The

  18. Preparation of alanine and tyrosine functionalized graphene oxide nanoflakes and their modified carbon paste electrodes for the determination of dopamine

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Mohan [Department of P.G. Studies and Research in Industrial Chemistry, Kuvempu University, Shankaraghatta, 577 451, Shimoga, Karnataka (India); Swamy, B.E. Kumara, E-mail: kumaraswamy21@yahoo.com [Department of P.G. Studies and Research in Industrial Chemistry, Kuvempu University, Shankaraghatta, 577 451, Shimoga, Karnataka (India); Asif, M.H. Mohammed [Nanoscience and Technology, Kuvempu University, Shankaraghatta, 577451, Shimoga, Karnataka (India); Viswanath, C.C. [Department of P.G. Studies and Research in Industrial Chemistry, Kuvempu University, Shankaraghatta, 577 451, Shimoga, Karnataka (India)

    2017-03-31

    Highlights: • The prepared graphene oxide was functionalized by alanine and tyrosine. • The prepared materials were used for sensor for dopamine. • The functionalized graphene oxide modified carbon paste electrodes shows good sensitivity, stability and repeatability. - Abstract: Herein, established the synthesis of graphene oxide (GO) by Hummers Method with addition of KMnO{sub 4} followed by thermal heating at 80 °C. The obtained GO was further functionalized by alanine and tyrosine. The prepared GO, alanine functionalized GO nanoflakes (AGONF) and tyrosine functionalized GO nanoflakes (TGONF) were characterized by spectroscopic technique using energy-dispersive spectroscopy (EDS), quantitatively by scanning electron microscopy (SEM) and structural studies along with interlayer distance verified through X-ray diffraction technique. Afterwards, the prepared AGONF and TGONF were used as the modifier for the carbon paste electrode (CPE). The electrochemical behavior of the AGONF and TGONF modified carbon paste electrodes (MCPEs) towards dopamine (DA) in phosphate buffer solution (PBS) were examined by cyclic voltammetric (CV) technique and the obtained consequences showed good electrocatalytic activity of MCPEs by increasing the redox peak current with a lower potential difference compared to the bare CPE (BCPE). The AGONF and TGONF MCPEs were further used for the optimization studies. From the pH studies, it was found that the equal number of proton and electron transfer reaction involved in both the modified electrodes. The scan rate studies demonstrate the adsorption controlled electrode process at AGONF MCPE and diffusion controlled at TGONF MCPE. The oxidation peak current increased linearly with two concentration interval of DA at a range of 2–7 μM and 10–30 μM in presence of PBS (pH 7.4) at MCPEs and the limit of detection (LOD) were found to be 0.84 μM and 0.96 μM for first interval DA concentration range (2–7 μM) at AGONF and TGONF MCPE

  19. New MRI technologies. Diffusion MRI and its application to functional neuroimaging and analyses of white matter integrity

    International Nuclear Information System (INIS)

    Kobayashi, Tetsuo

    2010-01-01

    Described is the technological aspect of MRI, MR diffusion-weighted imaging (MR-DWI), principles of its measurement and application for imaging the cerebral function and for aiding the quantitative diagnosis of brain diseases. The author explains the principle of MR imaging process; diffusion properties of water molecules, MR-DWI based on them and DW-fMRI of the brain; MR-diffusion tensor imaging (MR-DTI), its analysis and color acquisition, and tracking of white matter nerve fibers; analysis of white matter lesions by the tracking; and the new tracking method at the chiasm of nerve fascicles. The usual fMRI reflects the blood oxygen level depending (BOLD) signals whereas recently attracted DW-fMRI, the volume changes of nerve cells concomitant to nerve activation accompanying apparent changes of water diffusion coefficients in and out of cells which occur faster than BOLD signs, resulting in higher resolution of time and space. However, DWI requires the higher intensity of static magnetic field like 3T. MR-DTI acquires the anisotropic diffusion of water molecules using MR-DWI technique with application of 6 or more motion probing gradients, thus makes it possible to track the running directions of nerve fibers and capillary vessels, and is proposed to be a useful mean of specific fiber tracking in the white matter when displayed by 3 different colors exhibiting the directions like the right/left (x axis, red), anterior/posterior (y, green) and upper/lower (z, blue) sides of head. Recently, MR-DWI and MR-DTI have been found usable for pathogenic studies of brain diseases such as dementia. Tensor anisotropy is apparently lowered at the chiasm of nerve fascicles, the cause of tracking error, for which authors have developed a new method using the similarity of directional vector, not of tensor, before and behind the chiasm. As exemplified, MRI technology is further advancing even at present. (T.T.)

  20. Evaluation of a pre-surgical functional MRI workflow: From data acquisition to reporting.

    Science.gov (United States)

    Pernet, Cyril R; Gorgolewski, Krzysztof J; Job, Dominic; Rodriguez, David; Storkey, Amos; Whittle, Ian; Wardlaw, Joanna

    2016-02-01

    Present and assess clinical protocols and associated automated workflow for pre-surgical functional magnetic resonance imaging in brain tumor patients. Protocols were validated using a single-subject reliability approach based on 10 healthy control subjects. Results from the automated workflow were evaluated in 9 patients with brain tumors, comparing fMRI results to direct electrical stimulation (DES) of the cortex. Using a new approach to compute single-subject fMRI reliability in controls, we show that not all tasks are suitable in the clinical context, even if they show meaningful results at the group level. Comparison of the fMRI results from patients to DES showed good correspondence between techniques (odds ratio 36). Providing that validated and reliable fMRI protocols are used, fMRI can accurately delineate eloquent areas, thus providing an aid to medical decision regarding brain tumor surgery. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  1. High frame rate retrospectively triggered Cine MRI for assessment of murine diastolic function.

    Science.gov (United States)

    Coolen, Bram F; Abdurrachim, Desiree; Motaal, Abdallah G; Nicolay, Klaas; Prompers, Jeanine J; Strijkers, Gustav J

    2013-03-01

    To assess left ventricular (LV) diastolic function in mice with Cine MRI, a high frame rate (>60 frames per cardiac cycle) is required. For conventional electrocardiography-triggered Cine MRI, the frame rate is inversely proportional to the pulse repetition time (TR). However, TR cannot be lowered at will to increase the frame rate because of gradient hardware, spatial resolution, and signal-to-noise limitations. To overcome these limitations associated with electrocardiography-triggered Cine MRI, in this paper, we introduce a retrospectively triggered Cine MRI protocol capable of producing high-resolution high frame rate Cine MRI of the mouse heart for addressing left ventricular diastolic function. Simulations were performed to investigate the influence of MRI sequence parameters and the k-space filling trajectory in relation to the desired number of frames per cardiac cycle. An optimized protocol was applied in vivo and compared with electrocardiography-triggered Cine for which a high-frame rate could only be achieved by several interleaved acquisitions. Retrospective high frame rate Cine MRI proved superior to the interleaved electrocardiography-triggered protocols. High spatial-resolution Cine movies with frames rates up to 80 frames per cardiac cycle were obtained in 25 min. Analysis of left ventricular filling rate curves allowed accurate determination of early and late filling rates and revealed subtle impairments in left ventricular diastolic function of diabetic mice in comparison with nondiabetic mice. Copyright © 2012 Wiley Periodicals, Inc.

  2. Radioiodinated ligands for dopamine receptors

    International Nuclear Information System (INIS)

    Kung, H.F.

    1994-01-01

    The dopamine receptor system is important for normal brain function; it is also the apparent action site for various neuroleptic drugs for the treatment of schizophrenia and other metal disorders. In the past few years radioiodinated ligands for single photon emission tomography (SPECT) have been successfully developed and tested in humans: [ 123 I]TISCH for D1 dopamine receptors; [ 123 I]IBZM, epidepride, IBF and FIDA2, four iodobenzamide derivatives, for D2/D3 dopamine receptors. In addition, [ 123 I]β-CIT (RTI-55) and IPT, cocaine derivatives, for the dopamine reuptake site are potentially useful for diagnosis of loss of dopamine neurons. The first iodinated ligand, (R)trans-7-OH-PIPAT, for D3 dopamine receptors, was synthesized and characterized with cloned cell lines (Spodoptera frugiperda, Sf9) expressing the D2 and D3 dopamine receptors and with rat basal forebrain membrane preparations. Most of the known iodobenzamides displayed similar potency in binding to both D2 and D3 dopamine receptors expressed in the cell lines. Initial studies appear to suggest that by fine tuning the structures it may be possible to develop agents specific for D2 and D3 dopamine receptors. It is important to investigate D2/D3 selectivity for this series of potent ligands

  3. Exploring connectivity with large-scale Granger causality on resting-state functional MRI.

    Science.gov (United States)

    DSouza, Adora M; Abidin, Anas Z; Leistritz, Lutz; Wismüller, Axel

    2017-08-01

    Large-scale Granger causality (lsGC) is a recently developed, resting-state functional MRI (fMRI) connectivity analysis approach that estimates multivariate voxel-resolution connectivity. Unlike most commonly used multivariate approaches, which establish coarse-resolution connectivity by aggregating voxel time-series avoiding an underdetermined problem, lsGC estimates voxel-resolution, fine-grained connectivity by incorporating an embedded dimension reduction. We investigate application of lsGC on realistic fMRI simulations, modeling smoothing of neuronal activity by the hemodynamic response function and repetition time (TR), and empirical resting-state fMRI data. Subsequently, functional subnetworks are extracted from lsGC connectivity measures for both datasets and validated quantitatively. We also provide guidelines to select lsGC free parameters. Results indicate that lsGC reliably recovers underlying network structure with area under receiver operator characteristic curve (AUC) of 0.93 at TR=1.5s for a 10-min session of fMRI simulations. Furthermore, subnetworks of closely interacting modules are recovered from the aforementioned lsGC networks. Results on empirical resting-state fMRI data demonstrate recovery of visual and motor cortex in close agreement with spatial maps obtained from (i) visuo-motor fMRI stimulation task-sequence (Accuracy=0.76) and (ii) independent component analysis (ICA) of resting-state fMRI (Accuracy=0.86). Compared with conventional Granger causality approach (AUC=0.75), lsGC produces better network recovery on fMRI simulations. Furthermore, it cannot recover functional subnetworks from empirical fMRI data, since quantifying voxel-resolution connectivity is not possible as consequence of encountering an underdetermined problem. Functional network recovery from fMRI data suggests that lsGC gives useful insight into connectivity patterns from resting-state fMRI at a multivariate voxel-resolution. Copyright © 2017 Elsevier B.V. All

  4. The Effects of Acute Dopamine Precursor Depletion on the Cognitive Control Functions of Performance Monitoring and Conflict Processing: An Event-Related Potential (ERP) Study.

    Science.gov (United States)

    Larson, Michael J; Clayson, Peter E; Primosch, Mark; Leyton, Marco; Steffensen, Scott C

    2015-01-01

    Studies using medications and psychiatric populations implicate dopamine in cognitive control and performance monitoring processes. However, side effects associated with medication or studying psychiatric groups may confound the relationship between dopamine and cognitive control. To circumvent such possibilities, we utilized a randomized, double-blind, placebo-controlled, within-subjects design wherein participants were administered a nutritionally-balanced amino acid mixture (BAL) and an amino acid mixture deficient in the dopamine precursors tyrosine (TYR) and phenylalanine (PHE) on two separate occasions. Order of sessions was randomly assigned. Cognitive control and performance monitoring were assessed using response times (RT), error rates, the N450, an event-related potential (ERP) index of conflict monitoring, the conflict slow potential (conflict SP), an ERP index of conflict resolution, and the error-related negativity (ERN) and error positivity (Pe), ERPs associated with performance monitoring. Participants were twelve males who completed a Stroop color-word task while ERPs were collected four hours following acute PHE and TYR depletion (APTD) or balanced (BAL) mixture ingestion in two separate sessions. N450 and conflict SP ERP amplitudes significantly differentiated congruent from incongruent trials, but did not differ as a function of APTD or BAL mixture ingestion. Similarly, ERN and Pe amplitudes showed significant differences between error and correct trials that were not different between APTD and BAL conditions. Findings indicate that acute dopamine precursor depletion does not significantly alter cognitive control and performance monitoring ERPs. Current results do not preclude the role of dopamine in these processes, but suggest that multiple methods for dopamine-related hypothesis testing are needed.

  5. The Effects of Acute Dopamine Precursor Depletion on the Cognitive Control Functions of Performance Monitoring and Conflict Processing: An Event-Related Potential (ERP Study.

    Directory of Open Access Journals (Sweden)

    Michael J Larson

    Full Text Available Studies using medications and psychiatric populations implicate dopamine in cognitive control and performance monitoring processes. However, side effects associated with medication or studying psychiatric groups may confound the relationship between dopamine and cognitive control. To circumvent such possibilities, we utilized a randomized, double-blind, placebo-controlled, within-subjects design wherein participants were administered a nutritionally-balanced amino acid mixture (BAL and an amino acid mixture deficient in the dopamine precursors tyrosine (TYR and phenylalanine (PHE on two separate occasions. Order of sessions was randomly assigned. Cognitive control and performance monitoring were assessed using response times (RT, error rates, the N450, an event-related potential (ERP index of conflict monitoring, the conflict slow potential (conflict SP, an ERP index of conflict resolution, and the error-related negativity (ERN and error positivity (Pe, ERPs associated with performance monitoring. Participants were twelve males who completed a Stroop color-word task while ERPs were collected four hours following acute PHE and TYR depletion (APTD or balanced (BAL mixture ingestion in two separate sessions. N450 and conflict SP ERP amplitudes significantly differentiated congruent from incongruent trials, but did not differ as a function of APTD or BAL mixture ingestion. Similarly, ERN and Pe amplitudes showed significant differences between error and correct trials that were not different between APTD and BAL conditions. Findings indicate that acute dopamine precursor depletion does not significantly alter cognitive control and performance monitoring ERPs. Current results do not preclude the role of dopamine in these processes, but suggest that multiple methods for dopamine-related hypothesis testing are needed.

  6. Function and expression differences between ergot and non-ergot dopamine D2 agonists on heart valve interstitial cells.

    Science.gov (United States)

    Oana, Fumiki; Onozuka, Hiroshi; Tsuchioka, Akihiro; Suzuki, Takayuki; Tanaka, Nobuyuki; Kaidoh, Kouichi; Hoyano, Yuji; Hiratochi, Masahiro; Kikuchi, Shinji; Takehana, Yasuo; Shibata, Nobuo

    2014-03-01

    The symptoms of Parkinson's disease are alleviated by dopamine D2 agonists, which are classified as ergot dopamine D2 agonists and non-ergot D2 agonists. Among the former, pergolide has been associated with valvular heart disease, since it has both potent D2 receptor and serotonin 5-HT(2B) receptor agonistic properties. Among the latter, pramipexole has few incidences of heart valve disease onset, since it has an absence of 5-HT(2B) receptor agonism. A [3H]thymidine incorporation assay was performed to monitor function, and microarray global analysis to monitor gene expression, on porcine heart valve interstitial cells (VICs) treated with pergolide or pramipexole. The 5-HT(2B) receptor was abundantly expressed in porcine VICs. The 5-HT(2B) receptor agonist pergolide induced an increase in [3H]thymidine incorporation, accompanied by a decrease in 5-HT(2B) receptor mRNA expression. [3H]thymidine incorporation was blocked by lisuride, a 5-HT(2B) receptor antagonist, and also by LY-294002, a specific inhibitor of PI3K and Akt. Moreover, type 2 iodothyronine deiodinase (Dio2) expression in porcine VICs treated with pergolide was shown, by a global analysis of mRNA, to be markedly increased compared to that induced by pramipexole. Such changes in VICs may correlate with the mechanism of heart valve disease pathogenesis. There were substantial differences (increased [3H]thymidine incorporation, and Dio2 expression) between pergolide and pramipexole, which might correlate with the mechanism of heart valve disease onset.

  7. Dopamine transporter 3'UTR VNTR genotype is a marker of performance on executive function tasks in children with ADHD

    Directory of Open Access Journals (Sweden)

    Polotskaia Anna

    2008-06-01

    Full Text Available Abstract Background Attention-Deficit/Hyperactivity Disorder (ADHD is a heterogeneous disorder from both clinical and pathogenic viewpoints. Executive function deficits are considered among the most important pathogenic pathways leading to ADHD and may index part of the heterogeneity in this disorder. Methods To investigate the relationship between the dopamine transporter gene (SLC6A3 3'-UTR VNTR genotypes and executive function in children with ADHD, 196 children diagnosed with ADHD were sequentially recruited, genotyped, and tested using a battery of three neuropsychological tests aimed at assessing the different aspects of executive functioning. Results Taking into account a correction for multiple comparisons, the main finding of this study is a significant genotype effect on performances on the Tower of London (F = 6.902, p = 0.009 and on the Wechsler Intelligence Scale for Children, Third Edition (WISC-III Freedom From Distractibility Index (F = 7.125, p = 0.008, as well as strong trends on Self Ordered Pointing Task error scores (F = 4,996 p = 0.026 and WISC-III Digit Span performance (F = 6.28, p = 0.023. Children with the 9/10 genotype exhibited, on average, a poorer performance on all four measures compared to children with the 10/10 genotype. No effect of genotype on Wisconsin Card Sorting Test measures of performance was detected. Conclusion Results are compatible with the view that SLC6A3 genotype may modulate components of executive function performance in children with ADHD.

  8. The potential of functional MRI as a biomarker in early Alzheimer’s disease

    OpenAIRE

    Sperling, Reisa

    2011-01-01

    Functional magnetic resonance imaging (fMRI) is a relative newcomer in the field of biomarkers for Alzheimer’s disease (AD). fMRI has several potential advantages, particularly for clinical trials, as it is a non-invasive imaging technique that does not require the injection of contrast agent or radiation exposure and thus can be repeated many times during a longitudinal study. fMRI has relatively high spatial and reasonable temporal resolution, and can be acquired in the same session as stru...

  9. Epistasis between dopamine regulating genes identifies a nonlinear response of the human hippocampus during memory tasks.

    Science.gov (United States)

    Bertolino, Alessandro; Di Giorgio, Annabella; Blasi, Giuseppe; Sambataro, Fabio; Caforio, Grazia; Sinibaldi, Lorenzo; Latorre, Valeria; Rampino, Antonio; Taurisano, Paolo; Fazio, Leonardo; Romano, Raffaella; Douzgou, Sofia; Popolizio, Teresa; Kolachana, Bhaskar; Nardini, Marcello; Weinberger, Daniel R; Dallapiccola, Bruno

    2008-08-01

    Dopamine modulation of neuronal activity in prefrontal cortex maps to an inverted U-curve. Dopamine is also an important factor in regulation of hippocampal mediated memory processing. Here, we investigated the effect of genetic variation of dopamine inactivation via catechol-O-methyltransferase (COMT) and the dopamine transporter (DAT) on hippocampal activity in healthy humans during different memory conditions. Using blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) in 82 subjects matched for a series of demographic and genetic variables, we studied the effect of the COMT valine (Val)(158)methionine (Met) and the DAT 3' variable number tandem repeat (VNTR) polymorphisms on function of the hippocampus during encoding of recognition memory and during working memory. Our results consistently demonstrated a double dissociation so that DAT 9-repeat carrier alleles modulated activity in the hippocampus in the exact opposite direction of DAT 10/10-repeat alleles based on COMT Val(158)Met genotype during different memory conditions. Similar results were evident in ventrolateral and dorsolateral prefrontal cortex. These findings suggest that genetically determined dopamine signaling during memory processing maps to a nonlinear relationship also in the hippocampus. Our data also demonstrate in human brain epistasis of two genes implicated in dopamine signaling on brain activity during different memory conditions.

  10. Detection of Brain Reorganization in Pediatric Multiple Sclerosis Using Functional MRI

    Science.gov (United States)

    2015-10-01

    including the Wechsler Intelligence Scale for Children (WISC-IV) for verbal and non-verbal intelligence; the Boston Naming Test , which evaluates a...demonstrated congruency between fMRI mappings and patient performance; 2) testing of the fMRI methods we developed for use in POMS patients was carried out...adaptive functional reorganization as a way to explain how some early-stage MS patients are able to perform well in clinical cognitive testing

  11. Functional Topography of Human Corpus Callosum: An fMRI Mapping Study

    OpenAIRE

    Fabri, Mara; Polonara, Gabriele

    2013-01-01

    The concept of a topographical map of the corpus callosum (CC) has emerged from human lesion studies and from electrophysiological and anatomical tracing investigations in other mammals. Over the last few years a rising number of researchers have been reporting functional magnetic resonance imaging (fMRI) activation in white matter, particularly the CC. In this study the scope for describing CC topography with fMRI was explored by evoking activation through simple sensory stimulation and moto...

  12. Gait improvement after treadmill training in ischemic stroke survivors: A critical review of functional MRI studies ☆

    OpenAIRE

    Xiao, Xiang; Huang, Dongfeng; O’Young, Bryan

    2012-01-01

    Stroke survivors often present with abnormal gait, movement training can improve the walking performance post-stroke, and functional MRI can objectively evaluate the brain functions before and after movement training. This paper analyzes the functional MRI changes in patients with ischemic stroke after treadmill training with voluntary and passive ankle dorsiflexion. Functional MRI showed that there are some changes in some regions of patients with ischemic stroke including primary sensorimot...

  13. Hidden Markov event sequence models: toward unsupervised functional MRI brain mapping.

    Science.gov (United States)

    Faisan, Sylvain; Thoraval, Laurent; Armspach, Jean-Paul; Foucher, Jack R; Metz-Lutz, Marie-Noëlle; Heitz, Fabrice

    2005-01-01

    Most methods used in functional MRI (fMRI) brain mapping require restrictive assumptions about the shape and timing of the fMRI signal in activated voxels. Consequently, fMRI data may be partially and misleadingly characterized, leading to suboptimal or invalid inference. To limit these assumptions and to capture the broad range of possible activation patterns, a novel statistical fMRI brain mapping method is proposed. It relies on hidden semi-Markov event sequence models (HSMESMs), a special class of hidden Markov models (HMMs) dedicated to the modeling and analysis of event-based random processes. Activation detection is formulated in terms of time coupling between (1) the observed sequence of hemodynamic response onset (HRO) events detected in the voxel's fMRI signal and (2) the "hidden" sequence of task-induced neural activation onset (NAO) events underlying the HROs. Both event sequences are modeled within a single HSMESM. The resulting brain activation model is trained to automatically detect neural activity embedded in the input fMRI data set under analysis. The data sets considered in this article are threefold: synthetic epoch-related, real epoch-related (auditory lexical processing task), and real event-related (oddball detection task) fMRI data sets. Synthetic data: Activation detection results demonstrate the superiority of the HSMESM mapping method with respect to a standard implementation of the statistical parametric mapping (SPM) approach. They are also very close, sometimes equivalent, to those obtained with an "ideal" implementation of SPM in which the activation patterns synthesized are reused for analysis. The HSMESM method appears clearly insensitive to timing variations of the hemodynamic response and exhibits low sensitivity to fluctuations of its shape (unsustained activation during task). Real epoch-related data: HSMESM activation detection results compete with those obtained with SPM, without requiring any prior definition of the expected

  14. Large-scale functional MRI analysis to accumulate knowledge on brain functions

    International Nuclear Information System (INIS)

    Schwartz, Yannick

    2015-01-01

    How can we accumulate knowledge on brain functions? How can we leverage years of research in functional MRI to analyse finer-grained psychological constructs, and build a comprehensive model of the brain? Researchers usually rely on single studies to delineate brain regions recruited by mental processes. They relate their findings to previous works in an informal way by defining regions of interest from the literature. Meta-analysis approaches provide a more principled way to build upon the literature. This thesis investigates three ways to assemble knowledge using activation maps from a large amount of studies. First, we present an approach that uses jointly two similar fMRI experiments, to better condition an analysis from a statistical standpoint. We show that it is a valuable data-driven alternative to traditional regions of interest analyses, but fails to provide a systematic way to relate studies, and thus does not permit to integrate knowledge on a large scale. Because of the difficulty to associate multiple studies, we resort to using a single dataset sampling a large number of stimuli for our second contribution. This method estimates functional networks associated with functional profiles, where the functional networks are interacting brain regions and the functional profiles are a weighted set of cognitive descriptors. This work successfully yields known brain networks and automatically associates meaningful descriptions. Its limitations lie in the unsupervised nature of this method, which is more difficult to validate, and the use of a single dataset. It however brings the notion of cognitive labels, which is central to our last contribution. Our last contribution presents a method that learns functional atlases by combining several datasets. [Henson 2006] shows that forward inference, i.e. the probability of an activation given a cognitive process, is often not sufficient to conclude on the engagement of brain regions for a cognitive process

  15. Interaction between childhood adversity and functional polymorphisms in the dopamine pathway on first-episode psychosis.

    Science.gov (United States)

    Trotta, Antonella; Iyegbe, Conrad; Yiend, Jenny; Dazzan, Paola; David, Anthony S; Pariante, Carmine; Mondelli, Valeria; Colizzi, Marco; Murray, Robin M; Di Forti, Marta; Fisher, Helen L

    2018-04-10

    There is consistent evidence of a cumulative relationship between childhood adversity and psychosis, with number of adversities experienced increasing the probability of psychosis onset. It is possible that genetic factors moderate the association between childhood adversity and psychosis, potentially by influencing how an individual reacts biologically and/or psychologically following exposure to adversity, in such a way as to set them off on the path to psychosis. However, identifying the specific genetic variants involved and how they interact with childhood adversity remains challenging. We examined whether the association between cumulative exposure to childhood adversity and development of psychotic disorder was moderated by the COMT Val 158 Met, AKT1 rs2494732 or DRD2 rs1076560 polymorphisms, known to affect dopamine levels. Participants were 285 first-presentation psychosis cases and 256 geographically-matched controls drawn from the Genetics and Psychosis (GAP) study. Childhood adversity was assessed using the Childhood Experience of Care and Abuse Questionnaire (CECA.Q) and blood- and cheek-derived genotype data were collected. Our findings revealed no main effect of COMT Val 158 Met, AKT1 rs2494732 and DRD2 rs1076560 polymorphisms on psychosis case status or reports of childhood adversity. Individuals reporting a history of multiple adversities were more likely to be psychosis patients than controls, regardless of their genetic risk. There was no evidence of candidate genotype by childhood adversity interactions in relation to psychosis onset. These findings did not provide evidence of a possible role of COMT Val 158 Met, AKT1 rs2494732 or DRD2 rs1076560 genotypes in modifying the association between childhood adversity and onset of psychosis. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Blood Flow and Brain Function: Investigations of neurovascular coupling using BOLD fMRI at 7 tesla

    NARCIS (Netherlands)

    Siero, J.C.W.

    2013-01-01

    The advent of ultra high field (7 tesla) MRI systems has opened the possibility to probe biological processes of the human body in great detail. Especially for studying brain function using BOLD fMRI there is a large benefit from the increased magnetic field strength. BOLD fMRI is the working horse

  17. Functional MRI of the pharynx in obstructive sleep apnea (OSA) with rapid 2-D flash sequences

    International Nuclear Information System (INIS)

    Jaeger, L.; Guenther, E.; Gauger, J.; Nitz, W.; Kastenbauer, E.; Reiser, M.

    1996-01-01

    Functional imaging of the pharynx used to be the domain of cineradiography, CT and ultrafast CT. The development of modern MRI techniques led to new access to functional disorders of the pharynx. The aim of this study was to implement a new MRI technique to examine oropharyngeal obstructive mechanisms in patients with obstructive sleep apnea (OSA). Sixteen patients suffering from OSA and 6 healthy volunteers were examined on a 1.5 T whole-body imager ('Vision', Siemens, Erlangen Medical Engineering, Germany) using a circular polarized head coil. Imaging was performed with 2D flash sequences in midsagittal and axial planes. Patients and volunteers were asked to breathe normally through the nose and to simulate snoring and the Mueller maneuver during magnetic resonance imaging (MRI). Prior to MRI, all patients underwent an ear, nose and throat (ENT) examination, functional fiberoptic nasopharyngoscopy and polysomnography. A temporal resolution of 6 images/s and an in-plane resolution of 2.67x1.8 mm were achieved. The mobility of the tongue, soft palate and pharyngeal surface could be clearly delineated. The MRI findings correlated well with the clinical examinations. We propose ultrafast MRI as a reliable and non-invasive method of evaluating pharyngeal obstruction and their levels. (orig.) [de

  18. Dopamine treatment and cognitive functioning in individuals with Parkinson's disease: the "cognitive flexibility" hypothesis seems to work.

    Science.gov (United States)

    Costa, Alberto; Peppe, Antonella; Mazzù, Ilenia; Longarzo, Mariachiara; Caltagirone, Carlo; Carlesimo, Giovanni A

    2014-01-01

    Previous data suggest that (i) dopamine modulates the ability to implement nonroutine schemata and update operations (flexibility processes) and that (ii) dopamine-related improvement may be related to baseline dopamine levels in target pathways (inverted U-shaped hypothesis). To investigate above hypotheses in individuals with Parkinson's disease (PD). Twenty PD patients were administered tasks varying as to flexibility load in two treatment conditions: (i) "off" condition, about 18 hours after dopamine dose and (ii) "on" condition, after dopamine administration. PD patients were separated into two groups: low performers (i.e., performance on Digit Span Backward below the sample mean) and high performers (i.e., performance above the mean). Twenty healthy individuals performed the tasks in two sessions without taking drugs. Passing from the "off" to the "on" state, only low performer PD patients significantly improved their performance on high-flexibility measures (interference condition of the Stroop test; P flexibility tasks. These findings document that high-flexibility processes are sensitive to dopamine neuromodulation in the early phases of PD. This is in line with the hypothesis that striatal dopamine pathways, affected early by PD, are precociously implicated in the expression of cognitive disorders in these individuals.

  19. Relationship between DCE-MRI morphological and functional features and histopathological characteristics of breast cancer

    International Nuclear Information System (INIS)

    Montemurro, Filippo; Redana, Stefania; Aglietta, Massimo; Martincich, Laura; Bertotto, Ilaria; Cellini, Lisa; Sarotto, Ivana; Ponzone, Riccardo; Sismondi, Piero; Regge, Daniele

    2007-01-01

    We studied whether dynamic contrast-enhanced MRI (DCE-MRI) could identify histopathological characteristics of breast cancer. Seventy-five patients with breast cancer underwent DCE-MRI followed by core biopsy. DCE-MRI findings were evaluated following the scoring system published by Fischer in 1999. In this scoring system, five DCE-MRI features, three morphological (shape, margins, enhancement kinetic) and two functional (initial peak of signal intensity (SI) increase and behavior of signal intensity curve), are defined by 14 parameters. Each parameter is assigned points ranging from 0 to 1 or 0 to 2, with higher points for those that are more likely to be associated with malignancy. The sum of all the points defines the degree of suspicion of malignancy, with a score 0 representing the lowest and 8 the highest degree of suspicion. Associations between DCE-MRI features and tumor histopathological characteristics assessed on core biopsies (histological type, grading, estrogen and progesterone receptor status, Ki67 and HER2 status) were studied by contingency tables and logistic regression analysis. We found a significant inverse association between the Fischer's score and HER2-overexpression (odds ratio-OR 0.608, p = 0.02). Based on our results, we suggest that lesions with intermediate-low suspicious DCE-MRI parameters may represent a subset of tumor with poor histopathological characteristics. (orig.)

  20. Hypercapnic evaluation of vascular reactivity in healthy aging and acute stroke via functional MRI.

    Science.gov (United States)

    Raut, Ryan V; Nair, Veena A; Sattin, Justin A; Prabhakaran, Vivek

    2016-01-01

    Functional MRI (fMRI) is well-established for the study of brain function in healthy populations, although its clinical application has proven more challenging. Specifically, cerebrovascular reactivity (CVR), which allows the assessment of the vascular response that serves as the basis for fMRI, has been shown to be reduced in healthy aging as well as in a range of diseases, including chronic stroke. However, the timing of when this occurs relative to the stroke event is unclear. We used a breath-hold fMRI task to evaluate CVR across gray matter in a group of acute stroke patients (< 10 days from stroke; N = 22) to address this question. These estimates were compared with those from both age-matched (N = 22) and younger (N = 22) healthy controls. As expected, young controls had the greatest mean CVR, as indicated by magnitude and extent of fMRI activation; however, stroke patients did not differ from age-matched controls. Moreover, the ipsilesional and contralesional hemispheres of stroke patients did not differ with respect to any of these measures. These findings suggest that fMRI remains a valid tool within the first few days of a stroke, particularly for group fMRI studies in which findings are compared with healthy subjects of similar age. However, given the relatively high variability in CVR observed in our stroke sample, caution is warranted when interpreting fMRI data from individual patients or a small cohort. We conclude that a breath-hold task can be a useful addition to functional imaging protocols for stroke patients.

  1. Hypercapnic evaluation of vascular reactivity in healthy aging and acute stroke via functional MRI

    Directory of Open Access Journals (Sweden)

    Ryan V. Raut

    2016-01-01

    Full Text Available Functional MRI (fMRI is well-established for the study of brain function in healthy populations, although its clinical application has proven more challenging. Specifically, cerebrovascular reactivity (CVR, which allows the assessment of the vascular response that serves as the basis for fMRI, has been shown to be reduced in healthy aging as well as in a range of diseases, including chronic stroke. However, the timing of when this occurs relative to the stroke event is unclear. We used a breath-hold fMRI task to evaluate CVR across gray matter in a group of acute stroke patients (<10 days from stroke; N = 22 to address this question. These estimates were compared with those from both age-matched (N = 22 and younger (N = 22 healthy controls. As expected, young controls had the greatest mean CVR, as indicated by magnitude and extent of fMRI activation; however, stroke patients did not differ from age-matched controls. Moreover, the ipsilesional and contralesional hemispheres of stroke patients did not differ with respect to any of these measures. These findings suggest that fMRI remains a valid tool within the first few days of a stroke, particularly for group fMRI studies in which findings are compared with healthy subjects of similar age. However, given the relatively high variability in CVR observed in our stroke sample, caution is warranted when interpreting fMRI data from individual patients or a small cohort. We conclude that a breath-hold task can be a useful addition to functional imaging protocols for stroke patients.

  2. Sources of variation influencing concordance between functional MRI and direct cortical stimulation in brain tumor surgery

    Directory of Open Access Journals (Sweden)

    Melanie A Morrison

    2016-10-01

    Full Text Available Object: Preoperative functional magnetic resonance imaging (fMRI remains a promising method to aid in the surgical management of patients diagnosed with brain tumors. For patients that are candidates for awake craniotomies, surgical decisions can potentially be improved by fMRI but this depends on the level of concordance between preoperative brain maps and the maps provided by the gold standard intraoperative method, direct cortical stimulation (DCS. There have been numerous studies of the concordance between fMRI and DCS using sensitivity and specificity measures, however the results are variable across studies and the key factors influencing variability are not well understood. Thus, the present work addresses the influence of technical factors on fMRI and DCS concordance. Methods: Motor and language mapping data were collected for a group of glioma patients (n = 14 who underwent both preoperative fMRI and intraoperative DCS in an awake craniotomy procedure for tumor removal. Normative fMRI data were also acquired in a healthy control group (n = 12. The fMRI and DCS mapping data were co-registered; true positive (TP, true negative (TN, false positive (FP and false negative (FN occurrences were tabulated over the exposed brain surface. Sensitivity and specificity were measured for the total group, and the motor and language sub-groups. The influence of grid placement, fMRI statistical thresholding, and task standardization were assessed. Correlations between proportions of agreement and error were carefully scrutinized to evaluate concordance more in-depth. Results: Concordance was significantly better for motor versus language mapping. There was an inverse relationship between TP and TN with increasing statistical threshold, and FP dominated the total error. Sensitivity and specificity were reduced when tasks were not standardized across fMRI and DCS. Conclusions: Although the agreement between fMRI and DCS is good, variability is introduced

  3. Structure-Guided Screening for Functionally Selective D2 Dopamine Receptor Ligands from a Virtual Chemical Library.

    Science.gov (United States)

    Männel, Barbara; Jaiteh, Mariama; Zeifman, Alexey; Randakova, Alena; Möller, Dorothee; Hübner, Harald; Gmeiner, Peter; Carlsson, Jens

    2017-10-20

    Functionally selective ligands stabilize conformations of G protein-coupled receptors (GPCRs) that induce a preference for signaling via a subset of the intracellular pathways activated by the endogenous agonists. The possibility to fine-tune the functional activity of a receptor provides opportunities to develop drugs that selectively signal via pathways associated with a therapeutic effect and avoid those causing side effects. Animal studies have indicated that ligands displaying functional selectivity at the D 2 dopamine receptor (D 2 R) could be safer and more efficacious drugs against neuropsychiatric diseases. In this work, computational design of functionally selective D 2 R ligands was explored using structure-based virtual screening. Molecular docking of known functionally selective ligands to a D 2 R homology model indicated that such compounds were anchored by interactions with the orthosteric site and extended into a common secondary pocket. A tailored virtual library with close to 13 000 compounds bearing 2,3-dichlorophenylpiperazine, a privileged orthosteric scaffold, connected to diverse chemical moieties via a linker was docked to the D 2 R model. Eighteen top-ranked compounds that occupied both the orthosteric and allosteric site were synthesized, leading to the discovery of 16 partial agonists. A majority of the ligands had comparable maximum effects in the G protein and β-arrestin recruitment assays, but a subset displayed preference for a single pathway. In particular, compound 4 stimulated β-arrestin recruitment (EC 50 = 320 nM, E max = 16%) but had no detectable G protein signaling. The use of structure-based screening and virtual libraries to discover GPCR ligands with tailored functional properties will be discussed.

  4. On the Averaging of Cardiac Diffusion Tensor MRI Data: The Effect of Distance Function Selection

    Science.gov (United States)

    Giannakidis, Archontis; Melkus, Gerd; Yang, Guang; Gullberg, Grant T.

    2016-01-01

    Diffusion tensor magnetic resonance imaging (DT-MRI) allows a unique insight into the microstructure of highly-directional tissues. The selection of the most proper distance function for the space of diffusion tensors is crucial in enhancing the clinical application of this imaging modality. Both linear and nonlinear metrics have been proposed in the literature over the years. The debate on the most appropriate DT-MRI distance function is still ongoing. In this paper, we presented a framework to compare the Euclidean, affine-invariant Riemannian and log-Euclidean metrics using actual high-resolution DT-MRI rat heart data. We employed temporal averaging at the diffusion tensor level of three consecutive and identically-acquired DT-MRI datasets from each of five rat hearts as a means to rectify the background noise-induced loss of myocyte directional regularity. This procedure is applied here for the first time in the context of tensor distance function selection. When compared with previous studies that used a different concrete application to juxtapose the various DT-MRI distance functions, this work is unique in that it combined the following: (i) Metrics were judged by quantitative –rather than qualitative– criteria, (ii) the comparison tools were non-biased, (iii) a longitudinal comparison operation was used on a same-voxel basis. The statistical analyses of the comparison showed that the three DT-MRI distance functions tend to provide equivalent results. Hence, we came to the conclusion that the tensor manifold for cardiac DT-MRI studies is a curved space of almost zero curvature. The signal to noise ratio dependence of the operations was investigated through simulations. Finally, the “swelling effect” occurrence following Euclidean averaging was found to be too unimportant to be worth consideration. PMID:27754986

  5. On the averaging of cardiac diffusion tensor MRI data: the effect of distance function selection

    Science.gov (United States)

    Giannakidis, Archontis; Melkus, Gerd; Yang, Guang; Gullberg, Grant T.

    2016-11-01

    Diffusion tensor magnetic resonance imaging (DT-MRI) allows a unique insight into the microstructure of highly-directional tissues. The selection of the most proper distance function for the space of diffusion tensors is crucial in enhancing the clinical application of this imaging modality. Both linear and nonlinear metrics have been proposed in the literature over the years. The debate on the most appropriate DT-MRI distance function is still ongoing. In this paper, we presented a framework to compare the Euclidean, affine-invariant Riemannian and log-Euclidean metrics using actual high-resolution DT-MRI rat heart data. We employed temporal averaging at the diffusion tensor level of three consecutive and identically-acquired DT-MRI datasets from each of five rat hearts as a means to rectify the background noise-induced loss of myocyte directional regularity. This procedure is applied here for the first time in the context of tensor distance function selection. When compared with previous studies that used a different concrete application to juxtapose the various DT-MRI distance functions, this work is unique in that it combined the following: (i) metrics were judged by quantitative—rather than qualitative—criteria, (ii) the comparison tools were non-biased, (iii) a longitudinal comparison operation was used on a same-voxel basis. The statistical analyses of the comparison showed that the three DT-MRI distance functions tend to provide equivalent results. Hence, we came to the conclusion that the tensor manifold for cardiac DT-MRI studies is a curved space of almost zero curvature. The signal to noise ratio dependence of the operations was investigated through simulations. Finally, the ‘swelling effect’ occurrence following Euclidean averaging was found to be too unimportant to be worth consideration.

  6. Functionalized-graphene modified graphite electrode for the selective determination of dopamine in presence of uric acid and ascorbic acid.

    Science.gov (United States)

    Mallesha, Malledevaru; Manjunatha, Revanasiddappa; Nethravathi, C; Suresh, Gurukar Shivappa; Rajamathi, Michael; Melo, Jose Savio; Venkatesha, Thimmappa Venkatarangaiah

    2011-06-01

    Graphene is chemically synthesized by solvothermal reduction of colloidal dispersions of graphite oxide. Graphite electrode is modified with functionalized-graphene for electrochemical applications. Electrochemical characterization of functionalized-graphene modified graphite electrode (FGGE) is carried out by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The behavior of FGGE towards ascorbic acid (AA), dopamine (DA) and uric acid (UA) has been investigated by CV, differential pulse voltammetry (DPV) and chronoamperommetry (CA). The FGGE showed excellent catalytic activity towards electrochemical oxidation of AA, DA and UA compared to that of the bare graphite electrode. The electrochemical oxidation signals of AA, DA and UA are well separated into three distinct peaks with peak potential separation of 193mv, 172mv and 264mV between AA-DA, DA-UA and AA-UA respectively in CV studies and the corresponding peak potential separations in DPV mode are 204mv, 141mv and 345mv. The FGGE is successfully used for the simultaneous detection of AA, DA and UA in their ternary mixture and DA in serum and pharmaceutical samples. The excellent electrocatalytic behavior of FGGE may lead to new applications in electrochemical analysis. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Dopamine-regulated adrenocorticotropic hormone secretion in lactating rats: functional plasticity of melanotropes.

    Science.gov (United States)

    Oláh, Márk; Fehér, Pálma; Ihm, Zsófia; Bácskay, Ildikó; Kiss, Timea; Freeman, Marc E; Nagy, Gyorgy M; Vecsernyés, Miklós

    2009-01-01

    Pro-opiomelanocortin (POMC) is processed to adrenocorticotropic hormone (ACTH) and beta-lipotropin in corticotropes of the anterior lobe, and to alpha-melanocyte-stimulating hormone (alpha-MSH) and beta-endorphin in melanotropes of the intermediate lobe (IL) of the pituitary gland. While ACTH secretion is predominantly under the stimulatory influence of the hypothalamic factors, hormone secretion of the IL is tonically inhibited by neuroendocrine dopamine (NEDA) neurons. Lobe-specific POMC processing is not absolute. For example, D(2) type DA receptor (D2R)-deficient mice have elevated plasma ACTH levels, although it is known that corticotropes do not express D2R(s). Moreover, observations that suckling does not influence alpha-MSH release, while it induces an increase in plasma ACTH is unexplained. The aim of the present study was to investigate the involvement of the NEDA system in the regulation of ACTH secretion and the participation of the IL in ACTH production in lactating rats. Untreated and estradiol (E(2))-substituted ovariectomized (OVX) females were also studied. The concentration of ACTH in the IL was higher in lactating rats than in OVX rats, while the opposite change in alpha-MSH level of the IL was observed. DA levels in the IL and the neural lobe were lower in lactating rats than in OVX rats. Suckling-induced ACTH response was eliminated by pretreatment with the DA receptor agonist, bromocriptine (BRC). Inhibition of DA biosynthesis by alpha-methyl-p-tyrosine (alphaMpT) and blockade of D2R by domperidone (DOM) elevated plasma ACTH levels, but did not influence plasma alpha-MSH levels in lactating rats. The same drugs had opposite effects in OVX and OVX + E(2) animals. In lactating mothers, BRC was able to block ACTH responses induced by both alphaMpT and DOM. Surgical denervation of the IL elevated basal plasma levels of ACTH. Taken together, these data indicate that melanotropes synthesize ACTH during lactation and its release from these cells is

  8. Diagnostic precision of PET imaging and functional MRI in disorders of consciousness

    DEFF Research Database (Denmark)

    Stender, Johan; Gosseries, Olivia; Bruno, Marie-Aurélie

    2014-01-01

    a validation study of two neuroimaging-based diagnostic methods: PET imaging and functional MRI (fMRI). METHODS: For this clinical validation study, we included patients referred to the University Hospital of Liège, Belgium, between January, 2008, and June, 2012, who were diagnosed by our unit...... with unresponsive wakefulness syndrome, locked-in syndrome, or minimally conscious state with traumatic or non-traumatic causes. We did repeated standardised clinical assessments with the Coma Recovery Scale-Revised (CRS-R), cerebral (18)F-fluorodeoxyglucose (FDG) PET, and fMRI during mental activation tasks. We...... state (48=traumatic, 78=non-traumatic; 110=chronic, 16=subacute). (18)F-FDG PET had high sensitivity for identification of patients in a minimally conscious state (93%, 95% CI 85-98) and high congruence (85%, 77-90) with behavioural CRS-R scores. The active fMRI method was less sensitive at diagnosis...

  9. Emerging role of functional brain MRI in low-grade glioma surgery

    DEFF Research Database (Denmark)

    Friismose, Ancuta; Traise, Peter; Markovic, Ljubo

    Learning objectives 1. To describe the use of functional MRI (fMRI) in cranial surgery planning for patients with low-grade gliomas (LGG). 2. To show the increasing importance of fMRI in the clinical setting. Background LGG include brain tumors classified by the World Health Organization as grade I...... be used to map eloquent cortex areas, thus minimizing postoperative deficits and improving surgical performance. Findings and procedure details Patients diagnosed with low-grade gliomas located in eloquent brain areas undergo fMRI prior to surgery. The exams are performed on a 3T MR system (Achieva TX....... Language comprehension and visual tasks can be added to visualize Wernicke’s area or the visual cortex. Diffusion tensor imaging (DTI) is used to map nerve tract course relative to the tumour. Conclusion FMRI has proven its clinical utility in locating eloquent brain areas with relation to tumor site...

  10. Determination of language lateralization using functional MRI during the performance of shiritori tasks in neurosurgery patients

    International Nuclear Information System (INIS)

    Takayama, Hideichi; Kobayashi, Masahito; Sugishita, Morihiro; Onozuka, Satoshi; Kawase, Takeshi

    2001-01-01

    Assessment of language lateralization is crucial in patients considered for neurological surgery. The authors used functional MRI (fMRI) in conjunction with shiritori, a kind of word-generation task as paradigms, to determine language lateralization in the patients. We used a 1.5 Tesla magnetic resonance imaging devise with an echo-planar imaging sequence. Thirty-two patients undergoing neurological surgery would alternately rest and silently perform shiritori during fMRI acquisition. Language lateralization was determined in 29 out of 32 patients. Twenty-two patients were considered as left-hemisphere dominant and seven were right-hemisphere dominant. Brain activation was seen in the prefrontal area, premotor area, superior temporal gyrus and parietal lobe of the dominant hemisphere, which is consistent with the results in normal adults. Language lateralization was particularly useful in a case of meningioma in the left lateral ventricle and in a case of AVM in the left temporoparietal region. fMRI with shiritori tasks revealed right-hemisphere dominance in both cases, which was also confirmed by intracarotid amobarbital (Wada) testing. Both lesions were treated successfully without causing any further deficit to the patients' language function. These results suggest that fMRI with shiritori tasks can be used to assess language lateralization non-invasively, compared with the current techniques, such as intracarotid amobarbital testing and cortical electrostimulation mapping. Thus, fMRI with shiritori tasks has significant clinical potential as a presurgical evaluation tool. (author)

  11. Estimation of gas and tissue lung volumes by MRI: functional approach of lung imaging.

    Science.gov (United States)

    Qanadli, S D; Orvoen-Frija, E; Lacombe, P; Di Paola, R; Bittoun, J; Frija, G

    1999-01-01

    The purpose of this work was to assess the accuracy of MRI for the determination of lung gas and tissue volumes. Fifteen healthy subjects underwent MRI of the thorax and pulmonary function tests [vital capacity (VC) and total lung capacity (TLC)] in the supine position. MR examinations were performed at inspiration and expiration. Lung volumes were measured by a previously validated technique on phantoms. Both individual and total lung volumes and capacities were calculated. MRI total vital capacity (VC(MRI)) was compared with spirometric vital capacity (VC(SP)). Capacities were correlated to lung volumes. Tissue volume (V(T)) was estimated as the difference between the total lung volume at full inspiration and the TLC. No significant difference was seen between VC(MRI) and VC(SP). Individual capacities were well correlated (r = 0.9) to static volume at full inspiration. The V(T) was estimated to be 836+/-393 ml. This preliminary study demonstrates that MRI can accurately estimate lung gas and tissue volumes. The proposed approach appears well suited for functional imaging of the lung.

  12. Determination of language lateralization using functional MRI during the performance of shiritori tasks in neurosurgery patients

    Energy Technology Data Exchange (ETDEWEB)

    Takayama, Hideichi; Kobayashi, Masahito [Mihara Memorial Hospital, Isesaki, Gunma (Japan); Sugishita, Morihiro; Onozuka, Satoshi; Kawase, Takeshi

    2001-03-01

    Assessment of language lateralization is crucial in patients considered for neurological surgery. The authors used functional MRI (fMRI) in conjunction with shiritori, a kind of word-generation task as paradigms, to determine language lateralization in the patients. We used a 1.5 Tesla magnetic resonance imaging devise with an echo-planar imaging sequence. Thirty-two patients undergoing neurological surgery would alternately rest and silently perform shiritori during fMRI acquisition. Language lateralization was determined in 29 out of 32 patients. Twenty-two patients were considered as left-hemisphere dominant and seven were right-hemisphere dominant. Brain activation was seen in the prefrontal area, premotor area, superior temporal gyrus and parietal lobe of the dominant hemisphere, which is consistent with the results in normal adults. Language lateralization was particularly useful in a case of meningioma in the left lateral ventricle and in a case of AVM in the left temporoparietal region. fMRI with shiritori tasks revealed right-hemisphere dominance in both cases, which was also confirmed by intracarotid amobarbital (Wada) testing. Both lesions were treated successfully without causing any further deficit to the patients' language function. These results suggest that fMRI with shiritori tasks can be used to assess language lateralization non-invasively, compared with the current techniques, such as intracarotid amobarbital testing and cortical electrostimulation mapping. Thus, fMRI with shiritori tasks has significant clinical potential as a presurgical evaluation tool. (author)

  13. Preliminary evaluation of MRI-derived input function for quantitative measurement of glucose metabolism in an integrated PET-MRI

    International Nuclear Information System (INIS)

    Anazodo, Udunna; Kewin, Matthew; Finger, Elizabeth; Thiessen, Jonathan; Hadway, Jennifer; Butler, John; Pavlosky, William; Prato, Frank; Thompson, Terry; St Lawrence, Keith

    2015-01-01

    PET semi-quantitative methods such as relative uptake value can be robust but offer no biological information and do not account for intra-subject variability in tracer administration or clearance. Simultaneous multimodal measurements that combine PET and MRI not only permit crucial multiparametric measurements, it provides means of applying tracer kinetic modelling without the need for serial arterial blood sampling. In this study we adapted an image-derived input function (IDIF) method to improve characterization of glucose metabolism in an ongoing dementia study. Here we present preliminary results in a small group of frontotemporal dementia patients and controls. IDIF was obtained directly from dynamic PET data guided by regions of interest drawn on carotid vessels on high resolution T1-weighted MR Images. IDIF was corrected for contamination of non-arterial voxels. A validation of the method was performed in a porcine model in a PET-CT scanner comparing IDIF to direct arterial blood samples. Metabolic rate of glucose (CMRglc) was measured voxel-by-voxel in gray matter producing maps that were compared between groups. Net influx rate (Ki) and global mean CMRglc are reported. A good correlation (r = 0.9 p<0.0001) was found between corrected IDIF and input function measured from direct arterial blood sampling in the validation study. In 3 FTD and 3 controls, a trend towards hypometabolism was found in frontal, temporal and parietal lobes similar to significant differences previously reported by other groups. The global mean CMRglc and Ki observed in control subjects are in line with previous reports. In general, kinetic modelling of PET-FDG using an MR-IDIF can improve characterization of glucose metabolism in dementia. This method is feasible in multimodal studies that aim to combine PET molecular imaging with MRI as dynamic PET can be acquired along with multiple MRI measurements.

  14. Preliminary evaluation of MRI-derived input function for quantitative measurement of glucose metabolism in an integrated PET-MRI

    Energy Technology Data Exchange (ETDEWEB)

    Anazodo, Udunna; Kewin, Matthew [Lawson Health Research Institute, Department of Medical Biophysics, Western University, London, Ontario (Canada); Finger, Elizabeth [Department of Clinical Neurological Sciences, Western University, London, Ontario (Canada); Thiessen, Jonathan; Hadway, Jennifer; Butler, John [Lawson Health Research Institute, Department of Medical Biophysics, Western University, London, Ontario (Canada); Pavlosky, William [Diagnostic Imaging, St Joseph' s Health Care, London, Ontario (Canada); Prato, Frank; Thompson, Terry; St Lawrence, Keith [Lawson Health Research Institute, Department of Medical Biophysics, Western University, London, Ontario (Canada)

    2015-05-18

    PET semi-quantitative methods such as relative uptake value can be robust but offer no biological information and do not account for intra-subject variability in tracer administration or clearance. Simultaneous multimodal measurements that combine PET and MRI not only permit crucial multiparametric measurements, it provides means of applying tracer kinetic modelling without the need for serial arterial blood sampling. In this study we adapted an image-derived input function (IDIF) method to improve characterization of glucose metabolism in an ongoing dementia study. Here we present preliminary results in a small group of frontotemporal dementia patients and controls. IDIF was obtained directly from dynamic PET data guided by regions of interest drawn on carotid vessels on high resolution T1-weighted MR Images. IDIF was corrected for contamination of non-arterial voxels. A validation of the method was performed in a porcine model in a PET-CT scanner comparing IDIF to direct arterial blood samples. Metabolic rate of glucose (CMRglc) was measured voxel-by-voxel in gray matter producing maps that were compared between groups. Net influx rate (Ki) and global mean CMRglc are reported. A good correlation (r = 0.9 p<0.0001) was found between corrected IDIF and input function measured from direct arterial blood sampling in the validation study. In 3 FTD and 3 controls, a trend towards hypometabolism was found in frontal, temporal and parietal lobes similar to significant differences previously reported by other groups. The global mean CMRglc and Ki observed in control subjects are in line with previous reports. In general, kinetic modelling of PET-FDG using an MR-IDIF can improve characterization of glucose metabolism in dementia. This method is feasible in multimodal studies that aim to combine PET molecular imaging with MRI as dynamic PET can be acquired along with multiple MRI measurements.

  15. Quantifying functional connectivity in multi-subject fMRI data using component models

    DEFF Research Database (Denmark)

    Madsen, Kristoffer Hougaard; Churchill, Nathan William; Mørup, Morten

    2017-01-01

    of functional connectivity, evaluated on both simulated and experimental resting-state fMRI data. It was demonstrated that highly flexible subject-specific component subspaces, as well as very constrained average models, are poor predictors of whole-brain functional connectivity, whereas the best...

  16. Functional MRI studies of the neural mechanisms of human brain attentional networks

    International Nuclear Information System (INIS)

    Hao Jing; Li Kuncheng; Chen Qi; Wang Yan; Peng Xiaozhe; Zhou Xiaolin

    2005-01-01

    Objective: To identify the neural mechanisms of the anterior attention network (AAN) and posterior attention network (PAN) , investigate the possible interaction between them with event-related functional MRI(ER-fMRI). Methods: Eight right-handed healthy volunteers participated in the experiment designed with inhibition of return in visual orienting and Stroop color-word interference effect. The fMRI data were collected on Siemens 1.5 T Sonata MRI systems and analyzed by AFNI to generate the activation map. Results: The data sets from 6 of 8 subjects were used in the study. The functional localizations of the Stroop and IOR, which manifest the function of the AAN and PAN respectively, were consistent with previous imaging researches. On cued locations, left inferior parietal lobule (IPL), area MT/V5, right dorsolateral prefrontal cortex (DLPFC) and left anterior cingulated cortex (ACC) were significantly activated. On uncued locations, right superior parietal lobule (SPL) and bilateral area MT/V5 were significantly activated. Conclusion: The AAN exerts control over the PAN, while its function can be in turn modulated by the PAN. There are interaction between the AAN and PAN. In addition, it is also proved that ER-fMRI is a feasible method to revise preexisting cognitive model and theory. (authors)

  17. Super-resolution microscopy reveals functional organization of dopamine transporters into cholesterol and neuronal activity-dependent nanodomains

    DEFF Research Database (Denmark)

    Rahbek-Clemmensen, Troels; Lycas, Matthew D.; Erlendsson, Simon

    2017-01-01

    is dynamically sequestrated into cholesterol-dependent nanodomains in the plasma membrane of presynaptic varicosities and neuronal projections of dopaminergic neurons. Stochastic optical reconstruction microscopy reveals irregular dopamine transporter nanodomains (∼70 nm mean diameter) that were highly sensitive...... to cholesterol depletion. Live photoactivated localization microscopy shows a similar dopamine transporter membrane organization in live heterologous cells. In neurons, dual-color dSTORM shows that tyrosine hydroxylase and vesicular monoamine transporter-2 are distinctively localized adjacent to...

  18. Cognitive function and MRI findings in very low birth weight infants

    Energy Technology Data Exchange (ETDEWEB)

    Imamura, Atsuko; Takagishi, Yuka; Takada, Satoru; Uetani, Yoshiyuki; Nakamura, Toru; Nakamura, Hajime [Kobe Univ. (Japan). School of Medicine; Inagaki, Yuko

    1996-07-01

    Twenty-two very low birth weight infants at preschool ages of 5-6 years were studied to clarify the correlation between cognitive function and MRI findings. Cognitive function was evaluated by the Wechsler Intelligence Scale for Children-Revised (WISC-R) and the Frostig developmental test of visual perception. Ventricular enlargement, assessed by the bioccipital index (B.I.) measured on MRI, was correlated to cognitive disorders. Children with periventricular high intensity areas (T{sub 2}-weighted images) extending from the posterior periventricular region to the parietal lobe tend to highly suffer from cerebral palsy and visuoperceptual impairment. These results indicate that the disorders of cognitive function in very low birth weight infants were caused by a damage of association fibers in periventricular areas which was detectable by MRI. (author)

  19. Cognitive function and MRI findings in very low birth weight infants

    International Nuclear Information System (INIS)

    Imamura, Atsuko; Takagishi, Yuka; Takada, Satoru; Uetani, Yoshiyuki; Nakamura, Toru; Nakamura, Hajime; Inagaki, Yuko.

    1996-01-01

    Twenty-two very low birth weight infants at preschool ages of 5-6 years were studied to clarify the correlation between cognitive function and MRI findings. Cognitive function was evaluated by the Wechsler Intelligence Scale for Children-Revised (WISC-R) and the Frostig developmental test of visual perception. Ventricular enlargement, assessed by the bioccipital index (B.I.) measured on MRI, was correlated to cognitive disorders. Children with periventricular high intensity areas (T 2 -weighted images) extending from the posterior periventricular region to the parietal lobe tend to highly suffer from cerebral palsy and visuoperceptual impairment. These results indicate that the disorders of cognitive function in very low birth weight infants were caused by a damage of association fibers in periventricular areas which was detectable by MRI. (author)

  20. Does functional MRI detect activation in white matter? A review of emerging evidence, issues, and future directions

    Science.gov (United States)

    Gawryluk, Jodie R.; Mazerolle, Erin L.; D'Arcy, Ryan C. N.

    2014-01-01

    Functional magnetic resonance imaging (fMRI) is a non-invasive technique that allows for visualization of activated brain regions. Until recently, fMRI studies have focused on gray matter. There are two main reasons white matter fMRI remains controversial: (1) the blood oxygen level dependent (BOLD) fMRI signal depends on cerebral blood flow and volume, which are lower in white matter than gray matter and (2) fMRI signal has been associated with post-synaptic potentials (mainly localized in gray matter) as opposed to action potentials (the primary type of neural activity in white matter). Despite these observations, there is no direct evidence against measuring fMRI activation in white matter and reports of fMRI activation in white matter continue to increase. The questions underlying white matter fMRI activation are important. White matter fMRI activation has the potential to greatly expand the breadth of brain connectivity research, as well as improve the assessment and diagnosis of white matter and connectivity disorders. The current review provides an overview of the motivation to investigate white matter fMRI activation, as well as the published evidence of this phenomenon. We speculate on possible neurophysiologic bases of white matter fMRI signals, and discuss potential explanations for why reports of white matter fMRI activation are relatively scarce. We end with a discussion of future basic and clinical research directions in the study of white matter fMRI. PMID:25152709

  1. Dynamic changes in dopamine neuron function after DNSP-11 treatment: effects in vivo and increased ERK 1/2 phosphorylation in vitro.

    Science.gov (United States)

    Fuqua, Joshua L; Littrell, Ofelia M; Lundblad, Martin; Turchan-Cholewo, Jadwiga; Abdelmoti, Lina G; Galperin, Emilia; Bradley, Luke H; Cass, Wayne A; Gash, Don M; Gerhardt, Greg A

    2014-04-01

    Glial cell-line derived neurotrophic factor (GDNF) has demonstrated robust effects on dopamine (DA) neuron function and survival. A post-translational processing model of the human GDNF proprotein theorizes the formation of smaller, amidated peptide(s) from the proregion that exhibit neurobiological function, including an 11-amino-acid peptide named dopamine neuron stimulating peptide-11 (DNSP-11). A single treatment of DNSP-11 was delivered to the substantia nigra in the rat to investigate effects on DA-neuron function. Four weeks after treatment, potassium (K+) and D-amphetamine evoked DA release were studied in the striatum using microdialysis. There were no significant changes in DA-release after DNSP-11 treatment determined by microdialysis. Dopamine release was further examined in discrete regions of the striatum using high-speed chronoamperometry at 1-, 2-, and 4-weeks after DNSP-11 treatment. Two weeks after DNSP-11 treatment, potassium-evoked DA release was increased in specific subregions of the striatum. However, spontaneous locomotor activity was unchanged by DNSP-11 treatment. In addition, we show that a single treatment of DNSP-11 in the MN9D dopaminergic neuronal cell line results in phosphorylation of ERK1/2, which suggests a novel cellular mechanism responsible for increases in DA function. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Striatal Dopamine D2/D3 Receptor Availability Is Associated with Executive Function in Healthy Controls but Not Methamphetamine Users.

    Directory of Open Access Journals (Sweden)

    Michael E Ballard

    Full Text Available Dopamine D2/D3 receptor availability in the striatum has been linked with executive function in healthy individuals, and is below control levels among drug addicts, possibly contributing to diminished executive function in the latter group. This study tested for an association of striatal D2/D3 receptor availability with a measure of executive function among research participants who met DSM-IV criteria for methamphetamine dependence.Methamphetamine users and non-user controls (n = 18 per group completed the Wisconsin Card Sorting Test and positron emission tomography with [18F]fallypride.The methamphetamine users displayed significantly lower striatal D2/D3 receptor availability on average than controls after controlling for age and education (p = 0.008, but they did not register greater proportions of either perseverative or non-perseverative errors when controlling for education (both ps ≥ 0.622. The proportion of non-perseverative, but not perseverative, errors was negatively correlated with striatal D2/D3 receptor availability among controls (r = -0.588, p = 0.010, but not methamphetamine users (r = 0.281, p = 0.258, and the group-wise interaction was significant (p = 0.030.These results suggest that cognitive flexibility, as measured by perseverative errors on the Wisconsin Card Sorting Test, is not determined by signaling through striatal D2/D3 receptors in healthy controls, and that in stimulant abusers, who have lower D2/D3 receptor availability, compensation can effectively maintain other executive functions, which are associated with D2/D3 receptor signaling in controls.

  3. Cryopreservation Maintains Functionality of Human iPSC Dopamine Neurons and Rescues Parkinsonian Phenotypes In Vivo

    Directory of Open Access Journals (Sweden)

    Dustin R. Wakeman

    2017-07-01

    Full Text Available A major challenge for clinical application of pluripotent stem cell therapy for Parkinson's disease (PD is large-scale manufacturing and cryopreservation of neurons that can be efficiently prepared with minimal manipulation. To address this obstacle, midbrain dopamine neurons were derived from human induced pluripotent stem cells (iPSC-mDA and cryopreserved in large production lots for biochemical and transplantation studies. Cryopreserved, post-mitotic iPSC-mDA neurons retained high viability with gene, protein, and electrophysiological signatures consistent with midbrain floor-plate lineage. To test therapeutic efficacy, cryopreserved iPSC-mDA neurons were transplanted without subculturing into the 6-OHDA-lesioned rat and MPTP-lesioned non-human-primate models of PD. Grafted neurons retained midbrain lineage with extensive fiber innervation in both rodents and monkeys. Behavioral assessment in 6-OHDA-lesioned rats demonstrated significant reversal in functional deficits up to 6 months post transplantation with reinnervation of the host striatum and no aberrant growth, supporting the translational development of pluripotent cell-based therapies in PD.

  4. Carbon nanotubes-functionalized urchin-like In2S3 nanostructure for sensitive and selective electrochemical sensing of dopamine

    International Nuclear Information System (INIS)

    Yang, Z.; Huang, X.; Li, J.; Zhang, Y.; Yu, S.; Xu, Q.; Hu, X.

    2012-01-01

    Urchin-like In 2 S 3 nanostructures were functionalized with multi-walled carbon nanotubes (MWCNTs) and deposited on a glassy carbon electrode (GCE) to obtain a new kind of sensor for dopamine (DA). The new electrode was characterized using scanning electron microscopy, energy dispersive X-ray spectroscopy, cyclic voltammetry and differential pulse voltammetry. It is found that the current response toward DA is significantly enhanced compared to that of a bare GCE or a GCE modified with MWCNTs. The peak separation between DA and ascorbic acid (AA) is up to 225 mV. The new electrode also has improved selectivity for DA over AA compared to the bare electrode. The new DA sensor has a wide linear range (0.5-300 μM), high sensitivity (594.9 μA mM -1 cm -2 ) and low detection limit (0.1 μM). CNTs wrapped on urchin-like nanostructures remarkable improve its electrocatalytic activity and thus provide a promising strategy to develop excellent composite materials for electrochemical sensing. (author)

  5. The dual-state theory of prefrontal cortex dopamine function with relevance to catechol-o-methyltransferase genotypes and schizophrenia.

    Science.gov (United States)

    Durstewitz, Daniel; Seamans, Jeremy K

    2008-11-01

    There is now general consensus that at least some of the cognitive deficits in schizophrenia are related to dysfunctions in the prefrontal cortex (PFC) dopamine (DA) system. At the cellular and synaptic level, the effects of DA in PFC via D1- and D2-class receptors are highly complex, often apparently opposing, and hence difficult to understand with regard to their functional implications. Biophysically realistic computational models have provided valuable insights into how the effects of DA on PFC neurons and synaptic currents as measured in vitro link up to the neural network and cognitive levels. They suggest the existence of two discrete dynamical regimes, a D1-dominated state characterized by a high energy barrier among different network patterns that favors robust online maintenance of information and a D2-dominated state characterized by a low energy barrier that is beneficial for flexible and fast switching among representational states. These predictions are consistent with a variety of electrophysiological, neuroimaging, and behavioral results in humans and nonhuman species. Moreover, these biophysically based models predict that imbalanced D1:D2 receptor activation causing extremely low or extremely high energy barriers among activity states could lead to the emergence of cognitive, positive, and negative symptoms observed in schizophrenia. Thus, combined experimental and computational approaches hold the promise of allowing a detailed mechanistic understanding of how DA alters information processing in normal and pathological conditions, thereby potentially providing new routes for the development of pharmacological treatments for schizophrenia.

  6. Detection of focal epileptic activity using combined simultaneous electroencephalogram-functional MRI

    International Nuclear Information System (INIS)

    Zhang Zhiqiang; Lu Guangming; Tian Lei; Sun Kanjian; Tan Qifu; Zhu Jianguo; Nie Cong; Hao Shaowei; Jiang Li; Liu Yijun

    2007-01-01

    Objective: To observe the brain activation of interictal epiletiform discharges (IEDs) and to localize the epileptogenic foci of epilepsy. Methods: The electroencephalogram (EEG) and functional MRI data of 12 focal epileptic patients were acquired using a combination of EEG and functional MRI simultaneously. The IEDs onset time detected with EEG were set as the time parameters in an event- related paradigm of functional MRI analysis. The spatial and temporal characters of IEDs activation were analyzed in detail. In order to confirm the consistency of this method, all patients were scanned repeatedly and the results were correlated with clinical evaluation. Results: Of the 12 patients, valid data from EEG- fMRI were obtained from 10 patients in a total of 18 sessions. Compared with the structural foci, the epileptic foci localization results of eleven sessions were good, five sessions were fairly good, and two sessions were poor. The results obtained from six patients in two separate sessions were concordant, respectively. Moreover, thalamic activation was detected in ten sessions, cerebellar activation was detected in all sessions, and the deactivation was found in the default mode loci in nine sessions. Conclusion: The method of performing EEG and fMRI simultaneously can potentially be a useful tool in epilepsy research. (authors)

  7. Pharmaco fMRI: Determining the functional anatomy of the effects of medication.

    Science.gov (United States)

    Wandschneider, Britta; Koepp, Matthias J

    2016-01-01

    Functional MRI studies have helped to elucidate underlying mechanisms in complex neurological and neuropsychiatric disorders. Disease processes often involve complex large-scale network interactions, extending beyond the presumed main disease focus. Given both the complexity of the clinical phenotype and the underlying dysfunctional brain circuits, so called pharmaco-fMRI (ph-MRI) studies probe pharmacological effects on functional neuro-anatomy, and can help to determine early treatment response, mechanisms of drug efficacy and side effects, and potentially advance CNS drug development. In this review, we discuss recent ph-MRI research in three major neuropsychiatric and neurological disorders and associated network alterations, namely selective serotonin and noradrenergic reuptake inhibitors in affective disorders and emotional processing circuits; antiepileptic drugs in epilepsy and cognitive networks; and stimulants in attention-deficit/hyperactivity disorder and networks of attention control. We conclude that ph-MRI studies show consistent and reproducible changes on disease relevant networks, and prove sensitive to early pharmacological effects on functional anatomy associated with disease. Further CNS drug research and development would benefit greatly from improved disease phenotyping, or biomarkers, using advanced imaging techniques.

  8. Pharmaco fMRI: Determining the functional anatomy of the effects of medication

    Directory of Open Access Journals (Sweden)

    Britta Wandschneider

    2016-01-01

    Full Text Available Functional MRI studies have helped to elucidate underlying mechanisms in complex neurological and neuropsychiatric disorders. Disease processes often involve complex large-scale network interactions, extending beyond the presumed main disease focus. Given both the complexity of the clinical phenotype and the underlying dysfunctional brain circuits, so called pharmaco-fMRI (ph-MRI studies probe pharmacological effects on functional neuro-anatomy, and can help to determine early treatment response, mechanisms of drug efficacy and side effects, and potentially advance CNS drug development. In this review, we discuss recent ph-MRI research in three major neuropsychiatric and neurological disorders and associated network alterations, namely selective serotonin and noradrenergic reuptake inhibitors in affective disorders and emotional processing circuits; antiepileptic drugs in epilepsy and cognitive networks; and stimulants in attention-deficit/hyperactivity disorder and networks of attention control. We conclude that ph-MRI studies show consistent and reproducible changes on disease relevant networks, and prove sensitive to early pharmacological effects on functional anatomy associated with disease. Further CNS drug research and development would benefit greatly from improved disease phenotyping, or biomarkers, using advanced imaging techniques.

  9. Dopamine-functionalized InP/ZnS quantum dots as fluorescence probes for the detection of adenosine in microfluidic chip

    OpenAIRE

    An, Seong Soo; Ankireddy,Seshadri Reddy; Kim,Jongsung

    2015-01-01

    Seshadri Reddy Ankireddy, Jongsung Kim Department of Chemical and Biological Engineering, Gachon University, Seongnam, Gyeonggi-Do, South Korea Abstract: Microbeads are frequently used as solid supports for biomolecules such as proteins and nucleic acids in heterogeneous microfluidic assays. Chip-based, quantum dot (QD)-bead-biomolecule probes have been used for the detection of various types of DNA. In this study, we developed dopamine (DA)-functionalized InP/ZnS QDs (QDs-DA) as fluorescen...

  10. Assessment of language lateralization with functional magnetic resonance imaging (fMRI)

    International Nuclear Information System (INIS)

    Salagierska-Barwinska, A.; Goraj, B.

    2004-01-01

    fMRI offers powerful methods to delineate which brain regions are engaged in language processing in the intact brain. Until now hemisphere dominance for language has been usually assessed by means of the intraoperative methods: the Wada test or electrocortical stimulation mapping. Recently functional MRI becomes the valuable method in determining hemisphere dominance for language. fMRI study was proved to be concordant with invasive measures. fMRI was carried out in 30 healthy selected participants (15 females: 10 strongly right-handed and 5 strongly left-handed; 15 males: 10 strongly right-handed and 5 strongly left-handed). The subject's handedness was assessed by standardized psychological tests inter alia the 'lateralization inventory'. Two different language tasks were used: a verb generation task and a phonological task. Subjects were scanned,while performing experimental block. The block contained alternately 8 active (language task) and 8 control conditions. Statistical analysis of evoked blood oxygenation level-dependent BOLD) responses, measured with echo planar imagining (1.5 T) were used. During a verb generation task in strongly right or left handed subjects the inferior frontal region was activated on the side opposite to the subject's handedness determined by the psychological test. Our fMRI studies demonstrated no gender effects on brain during these language tasks. Our study suggests that fMRI is a good device for the study of the language organization. The advantage of fMRI is its capacity for exact localization of activated areas. fMRI together with adequate neurolinguistic test could be promising routine preoperative tool in identification hemisphere dominance for language. These results encourage to further investigation for evaluating correlation in patients with brain injuries. (author)

  11. Relationship between functional connectivity and motor function assessment in stroke patients with hemiplegia: a resting-state functional MRI study

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ye; Wang, Li; Zhang, Jingna; Sang, Linqiong; Li, Pengyue; Qiu, Mingguo [Third Military Medical University, Department of Medical Imaging, College of Biomedical Engineering, Chongqing (China); Liu, Hongliang; Yan, Rubing [Third Military Medical University, Department of Rehabilitation, Southwest Hospital, Chongqing (China); Yang, Jun; Wang, Jian [Third Military Medical University, Department of Radiology, Southwest Hospital, Chongqing (China)

    2016-05-15

    Resting-state functional magnetic resonance imaging (fMRI) has been used to examine the brain mechanisms of stroke patients with hemiplegia, but the relationship between functional connectivity (FC) and treatment-induced motor function recovery has not yet been fully investigated. This study aimed to identify the brain FC changes in stroke patients and study the relationship between FC and motor function assessment using the resting-state fMRI. Seventeen stroke patients with hemiplegia and fifteen healthy control subjects (HCSs) were recruited in this study. We compared the FC between the ipsilesional primary motor cortex (M1) and the whole brain of the patients with the FC of the HCSs and studied the FC changes in the patients before and after conventional rehabilitation and motor imagery therapy. Additionally, correlations between the FC change and motor function of the patients were studied. Compared to the HCSs, the FC in the patient group was significantly increased between the ipsilesional M1 and the ipsilesional inferior parietal cortex, frontal gyrus, supplementary motor area (SMA), and contralesional angular and decreased between the ipsilesional M1 and bilateral M1. After the treatment, the FC between the ipsilesional M1 and contralesional M1 increased while the FC between the ipsilesional M1 and ipsilesional SMA and paracentral lobule decreased. A statistically significant correlation was found between the FC change in the bilateral M1 and the Fugl-Meyer assessment (FMA) score change. Our results revealed an abnormal motor network after stroke and suggested that the FC could serve as a biomarker of motor function recovery in stroke patients with hemiplegia. (orig.)

  12. Relationship between functional connectivity and motor function assessment in stroke patients with hemiplegia: a resting-state functional MRI study

    International Nuclear Information System (INIS)

    Zhang, Ye; Wang, Li; Zhang, Jingna; Sang, Linqiong; Li, Pengyue; Qiu, Mingguo; Liu, Hongliang; Yan, Rubing; Yang, Jun; Wang, Jian

    2016-01-01

    Resting-state functional magnetic resonance imaging (fMRI) has been used to examine the brain mechanisms of stroke patients with hemiplegia, but the relationship between functional connectivity (FC) and treatment-induced motor function recovery has not yet been fully investigated. This study aimed to identify the brain FC changes in stroke patients and study the relationship between FC and motor function assessment using the resting-state fMRI. Seventeen stroke patients with hemiplegia and fifteen healthy control subjects (HCSs) were recruited in this study. We compared the FC between the ipsilesional primary motor cortex (M1) and the whole brain of the patients with the FC of the HCSs and studied the FC changes in the patients before and after conventional rehabilitation and motor imagery therapy. Additionally, correlations between the FC change and motor function of the patients were studied. Compared to the HCSs, the FC in the patient group was significantly increased between the ipsilesional M1 and the ipsilesional inferior parietal cortex, frontal gyrus, supplementary motor area (SMA), and contralesional angular and decreased between the ipsilesional M1 and bilateral M1. After the treatment, the FC between the ipsilesional M1 and contralesional M1 increased while the FC between the ipsilesional M1 and ipsilesional SMA and paracentral lobule decreased. A statistically significant correlation was found between the FC change in the bilateral M1 and the Fugl-Meyer assessment (FMA) score change. Our results revealed an abnormal motor network after stroke and suggested that the FC could serve as a biomarker of motor function recovery in stroke patients with hemiplegia. (orig.)

  13. Poly(zwitterionic liquids) functionalized polypyrrole/graphene oxide nanosheets for electrochemically detecting dopamine at low concentration

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Hui; Liang, Jiachen; Ji, Chunguang; Zhang, Haifeng; Pei, Qi; Zhang, Yuyang; Zhang, Yu [Liaoning Key Laboratory for Green Synthesis and Preparative Chemistry of Advanced Materials, College of Chemistry, Liaoning University, Shenyang 110036 (China); Hisaeda, Yoshio [Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Song, Xi-Ming, E-mail: songlab@lnu.edu.cn [Liaoning Key Laboratory for Green Synthesis and Preparative Chemistry of Advanced Materials, College of Chemistry, Liaoning University, Shenyang 110036 (China); Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

    2016-08-01

    Poly(3-(1-vinylimidazolium-3-yl)propane-1-sulfonate) (PVIPS), a novel kind of poly(zwitterionic liquids) (PZILs) containing both imidazolium cation and sulfonate anion, was successfully modified on the surface of polypyrrole/graphene oxide nanosheets (PPy/GO) by covalent bonding. The obtained novel PZILs functionalized PPy/GO nanosheets (PVIPS/PPy/GO) modified glassy carbon electrode (GCE) presented the excellent electrochemical catalytic activity towards dopamine (DA) with high stability, sensitivity, selectivity and wide linear range (40–1220 nM), especially having a lower detection limit (17.3 nM). The excellent analytical performance is attributed to the strongly negative charges on the surface of modified GCE in aqueous solution, which is different from conventional poly(ionic liquids) modified GCE. DA cations could be quickly enriched on the electrode surface by electrostatic interaction in solution due to the existence of −SO{sub 3}{sup −} groups with negative charge at the end of pendant groups in zwitterionic PVIPS, resulting in a change of the electrons transmission mode in the oxidation of DA, that is, from a typical diffusion-controlled process at conventional poly(1-vinyl-3-ethylimidazole bromide) (PVEIB)/PPy/GO modified GCE to a typical surface-controlled process. - Graphical Abstract: Novel poly(zwitterionic liquids) functionalized polypyrrole/graphene oxide nanosheets were successfully synthesized and presented an excellent performance for determination to DA. Display Omitted - Highlights: • Zwitterionic PVIPS functionalized PPy/GO nanosheets were successfully synthesized. • Their surface charge property has been obviously changed to electronegativity. • The excellent electrochemical catalytic activities towards DA were achieved. • −SO{sub 3}{sup −} groups with negative charge changed the transmission mode of electrons. • PVIPS/PPy/GO can act as an electrode material for detecting DA at low concentration.

  14. Effects of anesthesia on renal function and metabolism in rats assessed by hyperpolarized MRI

    DEFF Research Database (Denmark)

    Qi, Haiyun; Mariager, Christian Østergaard; Lindhardt, Jakob

    2018-01-01

    . In the present study, we aimed to investigate the renal functional and metabolic consequences of 3 typical rodent anesthetics used in preclinical MRI: sevoflurane, inaction, and a mixture of fentanyl, fluanisone, and midazolam (FFM). METHODS: The renal effects of 3 different classes of anesthetics (inactin......, servoflurane, and FFM) were investigated using functional and metabolic MRI. The renal glucose metabolism and hemodynamics was characterized with hyperpolarized [1-13C]pyruvate MRI and by DCE imaging. RESULTS: Rats receiving sevoflurane or FFM had blood glucose levels that were 1.3-fold to 1.4-fold higher than...... rats receiving inactin. A 2.9-fold and 4.8-fold increased13C-lactate/13C-pyruvate ratio was found in the FFM mixture anesthetized group compared with the sevoflurane and the inactin anesthetized groups. The FFM anesthesia resulted in a 50% lower renal plasma flow compared with the sevoflurane...

  15. Functional and structural abnormalities associated with empathy in patients with schizophrenia: An fMRI and VBM study

    OpenAIRE

    Singh, Sadhana; Modi, Shilpi; Goyal, Satnam; Kaur, Prabhjot; Singh, Namita; Bhatia, Triptish; Deshpande, Smita N; Khushu, Subash

    2015-01-01

    Empathy deficit is a core feature of schizophrenia which may lead to social dysfunction. The present study was carried out to investigate functional and structural abnormalities associated with empathy in patients with schizophrenia using functional magnetic resonance imaging (fMRI) and voxel-based morphometry (VBM). A sample of 14 schizophrenia patients and 14 healthy control subjects matched for age, sex and education were examined with structural high-resolution T1-weighted MRI; fMRI image...

  16. Bayesian Inference for Functional Dynamics Exploring in fMRI Data

    Directory of Open Access Journals (Sweden)

    Xuan Guo

    2016-01-01

    Full Text Available This paper aims to review state-of-the-art Bayesian-inference-based methods applied to functional magnetic resonance imaging (fMRI data. Particularly, we focus on one specific long-standing challenge in the computational modeling of fMRI datasets: how to effectively explore typical functional interactions from fMRI time series and the corresponding boundaries of temporal segments. Bayesian inference is a method of statistical inference which has been shown to be a powerful tool to encode dependence relationships among the variables with uncertainty. Here we provide an introduction to a group of Bayesian-inference-based methods for fMRI data analysis, which were designed to detect magnitude or functional connectivity change points and to infer their functional interaction patterns based on corresponding temporal boundaries. We also provide a comparison of three popular Bayesian models, that is, Bayesian Magnitude Change Point Model (BMCPM, Bayesian Connectivity Change Point Model (BCCPM, and Dynamic Bayesian Variable Partition Model (DBVPM, and give a summary of their applications. We envision that more delicate Bayesian inference models will be emerging and play increasingly important roles in modeling brain functions in the years to come.

  17. Functional MRI in the Investigation of Blast-Related Traumatic Brain Injury

    Science.gov (United States)

    Graner, John; Oakes, Terrence R.; French, Louis M.; Riedy, Gerard

    2012-01-01

    This review focuses on the application of functional magnetic resonance imaging (fMRI) to the investigation of blast-related traumatic brain injury (bTBI). Relatively little is known about the exact mechanisms of neurophysiological injury and pathological and functional sequelae of bTBI. Furthermore, in mild bTBI, standard anatomical imaging techniques (MRI and computed tomography) generally fail to show focal lesions and most of the symptoms present as subjective clinical functional deficits. Therefore, an objective test of brain functionality has great potential to aid in patient diagnosis and provide a sensitive measurement to monitor disease progression and treatment. The goal of this review is to highlight the relevant body of blast-related TBI literature and present suggestions and considerations in the development of fMRI studies for the investigation of bTBI. The review begins with a summary of recent bTBI publications followed by discussions of various elements of blast-related injury. Brief reviews of some fMRI techniques that focus on mental processes commonly disrupted by bTBI, including working memory, selective attention, and emotional processing, are presented in addition to a short review of resting state fMRI. Potential strengths and weaknesses of these approaches as regards bTBI are discussed. Finally, this review presents considerations that must be made when designing fMRI studies for bTBI populations, given the heterogeneous nature of bTBI and its high rate of comorbidity with other physical and psychological injuries. PMID:23460082

  18. Functional alterations of V1 cortex in patients with primary open angle glaucoma using functional MRI retinotopic mapping

    International Nuclear Information System (INIS)

    Shi Linping; Cai Ping; Li Changying; Li Xueqin; Xie Bing; Li Sha; Liu Ting; Chen Xing; Shi Yanshu; Wang Jian

    2011-01-01

    Objective: To evaluate the functional changes of visual cortex (V1) in patients with primary open angle glaucoma (POAG) by fMRI retinotopic mapping technology. Methods: Fifteen POAG patients and 15 healthy volunteers underwent stimulations with fMRI retinotopic mapping stimulus and contrast-reversing checkerboard patterns stimulus on a Siemens Trio 3.0 T MRI whole-body scanner for functional data collection. Comparisons of V1 fMRI responses between the glaucomatous eyes and the healthy eyes of the patients were carried out using paired samples t-test, while independent samples t-test was used to compare V1 fMRI responses and activations between the healthy eyes of patients and the age-, gender- and side- matched eyes of normal people. Differences of V1 cortical functions and visual functions were analyzed by linear correlation analysis when the glaucomatous and the healthy eyes were simulated individually., Results: (1) V1 fMRI responses of the individually stimulated glaucomatous eyes [(1.24±0.72)%] were weaker than those of the healthy eyes [(2.18±0.93)%] (t=4.757, P 0.05). (2) Differences of V1 cortical functions were negatively correlated with those of visual functions in the individually stimulated glaucomatous and healthy eyes (r=-0.887, P< 0.01). (3) The activated area indexes of V1 cortexes in the healthy eyes from patients (0.72±0.12) were lower than those in the matched eyes of normal people (0.85±0.09) (t=-3.801, P<0.01) . Conclusion: Cortical function impairment was in accordance with visual function impairment in glaucoma. Located and quantified measurement with fMRI retinotopic mapping was a useful method for clinical follow-up and evaluation of functional alteration of glaucomatous visual cortex, and a potentially useful means of studying trans-synaptic degeneration of visual pathways of in vivo glaucoma. (authors)

  19. Comparison of quantitative regional ventilation-weighted fourier decomposition MRI with dynamic fluorinated gas washout MRI and lung function testing in COPD patients.

    Science.gov (United States)

    Kaireit, Till F; Gutberlet, Marcel; Voskrebenzev, Andreas; Freise, Julia; Welte, Tobias; Hohlfeld, Jens M; Wacker, Frank; Vogel-Claussen, Jens

    2018-06-01

    Ventilation-weighted Fourier decomposition-MRI (FD-MRI) has matured as a reliable technique for quantitative measures of regional lung ventilation in recent years, but has yet not been validated in COPD patients. To compare regional fractional lung ventilation obtained by ventilation-weighted FD-MRI with dynamic fluorinated gas washout MRI ( 19 F-MRI) and lung function test parameters. Prospective study. Twenty-seven patients with chronic obstructive pulmonary disease (COPD, median age 61 [54-67] years) were included. For FD-MRI and for 19 F-MRI a spoiled gradient echo sequence was used at 1.5T. FD-MRI coronal slices were acquired in free breathing. Dynamic 19 F-MRI was performed after inhalation of 25-30 L of a mixture of 79% fluorinated gas (C 3 F 8 ) and 21% oxygen via a closed face mask tubing using a dedicated coil tuned to 59.9 MHz. 19 F washout times in numbers of breaths ( 19 F-n breaths ) as well as fractional ventilation maps for both methods (FD-FV, 19 F-FV) were calculated. Slices were matched using a landmark driven algorithm, and only corresponding slices with an overlap of >90% were coregistered for evaluation. The obtained parameters were correlated with each other using Spearman's correlation coefficient (r). FD-FV strongly correlated with 19 F-n breaths on a global (r = -0.72, P Fourier decomposition-MRI is a promising noninvasive, radiation-free tool for quantification of regional ventilation in COPD patients. 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1534-1541. © 2017 International Society for Magnetic Resonance in Medicine.

  20. Probing dopamine transporter structure and function by Zn2+-site engineering

    DEFF Research Database (Denmark)

    Loland, Claus Juul; Norgaard-Nielsen, Kristine; Gether, Ulrik

    2003-01-01

    , it will be described how we have used Zn2+-binding sites as a tool to probe the structure and function of Na+/Cl--coupled biogenic amine transporters with specific focus on the human DAT (hDAT). The work has not only led to the definition of the first structural constrains in the tertiary structure of this class...

  1. INVESTIGATING THE ROLE OF PDZ-DOMAIN INTERACTIONS FOR DOPAMINE TRANSPORTER FUNCTION

    DEFF Research Database (Denmark)

    Fog, Jacob; Vægter, Christian Bjerggaard; Gether, Ulrik

    canonical PDZ domain interactions with proteins such as PICK1. To clarify the actual role of PDZ domain interactions for DAT function we have expressed the wild type DAT and a number of C-terminal mutants either alone or together with PICK1 in HEK293, N2A neuroblastoma and PC12 cells. Data obtained from...

  2. Motor function deficits in schizophrenia: an fMRI and VBM study

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Sadhana; Modi, Shilpi; Kumar, Pawan; Singh, Namita; Khushu, Subash [Institute of Nuclear Medicine and Allied Sciences (INMAS), NMR Research Center, Delhi (India); Goyal, Satnam; Bhatia, Triptish; Deshpande, Smita N. [RML Hospital, PGIMER, New Delhi (India)

    2014-05-15

    To investigate whether the motor functional alterations in schizophrenia (SZ) are also associated with structural changes in the related brain areas using functional magnetic resonance imaging (fMRI) and voxel-based morphometry (VBM). A sample of 14 right-handed SZ patients and 14 right-handed healthy control subjects matched for age, sex, and education were examined with structural high-resolution T1-weighted MRI; fMRI images were obtained during right index finger-tapping task in the same session. fMRI results showed reduced functional activation in the motor areas (contralateral precentral and postcentral gyrus) and ipsilateral cerebellum in SZ subjects as compared to healthy controls (n = 14). VBM analysis also revealed reduced grey matter in motor areas and white matter reduction in cerebellum of SZ subjects as compared to controls. The present study provides an evidence for a possible association between structural alterations in the motor cortex and disturbed functional activation in the motor areas in persons affected with SZ during a simple finger-tapping task. (orig.)

  3. Motor function deficits in schizophrenia: an fMRI and VBM study

    International Nuclear Information System (INIS)

    Singh, Sadhana; Modi, Shilpi; Kumar, Pawan; Singh, Namita; Khushu, Subash; Goyal, Satnam; Bhatia, Triptish; Deshpande, Smita N.

    2014-01-01

    To investigate whether the motor functional alterations in schizophrenia (SZ) are also associated with structural changes in the related brain areas using functional magnetic resonance imaging (fMRI) and voxel-based morphometry (VBM). A sample of 14 right-handed SZ patients and 14 right-handed healthy control subjects matched for age, sex, and education were examined with structural high-resolution T1-weighted MRI; fMRI images were obtained during right index finger-tapping task in the same session. fMRI results showed reduced functional activation in the motor areas (contralateral precentral and postcentral gyrus) and ipsilateral cerebellum in SZ subjects as compared to healthy controls (n = 14). VBM analysis also revealed reduced grey matter in motor areas and white matter reduction in cerebellum of SZ subjects as compared to controls. The present study provides an evidence for a possible association between structural alterations in the motor cortex and disturbed functional activation in the motor areas in persons affected with SZ during a simple finger-tapping task. (orig.)

  4. Predicting Treatment Outcome in PTSD : A Longitudinal Functional MRI Study on Trauma-Unrelated Emotional Processing

    NARCIS (Netherlands)

    Van Rooij, Sanne J H; Kennis, Mitzy; Vink, Matthijs; Geuze, Elbert

    2016-01-01

    In about 30-50% of patients with posttraumatic stress disorder (PTSD), symptoms persist after treatment. Although neurobiological research has advanced our understanding of PTSD, little is known about the neurobiology underlying persistence of PTSD. Two functional MRI scans were collected from 72

  5. Secretin-stimulated MRI characterization of pancreatic morphology and function in patients with chronic pancreatitis.

    Science.gov (United States)

    Madzak, Adnan; Olesen, Søren Schou; Haldorsen, Ingfrid Salvesen; Drewes, Asbjørn Mohr; Frøkjær, Jens Brøndum

    Chronic pancreatitis (CP) is characterized by abnormal pancreatic morphology and impaired endocrine and exocrine function. However, little is known about the relationship between pancreatic morphology and function, and also the association with the etiology and clinical manifestations of CP. The aim was to explore pancreatic morphology and function with advanced MRI in patients with CP and healthy controls (HC) METHODS: Eighty-two patients with CP and 22 HC were enrolled in the study. Morphological imaging parameters included pancreatic main duct diameter, gland volume, fat signal fraction and apparent diffusion coefficient (ADC) values. Functional secretin-stimulated MRI (s-MRI) parameters included pancreatic secretion (bowel fluid volume) and changes in pancreatic ADC value before and after secretin stimulation. Patients were classified according to the modified Cambridge and M-ANNHEIM classification system and fecal elastase was collected. All imaging parameters differentiated CP patients from HC; however, correlations between morphological and functional parameters in CP were weak. Patients with alcoholic and non-alcoholic etiology had comparable s-MRI findings. Fecal elastase was positively correlated to pancreatic gland volume (r = 0.68, P = 0.0016) and negatively correlated to Cambridge classification (r = -0.35, P pancreatic gland volume was significantly decreased in the severe stages of CP (P = 0.001). S-MRI provides detailed information about pancreatic morphology and function and represents a promising non-invasive imaging method to characterize pancreatic pathophysiology and may enable monitoring of disease progression in patients with CP. Copyright © 2017 IAP and EPC. Published by Elsevier B.V. All rights reserved.

  6. Parameterized hemodynamic response function data of healthy individuals obtained from resting-state functional MRI in a 7T MRI scanner

    Directory of Open Access Journals (Sweden)

    D. Rangaprakash

    2018-04-01

    Full Text Available Functional magnetic resonance imaging (fMRI, being an indirect measure of brain activity, is mathematically defined as a convolution of the unmeasured latent neural signal and the hemodynamic response function (HRF. The HRF is known to vary across the brain and across individuals, and it is modulated by neural as well as non-neural factors. Three parameters characterize the shape of the HRF, which is obtained by performing deconvolution on resting-state fMRI data: response height, time-to-peak and full-width at half-max. The data provided here, obtained from 47 healthy adults, contains these three HRF parameters at every voxel in the brain, as well as HRF parameters from the default-mode network (DMN. In addition, we have provided functional connectivity (FC data from the same DMN regions, obtained for two cases: data with deconvolution (HRF variability minimized and data with no deconvolution (HRF variability corrupted. This would enable researchers to compare regional changes in HRF with corresponding FC differences, to assess the impact of HRF variability on FC. Importantly, the data was obtained in a 7T MRI scanner. While most fMRI studies are conducted at lower field strengths, like 3T, ours is the first study to report HRF data obtained at 7T. FMRI data at ultra-high fields contains larger contributions from small vessels, consequently HRF variability is lower for small vessels at higher field strengths. This implies that findings made from this data would be more conservative than from data acquired at lower fields, such as 3T. Results obtained with this data and further interpretations are available in our recent research study (Rangaprakash et al., in press [1]. This is a valuable dataset for studying HRF variability in conjunction with FC, and for developing the HRF profile in healthy individuals, which would have direct implications for fMRI data analysis, especially resting-state connectivity modeling. This is the first public HRF

  7. Introducing Thermal Wave Transport Analysis (TWTA): A Thermal Technique for Dopamine Detection by Screen-Printed Electrodes Functionalized with Molecularly Imprinted Polymer (MIP) Particles.

    Science.gov (United States)

    Peeters, Marloes M; van Grinsven, Bart; Foster, Christopher W; Cleij, Thomas J; Banks, Craig E

    2016-04-26

    A novel procedure is developed for producing bulk modified Molecularly Imprinted Polymer (MIP) screen-printed electrodes (SPEs), which involves the direct mixing of the polymer particles within the screen-printed ink. This allowed reduction of the sample preparation time from 45 min to 1 min, and resulted in higher reproducibility of the electrodes. The samples are measured with a novel detection method, namely, thermal wave transport analysis (TWTA), relying on the analysis of thermal waves through a functional interface. As a first proof-of-principle, MIPs for dopamine are developed and successfully incorporated within a bulk modified MIP SPE. The detection limits of dopamine within buffer solutions for the MIP SPEs are determined via three independent techniques. With cyclic voltammetry this was determined to be 4.7 × 10(-6) M, whereas by using the heat-transfer method (HTM) 0.35 × 10(-6) M was obtained, and with the novel TWTA concept 0.26 × 10(-6) M is possible. This TWTA technique is measured simultaneously with HTM and has the benefits of reducing measurement time to less than 5 min and increasing effect size by nearly a factor of two. The two thermal methods are able to enhance dopamine detection by one order of magnitude compared to the electrochemical method. In previous research, it was not possible to measure neurotransmitters in complex samples with HTM, but with the improved signal-to-noise of TWTA for the first time, spiked dopamine concentrations were determined in a relevant food sample. In summary, novel concepts are presented for both the sensor functionalization side by employing screen-printing technology, and on the sensing side, the novel TWTA thermal technique is reported. The developed bio-sensing platform is cost-effective and suitable for mass-production due to the nature of screen-printing technology, which makes it very interesting for neurotransmitter detection in clinical diagnostic applications.

  8. Towards trans-diagnostic mechanisms in psychiatry: neurobehavioral profile of rats with a loss-of-function point mutation in the dopamine transporter gene.

    Science.gov (United States)

    Vengeliene, Valentina; Bespalov, Anton; Roßmanith, Martin; Horschitz, Sandra; Berger, Stefan; Relo, Ana L; Noori, Hamid R; Schneider, Peggy; Enkel, Thomas; Bartsch, Dusan; Schneider, Miriam; Behl, Berthold; Hansson, Anita C; Schloss, Patrick; Spanagel, Rainer

    2017-04-01

    The research domain criteria (RDoC) matrix has been developed to reorient psychiatric research towards measurable behavioral dimensions and underlying mechanisms. Here, we used a new genetic rat model with a loss-of-function point mutation in the dopamine transporter (DAT) gene ( Slc6a3 _N157K) to systematically study the RDoC matrix. First, we examined the impact of the Slc6a3 _N157K mutation on monoaminergic signaling. We then performed behavioral tests representing each of the five RDoC domains: negative and positive valence systems, cognitive, social and arousal/regulatory systems. The use of RDoC may be particularly helpful for drug development. We studied the effects of a novel pharmacological approach metabotropic glutamate receptor mGluR2/3 antagonism, in DAT mutants in a comparative way with standard medications. Loss of DAT functionality in mutant rats not only elevated subcortical extracellular dopamine concentration but also altered the balance of monoaminergic transmission. DAT mutant rats showed deficits in all five RDoC domains. Thus, mutant rats failed to show conditioned fear responses, were anhedonic, were unable to learn stimulus-reward associations, showed impaired cognition and social behavior, and were hyperactive. Hyperactivity in mutant rats was reduced by amphetamine and atomoxetine, which are well-established medications to reduce hyperactivity in humans. The mGluR2/3 antagonist LY341495 also normalized hyperactivity in DAT mutant rats without affecting extracellular dopamine levels. We systematically characterized an altered dopamine system within the context of the RDoC matrix and studied mGluR2/3 antagonism as a new pharmacological strategy to treat mental disorders with underlying subcortical dopaminergic hyperactivity. © 2017. Published by The Company of Biologists Ltd.

  9. Towards trans-diagnostic mechanisms in psychiatry: neurobehavioral profile of rats with a loss-of-function point mutation in the dopamine transporter gene

    Directory of Open Access Journals (Sweden)

    Valentina Vengeliene

    2017-04-01

    Full Text Available The research domain criteria (RDoC matrix has been developed to reorient psychiatric research towards measurable behavioral dimensions and underlying mechanisms. Here, we used a new genetic rat model with a loss-of-function point mutation in the dopamine transporter (DAT gene (Slc6a3_N157K to systematically study the RDoC matrix. First, we examined the impact of the Slc6a3_N157K mutation on monoaminergic signaling. We then performed behavioral tests representing each of the five RDoC domains: negative and positive valence systems, cognitive, social and arousal/regulatory systems. The use of RDoC may be particularly helpful for drug development. We studied the effects of a novel pharmacological approach metabotropic glutamate receptor mGluR2/3 antagonism, in DAT mutants in a comparative way with standard medications. Loss of DAT functionality in mutant rats not only elevated subcortical extracellular dopamine concentration but also altered the balance of monoaminergic transmission. DAT mutant rats showed deficits in all five RDoC domains. Thus, mutant rats failed to show conditioned fear responses, were anhedonic, were unable to learn stimulus-reward associations, showed impaired cognition and social behavior, and were hyperactive. Hyperactivity in mutant rats was reduced by amphetamine and atomoxetine, which are well-established medications to reduce hyperactivity in humans. The mGluR2/3 antagonist LY341495 also normalized hyperactivity in DAT mutant rats without affecting extracellular dopamine levels. We systematically characterized an altered dopamine system within the context of the RDoC matrix and studied mGluR2/3 antagonism as a new pharmacological strategy to treat mental disorders with underlying subcortical dopaminergic hyperactivity.

  10. Primary structure and functional characterization of a Drosophila dopamine receptor with high homology to human D1/5 receptors.

    Science.gov (United States)

    Gotzes, F; Balfanz, S; Baumann, A

    1994-01-01

    Members of the superfamily of G-protein coupled receptors share significant similarities in sequence and transmembrane architecture. We have isolated a Drosophila homologue of the mammalian dopamine receptor family using a low stringency hybridization approach. The deduced amino acid sequence is approximately 70% homologous to the human D1/D5 receptors. When expressed in HEK 293 cells, the Drosophila receptor stimulates cAMP production in response to dopamine application. This effect was mimicked by SKF 38393, a specific D1 receptor agonist, but inhibited by dopaminergic antagonists such as butaclamol and flupentixol. In situ hybridization revealed that the Drosophila dopamine receptor is highly expressed in the somata of the optic lobes. This suggests that the receptor might be involved in the processing of visual information and/or visual learning in invertebrates.

  11. Functional MRI, DTI and neurophysiology in horizontal gaze palsy with progressive scoliosis

    Energy Technology Data Exchange (ETDEWEB)

    Haller, Sven; Wetzel, Stephan G. [University Hospital Basel, Institute of Radiology, Department of Neuroradiology, Basel (Switzerland); Luetschg, Juerg [University Children' s Hospital (UKBB), Basel (Switzerland)

    2008-05-15

    Horizontal gaze palsy with progressive scoliosis (HGPPS) is an autosomal recessive disease due to a mutation in the ROBO3 gene. This rare disease is of particular interest because the absence, or at least reduction, of crossing of the ascending lemniscal and descending corticospinal tracts in the medulla predicts abnormal ipsilateral sensory and motor systems. We evaluated the use of functional magnetic resonance imaging (fMRI) for the first time in this disease and compared it to diffusion tensor imaging (DTI) tractography and neurophysiological findings in the same patient with genetically confirmed ROBO3 mutation. As expected, motor fMRI, somatosensory evoked potentials (SSEP) and motor evoked potentials (MEP) were dominantly ipsilateral to the stimulation side. DTI tractography revealed ipsilateral ascending and descending connectivity in the brainstem yet normal interhemispheric connections in the corpus callosum. Auditory fMRI revealed bilateral auditory activation to monaural left-sided auditory stimulation. No significant cortical activation was observed after monaural right-sided stimulation, a hearing defect having been excluded. Prosaccades fMRI showed no activations in the eye-movement network. Motor fMRI confirmed the established findings of DTI and neurophysiology in the same patient. In suspected HGPPS, any technique appears appropriate for further investigation. Auditory fMRI suggests that a monaural auditory system with bilateral auditory activations might be a physiological advantage as compared to a binaural yet only unilateral auditory system, in analogy to anisometropic amblyopia. Moving-head fMRI studies in the future might show whether the compensatory head movements instead of normal eye movements activate the eye-movement network. (orig.)

  12. Functional MRI, DTI and neurophysiology in horizontal gaze palsy with progressive scoliosis

    International Nuclear Information System (INIS)

    Haller, Sven; Wetzel, Stephan G.; Luetschg, Juerg

    2008-01-01

    Horizontal gaze palsy with progressive scoliosis (HGPPS) is an autosomal recessive disease due to a mutation in the ROBO3 gene. This rare disease is of particular interest because the absence, or at least reduction, of crossing of the ascending lemniscal and descending corticospinal tracts in the medulla predicts abnormal ipsilateral sensory and motor systems. We evaluated the use of functional magnetic resonance imaging (fMRI) for the first time in this disease and compared it to diffusion tensor imaging (DTI) tractography and neurophysiological findings in the same patient with genetically confirmed ROBO3 mutation. As expected, motor fMRI, somatosensory evoked potentials (SSEP) and motor evoked potentials (MEP) were dominantly ipsilateral to the stimulation side. DTI tractography revealed ipsilateral ascending and descending connectivity in the brainstem yet normal interhemispheric connections in the corpus callosum. Auditory fMRI revealed bilateral auditory activation to monaural left-sided auditory stimulation. No significant cortical activation was observed after monaural right-sided stimulation, a hearing defect having been excluded. Prosaccades fMRI showed no activations in the eye-movement network. Motor fMRI confirmed the established findings of DTI and neurophysiology in the same patient. In suspected HGPPS, any technique appears appropriate for further investigation. Auditory fMRI suggests that a monaural auditory system with bilateral auditory activations might be a physiological advantage as compared to a binaural yet only unilateral auditory system, in analogy to anisometropic amblyopia. Moving-head fMRI studies in the future might show whether the compensatory head movements instead of normal eye movements activate the eye-movement network. (orig.)

  13. Functional MRI, DTI and neurophysiology in horizontal gaze palsy with progressive scoliosis.

    Science.gov (United States)

    Haller, Sven; Wetzel, Stephan G; Lütschg, Jürg

    2008-05-01

    Horizontal gaze palsy with progressive scoliosis (HGPPS) is an autosomal recessive disease due to a mutation in the ROBO3 gene. This rare disease is of particular interest because the absence, or at least reduction, of crossing of the ascending lemniscal and descending corticospinal tracts in the medulla predicts abnormal ipsilateral sensory and motor systems. We evaluated the use of functional magnetic resonance imaging (fMRI) for the first time in this disease and compared it to diffusion tensor imaging (DTI) tractography and neurophysiological findings in the same patient with genetically confirmed ROBO3 mutation. As expected, motor fMRI, somatosensory evoked potentials (SSEP) and motor evoked potentials (MEP) were dominantly ipsilateral to the stimulation side. DTI tractography revealed ipsilateral ascending and descending connectivity in the brainstem yet normal interhemispheric connections in the corpus callosum. Auditory fMRI revealed bilateral auditory activation to monaural left-sided auditory stimulation. No significant cortical activation was observed after monaural right-sided stimulation, a hearing defect having been excluded. Prosaccades fMRI showed no activations in the eye-movement network. Motor fMRI confirmed the established findings of DTI and neurophysiology in the same patient. In suspected HGPPS, any technique appears appropriate for further investigation. Auditory fMRI suggests that a monaural auditory system with bilateral auditory activations might be a physiological advantage as compared to a binaural yet only unilateral auditory system, in analogy to anisometropic amblyopia. Moving-head fMRI studies in the future might show whether the compensatory head movements instead of normal eye movements activate the eye-movement network.

  14. Intraoperative functional MRI as a new approach to monitor deep brain stimulation in Parkinson's disease

    International Nuclear Information System (INIS)

    Hesselmann, Volker; Sorger, Bettina; Girnus, Ralf; Lasek, Kathrin; Schulte, Oliver; Krug, Barbara; Lackner, Klaus; Maarouf, Mohammad; Sturm, Volker; Wedekind, Christoph; Bunke, Juergen

    2004-01-01

    This article deals with technical aspects of intraoperative functional magnetic resonance imaging (fMRI) for monitoring the effect of deep brain stimulation (DBS) in a patient with Parkinson's disease. Under motor activation, therapeutic high-frequency stimulation of the subthalamic nucleus was accompanied by an activation decrease in the contralateral primary sensorimotor cortex and the ipsilateral cerebellum. Furthermore, an activation increase in the contralateral basal ganglia and insula region were detected. These findings demonstrate that fMRI constitutes a promising clinical application for investigating brain activity changes induced by DBS. (orig.)

  15. Functional MRI of the visual cortex and visual testing in patients with previous optic neuritis

    DEFF Research Database (Denmark)

    Langkilde, Annika Reynberg; Frederiksen, J.L.; Rostrup, Egill

    2002-01-01

    to both the results of the contrast sensitivity test and to the Snellen visual acuity. Our results indicate that fMRI is a useful method for the study of ON, even in cases where the visual acuity is severely impaired. The reduction in activated volume could be explained as a reduced neuronal input......The volume of cortical activation as detected by functional magnetic resonance imaging (fMRI) in the visual cortex has previously been shown to be reduced following optic neuritis (ON). In order to understand the cause of this change, we studied the cortical activation, both the size...... of the activated area and the signal change following ON, and compared the results with results of neuroophthalmological testing. We studied nine patients with previous acute ON and 10 healthy persons served as controls using fMRI with visual stimulation. In addition to a reduced activated volume, patients showed...

  16. Atlas of regional anatomy of the brain using MRI. With functional correlations

    International Nuclear Information System (INIS)

    Tamraz, J.C.

    2006-01-01

    The volume provides a unique review of the essential topographical anatomy of the brain from an MRI perspective, correlating high-quality anatomical plates with the corresponding high-resolution MRI images. The book includes a historical review of brain mapping and an analysis of the essential reference planes used for the study of the human brain. Subsequent chapters provide a detailed review of the sulcal and the gyral anatomy of the human cortex, guiding the reader through an interpretation of the individual brain atlas provided by high-resolution MRI. The relationship between brain structure and function is approached in a topographical fashion with analysis of the necessary imaging methodology and displayed anatomy. The central, perisylvian, mesial temporal and occipital areas receive special attention. Imaging of the core brain structures is included. An extensive coronal atlas concludes the book. (orig.)

  17. A functional MRI study of somatotopic representation of somatosensory stimulation in the cerebellum

    Energy Technology Data Exchange (ETDEWEB)

    Takanashi, M.; Abe, K.; Yanagihara, T.; Sakoda, S. [Dept. of Neurology D4, Osaka Univ. Graduate School of Medicine, Suita City, Osaka (Japan); Tanaka, H.; Hirabuki, N.; Nakamura, H.; Fujita, N. [Dept. of Radiology, Osaka Univ. Graduate School of Medicine, Suita City, Osaka (Japan)

    2003-03-01

    Somatotopic representation in the cerebral cortex of somatosensory stimulation has been widely reported, but that in the cerebellum has not. We investigated the latter in the human cerebellum by functional MRI (fMRI). Using a 1.5 tesla imager, we obtained multislice blood oxygen level-dependent fMRI with single-shot gradient-echo echoplanar imaging in seven right-handed volunteers during electrical stimulation of the left index finger and big toe. In the anterior and posterior cerebellum, activated pixels for the index finger were separate from those for the toe. This suggests that somatosensory stimulation of different parts of the body may involve distinct areas of in the cerebellum as well as the cerebral cortex. (orig.)

  18. A functional MRI study of somatotopic representation of somatosensory stimulation in the cerebellum

    International Nuclear Information System (INIS)

    Takanashi, M.; Abe, K.; Yanagihara, T.; Sakoda, S.; Tanaka, H.; Hirabuki, N.; Nakamura, H.; Fujita, N.

    2003-01-01

    Somatotopic representation in the cerebral cortex of somatosensory stimulation has been widely reported, but that in the cerebellum has not. We investigated the latter in the human cerebellum by functional MRI (fMRI). Using a 1.5 tesla imager, we obtained multislice blood oxygen level-dependent fMRI with single-shot gradient-echo echoplanar imaging in seven right-handed volunteers during electrical stimulation of the left index finger and big toe. In the anterior and posterior cerebellum, activated pixels for the index finger were separate from those for the toe. This suggests that somatosensory stimulation of different parts of the body may involve distinct areas of in the cerebellum as well as the cerebral cortex. (orig.)

  19. Functional magnetic resonance imaging (fMRI) of motor deficits in schizophrenia

    International Nuclear Information System (INIS)

    Wenz, F.; Floemer, F.; Kaick, G. van

    1995-01-01

    The purpose of this study was to investigate differences in the cerebral activation pattern in ten schizophrenic patients and ten healthy volunteers using functional MRI. fMRI was performed using a modified FLASH sequence (TR/TE/α=100/60/40 ) and a conventional 1.5 T MR scanner. Colorcoded statistical parametric maps based on Student's t-test were calculated. Activation strength was quantified using a 5x6 grid overlay. The volunteers showed a higher activation strength during left hand movement compared to right hand movement. This lateralization effect was reversed in patients who showed overall reduced activation strength. Disturbed interhemispheric balance in schizophrenic patients during motor task performance can be demonstrated using fMRI. (orig.) [de

  20. Functional and molecular imaging with MRI: potential applications in paediatric radiology

    International Nuclear Information System (INIS)

    Arthurs, Owen J.; Gallagher, Ferdia A.

    2011-01-01

    MRI is a very versatile tool for noninvasive imaging and it is particularly attractive as an imaging technique in paediatric patients given the absence of ionizing radiation. Recent advances in the field of MRI have enabled tissue function to be probed noninvasively, and increasingly MRI is being used to assess cellular and molecular processes. For example, dynamic contrast-enhanced MRI has been used to assess tissue vascularity, diffusion-weighted imaging can quantify molecular movements of water in tissue compartments and MR spectroscopy provides a quantitative assessment of metabolite levels. A number of targeted contrast agents have been developed that bind specifically to receptors on the vascular endothelium or cell surface and there are several MR methods for labelling cells and tracking cellular movements. Hyperpolarization techniques have the capability of massively increasing the sensitivity of MRI and these have been used to image tissue pH, successful response to drug treatment as well as imaging the microstructure of the lungs. Although there are many challenges to be overcome before these techniques can be translated into routine paediatric imaging, they could potentially be used to aid diagnosis, predict disease outcome, target biopsies and determine treatment response noninvasively. (orig.)

  1. Usefulness and limitation of functional MRI with echo planar imaging using clinical MR apparatus

    International Nuclear Information System (INIS)

    Kusunoki, Katsusuke; Zenke, Kiichiro; Saito, Masahiro; Sadamoto, Kazuhiko; Ohue, Shiro; Sakaki, Saburo; Kumon, Yoshiaki; Kabasawa, Hiroyuki; Nagasawa, Kiyoshi

    1998-01-01

    We studied blood oxygen level-dependent (BOLD) functional MRI (fMRI) with EPI sequence in 21 normal volunteers and 8 presurgical clinical patients using a 1.5 T clinical MRI apparatus. To optimize the imaging parameters, we compared the fMRI images obtained by GFE-EPI and by SE-EPI in normal volunteers while each squeezed a sponge ball. We identified the motor cortex in 85.7% of normal volunteers by GFE-EPI in contrast to only 28.6% by SE-EPI. In addition, our clinical MR apparatus, using optimized parameters, maximally provides 15 slices per 5 seconds. In patients with brain tumor close to the sensorimotor cortex, we attempted to identify the motor cortex preoperatively by this procedure and found a significant increase of signal intensity in the motor cortex in 5 of 8 patients. In conclusion, fMRI using EPI may be useful for identifying the motor cortex preoperatively. However, further development of the apparatus is needed to obtain better temporal and spatial resolution for clinical applications. (author)

  2. Functional brain activation differences in stuttering identified with a rapid fMRI sequence

    Science.gov (United States)

    Kraft, Shelly Jo; Choo, Ai Leen; Sharma, Harish; Ambrose, Nicoline G.

    2011-01-01

    The purpose of this study was to investigate whether brain activity related to the presence of stuttering can be identified with rapid functional MRI (fMRI) sequences that involved overt and covert speech processing tasks. The long-term goal is to develop sensitive fMRI approaches with developmentally appropriate tasks to identify deviant speech motor and auditory brain activity in children who stutter closer to the age at which recovery from stuttering is documented. Rapid sequences may be preferred for individuals or populations who do not tolerate long scanning sessions. In this report, we document the application of a picture naming and phoneme monitoring task in three minute fMRI sequences with adults who stutter (AWS). If relevant brain differences are found in AWS with these approaches that conform to previous reports, then these approaches can be extended to younger populations. Pairwise contrasts of brain BOLD activity between AWS and normally fluent adults indicated the AWS showed higher BOLD activity in the right inferior frontal gyrus (IFG), right temporal lobe and sensorimotor cortices during picture naming and and higher activity in the right IFG during phoneme monitoring. The right lateralized pattern of BOLD activity together with higher activity in sensorimotor cortices is consistent with previous reports, which indicates rapid fMRI sequences can be considered for investigating stuttering in younger participants. PMID:22133409

  3. Functional Selectivity of Allosteric Interactions within G Protein–Coupled Receptor Oligomers: The Dopamine D1-D3 Receptor Heterotetramer

    Science.gov (United States)

    Guitart, Xavier; Navarro, Gemma; Moreno, Estefania; Yano, Hideaki; Cai, Ning-Sheng; Sánchez-Soto, Marta; Kumar-Barodia, Sandeep; Naidu, Yamini T.; Mallol, Josefa; Cortés, Antoni; Lluís, Carme; Canela, Enric I.; Casadó, Vicent; McCormick, Peter J.

    2014-01-01

    The dopamine D1 receptor–D3 receptor (D1R-D3R) heteromer is being considered as a potential therapeutic target for neuropsychiatric disorders. Previous studies suggested that this heteromer could be involved in the ability of D3R agonists to potentiate locomotor activation induced by D1R agonists. It has also been postulated that its overexpression plays a role in L-dopa–induced dyskinesia and in drug addiction. However, little is known about its biochemical properties. By combining bioluminescence resonance energy transfer, bimolecular complementation techniques, and cell-signaling experiments in transfected cells, evidence was obtained for a tetrameric stoichiometry of the D1R–D3R heteromer, constituted by two interacting D1R and D3R homodimers coupled to Gs and Gi proteins, respectively. Coactivation of both receptors led to the canonical negative interaction at the level of adenylyl cyclase signaling, to a strong recruitment of β-arrestin-1, and to a positive cross talk of D1R and D3R agonists at the level of mitogen-activated protein kinase (MAPK) signaling. Furthermore, D1R or D3R antagonists counteracted β-arrestin-1 recruitment and MAPK activation induced by D3R and D1R agonists, respectively (cross-antagonism). Positive cross talk and cross-antagonism at the MAPK level were counteracted by specific synthetic peptides with amino acid sequences corresponding to D1R transmembrane (TM) domains TM5 and TM6, which also selectively modified the quaternary structure of the D1R-D3R heteromer, as demonstrated by complementation of hemiproteins of yellow fluorescence protein fused to D1R and D3R. These results demonstrate functional selectivity of allosteric modulations within the D1R-D3R heteromer, which can be involved with the reported behavioral synergism of D1R and D3R agonists. PMID:25097189

  4. Grass Carp Follisatin: Molecular Cloning, Functional Characterization, Dopamine D1 Regulation at Pituitary Level, and Implication in Growth Hormone Regulation

    Directory of Open Access Journals (Sweden)

    Roger S. K. Fung

    2017-08-01

    Full Text Available Activin is involved in pituitary hormone regulation and its pituitary actions can be nullified by local production of its binding protein follistatin. In our recent study with grass carp, local release of growth hormone (GH was shown to induce activin expression at pituitary level, which in turn could exert an intrapituitary feedback to inhibit GH synthesis and secretion. To further examine the activin/follistatin system in the carp pituitary, grass carp follistatin was cloned and confirmed to be single-copy gene widely expressed at tissue level. At the pituitary level, follistatin signals could be located in carp somatotrophs, gonadotrophs, and lactotrophs. Functional expression also revealed that carp follistatin was effective in neutralizing activin’s action in stimulating target promoter with activin-responsive elements. In grass carp pituitary cells, follistatin co-treatment was found to revert activin inhibition on GH mRNA expression. Meanwhile, follistatin mRNA levels could be up-regulated by local production of activin but the opposite was true for dopaminergic activation with dopamine (DA or its agonist apomorphine. Since GH stimulation by DA via pituitary D1 receptor is well-documented in fish models, the receptor specificity for follistatin regulation by DA was also investigated. Using a pharmacological approach, the inhibitory effect of DA on follistatin gene expression was confirmed to be mediated by pituitary D1 but not D2 receptor. Furthermore, activation of D1 receptor by the D1-specific agonist SKF77434 was also effective in blocking follistatin mRNA expression induced by activin and GH treatment both in carp pituitary cells as well as in carp somatotrophs enriched by density gradient centrifugation. These results, as a whole, suggest that activin can interact with dopaminergic input from the hypothalamus to regulate follistatin expression in carp pituitary, which may contribute to GH regulation by activin/follistatin system

  5. Preoperative functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS)

    DEFF Research Database (Denmark)

    Hartwigsen, G.; Siebner, Hartwig R.; Stippich, C.

    2010-01-01

    Neurosurgical resection of brain lesions aims to maximize excision while minimizing the risk of permanent injury to the surrounding intact brain tissue and resulting neurological deficits. While direct electrical cortical stimulation at the time of surgery allows the precise identification...... of essential cortex, it cannot provide information preoperatively for surgical planning.Brain imaging techniques such as functional magnetic resonance imaging (fMRI), magnetoencephalography (MEG) and transcranial magnetic stimulation (TMS) are increasingly being used to localize functionally critical cortical......, if the stimulated cortex makes a critical contribution to the brain functions subserving the task. While the relationship between task and functional activation as revealed by fMRI is correlative in nature, the neurodisruptive effect of TMS reflects a causal effect on brain activity.The use of preoperative f...

  6. Functional MRI in pre-surgical planning: Case study and cautionary notes

    Directory of Open Access Journals (Sweden)

    Bruce S Spottiswoode

    2012-09-01

    Full Text Available Background. Since its inception almost 20 years ago, functional magnetic resonance imaging (fMRI has greatly advanced our knowledge of human brain function. Although the clinical applications of fMRI are still limited, there have recently been encouraging advances for its use in pre-operative functional cortical mapping to identify potentially eloquent areas prior to neurosurgery. Objectives. We explore the potential use of this emerging technique by presenting a neurosurgical case study, as performed at the Cape Universities Brain Imaging Centre (CUBIC, Tygerberg, Cape Town. We conclude with a brief summary of the potential pitfalls of this technique, as well as cautionary guidelines based on our experience. Methods and results. A 22-year-old male patient from Tygerberg Hospital underwent the successful resection of an anaplastic astrocytoma after fMRI presurgical planning at our facility. The subject was able to leave the ward unassisted. Conclusion. If consideration is given to the many limitations of this emerging technique, fMRI can be useful in aiding the neurosurgeon in pre-operative planning of his surgical approach.

  7. Large-scale Granger causality analysis on resting-state functional MRI

    Science.gov (United States)

    D'Souza, Adora M.; Abidin, Anas Zainul; Leistritz, Lutz; Wismüller, Axel

    2016-03-01

    We demonstrate an approach to measure the information flow between each pair of time series in resting-state functional MRI (fMRI) data of the human brain and subsequently recover its underlying network structure. By integrating dimensionality reduction into predictive time series modeling, large-scale Granger Causality (lsGC) analysis method can reveal directed information flow suggestive of causal influence at an individual voxel level, unlike other multivariate approaches. This method quantifies the influence each voxel time series has on every other voxel time series in a multivariate sense and hence contains information about the underlying dynamics of the whole system, which can be used to reveal functionally connected networks within the brain. To identify such networks, we perform non-metric network clustering, such as accomplished by the Louvain method. We demonstrate the effectiveness of our approach to recover the motor and visual cortex from resting state human brain fMRI data and compare it with the network recovered from a visuomotor stimulation experiment, where the similarity is measured by the Dice Coefficient (DC). The best DC obtained was 0.59 implying a strong agreement between the two networks. In addition, we thoroughly study the effect of dimensionality reduction in lsGC analysis on network recovery. We conclude that our approach is capable of detecting causal influence between time series in a multivariate sense, which can be used to segment functionally connected networks in the resting-state fMRI.

  8. Whole brain functional connectivity in clinically isolated syndrome without conventional brain MRI lesions

    International Nuclear Information System (INIS)

    Liu, Yaou; Dai, Zhengjia; Duan, Yunyun; Huang, Jing; Ren, Zhuoqiong; Li, Kuncheng; Liu, Zheng; Dong, Huiqing; Shu, Ni; He, Yong; Vrenken, Hugo; Wattjes, Mike P.; Barkhof, Frederik

    2016-01-01

    To investigate brain functional connectivity (FC) alterations in patients with clinically isolated syndromes (CIS) presenting without conventional brain MRI lesions, and to identify the FC differences between the CIS patients who converted to multiple sclerosis (MS) and those not converted during a 5-year follow-up. We recruited 20 CIS patients without conventional brain lesions, 28 patients with MS and 28 healthy controls (HC). Normalized voxel-based functional connectivity strength (nFCS) was determined using resting-state fMRI (R-fMRI) and compared among groups. Furthermore, 5-years clinical follow-up of the CIS patients was performed to examine the differences in nFCS between converters and non-converters. Compared to HC, CIS patients showed significantly decreased nFCS in the visual areas and increased nFCS in several brain regions predominately in the temporal lobes. MS patients revealed more widespread higher nFCS especially in deep grey matter (DGM), compared to CIS and HC. In the four CIS patients converting to MS, significantly higher nFCS was found in right anterior cingulate gyrus (ACC) and fusiform gyrus (FG), compared to non-converted patients. We demonstrated both functional impairment and compensation in CIS by R-fMRI. nFCS alteration in ACC and FG seems to occur in CIS patients at risk of developing MS. (orig.)

  9. Mapping of cognitive functions in chronic intractable epilepsy: Role of fMRI

    International Nuclear Information System (INIS)

    Chaudhary, Kapil; Kumaran, S Senthil; Chandra, Sarat P; Wadhawan, Ashima Nehra; Tripathi, Manjari

    2014-01-01

    Functional magnetic resonance imaging (fMRI), a non-invasive technique with high spatial resolution and blood oxygen level dependent (BOLD) contrast, has been applied to localize and map cognitive functions in the clinical condition of chronic intractable epilepsy. fMRI was used to map the language and memory network in patients of chronic intractable epilepsy pre- and post-surgery. After obtaining approval from the institutional ethics committee, six patients with intractable epilepsy with an equal number of age-matched controls were recruited in the study. A 1.5 T MR scanner with 12-channel head coil, integrated with audio-visual fMRI accessories was used. Echo planar imaging sequence was used for BOLD studies. There were two sessions in TLE (pre- and post-surgery). In TLE patients, BOLD activation increased post-surgery in comparison of pre-surgery in inferior frontal gyrus (IFG), middle frontal gyrus (MFG), and superior temporal gyrus (STG), during semantic lexical, judgment, comprehension, and semantic memory tasks. Functional MRI is useful to study the basic concepts related to language and memory lateralization in TLE and guide surgeons for preservation of important brain areas during ATLR. This will help in understanding future directions for the diagnosis and treatment of such disease

  10. BOLDSync: a MATLAB-based toolbox for synchronized stimulus presentation in functional MRI.

    Science.gov (United States)

    Joshi, Jitesh; Saharan, Sumiti; Mandal, Pravat K

    2014-02-15

    Precise and synchronized presentation of paradigm stimuli in functional magnetic resonance imaging (fMRI) is central to obtaining accurate information about brain regions involved in a specific task. In this manuscript, we present a new MATLAB-based toolbox, BOLDSync, for synchronized stimulus presentation in fMRI. BOLDSync provides a user friendly platform for design and presentation of visual, audio, as well as multimodal audio-visual (AV) stimuli in functional imaging experiments. We present simulation experiments that demonstrate the millisecond synchronization accuracy of BOLDSync, and also illustrate the functionalities of BOLDSync through application to an AV fMRI study. BOLDSync gains an advantage over other available proprietary and open-source toolboxes by offering a user friendly and accessible interface that affords both precision in stimulus presentation and versatility across various types of stimulus designs and system setups. BOLDSync is a reliable, efficient, and versatile solution for synchronized stimulus presentation in fMRI study. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Mapping of cognitive functions in chronic intractable epilepsy: Role of fMRI

    Directory of Open Access Journals (Sweden)

    Kapil Chaudhary

    2014-01-01

    Full Text Available Background: Functional magnetic resonance imaging (fMRI, a non-invasive technique with high spatial resolution and blood oxygen level dependent (BOLD contrast, has been applied to localize and map cognitive functions in the clinical condition of chronic intractable epilepsy. Purpose: fMRI was used to map the language and memory network in patients of chronic intractable epilepsy pre- and post-surgery. Materials and Methods: After obtaining approval from the institutional ethics committee, six patients with intractable epilepsy with an equal number of age-matched controls were recruited in the study. A 1.5 T MR scanner with 12-channel head coil, integrated with audio-visual fMRI accessories was used. Echo planar imaging sequence was used for BOLD studies. There were two sessions in TLE (pre- and post-surgery. Results: In TLE patients, BOLD activation increased post-surgery in comparison of pre-surgery in inferior frontal gyrus (IFG, middle frontal gyrus (MFG, and superior temporal gyrus (STG, during semantic lexical, judgment, comprehension, and semantic memory tasks. Conclusion: Functional MRI is useful to study the basic concepts related to language and memory lateralization in TLE and guide surgeons for preservation of important brain areas during ATLR. This will help in understanding future directions for the diagnosis and treatment of such disease.

  12. Unsupervised classification of major depression using functional connectivity MRI.

    Science.gov (United States)

    Zeng, Ling-Li; Shen, Hui; Liu, Li; Hu, Dewen

    2014-04-01

    The current diagnosis of psychiatric disorders including major depressive disorder based largely on self-reported symptoms and clinical signs may be prone to patients' behaviors and psychiatrists' bias. This study aims at developing an unsupervised machine learning approach for the accurate identification of major depression based on single resting-state functional magnetic resonance imaging scans in the absence of clinical information. Twenty-four medication-naive patients with major depression and 29 demographically similar healthy individuals underwent resting-state functional magnetic resonance imaging. We first clustered the voxels within the perigenual cingulate cortex into two subregions, a subgenual region and a pregenual region, according to their distinct resting-state functional connectivity patterns and showed that a maximum margin clustering-based unsupervised machine learning approach extracted sufficient information from the subgenual cingulate functional connectivity map to differentiate depressed patients from healthy controls with a group-level clustering consistency of 92.5% and an individual-level classification consistency of 92.5%. It was also revealed that the subgenual cingulate functional connectivity network with the highest discriminative power primarily included the ventrolateral and ventromedial prefrontal cortex, superior temporal gyri and limbic areas, indicating that these connections may play critical roles in the pathophysiology of major depression. The current study suggests that subgenual cingulate functional connectivity network signatures may provide promising objective biomarkers for the diagnosis of major depression and that maximum margin clustering-based unsupervised machine learning approaches may have the potential to inform clinical practice and aid in research on psychiatric disorders. Copyright © 2013 Wiley Periodicals, Inc.

  13. Altered resting-state functional connectivity in post-traumatic stress disorder: a perfusion MRI study

    Science.gov (United States)

    Li, Baojuan; Liu, Jian; Liu, Yang; Lu, Hong-Bing; Yin, Hong

    2013-03-01

    The majority of studies on posttraumatic stress disorder (PTSD) so far have focused on delineating patterns of activations during cognitive processes. Recently, more and more researches have started to investigate functional connectivity in PTSD subjects using BOLD-fMRI. Functional connectivity analysis has been demonstrated as a powerful approach to identify biomarkers of different brain diseases. This study aimed to detect resting-state functional connectivity abnormities in patients with PTSD using arterial spin labeling (ASL) fMRI. As a completely non-invasive technique, ASL allows quantitative estimates of cerebral blood flow (CBF). Compared with BOLD-fMRI, ASL fMRI has many advantages, including less low-frequency signal drifts, superior functional localization, etc. In the current study, ASL images were collected from 10 survivors in mining disaster with recent onset PTSD and 10 survivors without PTSD. Decreased regional CBF in the right middle temporal gyrus, lingual gyrus, and postcentral gyrus was detected in the PTSD patients. Seed-based resting-state functional connectivity analysis was performed using an area in the right middle temporal gyrus as region of interest. Compared with the non-PTSD group, the PTSD subjects demonstrated increased functional connectivity between the right middle temporal gyrus and the right superior temporal gyrus, the left middle temporal gyrus. Meanwhile, decreased functional connectivity between the right middle temporal gyrus and the right postcentral gyrus, the right superior parietal lobule was also found in the PTSD patients. This is the first study which investigated resting-state functional connectivity in PTSD using ASL images. The results may provide new insight into the neural substrates of PTSD.

  14. Exploring structure and function of sensory cortex with 7T MRI.

    Science.gov (United States)

    Schluppeck, Denis; Sanchez-Panchuelo, Rosa-Maria; Francis, Susan T

    2018-01-01

    In this paper, we present an overview of 7T magnetic resonance imaging (MRI) studies of the detailed function and anatomy of sensory areas of the human brain. We discuss the motivation for the studies, with particular emphasis on increasing the spatial resolution of functional MRI (fMRI) using reduced field-of-view (FOV) data acquisitions. MRI at ultra-high-field (UHF) - defined here as 7T and above - has several advantages over lower field strengths. The intrinsic signal-to-noise ratio (SNR) of images is higher at UHF, and coupled with the increased blood-oxygen-level-dependent (BOLD) signal change, this results in increased BOLD contrast-to-noise ratio (CNR), which can be exploited to improve spatial resolution or detect weaker signals. Additionally, the BOLD signal from the intra-vascular (IV) compartment is relatively diminished compared to lower field strengths. Together, these properties make 7T functional MRI an attractive proposition for high spatial specificity measures. But with the advantages come some challenges. For example, increased vulnerability to susceptibility-induced geometric distortions and signal loss in EPI acquisitions tend to be much larger. Some of these technical issues can be addressed with currently available tools and will be discussed. We highlight the key methodological considerations for high resolution functional and structural imaging at 7 T. We then present recent data using the high spatial resolution available at UHF in studies of the visual and somatosensory cortex to highlight promising developments in this area. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Quantitative estimation of brain atrophy and function with PET and MRI two-dimensional projection images

    International Nuclear Information System (INIS)

    Saito, Reiko; Uemura, Koji; Uchiyama, Akihiko; Toyama, Hinako; Ishii, Kenji; Senda, Michio

    2001-01-01

    The purpose of this paper is to estimate the extent of atrophy and the decline in brain function objectively and quantitatively. Two-dimensional (2D) projection images of three-dimensional (3D) transaxial images of positron emission tomography (PET) and magnetic resonance imaging (MRI) were made by means of the Mollweide method which keeps the area of the brain surface. A correlation image was generated between 2D projection images of MRI and cerebral blood flow (CBF) or 18 F-fluorodeoxyglucose (FDG) PET images and the sulcus was extracted from the correlation image clustered by K-means method. Furthermore, the extent of atrophy was evaluated from the extracted sulcus on 2D-projection MRI and the cerebral cortical function such as blood flow or glucose metabolic rate was assessed in the cortex excluding sulcus on 2D-projection PET image, and then the relationship between the cerebral atrophy and function was evaluated. This method was applied to the two groups, the young and the aged normal subjects, and the relationship between the age and the rate of atrophy or the cerebral blood flow was investigated. This method was also applied to FDG-PET and MRI studies in the normal controls and in patients with corticobasal degeneration. The mean rate of atrophy in the aged group was found to be higher than that in the young. The mean value and the variance of the cerebral blood flow for the young are greater than those of the aged. The sulci were similarly extracted using either CBF or FDG PET images. The purposed method using 2-D projection images of MRI and PET is clinically useful for quantitative assessment of atrophic change and functional disorder of cerebral cortex. (author)

  16. A SVM-based quantitative fMRI method for resting-state functional network detection.

    Science.gov (United States)

    Song, Xiaomu; Chen, Nan-kuei

    2014-09-01

    Resting-state functional magnetic resonance imaging (fMRI) aims to measure baseline neuronal connectivity independent of specific functional tasks and to capture changes in the connectivity due to neurological diseases. Most existing network detection methods rely on a fixed threshold to identify functionally connected voxels under the resting state. Due to fMRI non-stationarity, the threshold cannot adapt to variation of data characteristics across sessions and subjects, and generates unreliable mapping results. In this study, a new method is presented for resting-state fMRI data analysis. Specifically, the resting-state network mapping is formulated as an outlier detection process that is implemented using one-class support vector machine (SVM). The results are refined by using a spatial-feature domain prototype selection method and two-class SVM reclassification. The final decision on each voxel is made by comparing its probabilities of functionally connected and unconnected instead of a threshold. Multiple features for resting-state analysis were extracted and examined using an SVM-based feature selection method, and the most representative features were identified. The proposed method was evaluated using synthetic and experimental fMRI data. A comparison study was also performed with independent component analysis (ICA) and correlation analysis. The experimental results show that the proposed method can provide comparable or better network detection performance than ICA and correlation analysis. The method is potentially applicable to various resting-state quantitative fMRI studies. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Functional MRI studies in human Ecstasy and cannabis users

    NARCIS (Netherlands)

    Jager, G.

    2006-01-01

    Cannabis and ecstasy are among the most widely used illicit drugs in the world. However, there are substantial concerns about their neurotoxic potential for brain and brain function. Despite previous research, some crucial questions regarding the causality, course and clinical relevance have

  18. Functional MRI of food-induced brain responses

    NARCIS (Netherlands)

    Smeets, P.A.M.

    2006-01-01

    The ultimate goal of this research was to find central biomarkers of satiety, i.e., physiological measures in the brain that relate to subjectively rated appetite, actual food intake, or both. This thesis describes the changes in brain activity in response to food stimuli as measured by functional

  19. Synthesis of functionalized magnetite nanoparticles to use as liver targeting MRI contrast agent

    International Nuclear Information System (INIS)

    Yazdani, Farshad; Fattahi, Bahare; Azizi, Najmodin

    2016-01-01

    The aim of this research was the preparation of functionalized magnetite nanoparticles to use as a liver targeting contrast agent in magnetic resonance imaging (MRI). For this purpose, Fe_3O_4 nanoparticles were synthesized via the co-precipitation method. The synthesized nanoparticles were coated with silica via the Stober method and finally the coated nanoparticles were functionalized with mebrofenin. Formation of crystalline magnetite particles was confirmed by X-ray diffraction (XRD) analysis. The Fourier transform infrared spectroscopy (FTIR) and energy dispersive X-ray analyzer (EDX) of the final product showed that silica had been effectively bonded onto the surface of the magnetite nanoparticles and the coated nanoparticles functionalized with mebrofenin. The magnetic resonance imaging of the functional nanoparticles showed that the Fe_3O_4–SiO_2-mebrofenin composite is an effective MRI contrast agent for liver targeting. - Highlights: • Superparamagnetic magnetite nanoparticles have been synthesized by simple and economical method. • Preperation of functional MNPs as a MRI contrast agent for liver targeting. • Gaining a good r_2 relaxivity of the coated functional nanoparticles.

  20. ICN_Atlas: Automated description and quantification of functional MRI activation patterns in the framework of intrinsic connectivity networks.

    Science.gov (United States)

    Kozák, Lajos R; van Graan, Louis André; Chaudhary, Umair J; Szabó, Ádám György; Lemieux, Louis

    2017-12-01

    Generally, the interpretation of functional MRI (fMRI) activation maps continues to rely on assessing their relationship to anatomical structures, mostly in a qualitative and often subjective way. Recently, the existence of persistent and stable brain networks of functional nature has been revealed; in particular these so-called intrinsic connectivity networks (ICNs) appear to link patterns of resting state and task-related state connectivity. These networks provide an opportunity of functionally-derived description and interpretation of fMRI maps, that may be especially important in cases where the maps are predominantly task-unrelated, such as studies of spontaneous brain activity e.g. in the case of seizure-related fMRI maps in epilepsy patients or sleep states. Here we present a new toolbox (ICN_Atlas) aimed at facilitating the interpretation of fMRI data in the context of ICN. More specifically, the new methodology was designed to describe fMRI maps in function-oriented, objective and quantitative way using a set of 15 metrics conceived to quantify the degree of 'engagement' of ICNs for any given fMRI-derived statistical map of interest. We demonstrate that the proposed framework provides a highly reliable quantification of fMRI activation maps using a publicly available longitudinal (test-retest) resting-state fMRI dataset. The utility of the ICN_Atlas is also illustrated on a parametric task-modulation fMRI dataset, and on a dataset of a patient who had repeated seizures during resting-state fMRI, confirmed on simultaneously recorded EEG. The proposed ICN_Atlas toolbox is freely available for download at http://icnatlas.com and at http://www.nitrc.org for researchers to use in their fMRI investigations. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  1. Mesolimbic dopamine function is not altered during continuous chronic treatment of rats with typical or atypical neuroleptic drugs

    Energy Technology Data Exchange (ETDEWEB)

    Rupniak, N M.J.; Hall, M D; Kelly, E; Fleminger, S; Kilpatrick, G; Jenner, P; Marsden, C D

    1985-01-01

    Rats were treated continuously for up to 20 months with either haloperidol (1.4-1.6 mg/kg/day), sulpiride (102-109 mg/kg/day) or clozapine (24-27 mg/kg/day). Bsub(max) for specific mesolimbic binding of TH-spiperone, TH-N, n-propylnorapomorphine or TH-piflutixol did not differ in tissue taken from animals treated for up to 12 months with haloperidol, sulpiride or clozapine by comparison to age-matched control rats. Mesolimbic dopamine (50 M)-stimulated adenylate cyclase activity was not altered in any drug treatment group. Spontaneous locomotor activity was transiently decreased during treatment with haloperidol for 1 or 3 months, but not by chronic sulpiride or clozapine treatment. Locomotor activity was not consistently increased in any drug treatment group. After 20 months of continuous drug treatment, focal bilateral application of dopamine (12.5 or 25 g) into the nucleus accumbens caused equivalent increases in locomotor activity in control rats and in animals receiving haloperidol, sulpiride of clozapine. These findings suggest that dopamine receptor blockade is not maintained in the mesolimbic area following chronic treatment with haloperidol, sulpiride or clozapine, and indicate that, under these conditions, clozapine and sulpiride may not act selectively on mesolimbic dopamine receptors. (Author).

  2. Mesolimbic dopamine function is not altered during continuous chronic treatment of rats with typical or atypical neuroleptic drugs

    International Nuclear Information System (INIS)

    Rupniak, N.M.J.; Hall, M.D.; Kelly, E.; Fleminger, S.; Kilpatrick, G.; Jenner, P.; Marsden, C.D.

    1985-01-01

    Rats were treated continuously for up to 20 months with either haloperidol (1.4-1.6 mg/kg/day), sulpiride (102-109 mg/kg/day) or clozapine (24-27 mg/kg/day). Bsub(max) for specific mesolimbic binding of 3 H-spiperone, 3 H-N, n-propylnorapomorphine or 3 H-piflutixol did not differ in tissue taken from animals treated for up to 12 months with haloperidol, sulpiride or clozapine by comparison to age-matched control rats. Mesolimbic dopamine (50 μM)-stimulated adenylate cyclase activity was not altered in any drug treatment group. Spontaneous locomotor activity was transiently decreased during treatment with haloperidol for 1 or 3 months, but not by chronic sulpiride or clozapine treatment. Locomotor activity was not consistently increased in any drug treatment group. After 20 months of continuous drug treatment, focal bilateral application of dopamine (12.5 or 25 μg) into the nucleus accumbens caused equivalent increases in locomotor activity in control rats and in animals receiving haloperidol, sulpiride of clozapine. These findings suggest that dopamine receptor blockade is not maintained in the mesolimbic area following chronic treatment with haloperidol, sulpiride or clozapine, and indicate that, under these conditions, clozapine and sulpiride may not act selectively on mesolimbic dopamine receptors. (Author)

  3. Exercise-induced rescue of tongue function without striatal dopamine sparing in a rat neurotoxin model of Parkinson disease.

    Science.gov (United States)

    Ciucci, Michelle R; Schaser, Allison J; Russell, John A

    2013-09-01

    Unilateral lesions to the medial forebrain bundle with 6-hydroxydopamine (6-OHDA) lead to force and timing deficits during a complex licking task. We hypothesized that training targeting tongue force generation during licking would improve timing and force measures and also lead to striatal dopamine sparing. Nine month-old male Fisher344/Brown Norway rats were used in this experiment. Sixteen rats were in the control condition and received tongue exercise (n=8) or no exercise (n=8). Fourteen rats were in the 6-OHDA lesion condition and underwent tongue exercise (n=7) and or no exercise (n=7). Following 4 weeks of training and post-training measures, all animals underwent bilateral stimulation of the hypoglossal nerves to measure muscle contractile properties and were then transcardially perfused and brain tissues collected for immunohistochemistry to examine striatal dopamine content. Results demonstrated that exercise animals performed better for maximal force, average force, and press rate than their no-exercise counterparts, and the 6-OHDA animals that underwent exercise performed as well as the Control No Exercise group. Interestingly, there were no group differences for tetanic muscle force, despite behavioral recovery of forces. Additionally, behavioral and neurochemical analyses indicate that there were no differences in striatal dopamine. Thus, targeted exercise can improve tongue force and timing deficits related to 6-OHDA lesions and this exercise likely has a central, versus peripheral (muscle strength) mechanism. However, this mechanism is not related to sparing of striatal dopamine content. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. D2 receptor genotype and striatal dopamine signaling predict motor cortical activity and behavior in humans.

    Science.gov (United States)

    Fazio, Leonardo; Blasi, Giuseppe; Taurisano, Paolo; Papazacharias, Apostolos; Romano, Raffaella; Gelao, Barbara; Ursini, Gianluca; Quarto, Tiziana; Lo Bianco, Luciana; Di Giorgio, Annabella; Mancini, Marina; Popolizio, Teresa; Rubini, Giuseppe; Bertolino, Alessandro

    2011-02-14

    Pre-synaptic D2 receptors regulate striatal dopamine release and DAT activity, key factors for modulation of motor pathways. A functional SNP of DRD2 (rs1076560 G>T) is associated with alternative splicing such that the relative expression of D2S (mainly pre-synaptic) vs. D2L (mainly post-synaptic) receptor isoforms is decreased in subjects with the T allele with a putative increase of striatal dopamine levels. To evaluate how DRD2 genotype and striatal dopamine signaling predict motor cortical activity and behavior in humans, we have investigated the association of rs1076560 with BOLD fMRI activity during a motor task. To further evaluate the relationship of this circuitry with dopamine signaling, we also explored the correlation between genotype based differences in motor brain activity and pre-synaptic striatal DAT binding measured with [(123)I] FP-CIT SPECT. Fifty healthy subjects, genotyped for DRD2 rs1076560 were studied with BOLD-fMRI at 3T while performing a visually paced motor task with their right hand; eleven of these subjects also underwent [(123)I]FP-CIT SPECT. SPM5 random-effects models were used for statistical analyses. Subjects carrying the T allele had greater BOLD responses in left basal ganglia, thalamus, supplementary motor area, and primary motor cortex, whose activity was also negatively correlated with reaction time at the task. Moreover, left striatal DAT binding and activity of left supplementary motor area were negatively correlated. The present results suggest that DRD2 genetic variation was associated with focusing of responses in the whole motor network, in which activity of predictable nodes was correlated with reaction time and with striatal pre-synaptic dopamine signaling. Our results in humans may help shed light on genetic risk for neurobiological mechanisms involved in the pathophysiology of disorders with dysregulation of striatal dopamine like Parkinson's disease. Copyright © 2010 Elsevier Inc. All rights reserved.

  5. Essential Control of the Function of the Striatopallidal Neuron by Pre-coupled Complexes of Adenosine A2A-Dopamine D2 Receptor Heterotetramers and Adenylyl Cyclase

    Directory of Open Access Journals (Sweden)

    Sergi Ferré

    2018-04-01

    Full Text Available The central adenosine system and adenosine receptors play a fundamental role in the modulation of dopaminergic neurotransmission. This is mostly achieved by the strategic co-localization of different adenosine and dopamine receptor subtypes in the two populations of striatal efferent neurons, striatonigral and striatopallidal, that give rise to the direct and indirect striatal efferent pathways, respectively. With optogenetic techniques it has been possible to dissect a differential role of the direct and indirect pathways in mediating “Go” responses upon exposure to reward-related stimuli and “NoGo” responses upon exposure to non-rewarded or aversive-related stimuli, respectively, which depends on their different connecting output structures and their differential expression of dopamine and adenosine receptor subtypes. The striatopallidal neuron selectively expresses dopamine D2 receptors (D2R and adenosine A2A receptors (A2AR, and numerous experiments using multiple genetic and pharmacological in vitro, in situ and in vivo approaches, demonstrate they can form A2AR-D2R heteromers. It was initially assumed that different pharmacological interactions between dopamine and adenosine receptor ligands indicated the existence of different subpopulations of A2AR and D2R in the striatopallidal neuron. However, as elaborated in the present essay, most evidence now indicates that all interactions can be explained with a predominant population of striatal A2AR-D2R heteromers forming complexes with adenylyl cyclase subtype 5 (AC5. The A2AR-D2R heteromer has a tetrameric structure, with two homodimers, which allows not only multiple allosteric interactions between different orthosteric ligands, agonists, and antagonists, but also the canonical Gs-Gi antagonistic interaction at the level of AC5. We present a model of the function of the A2AR-D2R heterotetramer-AC5 complex, which acts as an integrative device of adenosine and dopamine signals that

  6. The Relationship Between Dopamine Neurotransmitter Dynamics and the Blood-Oxygen-Level-Dependent (BOLD Signal: A Review of Pharmacological Functional Magnetic Resonance Imaging

    Directory of Open Access Journals (Sweden)

    Tyler J. Bruinsma

    2018-04-01

    Full Text Available Functional magnetic resonance imaging (fMRI is widely used in investigations of normal cognition and brain disease and in various clinical applications. Pharmacological fMRI (pharma-fMRI is a relatively new application, which is being used to elucidate the effects and mechanisms of pharmacological modulation of brain activity. Characterizing the effects of neuropharmacological agents on regional brain activity using fMRI is challenging because drugs modulate neuronal function in a wide variety of ways, including through receptor agonist, antagonist, and neurotransmitter reuptake blocker events. Here we review current knowledge on neurotransmitter-mediated blood-oxygen-level dependent (BOLD fMRI mechanisms as well as recently updated methodologies aimed at more fully describing the effects of neuropharmacologic agents on the BOLD signal. We limit our discussion to dopaminergic signaling as a useful lens through which to analyze and interpret neurochemical-mediated changes in the hemodynamic BOLD response. We also discuss the need for future studies that use multi-modal approaches to expand the understanding and application of pharma-fMRI.

  7. Functional MRI for immediate monitoring stereotactic thalamotomy in a patient with essential tremor

    International Nuclear Information System (INIS)

    Hesselmann, Volker; Schaaf, Maike; Krug, Barbara; Lackner, Klaus; Maarouf, Mohammed; Hunsche, Stefan; Sturm, Volker; Lasek, Kathrin; Wedekind, Christoph

    2006-01-01

    The effect of stereotactic thalamotomy was assessed with pre- and postoperative functional magnetic resonance imaging (fMRI) under motor stimulation. A patient with unilateral essential tremor (ET) of the left arm underwent stereotactically guided thalamotomy of the right ventral intermediate thalamic nucleus (VIM). FMRI was done directly before and after surgery on a 1.5-Tesla scanner. The stimulation paradigm was maintainance of the affected arm in an extended position and hand clenching being performed in a block design manner. Statistical analysis was done with Brain Voyager 2000. After thalamotomy the tremor diminished completely. As a difference between the pre- and postoperative fMRI, a significant activation was found in the VIM contralateral to the activation site, adjacent to the inferior olivary nucleus contralateral to the activation site and in the dorsal cingulum. In conclusion, fMRI can detect the functional effect of thalamotomy for tremor treatment. Direct postoperative fMRI provides a sufficient method for estimating the effect of thalamotomy immediately after intervention. The importance of the intermediate thalamic nucleus and the olivary nucleus in tremor generation is supported by our findings. (orig.)

  8. MRI evaluation and functional assessment of brain injury after hypoxic ischemia in neonatal mice.

    Science.gov (United States)

    Adén, Ulrika; Dahlberg, Viktoria; Fredholm, Bertil B; Lai, Li-Ju; Chen, Zhengguan; Bjelke, Börje

    2002-05-01

    Severe perinatal asphyxia is an important cause of brain injury in the newborn infant. We examined early events after hypoxic ischemia (HI) in the 7-day-old mouse brain by MRI and related them to long-term functional effects and histopathology in the same animals at 4 to 5 weeks of age. HI was induced in 7-day-old CD1 mice by exposure to 8% oxygen for 30 minutes after occlusion of the left common carotid artery. The resulting unilateral focal lesion was evaluated in vivo by MRI (T2 maps and apparent diffusion coefficient maps) at 3, 6, and 24 hours and 5 days after hypoxia. Locomotion and sensorimotor function were analyzed after 3 weeks. Four weeks after HI, the mice were killed, and cresyl violet-stained brain sections were examined morphologically. A decrease in apparent diffusion coefficient values in cortex on the affected side was found at 3 hours after HI. T2 values were significantly increased after 6 hours and remained so for 5 days. Maximal size of the lesion was attained at 3 to 6 hours after HI and declined thereafter. Animals with MRI-detected lesions had decreased forward locomotion, performed worse than controls in the beam-walking test, and showed a unilateral hypotrophy in the cresyl violet-stained brain sections 4 weeks later. The temporal progression of the damage after HI in 7-day-old mice differs from that of the adult brain as judged by MRI. The early lesions detected by MRI were related to functional impairments for these mice in near-adult life.

  9. Graph-based network analysis of resting-state functional MRI

    Directory of Open Access Journals (Sweden)

    Jinhui Wang

    2010-06-01

    Full Text Available In the past decade, resting-state functional MRI (R-fMRI measures of brain activity have attracted considerable attention. Based on changes in the blood oxygen level-dependent signal, R-fMRI offers a novel way to assess the brain’s spontaneous or intrinsic (i.e., task-free activity with both high spatial and temporal resolutions. The properties of both the intra- and inter-regional connectivity of resting-state brain activity have been well documented, promoting our understanding of the brain as a complex network. Specifically, the topological organization of brain networks has been recently studied with graph theory. In this review, we will summarize the recent advances in graph-based brain network analyses of R-fMRI signals, both in typical and atypical populations. Application of these approaches to R-fMRI data has demonstrated non-trivial topological properties of functional networks in the human brain. Among these is the knowledge that the brain’s intrinsic activity is organized as a small-world, highly efficient network, with significant modularity and highly connected hub regions. These network properties have also been found to change throughout normal development, aging and in various pathological conditions. The literature reviewed here suggests that graph-based network analyses are capable of uncovering system-level changes associated with different processes in the resting brain, which could provide novel insights into the understanding of the underlying physiological mechanisms of brain function. We also highlight several potential research topics in the future.

  10. Graph-based network analysis of resting-state functional MRI.

    Science.gov (United States)

    Wang, Jinhui; Zuo, Xinian; He, Yong

    2010-01-01

    In the past decade, resting-state functional MRI (R-fMRI) measures of brain activity have attracted considerable attention. Based on changes in the blood oxygen level-dependent signal, R-fMRI offers a novel way to assess the brain's spontaneous or intrinsic (i.e., task-free) activity with both high spatial and temporal resolutions. The properties of both the intra- and inter-regional connectivity of resting-state brain activity have been well documented, promoting our understanding of the brain as a complex network. Specifically, the topological organization of brain networks has been recently studied with graph theory. In this review, we will summarize the recent advances in graph-based brain network analyses of R-fMRI signals, both in typical and atypical populations. Application of these approaches to R-fMRI data has demonstrated non-trivial topological properties of functional networks in the human brain. Among these is the knowledge that the brain's intrinsic activity is organized as a small-world, highly efficient network, with significant modularity and highly connected hub regions. These network properties have also been found to change throughout normal development, aging, and in various pathological conditions. The literature reviewed here suggests that graph-based network analyses are capable of uncovering system-level changes associated with different processes in the resting brain, which could provide novel insights into the understanding of the underlying physiological mechanisms of brain function. We also highlight several potential research topics in the future.

  11. Community structure in networks of functional connectivity: resolving functional organization in the rat brain with pharmacological MRI.

    Science.gov (United States)

    Schwarz, Adam J; Gozzi, Alessandro; Bifone, Angelo

    2009-08-01

    In the study of functional connectivity, fMRI data can be represented mathematically as a network of nodes and links, where image voxels represent the nodes and the connections between them reflect a degree of correlation or similarity in their response. Here we show that, within this framework, functional imaging data can be partitioned into 'communities' of tightly interconnected voxels corresponding to maximum modularity within the overall network. We evaluated this approach systematically in application to networks constructed from pharmacological MRI (phMRI) of the rat brain in response to acute challenge with three different compounds with distinct mechanisms of action (d-amphetamine, fluoxetine, and nicotine) as well as vehicle (physiological saline). This approach resulted in bilaterally symmetric sub-networks corresponding to meaningful anatomical and functional connectivity pathways consistent with the purported mechanism of action of each drug. Interestingly, common features across all three networks revealed two groups of tightly coupled brain structures that responded as functional units independent of the specific neurotransmitter systems stimulated by the drug challenge, including a network involving the prefrontal cortex and sub-cortical regions extending from the striatum to the amygdala. This finding suggests that each of these networks includes general underlying features of the functional organization of the rat brain.

  12. Preliminary study on the mechanism of reading recovery in a pure alexia by using functional MRI

    International Nuclear Information System (INIS)

    Ma Lin; Li Dejun; Weng Xuchu; Tang Yiyuan; Zhang Wutian; Sun Weijian; Feng Shiwen

    2004-01-01

    Objective: To observe the changes of the brain function during reading recovery by using functional MRI (fMRI), and to provide the experimental data in elucidating the mechanism on the recovery of reading and language function. Methods: fMRI was performed in a native Chinese patient with pure alexia on the 45 th and 130 th day after the onset, respectively. Three kinds of Chinese characters were presented during the scan and the patient was asked to make the judgement weather he could recognize the characters or not. The brain activation maps were acquired after postprocessing, and the activated location and volume were compared between the first and second experiments. Results: In both experiments, Broca area, Wernicke area, and the right extrastriate were significantly activated, while the left extrastriate around the lesion was markedly activated only in the second experiment, and the volume of activation in the right extrastriate in the second experiment was about 3 times as large as that in the first experiment. Conclusion: The left extrastriate cortex is one of the key areas responsible for reading function in the brain. The recovery of reading function can be compensated in contralateral corresponding cortical area, or it can be the result of reorganization in ipsilateral peri-lesion cortex. Both mechanisms may simultaneously play important roles in reading recovery

  13. Alterations in renal morphology and function after ESWL therapy: evaluation with dynamic contrast-enhanced MRI

    International Nuclear Information System (INIS)

    Krestin, G.P.; Fischbach, R.; Vorreuther, R.; Schulthess, G.K. von

    1993-01-01

    Contrast-enhanced gradient-echo MRI was used to evaluate morphological and functional alterations in the kidneys after extracorporeal shock wave lithotripsy (ESWL). Dynamic MRI with a temporal resolution of 10 s per image was performed by repeated imaging in the coronal plane after administration of gadolinium-DTPA (0.1 mmol/kg) before and after ESWL for renal calculi in 25 patients. Before ESWL 22 patients had normally functioning kidneys, characterised by a marked decrease in signal intensity in the renal medulla 30-40 s after the onset of cortical perfusion. After ESWL 8 patients had functional abnormalities: in 2 cases the medullary signal decrease was disturbed throughout the whole organ, while 6 kidneys demonstrated regional loss of concentrating ability in the medulla. Morphological alterations (oedema with blurred contours and loss of corticomedullary differentiation; parenchymal haemorrhage and haemorrhage in a cortical cyst; subcapsular, perirenal and pararenal haematoma) were detected in 9 cases. Haemorrhage was encountered more often after administration of more than 2500 shock waves; however, no such correlation was seen in the kidneys with functional disturbances following ESWL therapy. MRI proved to be a sensitive method for the assessment of morphological and functional alterations after ESWL, but longer follow-up studies are required to identify the clinical impact of these early changes. (orig.)

  14. Alterations in renal morphology and function after ESWL therapy: evaluation with dynamic contrast-enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Krestin, G.P. [Dept. of Medical Radiology, University Hospital Zurich (Switzerland); Fischbach, R. [Dept. of Radiology, Univ. of Cologne (Germany); Vorreuther, R. [Dept. of Urology, Univ. of Cologne (Germany); Schulthess, G.K. von [Dept. of Medical Radiology, University Hospital Zurich (Switzerland)

    1993-06-01

    Contrast-enhanced gradient-echo MRI was used to evaluate morphological and functional alterations in the kidneys after extracorporeal shock wave lithotripsy (ESWL). Dynamic MRI with a temporal resolution of 10 s per image was performed by repeated imaging in the coronal plane after administration of gadolinium-DTPA (0.1 mmol/kg) before and after ESWL for renal calculi in 25 patients. Before ESWL 22 patients had normally functioning kidneys, characterised by a marked decrease in signal intensity in the renal medulla 30-40 s after the onset of cortical perfusion. After ESWL 8 patients had functional abnormalities: in 2 cases the medullary signal decrease was disturbed throughout the whole organ, while 6 kidneys demonstrated regional loss of concentrating ability in the medulla. Morphological alterations (oedema with blurred contours and loss of corticomedullary differentiation; parenchymal haemorrhage and haemorrhage in a cortical cyst; subcapsular, perirenal and pararenal haematoma) were detected in 9 cases. Haemorrhage was encountered more often after administration of more than 2500 shock waves; however, no such correlation was seen in the kidneys with functional disturbances following ESWL therapy. MRI proved to be a sensitive method for the assessment of morphological and functional alterations after ESWL, but longer follow-up studies are required to identify the clinical impact of these early changes. (orig.)

  15. Differentiating between bipolar and unipolar depression in functional and structural MRI studies.

    Science.gov (United States)

    Han, Kyu-Man; De Berardis, Domenico; Fornaro, Michele; Kim, Yong-Ku

    2018-03-28

    Distinguishing depression in bipolar disorder (BD) from unipolar depression (UD) solely based on clinical clues is difficult, which has led to the exploration of promising neural markers in neuroimaging measures for discriminating between BD depression and UD. In this article, we review structural and functional magnetic resonance imaging (MRI) studies that directly compare UD and BD depression based on neuroimaging modalities including functional MRI studies on regional brain activation or functional connectivity, structural MRI on gray or white matter morphology, and pattern classification analyses using a machine learning approach. Numerous studies have reported distinct functional and structural alterations in emotion- or reward-processing neural circuits between BD depression and UD. Different activation patterns in neural networks including the amygdala, anterior cingulate cortex (ACC), prefrontal cortex (PFC), and striatum during emotion-, reward-, or cognition-related tasks have been reported between BD and UD. A stronger functional connectivity pattern in BD was pronounced in default mode and in frontoparietal networks and brain regions including the PFC, ACC, parietal and temporal regions, and thalamus compared to UD. Gray matter volume differences in the ACC, hippocampus, amygdala, and dorsolateral prefrontal cortex (DLPFC) have been reported between BD and UD, along with a thinner DLPFC in BD compared to UD. BD showed reduced integrity in the anterior part of the corpus callosum and posterior cingulum compared to UD. Several studies performed pattern classification analysis using structural and functional MRI data to distinguish between UD and BD depression using a supervised machine learning approach, which yielded a moderate level of accuracy in classification. Copyright © 2018 Elsevier Inc. All rights reserved.

  16. Subjective cognitive impairment: functional MRI during a divided attention task.

    Science.gov (United States)

    Rodda, J; Dannhauser, T; Cutinha, D J; Shergill, S S; Walker, Z

    2011-10-01

    Individuals with subjective cognitive impairment (SCI) have persistent memory complaints but normal neurocognitive performance. For some, this may represent a pre-mild cognitive impairment (MCI) stage of Alzheimer's disease (AD). Given that attentional deficits and associated brain activation changes are present early in the course of AD, we aimed to determine whether SCI is associated with brain activation changes during attentional processing. Eleven SCI subjects and 10 controls completed a divided attention task during functional magnetic resonance imaging. SCI and control groups did not differ in sociodemographic, neurocognitive or behavioural measures. When group activation during the divided attention task was compared, the SCI group demonstrated increased activation in left medial temporal lobe, bilateral thalamus, posterior cingulate and caudate. This pattern of increased activation is similar to the pattern of decreased activation reported during divided attention in AD and may indicate compensatory changes. These findings suggest the presence of early functional changes in SCI; longitudinal studies will help to further elucidate the relationship between SCI and AD. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

  17. Atypical hemispheric dominance for attention: functional MRI topography.

    Science.gov (United States)

    Flöel, Agnes; Jansen, Andreas; Deppe, Michael; Kanowski, Martin; Konrad, Carsten; Sommer, Jens; Knecht, Stefan

    2005-09-01

    The right hemisphere is predominantly involved in tasks associated with spatial attention. However, left hemispheric dominance for spatial attention can be found in healthy individuals, and both spatial attention and language can be lateralized to the same hemisphere. Little is known about the underlying regional distribution of neural activation in these 'atypical' individuals. Previously a large number of healthy subjects were screened for hemispheric dominance of visuospatial attention and language, using functional Doppler ultrasonography. From this group, subjects were chosen who were 'atypical' for hemispheric dominance of visuospatial attention and language, and their pattern of brain activation was studied with functional magnetic resonance imaging during a task probing spatial attention. Right-handed subjects with the 'typical' pattern of brain organization served as control subjects. It was found that subjects with an inverted lateralization of language and spatial attention (language right, attention left) recruited left-hemispheric areas in the attention task, homotopic to those recruited by control subjects in the right hemisphere. Subjects with lateralization of both language and attention to the right hemisphere activated an attentional network in the right hemisphere that was comparable to control subjects. The present findings suggest that not the hemispheric side, but the intrahemispheric pattern of activation is the distinct feature for the neural processes underlying language and attention.

  18. Orofacial complex regional pain syndrome: pathophysiologic mechanisms and functional MRI.

    Science.gov (United States)

    Lee, Yeon-Hee; Lee, Kyung Mi; Kim, Hyug-Gi; Kang, Soo-Kyung; Auh, Q-Schick; Hong, Jyung-Pyo; Chun, Yang-Hyun

    2017-08-01

    Complex regional pain syndrome (CRPS) is one of the most challenging chronic pain conditions and is characterized by burning pain, allodynia, hyperalgesia, autonomic changes, trophic changes, edema, and functional loss involving mainly the extremities. Until recently, very few reports have been published concerning CRPS involving the orofacial area. We report on a 50-year-old female patient who presented with unbearable pain in all of her teeth and hypersensitivity of the facial skin. She also reported intractable pain in both extremities accompanied by temperature changes and orofacial pain that increased when the other pains were aggravated. In the case of CRPS with trigeminal neuropathic pain, protocols for proper diagnosis and prompt treatment have yet to be established in academia or in the clinical field. We performed functional magnetic resonance imaging for a thorough analysis of the cortical representation of the affected orofacial area immediately before and immediately after isolated light stimulus of the affected hand and foot and concluded that CRPS can be correlated with trigeminal neuropathy in the orofacial area. Furthermore, the patient was treated with carbamazepine administration and stellate ganglion block, which can result in a rapid improvement of pain in the trigeminal region. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Arcuate fasciculus laterality by diffusion tensor imaging correlates with language laterality by functional MRI in preadolescent children.

    Science.gov (United States)

    Sreedharan, Ruma Madhu; Menon, Amitha C; James, Jija S; Kesavadas, Chandrasekharan; Thomas, Sanjeev V

    2015-03-01

    Language lateralization is unique to humans. Functional MRI (fMRI) and diffusion tensor imaging (DTI) enable the study of language areas and white matter fibers involved in language, respectively. The objective of this study was to correlate arcuate fasciculus (AF) laterality by diffusion tensor imaging with that by fMRI in preadolescent children which has not yet been reported. Ten children between 8 and 12 years were subjected to fMRI and DTI imaging using Siemens 1.5 T MRI. Two language fMRI paradigms--visual verb generation and word pair task--were used. Analysis was done using SPM8 software. In DTI, the fiber volume of the arcuate fasciculus (AFV) and fractional anisotropy (FA) was measured. The fMRI Laterality Index (fMRI-LI) and DTI Laterality Index (DTI-LI) were calculated and their correlation assessed using the Pearson Correlation Index. Of ten children, mean age 10.6 years, eight showed left lateralization while bilateral language lateralization was seen in two. AFV by DTI was more on the left side in seven of the eight children who had left lateralization by fMRI. DTI could not trace the AF in one child. Of the two with bilateral language lateralization on fMRI, one showed larger AFV on the right side while the other did not show any asymmetry. There was a significant correlation (p laterality in children with a high degree of correlation between the two imaging modalities.

  20. Functional MRI of the olfactory system in conscious dogs.

    Directory of Open Access Journals (Sweden)

    Hao Jia

    Full Text Available We depend upon the olfactory abilities of dogs for critical tasks such as detecting bombs, landmines, other hazardous chemicals and illicit substances. Hence, a mechanistic understanding of the olfactory system in dogs is of great scientific interest. Previous studies explored this aspect at the cellular and behavior levels; however, the cognitive-level neural substrates linking them have never been explored. This is critical given the fact that behavior is driven by filtered sensory representations in higher order cognitive areas rather than the raw odor maps of the olfactory bulb. Since sedated dogs cannot sniff, we investigated this using functional magnetic resonance imaging of conscious dogs. We addressed the technical challenges of head motion using a two pronged strategy of behavioral training to keep dogs' head as still as possible and a single camera optical head motion tracking system to account for residual jerky movements. We built a custom computer-controlled odorant delivery system which was synchronized with image acquisition, allowing the investigation of brain regions activated by odors. The olfactory bulb and piriform lobes were commonly activated in both awake and anesthetized dogs, while the frontal cortex was activated mainly in conscious dogs. Comparison of responses to low and high odor intensity showed differences in either the strength or spatial extent of activation in the olfactory bulb, piriform lobes, cerebellum, and frontal cortex. Our results demonstrate the viability of the proposed method for functional imaging of the olfactory system in conscious dogs. This could potentially open up a new field of research in detector dog technology.

  1. Frontal-subcortical circuits in obsessive-compulsive disorder: role of the dopamine D1 receptor

    International Nuclear Information System (INIS)

    Olver, J.S.; Reutens, D.C.; Maruff, P.; Burrows, G.D.; Norman, T.R.; Ellen, S.R.; Pantelis, C.; Tochon-Danguy, H.; Ackermann, U.; Stekelenberg, N.

    2000-01-01

    Full text: Obsessive-Compulsive Disorder (OCD) is an anxiety disorder which is increasingly being recognised as a neurobiological disorder. While serotonergic mechanisms have been proposed, the major competing theory in the pathophysiology of OCD involves the neurotransmitter dopamine. The Dopamine D1 receptor is implicated in OCD following the finding of specific spatial working memory abnormalities in a series of neuropsychological studies. Spatial working memory is known to depend on the integrity of D1 receptor function in the Dorso-lateral Prefrontal Cortex (DLPFC) of primates. This study aims to examine the role of dopamine in patients with OCD and in particular to test the hypothesis that there is an upregulation of dopamine D1 receptors in the DLPFC which correlates with spatial working memory deficits in OCD. Three OCD patients and three normal controls underwent Positron Emission Tomography (PET) following intravenous injection of the D1 antagonist PET ligand SCH23390. Reconstructed PET images were co registered with subject Magnetic Resonance Images (MRI) and regions of interest drawn manually. We will present the analysis of the Binding Potentials of SCH23390 in the regions of interest of the first three OCD patients and compare them with three normal control patients. In conclusion Dopamine-Serotonergic interactions are involved in the pathophysiology of OCD. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc

  2. Assessment of the right ventricular function in patients with chronic obstructive pulmonary disease using MRI

    International Nuclear Information System (INIS)

    Gao Yan; Du Xiangying; Qin Wen; Li Kuncheng

    2011-01-01

    Background: Chronic obstructive pulmonary disease (COPD) is often associated with changes of the structure and the function of the right ventricle (RV). Therefore, the assessment of right ventricular function and myocardial mass (MM) is clinically important for the evaluation of the severity of COPD, which may provide an objective basis for therapeutic strategy. Purpose: To assess the right ventricular function and RV MM in patients with mild to severe COPD using magnetic resonance imaging (MRI). Material and Methods: We prospectively studied 49 COPD patients determined by the pulmonary function test (PFT). Using the Global Initiative for COPD classification, the COPD patients were divided into three groups according to the severity of the disease: group I = mild (n = 18); group II = moderate (n = 16); and group III = severe (n = 15). The patient groups were compared to a control group consisting of 30 age-matched, healthy, non-smoking subjects. The RV function and RV MM were obtained by 1.5T cardiac MRI in all of the four groups. The results were compared among the four groups using the ANOVA. Pearson's correlation was used to evaluate the relationship between the right ventricular ejection fraction (RVEF) and MM with the PFT results in COPD patients. Results: The RVEF was significantly lower in group III than in the other groups (P < 0.01). The RV MM differed significantly among all groups (P < 0.01) and gradually increased with the severity of COPD (P < 0.01). The correlation was significant between the MRI results and forced expiratory volume in 1 s (r = 0.860 for RVEF, r = -0.838 for RV MM) in COPD patients. Conclusion: The RVEF and RV MM measured by MRI correlate significantly with the severity of disease as determined by PFT in patients with COPD

  3. Assessment of the right ventricular function in patients with chronic obstructive pulmonary disease using MRI

    Energy Technology Data Exchange (ETDEWEB)

    Gao Yan; Du Xiangying; Qin Wen; Li Kuncheng (Dept. of Radiology, Xuanwu Hospital of Capital Medical Univ., Beijing (China)), email: kuncheng.li@gmail.com

    2011-09-15

    Background: Chronic obstructive pulmonary disease (COPD) is often associated with changes of the structure and the function of the right ventricle (RV). Therefore, the assessment of right ventricular function and myocardial mass (MM) is clinically important for the evaluation of the severity of COPD, which may provide an objective basis for therapeutic strategy. Purpose: To assess the right ventricular function and RV MM in patients with mild to severe COPD using magnetic resonance imaging (MRI). Material and Methods: We prospectively studied 49 COPD patients determined by the pulmonary function test (PFT). Using the Global Initiative for COPD classification, the COPD patients were divided into three groups according to the severity of the disease: group I = mild (n = 18); group II = moderate (n = 16); and group III = severe (n = 15). The patient groups were compared to a control group consisting of 30 age-matched, healthy, non-smoking subjects. The RV function and RV MM were obtained by 1.5T cardiac MRI in all of the four groups. The results were compared among the four groups using the ANOVA. Pearson's correlation was used to evaluate the relationship between the right ventricular ejection fraction (RVEF) and MM with the PFT results in COPD patients. Results: The RVEF was significantly lower in group III than in the other groups (P < 0.01). The RV MM differed significantly among all groups (P < 0.01) and gradually increased with the severity of COPD (P < 0.01). The correlation was significant between the MRI results and forced expiratory volume in 1 s (r = 0.860 for RVEF, r = -0.838 for RV MM) in COPD patients. Conclusion: The RVEF and RV MM measured by MRI correlate significantly with the severity of disease as determined by PFT in patients with COPD

  4. A comparative study of single and multiple hand tasks using functional MRI

    International Nuclear Information System (INIS)

    Shin, Byung Suck; Lee, Ho Kyu; Park, Sung Tae; Kim, Dong Eun; Lee, Myung Jun; Choi, Choong Gon; Kim, Jae Kyun; Suh, Dae Chul; Lim, Tae Hwan

    1998-01-01

    The purpose of this study is to assess, using functional MRI and by comparing activated motor sensory areas, the independence of brain activation during single and alternative multiple hand tasks. The subjects were six healthy volunteers. Using at 1.5T Siemens system and single shot FID-EPI sequencing (T2 weighted image; TR/TE 0.96 msec/ 61msec, flip angle 90 deg, matrix size 96 x 128, slice thickness/gap 5 mm/0.8 mm, FOV 200 mm) and T1-weighted anatomic images, functional MRI was performed. The paradigm of motor tasks consisted of appositional finger movements; the first involved the separate use of the right, left, and both hands in sequence. Using cross-correlation method (threshold : 0.6) and fMRI analysis software (stimulate 5.0), functional images were obtained. The activated area of brain cortex, the number of pixel, the average percentage change in signal intensity, and correlation of the time-signal intensity curve in the activated motor area were analysed and compared between the two task groups. Statistical analysis involved the use of Wilcoxon signed-rank test. Brain activation did not differ according to whether the motor task was single or alternative. We therefore suggest that during multiple stimuli, the relevant functional area and neuronal column are activated independently. (author). 19 refs., 2 tabs., 3 figs

  5. Multivariate spatial Gaussian mixture modeling for statistical clustering of hemodynamic parameters in functional MRI

    International Nuclear Information System (INIS)

    Fouque, A.L.; Ciuciu, Ph.; Risser, L.; Fouque, A.L.; Ciuciu, Ph.; Risser, L.

    2009-01-01

    In this paper, a novel statistical parcellation of intra-subject functional MRI (fMRI) data is proposed. The key idea is to identify functionally homogenous regions of interest from their hemodynamic parameters. To this end, a non-parametric voxel-based estimation of hemodynamic response function is performed as a prerequisite. Then, the extracted hemodynamic features are entered as the input data of a Multivariate Spatial Gaussian Mixture Model (MSGMM) to be fitted. The goal of the spatial aspect is to favor the recovery of connected components in the mixture. Our statistical clustering approach is original in the sense that it extends existing works done on univariate spatially regularized Gaussian mixtures. A specific Gibbs sampler is derived to account for different covariance structures in the feature space. On realistic artificial fMRI datasets, it is shown that our algorithm is helpful for identifying a parsimonious functional parcellation required in the context of joint detection estimation of brain activity. This allows us to overcome the classical assumption of spatial stationarity of the BOLD signal model. (authors)

  6. Tablet-Based Functional MRI of the Trail Making Test: Effect of Tablet Interaction Mode

    Directory of Open Access Journals (Sweden)

    Mahta Karimpoor

    2017-10-01

    Full Text Available The Trail Making Test (TMT is widely used for assessing executive function, frontal lobe abilities, and visual motor skills. Part A of this pen-and-paper test (TMT-A involves linking numbers randomly distributed in space, in ascending order. Part B (TMT-B alternates between linking numbers and letters. TMT-B is more demanding than TMT-A, but the mental processing that supports the performance of this test remains incompletely understood. Functional MRI (fMRI may help to clarify the relationship between TMT performance and brain activity, but providing an environment that supports real-world pen-and-paper interactions during fMRI is challenging. Previously, an fMRI-compatible tablet system was developed for writing and drawing with two modes of interaction: the original cursor-based, proprioceptive approach, and a new mode involving augmented reality to provide visual feedback of hand position (VFHP for enhanced user interaction. This study characterizes the use of the tablet during fMRI of young healthy adults (n = 22, with half of the subjects performing TMT with VFHP and the other half performing TMT without VFHP. Activation maps for both TMT-A and TMT-B performance showed considerable overlap between the two tablet modes, and no statistically differences in brain activity were detected when contrasting TMT-B vs. TMT-A for the two tablet modes. Behavioral results also showed no statistically different interaction effects for TMT-B vs. TMT-A for the two tablet modes. Tablet-based TMT scores showed reasonable convergent validity with those obtained by administering the standard pen-and-paper TMT to the same subjects. Overall, the results suggest that despite the slightly different mechanisms involved for the two modes of tablet interaction, both are suitable for use in fMRI studies involving TMT performance. This study provides information for using tablet-based TMT methods appropriately in future fMRI studies involving patients and healthy

  7. SLC6A3 coding variant Ala559Val found in two autism probands alters dopamine transporter function and trafficking.

    Science.gov (United States)

    Bowton, E; Saunders, C; Reddy, I A; Campbell, N G; Hamilton, P J; Henry, L K; Coon, H; Sakrikar, D; Veenstra-VanderWeele, J M; Blakely, R D; Sutcliffe, J; Matthies, H J G; Erreger, K; Galli, A

    2014-10-14

    Emerging evidence associates dysfunction in the dopamine (DA) transporter (DAT) with the pathophysiology of autism spectrum disorder (ASD). The human DAT (hDAT; SLC6A3) rare variant with an Ala to Val substitution at amino acid 559 (hDAT A559V) was previously reported in individuals with bipolar disorder or attention-deficit hyperactivity disorder (ADHD). We have demonstrated that this variant is hyper-phosphorylated at the amino (N)-terminal serine (Ser) residues and promotes an anomalous DA efflux phenotype. Here, we report the novel identification of hDAT A559V in two unrelated ASD subjects and provide the first mechanistic description of its impaired trafficking phenotype. DAT surface expression is dynamically regulated by DAT substrates including the psychostimulant amphetamine (AMPH), which causes hDAT trafficking away from the plasma membrane. The integrity of DAT trafficking directly impacts DA transport capacity and therefore dopaminergic neurotransmission. Here, we show that hDAT A559V is resistant to AMPH-induced cell surface redistribution. This unique trafficking phenotype is conferred by altered protein kinase C β (PKCβ) activity. Cells expressing hDAT A559V exhibit constitutively elevated PKCβ activity, inhibition of which restores the AMPH-induced hDAT A559V membrane redistribution. Mechanistically, we link the inability of hDAT A559V to traffic in response to AMPH to the phosphorylation of the five most distal DAT N-terminal Ser. Mutation of these N-terminal Ser to Ala restores AMPH-induced trafficking. Furthermore, hDAT A559V has a diminished ability to transport AMPH, and therefore lacks AMPH-induced DA efflux. Pharmacological inhibition of PKCβ or Ser to Ala substitution in the hDAT A559V background restores AMPH-induced DA efflux while promoting intracellular AMPH accumulation. Although hDAT A559V is a rare variant, it has been found in multiple probands with neuropsychiatric disorders associated with imbalances in DA neurotransmission

  8. Functional selectivity of allosteric interactions within G protein-coupled receptor oligomers: the dopamine D1-D3 receptor heterotetramer.

    Science.gov (United States)

    Guitart, Xavier; Navarro, Gemma; Moreno, Estefania; Yano, Hideaki; Cai, Ning-Sheng; Sánchez-Soto, Marta; Kumar-Barodia, Sandeep; Naidu, Yamini T; Mallol, Josefa; Cortés, Antoni; Lluís, Carme; Canela, Enric I; Casadó, Vicent; McCormick, Peter J; Ferré, Sergi

    2014-10-01

    The dopamine D1 receptor-D3 receptor (D1R-D3R) heteromer is being considered as a potential therapeutic target for neuropsychiatric disorders. Previous studies suggested that this heteromer could be involved in the ability of D3R agonists to potentiate locomotor activation induced by D1R agonists. It has also been postulated that its overexpression plays a role in L-dopa-induced dyskinesia and in drug addiction. However, little is known about its biochemical properties. By combining bioluminescence resonance energy transfer, bimolecular complementation techniques, and cell-signaling experiments in transfected cells, evidence was obtained for a tetrameric stoichiometry of the D1R-D3R heteromer, constituted by two interacting D1R and D3R homodimers coupled to Gs and Gi proteins, respectively. Coactivation of both receptors led to the canonical negative interaction at the level of adenylyl cyclase signaling, to a strong recruitment of β-arrestin-1, and to a positive cross talk of D1R and D3R agonists at the level of mitogen-activated protein kinase (MAPK) signaling. Furthermore, D1R or D3R antagonists counteracted β-arrestin-1 recruitment and MAPK activation induced by D3R and D1R agonists, respectively (cross-antagonism). Positive cross talk and cross-antagonism at the MAPK level were counteracted by specific synthetic peptides with amino acid sequences corresponding to D1R transmembrane (TM) domains TM5 and TM6, which also selectively modified the quaternary structure of the D1R-D3R heteromer, as demonstrated by complementation of hemiproteins of yellow fluorescence protein fused to D1R and D3R. These results demonstrate functional selectivity of allosteric modulations within the D1R-D3R heteromer, which can be involved with the reported behavioral synergism of D1R and D3R agonists. U.S. Government work not protected by U.S. copyright.

  9. Aggression-related brain function assessed with the Point Subtraction Aggression Paradigm in fMRI

    DEFF Research Database (Denmark)

    Skibsted, Anine P; Cunha-Bang, Sofi da; Carré, Justin M

    2017-01-01

    The Point Subtraction Aggression Paradigm (PSAP) measures aggressive behavior in response to provocations. The aim of the study was to implement the PSAP in a functional neuroimaging environment (fMRI) and evaluate aggression-related brain reactivity including response to provocations and associa......The Point Subtraction Aggression Paradigm (PSAP) measures aggressive behavior in response to provocations. The aim of the study was to implement the PSAP in a functional neuroimaging environment (fMRI) and evaluate aggression-related brain reactivity including response to provocations...... and associations with aggression within the paradigm. Twenty healthy participants completed two 12-min PSAP sessions within the scanner. We evaluated brain responses to aggressive behavior (removing points from an opponent), provocations (point subtractions by the opponent), and winning points. Our results showed...... with the involvement of these brain regions in emotional and impulsive behavior. Striatal reactivity may suggest an involvement of reward during winning and stealing points....

  10. An iterative two-threshold analysis for single-subject functional MRI of the human brain

    Energy Technology Data Exchange (ETDEWEB)

    Auer, Tibor; Schweizer, Renate; Frahm, Jens [Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut fuer Biophysikalische Chemie, Goettingen (Germany)

    2011-11-15

    Current thresholding strategies for the analysis of functional MRI (fMRI) datasets may suffer from specific limitations (e.g. with respect to the required smoothness) or lead to reduced performance for a low signal-to-noise ratio (SNR). Although a previously proposed two-threshold (TT) method offers a promising solution to these problems, the use of preset settings limits its performance. This work presents an optimised TT approach that estimates the required parameters in an iterative manner. The iterative TT (iTT) method is compared with the original TT method, as well as other established voxel-based and cluster-based thresholding approaches and spatial mixture modelling (SMM) for both simulated data and fMRI of a hometown walking task at different experimental settings (spatial resolution, filtering and SNR). In general, the iTT method presents with remarkable sensitivity and good specificity that outperforms all conventional approaches tested except for SMM in a few cases. This also holds true for challenging conditions such as high spatial resolution, the absence of filtering, high noise level, or a low number of task repetitions. Thus, iTT emerges as a good candidate for both scientific fMRI studies at high spatial resolution and more routine applications for clinical purposes. (orig.)

  11. Study on cerebral activation areas during repetition with functional MRI in normal adults

    International Nuclear Information System (INIS)

    Koseki, Yohju

    2009-01-01

    For cerebral activation of speech areas in functional MRI (f-MRI) study, the usefulness of an optical microphone, which made it possible to perform task repetition at real time during scanning, was examined. Subjects were 25 healthy adults (mean age, 27.1±5.6 years), who consisted of 15 right-handed and 10 left-handed or ambidextrous persons. Tasks comprised repetition of monosyllables, non-words, words and sentences. The repetition tasks were covertly performed during scanning of f-MRI by using an optical microphone. In both the right-handed and non-right-handed groups, activations in the left superior temporal gyrus (sensory speech area) were most frequently observed during all of the tasks. In the right-handed group, activations in the left inferior frontal (motor speech area) and superior temporal gyri were significantly more often observed than those in the right inferior frontal and superior temporal gyri. From an assessment of the laterality index (LI), left-side dominant activation was frequently seen in most of the cerebral regions including sensory and motor speech areas, although right-side and bilateral dominant activations were observed in a few cases. In both groups, activations in regions associated with sensory speech were significantly more often seen than those in regions associated with motor speech. The present predominant activations in regions involved in sensory speech indicate that the optical microphone is useful in f-MRI studies using task repetition. (author)

  12. Identification by functional MRI of human cerebral region activated by taste stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Kakimoto, Naoya [Osaka Univ. (Japan). Faculty of Dentistry

    2000-09-01

    The purpose of this study was the examination of possible imaging of the primary taste region of human cerebral cortex by functional MRI (fMRI). Subjects were 19-36 years old, healthy adult male and female volunteers given information concerning the purpose, significance and method of the study. MRI equipment was 1.5 T Signa Horizon (GE) with Head Coil. Images were processed by the software FuncTool on the Advantage Windows Workstation (GE). Taste stimulation was done by swab bearing the solution of 4% quinine hydrochloride, 20% sodium chloride or distilled water (control) or by dripping from the syringe of the solutions, 8% tartaric acid or 80% sugar. Preliminary examinations with the swab suggested the possibility of the identification. Further, with use of dripping apparatus, the taste active region was shown to be identified by fMRI and of which area tended to be larger in male than in female: a significant difference was seen for the quinine hydrochloride. As above, the method was suggested to be a diagnostic mean for the taste perception. (K.H.)

  13. Identification by functional MRI of human cerebral region activated by taste stimulation

    International Nuclear Information System (INIS)

    Kakimoto, Naoya

    2000-01-01

    The purpose of this study was the examination of possible imaging of the primary taste region of human cerebral cortex by functional MRI (fMRI). Subjects were 19-36 years old, healthy adult male and female volunteers given information concerning the purpose, significance and method of the study. MRI equipment was 1.5 T Signa Horizon (GE) with Head Coil. Images were processed by the software FuncTool on the Advantage Windows Workstation (GE). Taste stimulation was done by swab bearing the solution of 4% quinine hydrochloride, 20% sodium chloride or distilled water (control) or by dripping from the syringe of the solutions, 8% tartaric acid or 80% sugar. Preliminary examinations with the swab suggested the possibility of the identification. Further, with use of dripping apparatus, the taste active region was shown to be identified by fMRI and of which area tended to be larger in male than in female: a significant difference was seen for the quinine hydrochloride. As above, the method was suggested to be a diagnostic mean for the taste perception. (K.H.)

  14. Study of human brain functions by functional magnetic resonance imaging (fMRI) and spectroscopy (fMRS)

    International Nuclear Information System (INIS)

    Jagannathan, N.R.

    1998-01-01

    Functional magnetic resonance imaging (fMRI) has become a powerful tool in the detection and assessment of cerebral pathophysiology and the regional mapping and characterization of cognitive processes such as motor skills, vision, language and memory. The results of the effect of motor cortex stimulation during repetitive hand squeezing task activation using in-vivo single voxel NMR spectroscopy carried out on normal volunteer subjects are presented

  15. Functional connectivity in resting-state fMRI: Is linear correlation sufficient?

    Czech Academy of Sciences Publication Activity Database

    Hlinka, Jaroslav; Paluš, Milan; Vejmelka, Martin; Mantini, D.; Corbetta, M.

    2011-01-01

    Roč. 54, č. 3 (2011), s. 2218-2225 ISSN 1053-8119 R&D Projects: GA MŠk 7E08027 EU Projects: European Commission(XE) 200728 - BRAINSYNC Institutional research plan: CEZ:AV0Z10300504 Keywords : fMRI * functional connectivity * Gaussianity * nonlinearity * correlation * mutual information Subject RIV: FH - Neurology Impact factor: 5.895, year: 2011

  16. How does MRI work? An introduction into physics and functionality of magnetic resonance imaging. 6. ed.

    International Nuclear Information System (INIS)

    Weishaupt, Dominik; Marincek, Borut

    2009-01-01

    The book provides the basic physics and describes the functionality of magnetic resonance tomography in a very illustrative way. The following topics are covered: Spins and the magnetic resonance phenomenon, image contrast, three-dimensional structure, signal-to-noise ratio, description of a magnetic resonance tomography, basic pulse sequences, fast pulse sequences, methods for fat suppression, parallel imaging, cardiovascular imaging, MR contrast media, MR image artifacts, high-field MRI, imaging beyond morphology and structure, safety and risks [de

  17. Genetic and Diagnostic Biomarker Development in ASD Toddlers Using Resting State Functional MRI

    Science.gov (United States)

    2016-09-01

    temporal lobe and partial volumes of sulcal CSF at this early stage in brain development when white matter tracts are not yet robust enough to be...ages 3 to 4 years. 2. KEYWORDS Autism spectrum disorder, ASD, early brain development , intrinsic functional brain networks, fMRI, infants, toddlers...TD in bottom left triangle and ASD in top right triangle. Figure 4. Within-network ( left ) and Between-Network (Out-of-Network) ( right ) connectivity

  18. Scanning fast and slow: current limitations of 3 Tesla functional MRI and future potential

    Directory of Open Access Journals (Sweden)

    Roland N Boubela

    2014-02-01

    Full Text Available Functional MRI at 3T has become a workhorse for the neurosciences, e.g., neurology, psychology, and psychiatry, enabling non-invasive investigation of brain function and connectivity. However, BOLD-based fMRI is a rather indirect measure of brain function, confounded by fluctuation related signals, e.g. head or brain motion, brain pulsation, blood flow, intermixed with susceptibility differences close or distant to the region of neuronal activity. Even though a plethora of preprocessing strategies have been published to address these confounds, their efficiency is still under discussion. In particular, physiological signal fluctuations closely related to brain supply may mask BOLD signal changes related to true neuronal activation. Here we explore recent technical and methodological advancements aimed at disentangling the various components, employing fast multiband vs. standard EPI, in combination with fast temporal ICA.Our preliminary results indicate that fast (TR< 0.5s scanning may help to identify and eliminate physiologic components, increasing tSNR and functional contrast. In addition, biological variability can be studied and task performance better correlated to other measures. This should increase specificity and reliability in fMRI studies. Furthermore, physiological signal changes during scanning may then be recognized as a source of information rather than a nuisance. As we are currently still undersampling the complexity of the brain, even at a rather coarse macroscopic level, we should be very cautious in the interpretation of neuroscientific findings, in particular when comparing different groups (e.g., age, sex, medication, pathology, etc.. From a technical point of view our goal should be to sample brain activity at layer specific resolution with low TR, covering as much of the brain as possible without violating SAR limits. We hope to stimulate discussion towards a better understanding and a more quantitative use of fMRI.

  19. The effect of fMRI task combinations on determining the hemispheric dominance of language functions

    Energy Technology Data Exchange (ETDEWEB)

    Niskanen, Eini [University of Eastern Finland, Department of Applied Physics, Kuopio (Finland); Kuopio University Hospital, Department of Clinical Radiology, Kuopio (Finland); Koenoenen, Mervi [Kuopio University Hospital, Department of Clinical Radiology, Kuopio (Finland); Kuopio University Hospital, Department of Clinical Neurophysiology, Kuopio (Finland); Villberg, Ville; Aeikiae, Marja [Kuopio University Hospital, Department of Neurology, Kuopio (Finland); Nissi, Mikko; Ranta-aho, Perttu; Karjalainen, Pasi [University of Eastern Finland, Department of Applied Physics, Kuopio (Finland); Saeisaenen, Laura; Mervaala, Esa [Kuopio University Hospital, Department of Clinical Neurophysiology, Kuopio (Finland); University of Eastern Finland, Institute of Clinical Medicine, Clinical Neurophysiology, Kuopio (Finland); Kaelviaeinen, Reetta [Kuopio University Hospital, Department of Neurology, Kuopio (Finland); University of Eastern Finland, Institute of Clinical Medicine, Neurology, Kuopio (Finland); Vanninen, Ritva [Kuopio University Hospital, Department of Clinical Radiology, Kuopio (Finland); University of Eastern Finland, Institute of Clinical Medicine, Clinical Radiology, Kuopio (Finland)

    2012-04-15

    The purpose of this study is to establish the most suitable combination of functional magnetic resonance imaging (fMRI) language tasks for clinical use in determining language dominance and to define the variability in laterality index (LI) and activation power between different combinations of language tasks. Activation patterns of different fMRI analyses of five language tasks (word generation, responsive naming, letter task, sentence comprehension, and word pair) were defined for 20 healthy volunteers (16 right-handed). LIs and sums of T values were calculated for each task separately and for four combinations of tasks in predefined regions of interest. Variability in terms of activation power and lateralization was defined in each analysis. In addition, the visual assessment of lateralization of language functions based on the individual fMRI activation maps was conducted by an experienced neuroradiologist. A combination analysis of word generation, responsive naming, and sentence comprehension was the most suitable in terms of activation power, robustness to detect essential language areas, and scanning time. In general, combination analyses of the tasks provided higher overall activation levels than single tasks and reduced the number of outlier voxels disturbing the calculation of LI. A combination of auditory and visually presented tasks that activate different aspects of language functions with sufficient activation power may be a useful task battery for determining language dominance in patients. (orig.)

  20. The effect of fMRI task combinations on determining the hemispheric dominance of language functions

    International Nuclear Information System (INIS)

    Niskanen, Eini; Koenoenen, Mervi; Villberg, Ville; Aeikiae, Marja; Nissi, Mikko; Ranta-aho, Perttu; Karjalainen, Pasi; Saeisaenen, Laura; Mervaala, Esa; Kaelviaeinen, Reetta; Vanninen, Ritva

    2012-01-01

    The purpose of this study is to establish the most suitable combination of functional magnetic resonance imaging (fMRI) language tasks for clinical use in determining language dominance and to define the variability in laterality index (LI) and activation power between different combinations of language tasks. Activation patterns of different fMRI analyses of five language tasks (word generation, responsive naming, letter task, sentence comprehension, and word pair) were defined for 20 healthy volunteers (16 right-handed). LIs and sums of T values were calculated for each task separately and for four combinations of tasks in predefined regions of interest. Variability in terms of activation power and lateralization was defined in each analysis. In addition, the visual assessment of lateralization of language functions based on the individual fMRI activation maps was conducted by an experienced neuroradiologist. A combination analysis of word generation, responsive naming, and sentence comprehension was the most suitable in terms of activation power, robustness to detect essential language areas, and scanning time. In general, combination analyses of the tasks provided higher overall activation levels than single tasks and reduced the number of outlier voxels disturbing the calculation of LI. A combination of auditory and visually presented tasks that activate different aspects of language functions with sufficient activation power may be a useful task battery for determining language dominance in patients. (orig.)

  1. The Use of Functional MRI to Study Appetite Control in the CNS

    Directory of Open Access Journals (Sweden)

    Akila De Silva

    2012-01-01

    Full Text Available Functional magnetic resonance imaging (fMRI has provided the opportunity to safely investigate the workings of the human brain. This paper focuses on its use in the field of human appetitive behaviour and its impact in obesity research. In the present absence of any safe or effective centrally acting appetite suppressants, a better understanding of how appetite is controlled is vital for the development of new antiobesity pharmacotherapies. Early functional imaging techniques revealed an attenuation of brain reward area activity in response to visual food stimuli when humans are fed—in other words, the physiological state of hunger somehow increases the appeal value of food. Later studies have investigated the action of appetite modulating hormones on the fMRI signal, showing how the attenuation of brain reward region activity that follows feeding can be recreated in the fasted state by the administration of anorectic gut hormones. Furthermore, differences in brain activity between obese and lean individuals have provided clues about the possible aetiology of overeating. The hypothalamus acts as a central gateway modulating homeostatic and nonhomeostatic drives to eat. As fMRI techniques constantly improve, functional data regarding the role of this small but hugely important structure in appetite control is emerging.

  2. Multimodal functional network connectivity: an EEG-fMRI fusion in network space.

    Directory of Open Access Journals (Sweden)

    Xu Lei

    Full Text Available EEG and fMRI recordings measure the functional activity of multiple coherent networks distributed in the cerebral cortex. Identifying network interaction from the complementary neuroelectric and hemodynamic signals may help to explain the complex relationships between different brain regions. In this paper, multimodal functional network connectivity (mFNC is proposed for the fusion of EEG and fMRI in network space. First, functional networks (FNs are extracted using spatial independent component analysis (ICA in each modality separately. Then the interactions among FNs in each modality are explored by Granger causality analysis (GCA. Finally, fMRI FNs are matched to EEG FNs in the spatial domain using network-based source imaging (NESOI. Investigations of both synthetic and real data demonstrate that mFNC has the potential to reveal the underlying neural networks of each modality separately and in their combination. With mFNC, comprehensive relationships among FNs might be unveiled for the deep exploration of neural activities and metabolic responses in a specific task or neurological state.

  3. Cerebral activation during Chinese semantic associative task in Xinjiang' Uyghurs: a functional MRI study

    International Nuclear Information System (INIS)

    Yang Lixia; Jia Wenxiao; Tang Weijun; Wang Hong; Ding Shuang; Wang Hao

    2010-01-01

    Objective: To explore the cerebral activation in Xinjiang' Uyghurs when performing a Chinese word tasks by the functional magnetic resonance image (fMRI). Methods: Twenty-one healthy Xinjiang' Uyghurs and 11 healthy Hans were scanned using functional magnetic resonance imaging (fMRI) on a 1.5 T MRI scanner with a single run. Different Chinese words were displayed in each block to avoid any practice effect. SPM5.0 software was used for image data processing. To evaluate the inter subject consistency of brain activations associated with Chinese character and word reading, we created penetrance maps by combining binary individual functional maps. Results: For Uyghur-Chinese bilingual subjects, activations related to generated a word that was semantically related to each stimulus. The results indicated that reading Chinese is characterized by extensive activity of the neural systems. Peak activations occurred in the left middle frontal cortex at Brodmann Areas (BA9 and BA47). The left temporal (BA37) cortices were also strongly activated. Other important activated areas included bilateral visual systems (BA17-19) and cerebellum. The location of peak activation in the left frontal regions was similar in Native Uyghurs and Hans. But the active areas in Uyghurs are more extensive than that of Hans. Conclusions: The location of peak activation in the left frontal regions was similar in Native Uyghurs and Hans. More brain areas were needed for Xinjiang' Uyghur speakers during processing Chinese words. (authors)

  4. Functional MRI of the cervical spine after distortion injury; MR-Funktionsdiagnostik der Halswirbelsaeule nach Schleudertrauma

    Energy Technology Data Exchange (ETDEWEB)

    Schnarkowski, P. [Muenchen Univ. (Germany). Inst. fuer Radiologische Diagnostik; Weidenmaier, W. [Muenchen Univ. (Germany). Inst. fuer Radiologische Diagnostik; Heuck, A. [Muenchen Univ. (Germany). Inst. fuer Radiologische Diagnostik; Reiser, M.F. [Muenchen Univ. (Germany). Inst. fuer Radiologische Diagnostik

    1995-04-01

    50 patients with a history of distortion injury of the cervical spine were examined with static and functional MRI. Functional MRI consisted of different patient`s positions from maximal extension to maximal flexion (30 , 0 , 25 , 40 , 50 ). T{sub 2}*-weighted gradient echo sequences were performed in a sagittal view for the different positions. Ligamentous instabilities and disc protrusions were seen only in functional MRI in 17 patients. These findings correlated with the neurological symptoms. Two patients were treated by operative fusion because of these findings. (orig.) [Deutsch] Bei 50 Patienten mit einem Schleudertrauma der Halswirbelsaeule wurden zu den statischen Magnetresonanztomogrammen der Halswirbelsaeule MR-Funktionsaufnahmen durchgefuehrt. Diese Funktionsaufnahmen erfolgten in 5 verschiedenen Flexionsgraden von maximaler Reklination bis zur maximalen Inklination (30 , 0 , 25 , 40 , 50 ). T{sub 2}*-gewichtete Gradienten-Echo-Sequenzen in sagittaler Schnittfuehrung wurden fuer jeden Flexionsgrad angefertigt. Bandinstabilitaeten und Bandscheibenvorwoelbungen konnten bei 17 Patienten nur in bestimmten Flexionsgraden erfasst werden. Diese 17 Patienten zeigten eine umschriebene neurologische Symptomatik, die von ihrer Lokalisation mit den in der MR-Funktionsdiagnostik erhobenen Befunden korrelierten. Zwei Patienten wurden aufgrund diese Befunde mit einer operativen Fusion therapiert. (orig.)

  5. Integration of fMRI, NIROT and ERP for studies of human brain function.

    Science.gov (United States)

    Gore, John C; Horovitz, Silvina G; Cannistraci, Christopher J; Skudlarski, Pavel

    2006-05-01

    Different methods of assessing human brain function possess specific advantages and disadvantages compared to others, but it is believed that combining different approaches will provide greater information than can be obtained from each alone. For example, functional magnetic resonance imaging (fMRI) has good spatial resolution but poor temporal resolution, whereas the converse is true for electrophysiological recordings (event-related potentials or ERPs). In this review of recent work, we highlight a novel approach to combining these modalities in a manner designed to increase information on the origins and locations of the generators of specific ERPs and the relationship between fMRI and ERP signals. Near infrared imaging techniques have also been studied as alternatives to fMRI and can be readily integrated with simultaneous electrophysiological recordings. Each of these modalities may in principle be also used in so-called steady-state acquisitions in which the correlational structure of signals from the brain may be analyzed to provide new insights into brain function.

  6. The effect of fMRI task combinations on determining the hemispheric dominance of language functions.

    Science.gov (United States)

    Niskanen, Eini; Könönen, Mervi; Villberg, Ville; Nissi, Mikko; Ranta-Aho, Perttu; Säisänen, Laura; Karjalainen, Pasi; Aikiä, Marja; Kälviäinen, Reetta; Mervaala, Esa; Vanninen, Ritva

    2012-04-01

    The purpose of this study is to establish the most suitable combination of functional magnetic resonance imaging (fMRI) language tasks for clinical use in determining language dominance and to define the variability in laterality index (LI) and activation power between different combinations of language tasks. Activation patterns of different fMRI analyses of five language tasks (word generation, responsive naming, letter task, sentence comprehension, and word pair) were defined for 20 healthy volunteers (16 right-handed). LIs and sums of T values were calculated for each task separately and for four combinations of tasks in predefined regions of interest. Variability in terms of activation power and lateralization was defined in each analysis. In addition, the visual assessment of lateralization of language functions based on the individual fMRI activation maps was conducted by an experienced neuroradiologist. A combination analysis of word generation, responsive naming, and sentence comprehension was the most suitable in terms of activation power, robustness to detect essential language areas, and scanning time. In general, combination analyses of the tasks provided higher overall activation levels than single tasks and reduced the number of outlier voxels disturbing the calculation of LI. A combination of auditory and visually presented tasks that activate different aspects of language functions with sufficient activation power may be a useful task battery for determining language dominance in patients.

  7. Blood oxygen-level dependent functional assessment of cerebrovascular reactivity: Feasibility for intraoperative 3 Tesla MRI.

    Science.gov (United States)

    Fierstra, Jorn; Burkhardt, Jan-Karl; van Niftrik, Christiaan Hendrik Bas; Piccirelli, Marco; Pangalu, Athina; Kocian, Roman; Neidert, Marian Christoph; Valavanis, Antonios; Regli, Luca; Bozinov, Oliver

    2017-02-01

    To assess the feasibility of functional blood oxygen-level dependent (BOLD) MRI to evaluate intraoperative cerebrovascular reactivity (CVR) at 3 Tesla field strength. Ten consecutive neurosurgical subjects scheduled for a clinical intraoperative MRI examination were enrolled in this study. In addition to the clinical protocol a BOLD sequence was implemented with three cycles of 44 s apnea to calculate CVR values on a voxel-by-voxel basis throughout the brain. The CVR range was then color-coded and superimposed on an anatomical volume to create high spatial resolution CVR maps. Ten subjects (mean age 34.8 ± 13.4; 2 females) uneventfully underwent the intraoperative BOLD protocol, with no complications occurring. Whole-brain CVR for all subjects was (mean ± SD) 0.69 ± 0.42, whereas CVR was markedly higher for tumor subjects as compared to vascular subjects, 0.81 ± 0.44 versus 0.33 ± 0.10, respectively. Furthermore, color-coded functional maps could be robustly interpreted for a whole-brain assessment of CVR. We demonstrate that intraoperative BOLD MRI is feasible in creating functional maps to assess cerebrovascular reactivity throughout the brain in subjects undergoing a neurosurgical procedure. Magn Reson Med 77:806-813, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  8. Multimodality Functional Imaging in Radiation Therapy Planning: Relationships between Dynamic Contrast-Enhanced MRI, Diffusion-Weighted MRI, and 18F-FDG PET

    Directory of Open Access Journals (Sweden)

    Moisés Mera Iglesias

    2015-01-01

    Full Text Available Objectives. Biologically guided radiotherapy needs an understanding of how different functional imaging techniques interact and link together. We analyse three functional imaging techniques that can be useful tools for achieving this objective. Materials and Methods. The three different imaging modalities from one selected patient are ADC maps, DCE-MRI, and 18F-FDG PET/CT, because they are widely used and give a great amount of complementary information. We show the relationship between these three datasets and evaluate them as markers for tumour response or hypoxia marker. Thus, vascularization measured using DCE-MRI parameters can determine tumour hypoxia, and ADC maps can be used for evaluating tumour response. Results. ADC and DCE-MRI include information from 18F-FDG, as glucose metabolism is associated with hypoxia and tumour cell density, although 18F-FDG includes more information about the malignancy of the tumour. The main disadvantage of ADC maps is the distortion, and we used only low distorted regions, and extracellular volume calculated from DCE-MRI can be considered equivalent to ADC in well-vascularized areas. Conclusion. A dataset for achieving the biologically guided radiotherapy must include a tumour density study and a hypoxia marker. This information can be achieved using only MRI data or only PET/CT studies or mixing both datasets.

  9. Infinite Relational Modeling of Functional Connectivity in Resting State fMRI

    DEFF Research Database (Denmark)

    Mørup, Morten; Madsen, Kristoffer H.; Dogonowski, Anne Marie

    2010-01-01

    Functional magnetic resonance imaging (fMRI) can be applied to study the functional connectivity of the neural elements which form complex network at a whole brain level. Most analyses of functional resting state networks (RSN) have been based on the analysis of correlation between the temporal...... dynamics of various regions of the brain. While these models can identify coherently behaving groups in terms of correlation they give little insight into how these groups interact. In this paper we take a different view on the analysis of functional resting state networks. Starting from the definition...... of resting state as functional coherent groups we search for functional units of the brain that communicate with other parts of the brain in a coherent manner as measured by mutual information. We use the infinite relational model (IRM) to quantify functional coherent groups of resting state networks...

  10. Polymorphisms in the dopamine D4 receptor gene (DRD4) contribute to individual differences in human sexual behavior: desire, arousal and sexual function.

    Science.gov (United States)

    Ben Zion, I Z; Tessler, R; Cohen, L; Lerer, E; Raz, Y; Bachner-Melman, R; Gritsenko, I; Nemanov, L; Zohar, A H; Belmaker, R H; Benjamin, J; Ebstein, R P

    2006-08-01

    Although there is some evidence from twin studies that individual differences in sexual behavior are heritable, little is known about the specific molecular genetic design of human sexuality. Recently, a specific dopamine D4 receptor (DRD4) agonist was shown in rats to induce penile erection through a central mechanism. These findings prompted us to examine possible association between the well-characterized DRD4 gene and core phenotypes of human sexual behavior that included desire, arousal and function in a group of 148 nonclinical university students. We observed association between the exon 3 repeat region, and the C-521T and C-616G promoter region SNPs, with scores on scales that measure human sexual behavior. The single most common DRD4 5-locus haplotype (19%) was significantly associated with Desire, Function and Arousal scores. The current results are consistent with animal studies that show a role for dopamine and specifically the DRD4 receptor in sexual behavior and suggest that one pathway by which individual variation in human desire, arousal and function are mediated is based on allelic variants coding for differences in DRD4 receptor gene expression and protein concentrations in key brain areas.

  11. Neural correlates of the popular music phenomenon: evidence from functional MRI and PET imaging

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Qiaozhen [The Second Affiliated Hospital of Zhejiang University School of Medicine, Department of Psychiatry, Hangzhou (China); Zhejiang University Medical PET Center, Hangzhou (China); Institute of Nuclear Medicine and Molecular Imaging of Zhejiang University, Hangzhou (China); Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou (China); The Second Affiliated Hospital of Zhejiang University School of Medicine, Department of Nuclear Medicine, Hangzhou, Zhejiang (China); Zhang, Ying; Hou, Haifeng; Du, Fenglei; Wu, Shuang; Chen, Lin; Shen, Yehua; Chao, Fangfang; Zhang, Hong; Tian, Mei [Zhejiang University Medical PET Center, Hangzhou (China); Institute of Nuclear Medicine and Molecular Imaging of Zhejiang University, Hangzhou (China); Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou (China); The Second Affiliated Hospital of Zhejiang University School of Medicine, Department of Nuclear Medicine, Hangzhou, Zhejiang (China); Chung, June-key [Seoul National University Hospital, Department of Nuclear Medicine, Seoul (Korea, Republic of)

    2017-06-15

    Music can induce different emotions. However, its neural mechanism remains unknown. The aim of this study was to use functional magnetic resonance imaging (fMRI) and position emission tomography (PET) imaging for mapping of neural changes under the most popular music in healthy volunteers. Blood-oxygen-level-dependent (BOLD) fMRI and monoamine receptor PET imaging with {sup 11}C-N-methylspiperone ({sup 11}C-NMSP) were conducted under the popular music Gangnam Style and light music A Comme Amour in healthy subjects. PET and fMRI images were analyzed by using the Statistical Parametric Mapping software (SPM). Significantly increased fMRI BOLD signals were found in the bilateral superior temporal cortices, left cerebellum, left putamen and right thalamus cortex. Monoamine receptor availability was increased significantly in the left superior temporal gyrus and left putamen, but decreased in the bilateral superior occipital cortices under the Gangnam Style compared with the light music condition. Significant positive correlation was found between {sup 11}C-NMSP binding and fMRI BOLD signals in the left temporal cortex. Furthermore, increased {sup 11}C-NMSP binding in the left putamen was positively correlated with the mood arousal level score under the Gangnam Style condition. Popular music Gangnam Style can arouse pleasure experience and strong emotional response. The left putamen is positively correlated with the mood arousal level score under the Gangnam Style condition. Our results revealed characteristic patterns of brain activity associated with Gangnam Style, and may also provide more general insights into the music-induced emotional processing. (orig.)

  12. Enhancing motor network activity using real-time functional MRI neurofeedback of left premotor cortex

    Directory of Open Access Journals (Sweden)

    Theo Ferreira Marins

    2015-12-01

    Full Text Available Neurofeedback by functional Magnetic Resonance Imaging (fMRI is a technique of potential therapeutic relevance that allows individuals to be aware of their own neurophysiological responses and to voluntarily modulate the activity of specific brain regions, such as the premotor cortex (PMC, important for motor recovery after brain injury. We investigated (i whether healthy human volunteers are able to up-regulate the activity of the left PMC during a right hand finger tapping motor imagery (MI task while receiving continuous fMRI-neurofeedback, and (ii whether successful modulation of brain activity influenced non-targeted motor control regions. During the MI task, participants of the neurofeedback group (NFB received ongoing visual feedback representing the level of fMRI responses within their left PMC. Control (CTL group participants were shown similar visual stimuli, but these were non-contingent on brain activity. Both groups showed equivalent levels of behavioral ratings on arousal and motor imagery, before and during the fMRI protocol. In the NFB, but not in CLT group, brain activation during the last run compared to the first run revealed increased activation in the left PMC. In addition, the NFB group showed increased activation in motor control regions extending beyond the left PMC target area, including the supplementary motor area, basal ganglia and cerebellum. Moreover, in the last run, the NFB group showed stronger activation in the left PMC/inferior frontal gyrus when compared to the CTL group. Our results indicate that modulation of PMC and associated motor control areas can be achieved during a single neurofeedback-fMRI session. These results contribute to a better understanding of the underlying mechanisms of MI-based neurofeedback training, with direct implications for rehabilitation strategies in severe brain disorders, such as stroke.

  13. Neural correlates of the popular music phenomenon: evidence from functional MRI and PET imaging.

    Science.gov (United States)

    Chen, Qiaozhen; Zhang, Ying; Hou, Haifeng; Du, Fenglei; Wu, Shuang; Chen, Lin; Shen, Yehua; Chao, Fangfang; Chung, June-Key; Zhang, Hong; Tian, Mei

    2017-06-01

    Music can induce different emotions. However, its neural mechanism remains unknown. The aim of this study was to use functional magnetic resonance imaging (fMRI) and position emission tomography (PET) imaging for mapping of neural changes under the most popular music in healthy volunteers. Blood-oxygen-level-dependent (BOLD) fMRI and monoamine receptor PET imaging with 11 C-N-methylspiperone ( 11 C-NMSP) were conducted under the popular music Gangnam Style and light music A Comme Amour in healthy subjects. PET and fMRI images were analyzed by using the Statistical Parametric Mapping software (SPM). Significantly increased fMRI BOLD signals were found in the bilateral superior temporal cortices, left cerebellum, left putamen and right thalamus cortex. Monoamine receptor availability was increased significantly in the left superior temporal gyrus and left putamen, but decreased in the bilateral superior occipital cortices under the Gangnam Style compared with the light music condition. Significant positive correlation was found between 11 C-NMSP binding and fMRI BOLD signals in the left temporal cortex. Furthermore, increased 11 C-NMSP binding in the left putamen was positively correlated with the mood arousal level score under the Gangnam Style condition. Popular music Gangnam Style can arouse pleasure experience and strong emotional response. The left putamen is positively correlated with the mood arousal level score under the Gangnam Style condition. Our results revealed characteristic patterns of brain activity associated with Gangnam Style, and may also provide more general insights into the music-induced emotional processing.

  14. Neural correlates of the popular music phenomenon: evidence from functional MRI and PET imaging

    International Nuclear Information System (INIS)

    Chen, Qiaozhen; Zhang, Ying; Hou, Haifeng; Du, Fenglei; Wu, Shuang; Chen, Lin; Shen, Yehua; Chao, Fangfang; Zhang, Hong; Tian, Mei; Chung, June-key

    2017-01-01

    Music can induce different emotions. However, its neural mechanism remains unknown. The aim of this study was to use functional magnetic resonance imaging (fMRI) and position emission tomography (PET) imaging for mapping of neural changes under the most popular music in healthy volunteers. Blood-oxygen-level-dependent (BOLD) fMRI and monoamine receptor PET imaging with "1"1C-N-methylspiperone ("1"1C-NMSP) were conducted under the popular music Gangnam Style and light music A Comme Amour in healthy subjects. PET and fMRI images were analyzed by using the Statistical Parametric Mapping software (SPM). Significantly increased fMRI BOLD signals were found in the bilateral superior temporal cortices, left cerebellum, left putamen and right thalamus cortex. Monoamine receptor availability was increased significantly in the left superior temporal gyrus and left putamen, but decreased in the bilateral superior occipital cortices under the Gangnam Style compared with the light music condition. Significant positive correlation was found between "1"1C-NMSP binding and fMRI BOLD signals in the left temporal cortex. Furthermore, increased "1"1C-NMSP binding in the left putamen was positively correlated with the mood arousal level score under the Gangnam Style condition. Popular music Gangnam Style can arouse pleasure experience and strong emotional response. The left putamen is positively correlated with the mood arousal level score under the Gangnam Style condition. Our results revealed characteristic patterns of brain activity associated with Gangnam Style, and may also provide more general insights into the music-induced emotional processing. (orig.)

  15. Clinical application of functional MRI for chronic epilepsy; Klinischer Einsatz der funktionellen MRT bei chronischer Epilepsie

    Energy Technology Data Exchange (ETDEWEB)

    Woermann, F.G.; Labudda, K. [Krankenhaus Mara, Epilepsiezentrum Bethel, Abteilung fuer Magentresonanztomographie, Bielefeld (Germany)

    2010-02-15

    Functional magnetic resonance imaging (fMRI) is frequently used in the presurgical diagnostic procedure of epilepsy patients, in particular for lateralization of speech and memory and for localization of the primary motor cortex to delineate the epileptogenic lesion from eloquent brain areas. fMRI is one of the non-invasive procedures in the presurgical diagnostic process, together with medical history, seizure semiology, neurological examination, interictal and ictal EEG, structural MRI, video EEG monitoring and neuropsychology. This diagnostic sequence leads either to the decision for or against elective epilepsy surgery or to the decision to proceed with invasive diagnostic techniques (Wada test, intra-operative or extra-operative cortical stimulation). It is difficult to evaluate the contribution of the fMRI test in isolation to the validity of the entire diagnostic sequence. Complications such as memory loss and aphasia in temporal lobe resections or paresis after frontal lobe resections are rare and rarely of disastrous extent. This further complicates the evaluation of the clinical relevance of fMRI as a predictive tool. In this article studies which investigated the concordance between fMRI and other diagnostic gold standards will be presented as well as the association between presurgical fMRI and postsurgical morbidity. (orig.) [German] Die funktionelle Magnetresonanztomographie (fMRT) wird im Rahmen der Epilepsiediagnostik vor epilepsiechirurgischen Eingriffen insbesondere zur Lateralisation von Sprache und Gedaechtnis und zur Lokalisation der Zentralregion eingesetzt, um den eloquenten Kortex von der epilepsieverursachenden, chirurgisch zugaenglichen Laesion abzugrenzen. Dabei ist die fMRT Teil einer Sequenz nichtinvasiver klinischer Tests (Anamnese, Anfall-Semiologie, neurologischer Status, interiktales und iktales EEG, strukturelles MRT, Video-EEG-Monitoring, Neuropsychologie). Das Ergebnis dieser Sequenz ist die Entscheidung fuer oder gegen einen

  16. Scanning fast and slow: current limitations of 3 Tesla functional MRI and future potential

    Science.gov (United States)

    Boubela, Roland N.; Kalcher, Klaudius; Nasel, Christian; Moser, Ewald

    2014-02-01

    Functional MRI at 3T has become a workhorse for the neurosciences, e.g., neurology, psychology, and psychiatry, enabling non-invasive investigation of brain function and connectivity. However, BOLD-based fMRI is a rather indirect measure of brain function, confounded by fluctuation related signals, e.g. head or brain motion, brain pulsation, blood flow, intermixed with susceptibility differences close or distant to the region of neuronal activity. Even though a plethora of preprocessing strategies have been published to address these confounds, their efficiency is still under discussion. In particular, physiological signal fluctuations closely related to brain supply may mask BOLD signal changes related to "true" neuronal activation. Here we explore recent technical and methodological advancements aimed at disentangling the various components, employing fast multiband vs. standard EPI, in combination with fast temporal ICA.Our preliminary results indicate that fast (TRstudied and task performance better correlated to other measures. This should increase specificity and reliability in fMRI studies. Furthermore, physiological signal changes during scanning may then be recognized as a source of information rather than a nuisance. As we are currently still undersampling the complexity of the brain, even at a rather coarse macroscopic level, we should be very cautious in the interpretation of neuroscientific findings, in particular when comparing different groups (e.g., age, sex, medication, pathology, etc.). From a technical point of view our goal should be to sample brain activity at layer specific resolution with low TR, covering as much of the brain as possible without violating SAR limits. We hope to stimulate discussion towards a better understanding and a more quantitative use of fMRI.

  17. Arcuate fasciculus laterality by diffusion tensor imaging correlates with language laterality by functional MRI in preadolescent children

    International Nuclear Information System (INIS)

    Sreedharan, Ruma Madhu; Menon, Amitha C.; Thomas, Sanjeev V.; James, Jija S.; Kesavadas, Chandrasekharan

    2015-01-01

    Language lateralization is unique to humans. Functional MRI (fMRI) and diffusion tensor imaging (DTI) enable the study of language areas and white matter fibers involved in language, respectively. The objective of this study was to correlate arcuate fasciculus (AF) laterality by diffusion tensor imaging with that by fMRI in preadolescent children which has not yet been reported. Ten children between 8 and 12 years were subjected to fMRI and DTI imaging using Siemens 1.5 T MRI. Two language fMRI paradigms - visual verb generation and word pair task - were used. Analysis was done using SPM8 software. In DTI, the fiber volume of the arcuate fasciculus (AFV) and fractional anisotropy (FA) was measured. The fMRI Laterality Index (fMRI-LI) and DTI Laterality Index (DTI-LI) were calculated and their correlation assessed using the Pearson Correlation Index. Of ten children, mean age 10.6 years, eight showed left lateralization while bilateral language lateralization was seen in two. AFV by DTI was more on the left side in seven of the eight children who had left lateralization by fMRI. DTI could not trace the AF in one child. Of the two with bilateral language lateralization on fMRI, one showed larger AFV on the right side while the other did not show any asymmetry. There was a significant correlation (p < 0.02) between fMRI-LI and DTI-LI. Group mean of AFV by DTI was higher on the left side (2659.89 ± 654.75 mm 3 ) as compared to the right (1824.11 ± 582.81 mm 3 ) (p < 0.01). Like fMRI, DTI also reveals language laterality in children with a high degree of correlation between the two imaging modalities. (orig.)

  18. Arcuate fasciculus laterality by diffusion tensor imaging correlates with language laterality by functional MRI in preadolescent children

    Energy Technology Data Exchange (ETDEWEB)

    Sreedharan, Ruma Madhu [Government Medical College Hospital, Department of Radiology, Trivandrum, Kerala (India); Menon, Amitha C.; Thomas, Sanjeev V. [Sree Chitra, Thirunal Institute for Medical Sciences and Technology, Department of Neurology, Thiruvananthapuram, Kerala (India); James, Jija S.; Kesavadas, Chandrasekharan [SCTIMST, Department of Imaging Science and Interventional Radiology, Trivandrum, Kerala (India)

    2015-03-01

    Language lateralization is unique to humans. Functional MRI (fMRI) and diffusion tensor imaging (DTI) enable the study of language areas and white matter fibers involved in language, respectively. The objective of this study was to correlate arcuate fasciculus (AF) laterality by diffusion tensor imaging with that by fMRI in preadolescent children which has not yet been reported. Ten children between 8 and 12 years were subjected to fMRI and DTI imaging using Siemens 1.5 T MRI. Two language fMRI paradigms - visual verb generation and word pair task - were used. Analysis was done using SPM8 software. In DTI, the fiber volume of the arcuate fasciculus (AFV) and fractional anisotropy (FA) was measured. The fMRI Laterality Index (fMRI-LI) and DTI Laterality Index (DTI-LI) were calculated and their correlation assessed using the Pearson Correlation Index. Of ten children, mean age 10.6 years, eight showed left lateralization while bilateral language lateralization was seen in two. AFV by DTI was more on the left side in seven of the eight children who had left lateralization by fMRI. DTI could not trace the AF in one child. Of the two with bilateral language lateralization on fMRI, one showed larger AFV on the right side while the other did not show any asymmetry. There was a significant correlation (p < 0.02) between fMRI-LI and DTI-LI. Group mean of AFV by DTI was higher on the left side (2659.89 ± 654.75 mm{sup 3}) as compared to the right (1824.11 ± 582.81 mm{sup 3}) (p < 0.01). Like fMRI, DTI also reveals language laterality in children with a high degree of correlation between the two imaging modalities. (orig.)

  19. NEUROTRANSMITTERS AND IMMUNITY: 1. DOPAMINE

    Directory of Open Access Journals (Sweden)

    Lucian Hritcu

    2007-08-01

    Full Text Available Dopamine is one of the principal neurotransmitters in the central nervous system (CNC, and its neuronal pathways are involved in several key functions such as behavior (Hefco et al., 2003a,b, control of movement, endocrine regulation, immune response (Fiserova et al., 2002; Levite et al., 2001, Hritcu et al., 2006a,b,c, and cardiovascular function. Dopamine has at least five G-protein, coupled receptor subtypes, D1-D5, each arising from a different gene (Sibley et al., 1993. Traditionally, these receptors have been classified into D1-like (the D1 and D5 and D2-like (D2, D3 and D4 receptors subtypes, primarily according to their ability to stimulate or inhibit adenylate cyclase, respectively, and to their pharmacological characteristics (Seeman et al., 1993. Receptors for dopamine (particularly of D2 subclass are the primary therapeutic target in a number of neuropathological disorders including schizophrenia, Parkinson’s disease and Huntington’s chorea (Seeman et al., 1987. Neither dopamine by itself, nor dopaminergic agonists by themselves, has been shown to activate T cell function. Nevertheless, lymphocytes are most probably exposed to dopamine since the primary and secondary lymphoid organs of various mammals are markedly innervated, and contain nerve fibers which stain for tyrosine hydroxylase (Weihe et al., 1991, the enzyme responsible for dopamine synthesis. Moreover, cathecolamines and their metabolites are present in single lymphocytes and in extracts of T and B cell clones, and pharmacological inhibition of tyrosine hydroxylase reduces catecholamine levels, suggesting catecholamine synthesis by lymphocytes (Bergquist et al., 1994. The existence of putative dopamine receptors of D2, D3, D4 and D5 subtypes on immune cells has been proposed of several authors, primarily on the basis of dopaminergic ligand binding assays and specific mRNA expression as monitored by reverse transcription-PCR. Several experiments evoked the idea of a

  20. High spatial resolution brain functional MRI using submillimeter balanced steady-state free precession acquisition

    International Nuclear Information System (INIS)

    Wu, Pei-Hsin; Chung, Hsiao-Wen; Tsai, Ping-Huei; Wu, Ming-Long; Chuang, Tzu-Chao; Shih, Yi-Yu; Huang, Teng-Yi

    2013-01-01

    Purpose: One of the technical advantages of functional magnetic resonance imaging (fMRI) is its precise localization of changes from neuronal activities. While current practice of fMRI acquisition at voxel size around 3 × 3 × 3 mm 3 achieves satisfactory results in studies of basic brain functions, higher spatial resolution is required in order to resolve finer cortical structures. This study investigated spatial resolution effects on brain fMRI experiments using balanced steady-state free precession (bSSFP) imaging with 0.37 mm 3 voxel volume at 3.0 T. Methods: In fMRI experiments, full and unilateral visual field 5 Hz flashing checkerboard stimulations were given to healthy subjects. The bSSFP imaging experiments were performed at three different frequency offsets to widen the coverage, with functional activations in the primary visual cortex analyzed using the general linear model. Variations of the spatial resolution were achieved by removing outerk-space data components. Results: Results show that a reduction in voxel volume from 3.44 × 3.44 × 2 mm 3 to 0.43 × 0.43 × 2 mm 3 has resulted in an increase of the functional activation signals from (7.7 ± 1.7)% to (20.9 ± 2.0)% at 3.0 T, despite of the threefold SNR decreases in the original images, leading to nearly invariant functional contrast-to-noise ratios (fCNR) even at high spatial resolution. Activation signals aligning nicely with gray matter sulci at high spatial resolution would, on the other hand, have possibly been mistaken as noise at low spatial resolution. Conclusions: It is concluded that the bSSFP sequence is a plausible technique for fMRI investigations at submillimeter voxel widths without compromising fCNR. The reduction of partial volume averaging with nonactivated brain tissues to retain fCNR is uniquely suitable for high spatial resolution applications such as the resolving of columnar organization in the brain

  1. High spatial resolution brain functional MRI using submillimeter balanced steady-state free precession acquisition

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Pei-Hsin; Chung, Hsiao-Wen [Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Tsai, Ping-Huei [Imaging Research Center, Taipei Medical University, Taipei 11031, Taiwan and Department of Medical Imaging, Taipei Medical University Hospital, Taipei Medical University, Taipei 11031, Taiwan (China); Wu, Ming-Long, E-mail: minglong.wu@csie.ncku.edu.tw [Institute of Medical Informatics, National Cheng-Kung University, Tainan 70101, Taiwan and Department of Computer Science and Information Engineering, National Cheng-Kung University, Tainan 70101, Taiwan (China); Chuang, Tzu-Chao [Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan (China); Shih, Yi-Yu [Siemens Limited Healthcare Sector, Taipei 11503, Taiwan (China); Huang, Teng-Yi [Department of Electrical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China)

    2013-12-15

    Purpose: One of the technical advantages of functional magnetic resonance imaging (fMRI) is its precise localization of changes from neuronal activities. While current practice of fMRI acquisition at voxel size around 3 × 3 × 3 mm{sup 3} achieves satisfactory results in studies of basic brain functions, higher spatial resolution is required in order to resolve finer cortical structures. This study investigated spatial resolution effects on brain fMRI experiments using balanced steady-state free precession (bSSFP) imaging with 0.37 mm{sup 3} voxel volume at 3.0 T. Methods: In fMRI experiments, full and unilateral visual field 5 Hz flashing checkerboard stimulations were given to healthy subjects. The bSSFP imaging experiments were performed at three different frequency offsets to widen the coverage, with functional activations in the primary visual cortex analyzed using the general linear model. Variations of the spatial resolution were achieved by removing outerk-space data components. Results: Results show that a reduction in voxel volume from 3.44 × 3.44 × 2 mm{sup 3} to 0.43 × 0.43 × 2 mm{sup 3} has resulted in an increase of the functional activation signals from (7.7 ± 1.7)% to (20.9 ± 2.0)% at 3.0 T, despite of the threefold SNR decreases in the original images, leading to nearly invariant functional contrast-to-noise ratios (fCNR) even at high spatial resolution. Activation signals aligning nicely with gray matter sulci at high spatial resolution would, on the other hand, have possibly been mistaken as noise at low spatial resolution. Conclusions: It is concluded that the bSSFP sequence is a plausible technique for fMRI investigations at submillimeter voxel widths without compromising fCNR. The reduction of partial volume averaging with nonactivated brain tissues to retain fCNR is uniquely suitable for high spatial resolution applications such as the resolving of columnar organization in the brain.

  2. Bayesian switching factor analysis for estimating time-varying functional connectivity in fMRI.

    Science.gov (United States)

    Taghia, Jalil; Ryali, Srikanth; Chen, Tianwen; Supekar, Kaustubh; Cai, Weidong; Menon, Vinod

    2017-07-15

    There is growing interest in understanding the dynamical properties of functional interactions between distributed brain regions. However, robust estimation of temporal dynamics from functional magnetic resonance imaging (fMRI) data remains challenging due to limitations in extant multivariate methods for modeling time-varying functional interactions between multiple brain areas. Here, we develop a Bayesian generative model for fMRI time-series within the framework of hidden Markov models (HMMs). The model is a dynamic variant of the static factor analysis model (Ghahramani and Beal, 2000). We refer to this model as Bayesian switching factor analysis (BSFA) as it integrates factor analysis into a generative HMM in a unified Bayesian framework. In BSFA, brain dynamic functional networks are represented by latent states which are learnt from the data. Crucially, BSFA is a generative model which estimates the temporal evolution of brain states and transition probabilities between states as a function of time. An attractive feature of BSFA is the automatic determination of the number of latent states via Bayesian model selection arising from penalization of excessively complex models. Key features of BSFA are validated using extensive simulations on carefully designed synthetic data. We further validate BSFA using fingerprint analysis of multisession resting-state fMRI data from the Human Connectome Project (HCP). Our results show that modeling temporal dependencies in the generative model of BSFA results in improved fingerprinting of individual participants. Finally, we apply BSFA to elucidate the dynamic functional organization of the salience, central-executive, and default mode networks-three core neurocognitive systems with central role in cognitive and affective information processing (Menon, 2011). Across two HCP sessions, we demonstrate a high level of dynamic interactions between these networks and determine that the salience network has the highest temporal

  3. Memory Deficits in Schizophrenia: A Selective Review of Functional Magnetic Resonance Imaging (fMRI Studies

    Directory of Open Access Journals (Sweden)

    Adrienne C. Lahti

    2013-06-01

    Full Text Available Schizophrenia is a complex chronic mental illness that is characterized by positive, negative and cognitive symptoms. Cognitive deficits are most predictive of long-term outcomes, with abnormalities in memory being the most robust finding. The advent of functional magnetic resonance imaging (fMRI has allowed exploring neural correlates of memory deficits in vivo. In this article, we will give a selective review of fMRI studies probing brain regions and functional networks that are thought to be related to abnormal memory performance in two memory systems prominently affected in schizophrenia; working memory and episodic memory. We revisit the classic “hypofrontality” hypothesis of working memory deficits and explore evidence for frontotemporal dysconnectivity underlying episodic memory abnormalities. We conclude that fMRI studies of memory deficits in schizophrenia are far from universal. However, the current literature does suggest that alterations are not isolated to a few brain regions, but are characterized by abnormalities within large-scale brain networks.

  4. Study of physiology of visual cortex activated by rotating grating with functional MRI

    International Nuclear Information System (INIS)

    Liang Ping; Shao Qing; Zhang Zhiqiang; Lu Guangming

    2004-01-01

    Objective: To research the physiology of visual cortex activated by rotating grating with functional-MRI (fMRI), and to identify the components of the activation. Methods: Functional MRI was performed in 9 healthy volunteers by using GRE-EPI sequences on a 1.5 T MR scanner. In the block designing, rotating grating, static grating, and luminance were plotted as task states, while static grating, luminance, and darkness were set as control states. The stimuli tasks included six steps. Imaging processing and statistical analysis was carried out off-line using SPM99 in single-subject method. Results: Some respective areas of visual cortex were activated by the various stimuli information supplied by rotating grating. The strong activation in the middle of occipital lobe located at primary vision area was related to the stimuli of white luminance. Its average maximum points were at 13, -98, -2 and 11, -100, -41 The bilateral activations of Brodmann 19th area located at MT area were related to visual motion perception. Its average maximum points were at 46, -72, -2 and -44, -74, 0. The mild activation in the middle of occipital lobe was related to form perception. Its average maximum points were at -12, -98, -6 and -16, -96, -6. Conclusion: The plotting of control state is important in bock design. The effective visual information of rotating grating includes components of luminance, visual motion perception, and form perception. FMRI has potential as a tool for studying the basic physiology of visual cortex. (authors)

  5. Motor association cortex activity in Parkinson's disease. A functional MRI study

    International Nuclear Information System (INIS)

    Tada, Yukiko

    1998-01-01

    The purpose of this study was to examine the activation of motor association cortex using functional magnetic resonance imaging (fMRI) in patients with Parkinson's disease (PD) and control subjects during performed hand movements. There were 26 patients with PD (12 patients with Hoehn and Yahr stage I-II, 14 patients with stage III) and 8 control subjects. Functional imaging was performed using a 1.5 tesla MRI system equipped with a single-shot, echo-planar pulse sequence. The significant signal changes were observed within the primary sensorimotor area, the supplementary motor area (SMA), and the parietal association area in both PD and control subjects. In PD subjects, the SMA was less activated than in control subjects; there were significant differences in the number of pixels activated in SMA between control and Yahr III group (p<0.01), and between Yahr I-II and Yahr III group (p<0.01). Our results demonstrated that movement related cerebral activity in the SMA is reduced in PD subjects, consistent with previously published data using other methods. It is well known from anatomical studies that one of the major cortical outputs of the basal ganglia is the SMA. This may explain the hypoactivation of the SMA in PD. Studies using fMRI provide a promising method not only for localizing cortical activation related to voluntary movements but also for investigating pathophysiology of movement disorders. (author)

  6. Bayesian spatiotemporal model of fMRI data using transfer functions.

    Science.gov (United States)

    Quirós, Alicia; Diez, Raquel Montes; Wilson, Simon P

    2010-09-01

    This research describes a new Bayesian spatiotemporal model to analyse BOLD fMRI studies. In the temporal dimension, we describe the shape of the hemodynamic response function (HRF) with a transfer function model. The spatial continuity and local homogeneity of the evoked responses are modelled by a Gaussian Markov random field prior on the parameter indicating activations. The proposal constitutes an extension of the spatiotemporal model presented in a previous approach [Quirós, A., Montes Diez, R. and Gamerman, D., 2010. Bayesian spatiotemporal model of fMRI data, Neuroimage, 49: 442-456], offering more flexibility in the estimation of the HRF and computational advantages in the resulting MCMC algorithm. Simulations from the model are performed in order to ascertain the performance of the sampling scheme and the ability of the posterior to estimate model parameters, as well as to check the model sensitivity to signal to noise ratio. Results are shown on synthetic data and on a real data set from a block-design fMRI experiment. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  7. Altered Structural and Functional Connectivity of Juvenile Myoclonic Epilepsy: An fMRI Study

    Directory of Open Access Journals (Sweden)

    Chengqing Zhong

    2018-01-01

    Full Text Available The aim of this study was to investigate the structural and functional connectivity (FC of juvenile myoclonic epilepsy (JME using resting state functional magnetic resonance imaging (rs-fMRI. High-resolution T1-weighted magnetic resonance imaging (MRI and rs-fMRI data were collected in 25 patients with JME and in 24 control subjects. A FC analysis was subsequently performed, with seeding at the regions that demonstrated between-group differences in gray matter volume (GMV. Then, the observed structural and FCs were associated with the clinical manifestations. The decreased GMV regions were found in the bilateral anterior cerebellum, the right orbital superior frontal gyrus, the left middle temporal gyrus, the left putamen, the right hippocampus, the bilateral caudate, and the right thalamus. The changed FCs were mainly observed in the motor-related areas and the cognitive-related areas. The significant findings of this study revealed an important role for the cerebellum in motor control and cognitive regulation in JME patients, which also have an effect on the activity of the occipital lobe. In addition, the changed FCs were related to the clinical features of JME patients. The current observations may contribute to the understanding of the pathogenesis of JME.

  8. Genetically determined interaction between the dopamine transporter and the D2 receptor on prefronto-striatal activity and volume in humans.

    Science.gov (United States)

    Bertolino, Alessandro; Fazio, Leonardo; Di Giorgio, Annabella; Blasi, Giuseppe; Romano, Raffaella; Taurisano, Paolo; Caforio, Grazia; Sinibaldi, Lorenzo; Ursini, Gianluca; Popolizio, Teresa; Tirotta, Emanuele; Papp, Audrey; Dallapiccola, Bruno; Borrelli, Emiliana; Sadee, Wolfgang

    2009-01-28

    Dopamine modulation of neuronal activity during memory tasks identifies a nonlinear inverted-U shaped function. Both the dopamine transporter (DAT) and dopamine D(2) receptors (encoded by DRD(2)) critically regulate dopamine signaling in the striatum and in prefrontal cortex during memory. Moreover, in vitro studies have demonstrated that DAT and D(2) proteins reciprocally regulate each other presynaptically. Therefore, we have evaluated the genetic interaction between a DRD(2) polymorphism (rs1076560) causing reduced presynaptic D(2) receptor expression and the DAT 3'-VNTR variant (affecting DAT expression) in a large sample of healthy subjects undergoing blood oxygenation level-dependent (BOLD)-functional magnetic resonance imaging (MRI) during memory tasks and structural MRI. Results indicated a significant DRD(2)/DAT interaction in prefrontal cortex and striatum BOLD activity during both working memory and encoding of recognition memory. The differential effect on BOLD activity of the DAT variant was mostly manifest in the context of the DRD(2) allele associated with lower presynaptic expression. Similar results were also evident for gray matter volume in caudate. These interactions describe a nonlinear relationship between compound genotypes and brain activity or gray matter volume. Complementary data from striatal protein extracts from wild-type and D(2) knock-out animals (D2R(-/-)) indicate that DAT and D(2) proteins interact in vivo. Together, our results demonstrate that the interaction between genetic variants in DRD(2) and DAT critically modulates the nonlinear relationship between dopamine and neuronal activity during memory processing.

  9. Functional network centrality in obesity: A resting-state and task fMRI study.

    Science.gov (United States)

    García-García, Isabel; Jurado, María Ángeles; Garolera, Maite; Marqués-Iturria, Idoia; Horstmann, Annette; Segura, Bàrbara; Pueyo, Roser; Sender-Palacios, María José; Vernet-Vernet, Maria; Villringer, Arno; Junqué, Carme; Margulies, Daniel S; Neumann, Jane

    2015-09-30

    Obesity is associated with structural and functional alterations in brain areas that are often functionally distinct and anatomically distant. This suggests that obesity is associated with differences in functional connectivity of regions distributed across the brain. However, studies addressing whole brain functional connectivity in obesity remain scarce. Here, we compared voxel-wise degree centrality and eigenvector centrality between participants with obesity (n=20) and normal-weight controls (n=21). We analyzed resting state and task-related fMRI data acquired from the same individuals. Relative to normal-weight controls, participants with obesity exhibited reduced degree centrality in the right middle frontal gyrus in the resting-state condition. During the task fMRI condition, obese participants exhibited less degree centrality in the left middle frontal gyrus and the lateral occipital cortex along with reduced eigenvector centrality in the lateral occipital cortex and occipital pole. Our results highlight the central role of the middle frontal gyrus in the pathophysiology of obesity, a structure involved in several brain circuits signaling attention, executive functions and motor functions. Additionally, our analysis suggests the existence of task-dependent reduced centrality in occipital areas; regions with a role in perceptual processes and that are profoundly modulated by attention. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  10. A functional MRI study of language networks in left medial temporal lobe epilepsy

    International Nuclear Information System (INIS)

    Yu Aihong; Wang Xiaoyi; Xu Guoqing; Li Yongjie; Qin Wen; Li Kuncheng; Wang, Yuping

    2011-01-01

    Purpose: The purpose of this study was to investigate the abnormality of language networks in left medial temporal lobe epilepsy (MTLE) using fMRI. Materials and methods: Eight patients with left MTLE and 15 healthy subjects were evaluated. An auditory semantic judgment (AJ) paradigm was used. The fMRI data were collected on a 3T MR system and analyzed by AFNI (analysis of functional neuroimages) to generate the activation map. Results: Behavioral data showed that the reaction time of the left MTLE patients was significantly longer than that of controls on the AJ task (t = -3.396, P < 0.05). The left MTLE patients also exhibited diffusively decreased activation in the AJ task. Right hemisphere dominance of Broca's and Wernicke's areas was demonstrated in left MTLE patients. Conclusions: Long-term activation of spikes in left MTLE patients results in language impairment, which is associated with an abnormality of the brain neural network.

  11. Functional MRI of the visual cortex and visual testing in patients with previous optic neuritis

    DEFF Research Database (Denmark)

    Langkilde, Annika Reynberg; Frederiksen, J.L.; Rostrup, Egill

    2002-01-01

    of the activated area and the signal change following ON, and compared the results with results of neuroophthalmological testing. We studied nine patients with previous acute ON and 10 healthy persons served as controls using fMRI with visual stimulation. In addition to a reduced activated volume, patients showed...... a reduced blood oxygenation level dependent (BOLD) signal increase and a greater asymmetry in the visual cortex, compared with controls. The volume of visual cortical activation was significantly correlated to the result of the contrast sensitivity test. The BOLD signal increase correlated significantly......The volume of cortical activation as detected by functional magnetic resonance imaging (fMRI) in the visual cortex has previously been shown to be reduced following optic neuritis (ON). In order to understand the cause of this change, we studied the cortical activation, both the size...

  12. The application of functional MRI in evaluating ischemic injuries of lower limb skeletal muscle

    International Nuclear Information System (INIS)

    Xia Caifeng; Gu Jianping

    2011-01-01

    The ischemic injury of lower limb skeletal muscle is caused by various reasons that lead to limb arterial blood flow insufficiency and subsequent muscle tissue hypoxia. Exact and correct evaluation of the ischemic degree of the skeletal muscle is very important for the physicians to guide the clinical treatment, to assess the therapeutic effect and to judge the prognosis. With the development and updating of scanning hardware and software, together with the use of diffusion-weighted imaging (DWI), diffusion tensor imaging (DTI), perfusion-weighted imaging (PWI), blood oxygen level dependent (BOLD) imaging and magnetic resonance spectroscopy (MRS), etc. the application of MRI has been dramatically expanded both in clinical practice and scientific researches. Nowadays, functional MRI can accurately reflect the physiological structures and pathologic changes in detail. This article aims mainly to make a comprehensive review about the application of these techniques in assessing the ischemic injuries of lower limb skeletal muscle. (authors)

  13. A sensitive electrochemical sensor for paracetamole based on a glassy carbon electrode modified with multiwalled carbon nanotubes and dopamine nanospheres functionalized with gold nanoparticles

    International Nuclear Information System (INIS)

    Liu, Xue; Wang, Ling-Ling; Wang, Ya-Ya; Zhang, Xiao-Yan

    2014-01-01

    We describe an electrochemical sensor for paracetamole that is based on a glassy carbon electrode modified with multiwalled carbon nanotubes and dopamine nanospheres functionalized with gold nanoparticles. The functionalized nanospheres were prepared by a chemical route and characterized by scanning electron microscopy. The well-dispersed gold nanoparticles were anchored on the dopamine nanosphere via a chemical reduction of the gold precursor. The stepwise fabrication of the modified electrode and its electrochemical response to paracetamole were evaluated using electrochemical impedance spectroscopy and cyclic voltammetry. The modified electrode displayed improved electrocatalytic activity towards paracetamole, a lower oxidation potential (371 mV), and a larger peak current when compared to a bare electrode or other modified electrodes. The kinetic parameters governing the electro-oxidation of paracetamole were studied, and the analytical conditions were optimized. The peak current was linearly related to the concentration of paracetamole in 0.8–400 μM range, and the detection limit was 50 nM (at an SNR of 3). The method was successfully applied to the determination of paracetamole in spiked human urine samples and gave recoveries between 95.3 and 105.2 %. (author)

  14. Three-dimensional anisotropy contrast MRI and functional MRI of the human brain. Clinical application to assess pyramidal tract in patients with brain tumor and infarction

    International Nuclear Information System (INIS)

    Morikawa, Minoru; Kaminogo, Makio; Ishimaru, Hideki; Nakashima, Kazuaki; Kitagawa, Naoki; Ochi, Makoto; Hayashi, Kuniaki; Shibata, Shobu; Kabasawa, Hiroyuki

    2001-01-01

    We describe and evaluate the findings of three-dimensional anisotropy contrast MR axonography (3DAC MRX) and functional MRI (fMRI) in brain tumor and infarction. We obtained diffusion-weighted images (DWI) in 28 patients including 23 brain tumors and 15 acute infarctions located in or near pyramidal tract. Three anisotropic DWIs were transformed into graduations color-coded as red, green and blue, and then composed to form a combined color 3DAC MRX. We also performed functional MRI in 7 of the 28 patients and compared with cortical mapping of 3DAC MRX. 3DAC MRX with 23 brain tumors showed that the ipsilateral pyramidal tract was either discontinuous due to impaired anisotropy (n=8) or compressed due to mass effect (n=15). In 10 patients of acute infarction with motor impairment, pyramidal tract involvement was visually more conspicuous on 3DAC MRX compared to standard DWI. On functional MRI, hand motor activation was observed between blue vertical directional colors of pre- and post central gyrus. In conclusion, 3DAC MRX is a new noninvasive approach for visualization of the white matter neuronal tract and provides the information concerning pyramidal tract involvement. (author)

  15. Assessment of renal function after conformal radiotherapy and intensity-modulated radiotherapy by functional {sup 1}H-MRI and {sup 23}Na-MRI

    Energy Technology Data Exchange (ETDEWEB)

    Haneder, S.; Michaely, H.J.; Schoenberg, S.O. [Universitaetsmedizin Mannheim, Heidelberg Univ., Mannheim (Germany). Inst. of Clinical Radiology and Nuclear Medicine; Konstandin, S.; Schad, L.R. [Universitaetsmedizin Mannheim, Heidelberg Univ., Mannheim (Germany). Computer-Assisted Clinical Medicine; Siebenlist, K.; Wertz, H.; Wenz, F.; Lohr, F.; Boda-Heggemann, J. [Universitaetsmedizin Mannheim, Heidelberg Univ., Mannheim (Germany). Dept. of Radiation Oncology

    2012-12-15

    Purpose: Adjuvant radiochemotherapy (RCHT) improves survival of patients with locally advanced gastric cancer. Conventional three-dimensional conformal radiotherapy (3D-CRT) results in ablative doses to a significant amount of the left kidney, while image-guided intensity-modulated radiotherapy (IG-IMRT) provides excellent target coverage with improved kidney sparing. Few long-term results on IMRT for gastric cancer, however, have been published. Functional magnetic resonance imaging (fMRI) at 3.0 T including blood oxygenation-level dependent (BOLD) imaging, diffusion-weighted imaging (DWI) and, for the first time, {sup 23}Na imaging was used to evaluate renal status after radiotherapy with 3D-CRT or IG-IMRT. Patients and methods Four disease-free patients (2 after 3D-CRT and 2 after IMRT; FU for all patients > 5 years) were included in this feasibility study. Morphological sequences, axial DWI images, 2D-gradient echo (GRE)-BOLD images, and {sup 23}Na images were acquired. Mean values/standard deviations for ({sup 23}Na), the apparent diffusion coefficient (ADC), and R2{sup *} values were calculated for the upper/middle/lower parts of both kidneys. Corticomedullary {sup 23}Na-concentration gradients were determined. Results: Surprisingly, IG-IMRT patients showed no morphological alterations and no statistically significant differences of ADC and R2{sup *} values in all renal parts. Values for mean corticomedullary {sup 23}Na-concentration matched those for healthy volunteers. Results were similar in 3D-CRT patients, except for the cranial part of the left kidney. This was atrophic and presented significantly reduced functional parameters (p = 0.001 - p = 0.033). Reduced ADC values indicated reduced cell density and reduced extracellular space. Cortical and medullary R2{sup *} values of the left cranial kidney in the 3D-CRT group were higher, indicating more deoxygenated hemoglobin due to reduced blood flow/oxygenation. ({sup 23}Na) of the renal cranial parts in

  16. Assessment of renal function after conformal radiotherapy and intensity-modulated radiotherapy by functional 1H-MRI and 23Na-MRI

    International Nuclear Information System (INIS)

    Haneder, S.; Michaely, H.J.; Schoenberg, S.O.; Konstandin, S.; Schad, L.R.; Siebenlist, K.; Wertz, H.; Wenz, F.; Lohr, F.; Boda-Heggemann, J.

    2012-01-01

    Purpose: Adjuvant radiochemotherapy (RCHT) improves survival of patients with locally advanced gastric cancer. Conventional three-dimensional conformal radiotherapy (3D-CRT) results in ablative doses to a significant amount of the left kidney, while image-guided intensity-modulated radiotherapy (IG-IMRT) provides excellent target coverage with improved kidney sparing. Few long-term results on IMRT for gastric cancer, however, have been published. Functional magnetic resonance imaging (fMRI) at 3.0 T including blood oxygenation-level dependent (BOLD) imaging, diffusion-weighted imaging (DWI) and, for the first time, 23 Na imaging was used to evaluate renal status after radiotherapy with 3D-CRT or IG-IMRT. Patients and methods Four disease-free patients (2 after 3D-CRT and 2 after IMRT; FU for all patients > 5 years) were included in this feasibility study. Morphological sequences, axial DWI images, 2D-gradient echo (GRE)-BOLD images, and 23 Na images were acquired. Mean values/standard deviations for ( 23 Na), the apparent diffusion coefficient (ADC), and R2 * values were calculated for the upper/middle/lower parts of both kidneys. Corticomedullary 23 Na-concentration gradients were determined. Results: Surprisingly, IG-IMRT patients showed no morphological alterations and no statistically significant differences of ADC and R2 * values in all renal parts. Values for mean corticomedullary 23 Na-concentration matched those for healthy volunteers. Results were similar in 3D-CRT patients, except for the cranial part of the left kidney. This was atrophic and presented significantly reduced functional parameters (p = 0.001 - p = 0.033). Reduced ADC values indicated reduced cell density and reduced extracellular space. Cortical and medullary R2 * values of the left cranial kidney in the 3D-CRT group were higher, indicating more deoxygenated hemoglobin due to reduced blood flow/oxygenation. ( 23 Na) of the renal cranial parts in the 3D-CRT group was significantly reduced

  17. Functional MRI studies of acupuncture analgesia modulating within the human brain

    International Nuclear Information System (INIS)

    Hou Jinwen; Huang Weihao; Wang Qing; Feng Jingwei; Pu Yonglin; Gao Jiahong

    2002-01-01

    Objective: To evaluate the correlation between acupuncture analgesia and specific functional areas of the brain using functional magnetic resonance imaging (fMRI). Methods: Acupuncture stimulation was induced by manipulating acupuncture needle at the acupuncture point, large intestine 4 (LI 4, Hegu) on the right (dominant) hand of 8 healthy subjects. Functional MRI data were obtained from scanning the whole brain. A block-design paradigm was applied. Functional responses were established by students' group t-test analysis. Results: The data sets from 6 of 8 subjects were used in the study. Signal increases and signal decreases elicited by acupuncture stimulating were demonstrated in multiple brain regions. Signal increases in periaqueductal gray matter and ventral posterior nucleus of the left thalamus, and signal decreases in bilateral anterior cingulate cortex and bilateral occipital lobes were considered as the response to the acupuncture modulating within the human brain. Conclusion: The therapeutic effect of acupuncture analgesia was probably produced by the interaction of multiple brain structures of functional connectivity rather than through the activation of a single brain region

  18. Motor programme activating therapy influences adaptive brain functions in multiple sclerosis: clinical and MRI study.

    Science.gov (United States)

    Rasova, Kamila; Prochazkova, Marie; Tintera, Jaroslav; Ibrahim, Ibrahim; Zimova, Denisa; Stetkarova, Ivana

    2015-03-01

    There is still little scientific evidence for the efficacy of neurofacilitation approaches and their possible influence on brain plasticity and adaptability. In this study, the outcome of a new kind of neurofacilitation approach, motor programme activating therapy (MPAT), was evaluated on the basis of a set of clinical functions and with MRI. Eighteen patients were examined four times with standardized clinical tests and diffusion tensor imaging to monitor changes without therapy, immediately after therapy and 1 month after therapy. Moreover, the strength of effective connectivity was analysed before and after therapy. Patients underwent a 1-h session of MPAT twice a week for 2 months. The data were analysed by nonparametric tests of association and were subsequently statistically evaluated. The therapy led to significant improvement in clinical functions, significant increment of fractional anisotropy and significant decrement of mean diffusivity, and decrement of effective connectivity at supplementary motor areas was observed immediately after the therapy. Changes in clinical functions and diffusion tensor images persisted 1 month after completing the programme. No statistically significant changes in clinical functions and no differences in MRI-diffusion tensor images were observed without physiotherapy. Positive immediate and long-term effects of MPAT on clinical and brain functions, as well as brain microstructure, were confirmed.

  19. Visual grading of 2D and 3D functional MRI compared with image-based descriptive measures

    Energy Technology Data Exchange (ETDEWEB)

    Ragnehed, Mattias [Linkoeping University, Division of Radiological Sciences, Radiology, IMH, Linkoeping (Sweden); Linkoeping University, Center for Medical Image Science and Visualization, CMIV, Linkoeping (Sweden); Linkoeping University, Department of Medical and Health Sciences, Division of Radiological Sciences/Radiology, Faculty of Health Sciences, Linkoeping (Sweden); Leinhard, Olof Dahlqvist; Pihlsgaard, Johan; Lundberg, Peter [Linkoeping University, Center for Medical Image Science and Visualization, CMIV, Linkoeping (Sweden); Linkoeping University, Division of Radiological Sciences, Radiation Physics, IMH, Linkoeping (Sweden); Wirell, Staffan [Linkoeping University, Division of Radiological Sciences, Radiology, IMH, Linkoeping (Sweden); Linkoeping University Hospital, Department of Radiology, Linkoeping (Sweden); Soekjer, Hannibal; Faegerstam, Patrik [Linkoeping University Hospital, Department of Radiology, Linkoeping (Sweden); Jiang, Bo [Linkoeping University, Center for Medical Image Science and Visualization, CMIV, Linkoeping (Sweden); Smedby, Oerjan; Engstroem, Maria [Linkoeping University, Division of Radiological Sciences, Radiology, IMH, Linkoeping (Sweden); Linkoeping University, Center for Medical Image Science and Visualization, CMIV, Linkoeping (Sweden)

    2010-03-15

    A prerequisite for successful clinical use of functional magnetic resonance imaging (fMRI) is the selection of an appropriate imaging sequence. The aim of this study was to compare 2D and 3D fMRI sequences using different image quality assessment methods. Descriptive image measures, such as activation volume and temporal signal-to-noise ratio (TSNR), were compared with results from visual grading characteristics (VGC) analysis of the fMRI results. Significant differences in activation volume and TSNR were not directly reflected by differences in VGC scores. The results suggest that better performance on descriptive image measures is not always an indicator of improved diagnostic quality of the fMRI results. In addition to descriptive image measures, it is important to include measures of diagnostic quality when comparing different fMRI data acquisition methods. (orig.)

  20. Self-gated golden angle spiral cine MRI for coronary endothelial function assessment.

    Science.gov (United States)

    Bonanno, Gabriele; Hays, Allison G; Weiss, Robert G; Schär, Michael

    2018-08-01

    Depressed coronary endothelial function (CEF) is a marker for atherosclerotic disease, an independent predictor of cardiovascular events, and can be quantified non-invasively with ECG-triggered spiral cine MRI combined with isometric handgrip exercise (IHE). However, MRI-CEF measures can be hindered by faulty ECG-triggering, leading to prolonged breath-holds and degraded image quality. Here, a self-gated golden angle spiral method (SG-GA) is proposed to eliminate the need for ECG during cine MRI. SG-GA was tested against retrospectively ECG-gated golden angle spiral MRI (ECG-GA) and gold-standard ECG-triggered spiral cine MRI (ECG-STD) in 10 healthy volunteers. CEF data were obtained from cross-sectional images of the proximal right and left coronary arteries in a 3T scanner. Self-gating heart rates were compared to those from simultaneous ECG-gating. Coronary vessel sharpness and cross-sectional area (CSA) change with IHE were compared among the 3 methods. Self-gating precision, accuracy, and correlation-coefficient were 7.7 ± 0.5 ms, 9.1 ± 0.7 ms, and 0.93 ± 0.01, respectively (mean ± standard error). Vessel sharpness by SG-GA was equal or higher than ECG-STD (rest: 63.0 ± 1.7% vs. 61.3 ± 1.3%; exercise: 62.6 ± 1.3% vs. 56.7 ± 1.6%, P < 0.05). CSA changes were in agreement among the 3 methods (ECG-STD = 8.7 ± 4.0%, ECG-GA = 9.6 ± 3.1%, SG-GA = 9.1 ± 3.5%, P = not significant). CEF measures can be obtained with the proposed self-gated high-quality cine MRI method even when ECG is faulty or not available. Magn Reson Med 80:560-570, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  1. Functional MRI study of diencephalic amnesia in Wernicke-Korsakoff syndrome.

    Science.gov (United States)

    Caulo, M; Van Hecke, J; Toma, L; Ferretti, A; Tartaro, A; Colosimo, C; Romani, G L; Uncini, A

    2005-07-01

    Anterograde amnesia in Wernicke-Korsakoff syndrome is associated with diencephalic lesions, mainly in the anterior thalamic nuclei. Whether diencephalic and temporal lobe amnesias are distinct entities is still not clear. We investigated episodic memory for faces using functional MRI (fMRI) in eight controls and in a 34-year-old man with Wernicke-Korsakoff syndrome and diencephalic lesions but without medial temporal lobe (MTL) involvement at MRI. fMRI was performed with a 1.5 tesla unit. Three dual-choice tasks were employed: (i) face encoding (18 faces were randomly presented three times and subjects were asked to memorize the faces); (ii) face perception (subjects indicated which of two faces matched a third face); and (iii) face recognition (subjects indicated which of two faces belonged to the group they had been asked to memorize during encoding). All activation was greater in the right hemisphere. In controls both the encoding and recognition tasks activated two hippocampal regions (anterior and posterior). The anterior hippocampal region was more activated during recognition. Activation in the prefrontal cortex was greater during recognition. In the subject with Wernicke-Korsakoff syndrome, fMRI did not show hippocampal activation during either encoding or recognition. During recognition, although behavioural data showed defective retrieval, the prefrontal regions were activated as in controls, except for the ventrolateral prefrontal cortex. fMRI activation of the visual cortices and the behavioural score on the perception task indicated that the subject with Wernicke-Korsakoff syndrome perceived the faces, paid attention to the task and demonstrated accurate judgement. In the subject with Wernicke-Korsakoff syndrome, although the anatomical damage does not involve the MTL, the hippocampal memory encoding has been lost, possibly as a consequence of the hippocampal-anterior thalamic axis involvement. Anterograde amnesia could therefore be the expression of

  2. Functional brain segmentation using inter-subject correlation in fMRI.

    Science.gov (United States)

    Kauppi, Jukka-Pekka; Pajula, Juha; Niemi, Jari; Hari, Riitta; Tohka, Jussi

    2017-05-01

    The human brain continuously processes massive amounts of rich sensory information. To better understand such highly complex brain processes, modern neuroimaging studies are increasingly utilizing experimental setups that better mimic daily-life situations. A new exploratory data-analysis approach, functional segmentation inter-subject correlation analysis (FuSeISC), was proposed to facilitate the analysis of functional magnetic resonance (fMRI) data sets collected in these experiments. The method provides a new type of functional segmentation of brain areas, not only characterizing areas that display similar processing across subjects but also areas in which processing across subjects is highly variable. FuSeISC was tested using fMRI data sets collected during traditional block-design stimuli (37 subjects) as well as naturalistic auditory narratives (19 subjects). The method identified spatially local and/or bilaterally symmetric clusters in several cortical areas, many of which are known to be processing the types of stimuli used in the experiments. The method is not only useful for spatial exploration of large fMRI data sets obtained using naturalistic stimuli, but also has other potential applications, such as generation of a functional brain atlases including both lower- and higher-order processing areas. Finally, as a part of FuSeISC, a criterion-based sparsification of the shared nearest-neighbor graph was proposed for detecting clusters in noisy data. In the tests with synthetic data, this technique was superior to well-known clustering methods, such as Ward's method, affinity propagation, and K-means ++. Hum Brain Mapp 38:2643-2665, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  3. Low-frequency hippocampal-cortical activity drives brain-wide resting-state functional MRI connectivity.

    Science.gov (United States)

    Chan, Russell W; Leong, Alex T L; Ho, Leon C; Gao, Patrick P; Wong, Eddie C; Dong, Celia M; Wang, Xunda; He, Jufang; Chan, Ying-Shing; Lim, Lee Wei; Wu, Ed X

    2017-08-15

    The hippocampus, including the dorsal dentate gyrus (dDG), and cortex engage in bidirectional communication. We propose that low-frequency activity in hippocampal-cortical pathways contributes to brain-wide resting-state connectivity to integrate sensory information. Using optogenetic stimulation and brain-wide fMRI and resting-state fMRI (rsfMRI), we determined the large-scale effects of spatiotemporal-specific downstream propagation of hippocampal activity. Low-frequency (1 Hz), but not high-frequency (40 Hz), stimulation of dDG excitatory neurons evoked robust cortical and subcortical brain-wide fMRI responses. More importantly, it enhanced interhemispheric rsfMRI connectivity in various cortices and hippocampus. Subsequent local field potential recordings revealed an increase in slow oscillations in dorsal hippocampus and visual cortex, interhemispheric visual cortical connectivity, and hippocampal-cortical connectivity. Meanwhile, pharmacological inactivation of dDG neurons decreased interhemispheric rsfMRI connectivity. Functionally, visually evoked fMRI responses in visual regions also increased during and after low-frequency dDG stimulation. Together, our results indicate that low-frequency activity robustly propagates in the dorsal hippocampal-cortical pathway, drives interhemispheric cortical rsfMRI connectivity, and mediates visual processing.

  4. The approach to developmental dyslexia. The use of functional MRI studies

    International Nuclear Information System (INIS)

    Seki, Ayumi; Koeda, Tatsuya; Okada, Tomohisa; Sadato, Norihiro

    2004-01-01

    Developmental dyslexia is defined as a specific and significant impairment in reading ability that cannot be accounted for by any deficit in general intelligence or sensory acuity. It has been known that dyslexic children exhibit deficits for phonological awareness tasks, which require the ability to manipulate abstract phonological representations. A lower prevalence of dyslexia in Japanese suggests that the Japanese language may be more easily learned and manipulated by people with dyslexia. There are two supposable approaches to studying the mechanism of dyslexia using the functional MRI (fMRI). One is the study in healthy Japanese to investigate advantageous properties of Japanese related to less prevalence of dyslexia and the other is the comparative study in children to investigate the different cortical activity of dyslexia and normal readers. First, fMRI was used to investigate the neural substrates underlying phonological manipulation of the Japanese language. The posterior parts of the superior temporal sulcus (STS) were active during the auditory tasks, suggesting that phonological representations are manipulated in this area. In contrast, the intraparietal sulci (IPS), which have been implicated in visuospatial tasks, were active during the visual tasks, indicating that phonemic manipulation of kana'' letters is visuospatial. We suggest that because of the phonological and orthographical simplicities of the Japanese language, dyslexic children more easily learn the correspondence between letters and sounds. (author)

  5. Cardiac MRI in pulmonary artery hypertension: correlations between morphological and functional parameters and invasive measurements

    Energy Technology Data Exchange (ETDEWEB)

    Alunni, Jean-Philippe; Otal, Philippe; Rousseau, Herve; Chabbert, Valerie [CHU Rangueil, Department of Radiology, Toulouse (France); Degano, Bruno; Tetu, Laurent; Didier, Alain [CHU Larrey, Department of Pneumology, Toulouse (France); Arnaud, Catherine [CHU Rangueil, Department of Methods in Clinical Research, Toulouse (France); Blot-Souletie, Nathalie [CHU Rangueil, Department of Cardiology, Toulouse (France)

    2010-05-15

    To compare cardiac MRI with right heart catheterisation in patients with pulmonary hypertension (PH) and to evaluate its ability to assess PH severity. Forty patients were included. MRI included cine and phase-contrast sequences, study of ventricular function, cardiac cavity areas and ratios, position of the interventricular septum (IVS) in systole and diastole, and flow measurements. We defined four groups according to the severity of PH and three groups according to IVS position: A, normal position; B, abnormal in diastole; C, abnormal in diastole and systole. IVS position was correlated with pulmonary artery pressures and PVR (pulmonary vascular resistance). Median pulmonary artery pressures and resistance were significantly higher in patients with an abnormal septal position compared with those with a normal position. Correlations were good between the right ventricular ejection fraction and PVR, right ventricular end-systolic volume and PAP, percentage of right ventricular area change and PVR, and diastolic and systolic ventricular area ratio and PVR. These parameters were significantly associated with PH severity. Cardiac MRI can help to assess the severity of PH. (orig.)

  6. Robust preprocessing for stimulus-based functional MRI of the moving fetus.

    Science.gov (United States)

    You, Wonsang; Evangelou, Iordanis E; Zun, Zungho; Andescavage, Nickie; Limperopoulos, Catherine

    2016-04-01

    Fetal motion manifests as signal degradation and image artifact in the acquired time series of blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) studies. We present a robust preprocessing pipeline to specifically address fetal and placental motion-induced artifacts in stimulus-based fMRI with slowly cycled block design in the living fetus. In the proposed pipeline, motion correction is optimized to the experimental paradigm, and it is performed separately in each phase as well as in each region of interest (ROI), recognizing that each phase and organ experiences different types of motion. To obtain the averaged BOLD signals for each ROI, both misaligned volumes and noisy voxels are automatically detected and excluded, and the missing data are then imputed by statistical estimation based on local polynomial smoothing. Our experimental results demonstrate that the proposed pipeline was effective in mitigating the motion-induced artifacts in stimulus-based fMRI data of the fetal brain and placenta.

  7. Evaluation of renal function with dynamic MRI-T2-weighted gradient echo technique

    International Nuclear Information System (INIS)

    Kato, Katsuya

    1995-01-01

    To evaluate the usefulness of dynamic MRI of kidneys in healthy volunteers and patients with different 24-hour creatinine clearance (Ccr) levels, a dynamic study that employed the T2 weighted gradient echo technique (FLASH: TR/TE=34/25 msec, flip angle= 20 degrees) with single images during breathhold was performed on 10 healthy volunteers and 35 patients, all examined for the Ccr and suspected of having renal parenchymal disease after a phantom study. T1-weighted and dynamic MR imagings were obtained with a 1.5T imager. I analyzed the time-intensity curve of renal cortex and medulla, and defined a cortex decreased ratio (CDR) and medulla decreased ratio (MDR) in comparison with the Ccr. The cortico-medullary difference ratio (CMDR) of T1WI was also compared with the Ccr. The parameters of the T2 dynamic MRI study (CDR, MDR) better correlated with the Ccr than CMDR. Renal function can be quantitatively evaluated with the T2 dynamic MRI and there is a possibility that we can qualitatively evaluate the renal dysfunction and estimate its cause. (author)

  8. Resting-state, functional MRI on regional homogeneity changes of brain in the heavy smokers

    International Nuclear Information System (INIS)

    Yang Shiqi; Wu Guangyao; Lin Fuchun; Kong Xiangquan; Zhou Guofeng; Pang Haopeng; Zhu Ling; Liu Guobing; Lei Hao

    2012-01-01

    Objective: To explore the mechanism of self-awareness in the heavy smokers (HS) by using regional homogeneity (ReHo) combined with resting-state functional MRI (fMRI). Methods: Thirty HS and 31 healthy non-smokers (NS) matched for age and sex underwent a 3.0 T resting-state fMRI. The data were post-processed by SPM 5 and then the ReHo values were calculated by REST software. The ReHo values between the two groups were compared by two-sample t-test. The brain map with significant difference of ReHo value was obtained. Results: Compared with that in NS group, the regions with decreased ReHo value included the bilateral precuneus, superior frontal gyrus,medial prefrontal cortex, right angular gyrus, inferior frontal gyrus, inferior occipital gyrus, cerebellum, and left middle frontal gyrus in HS group. The regions of increased ReHo value included the bilateral insula, parahippocampal gyrus, white matter of parietal lobe, pons, left inferior parietal lobule, lingual gyrus, thalamus, inferior orbital gyrus, white matter of temporal-frontal lobe, and cerebellum. The difference was more obvious in the left hemisphere. Conclusions: In HS, abnormal ReHo on a resting state which reflects network of smoking addiction. This method may be helpful in understanding the mechanism of self-awareness in HS. (authors)

  9. Functional subdivision of group-ICA results of fMRI data collected during cinema viewing.

    Directory of Open Access Journals (Sweden)

    Siina Pamilo

    Full Text Available Independent component analysis (ICA can unravel functional brain networks from functional magnetic resonance imaging (fMRI data. The number of the estimated components affects both the spatial pattern of the identified networks and their time-course estimates. Here group-ICA was applied at four dimensionalities (10, 20, 40, and 58 components to fMRI data collected from 15 subjects who viewed a 15-min silent film ("At land" by Maya Deren. We focused on the dorsal attention network, the default-mode network, and the sensorimotor network. The lowest dimensionalities demonstrated most prominent activity within the dorsal attention network, combined with the visual areas, and in the default-mode network; the sensorimotor network only appeared with ICA comprising at least 20 components. The results suggest that even very low-dimensional ICA can unravel the most prominent functionally-connected brain networks. However, increasing the number of components gives a more detailed picture and functionally feasible subdivision of the major networks. These results improve our understanding of the hierarchical subdivision of brain networks during viewing of a movie that provides continuous stimulation embedded in an attention-directing narrative.

  10. Functional subdivision of group-ICA results of fMRI data collected during cinema viewing.

    Science.gov (United States)

    Pamilo, Siina; Malinen, Sanna; Hlushchuk, Yevhen; Seppä, Mika; Tikka, Pia; Hari, Riitta

    2012-01-01

    Independent component analysis (ICA) can unravel functional brain networks from functional magnetic resonance imaging (fMRI) data. The number of the estimated components affects both the spatial pattern of the identified networks and their time-course estimates. Here group-ICA was applied at four dimensionalities (10, 20, 40, and 58 components) to fMRI data collected from 15 subjects who viewed a 15-min silent film ("At land" by Maya Deren). We focused on the dorsal attention network, the default-mode network, and the sensorimotor network. The lowest dimensionalities demonstrated most prominent activity within the dorsal attention network, combined with the visual areas, and in the default-mode network; the sensorimotor network only appeared with ICA comprising at least 20 components. The results suggest that even very low-dimensional ICA can unravel the most prominent functionally-connected brain networks. However, increasing the number of components gives a more detailed picture and functionally feasible subdivision of the major networks. These results improve our understanding of the hierarchical subdivision of brain networks during viewing of a movie that provides continuous stimulation embedded in an attention-directing narrative.

  11. Morphologic and functional scoring of cystic fibrosis lung disease using MRI

    International Nuclear Information System (INIS)

    Eichinger, Monika; Optazaite, Daiva-Elzbieta; Kopp-Schneider, Annette; Hintze, Christian; Biederer, Jürgen; Niemann, Anne; Mall, Marcus A.; Wielpütz, Mark O.; Kauczor, Hans-Ulrich; Puderbach, Michael

    2012-01-01

    Magnetic resonance imaging (MRI) gains increasing importance in the assessment of cystic fibrosis (CF) lung disease. The aim of this study was to develop a morpho-functional MR-scoring-system and to evaluate its intra- and inter-observer reproducibility and clinical practicability to monitor CF lung disease over a broad severity range from infancy to adulthood. 35 CF patients with broad age range (mean 15.3 years; range 0.5–42) were examined by morphological and functional MRI. Lobe based analysis was performed for parameters bronchiectasis/bronchial-wall-thickening, mucus plugging, abscesses/sacculations, consolidations, special findings and perfusion defects. The maximum global score was 72. Two experienced radiologists scored the images at two time points (interval 10 weeks). Upper and lower limits of agreement, concordance correlation coefficients (CCC), total deviation index and coverage probability were calculated for global, morphology, function, component and lobar scores. Global scores ranged from 6 to 47. Intra- and inter-reader agreement for global scores were good (CCC: 0.98 (R1), 0.94 (R2), 0.97 (R1/R2)) and were comparable between high and low scores. Our results indicate that the proposed morpho-functional MR-scoring-system is reproducible and applicable for semi-quantitative evaluation of a large spectrum of CF lung disease severity. This scoring-system can be applied for the routine assessment of CF lung disease and maybe as endpoint for clinical trials.

  12. Functional Subdivision of Group-ICA Results of fMRI Data Collected during Cinema Viewing

    Science.gov (United States)

    Pamilo, Siina; Malinen, Sanna; Hlushchuk, Yevhen; Seppä, Mika; Tikka, Pia; Hari, Riitta

    2012-01-01

    Independent component analysis (ICA) can unravel functional brain networks from functional magnetic resonance imaging (fMRI) data. The number of the estimated components affects both the spatial pattern of the identified networks and their time-course estimates. Here group-ICA was applied at four dimensionalities (10, 20, 40, and 58 components) to fMRI data collected from 15 subjects who viewed a 15-min silent film (“At land” by Maya Deren). We focused on the dorsal attention network, the default-mode network, and the sensorimotor network. The lowest dimensionalities demonstrated most prominent activity within the dorsal attention network, combined with the visual areas, and in the default-mode network; the sensorimotor network only appeared with ICA comprising at least 20 components. The results suggest that even very low-dimensional ICA can unravel the most prominent functionally-connected brain networks. However, increasing the number of components gives a more detailed picture and functionally feasible subdivision of the major networks. These results improve our understanding of the hierarchical subdivision of brain networks during viewing of a movie that provides continuous stimulation embedded in an attention-directing narrative. PMID:22860044

  13. Functional MRI for planning in neurosurgery; Funktionelle MR-Bildgebung fuer die neurochirurgische Operationsplanung

    Energy Technology Data Exchange (ETDEWEB)

    Erb, M. [Sektion fuer Experimentelle Kernspinresonanz des ZNS, Abt. Neuroradiologie, Universitaetsklinikum Tuebingen (Germany); Saur, R. [Sektion fuer Experimentelle Kernspinresonanz des ZNS, Abt. Neuroradiologie, Universitaetsklinikum Tuebingen (Germany); Augenklinik des Universitaetsklinikums Tuebingen (Germany); Klinik fuer Psychiatrie und Psychotherapie des Universitaetsklinikums Tuebingen (Germany)

    2007-07-01

    Beside structural images from CT and MR, functional data about localization of brain activations with different tasks becomes more and more important for presurgical planning. With this method, it's possible to depict mainly primary sensory and motoric areas, but also higher functions like speech and memory. To judge this information adequately, one has to be aware of the variability of activation pattern dependent on chosen threshold. Especially, the absence of such activation at a given location does not necessary mean that this area has no function. The reliability of a measurement strongly depends on efficiency of experimental design and cooperation of the patient. Therefore, short and easy tasks which can be performed in a block design should be preferred. Information about localization of functions determined by fMRI can mainly be used for presurgical planning. Intraoperative usage in the navigation system is problematic due to the brain shift. Therefore, intraoperative imaging together with dynamic adaptation using nonlinear deformation algorithms may improve the value of fMRI in the future. (orig.)

  14. Neural Changes following Behavioral Activation for a Depressed Breast Cancer Patient: A Functional MRI Case Study

    Directory of Open Access Journals (Sweden)

    Michael J. Gawrysiak

    2012-01-01

    Full Text Available Functional neuroimaging is an innovative but at this stage underutilized method to assess the efficacy of psychotherapy for depression. Functional magnetic resonance imaging (fMRI was used in this case study to examine changes in brain activity in a depressed breast cancer patient receiving an 8-session Behavioral Activation Treatment for Depression (BATD, based on the work of Hopko and Lejuez (2007. A music listening paradigm was used during fMRI brain scans to assess reward responsiveness at pre- and posttreatment. Following treatment, the patient exhibited attenuated depression and changes in blood oxygenation level dependence (BOLD response in regions of the prefrontal cortex and the subgenual cingulate cortex. These preliminary findings outline a novel means to assess psychotherapy efficacy and suggest that BATD elicits functional brain changes in areas implicated in the pathophysiology of depression. Further research is necessary to explore neurobiological mechanisms of change in BATD, particularly the potential mediating effects of reward responsiveness and associated brain functioning.

  15. Noninvasive determination of language dominance using functional MRI and near-infrared spectroscopy

    International Nuclear Information System (INIS)

    Ota, Takahiro; Kamada, Kyousuke; Saito, Nobuhito

    2009-01-01

    Identification of the language dominant hemisphere is important in cases necessary for partial encephalotomy due to epilepsy and tumor. Functional MRI (fMRI) essentially detects oxy-Hb/deoxy-Hb ratio in the brain region resulted from blood flow change and near-infrared spectroscopy (NIRS), the Hb level change in the tissue, in which the image can be detected by light-receiving proves of NIR-light (780-1500 nm wavelength) irradiated and passed through the tissues. This paper describes the comparison of the two methods for determination of language dominance with reference to that identified by Wada test, a gold standard but inconvenient for both operators and patients. Subjects are 11 brain tumor and 11 epilepsy patients (M 10/F 12, av. age of 36.7 y, 19 right-handed), whose dominances are successfully determined previously by Wada test. fMRI is conducted with 3T machine (General Electric, USA) with phased-array coil in patients receiving various language tasks, and data are processed by Dr. View (Asahi Kasei) to calculate the laterality index for the dominance. NIRS is conducted with Hitachi-Medico ETG-4000 with 695 and 830 nm IR in patients receiving other different language tasks, on whose frontotemporal region of head surface 12-channel probes are equipped. Data are processed by the equipped software to calculate the difference of oxy-Hb change rates between the two hemispheres for the dominance determination. Consistency of fMRI in determining the dominance with Wada test is found 86.3% and of NIRS, 72.7%, which suggests the latter can be only supplementary to the former. However, NIRS is noted to be useful in atypical cases like those with right or bilateral dominance. (K.T.)

  16. Simultaneous functional imaging using fPET and fMRI

    Energy Technology Data Exchange (ETDEWEB)

    Villien, Marjorie [CERMEP (France)

    2015-05-18

    Brain mapping of task-associated changes in metabolism with PET has been accomplished by subtracting scans acquired during two distinct static states. We have demonstrated that PET can provide truly dynamic information on cerebral energy metabolism using constant infusion of FDG and multiple stimuli in a single experiment. We demonstrate here that the functional PET (fPET-FDG) method accomplished simultaneously with fMRI, can enable the first direct comparisons in time, space and magnitude of hemodynamics and oxygen and glucose consumption. The imaging studies were performed on a 3T Tim-Trio MR scanner modified to support an MR-compatible BrainPET insert. Ten healthy subjects were included. The total PET acquisition and infusion time was 90 minutes. We did 3 blocks of right hand fingers tapping for 10 minutes at 30, 50 and 70 minutes after the beginning of the PET acquisition. ASL and BOLD imaging were acquired simultaneously during the motor paradigm. Changes in glucose utilization are easily observed as changes in the TAC slope of the PET data (FDG utilization rate) and in the derivative signal during motor stimuli in the activated voxels. PET and MRI (ASL, and BOLD) activations are largely colocalized but with very different statistical significance and temporal dynamic, especially in the ipsilateral side of the stimuli. This study demonstrated that motor activation can be measured dynamically during a single FDG PET scan. The complementary nature of fPET-FDG to fMRI capitalizes on the emerging technology of hybrid MR-PET scanners. fPET-FDG, combined with quantitative fMRI methods, allow us to simultaneously measure dynamic changes in glucose utilization and hemodynamic, addressing vital questions about neurovascular coupling.

  17. Neural plasticity in functional and anatomical MRI studies of children with Tourette syndrome.

    Science.gov (United States)

    Eichele, Heike; Plessen, Kerstin J

    2013-01-01

    Tourette syndrome (TS) is a neuropsychiatric disorder with childhood onset characterized by chronic motor and vocal tics. The typical clinical course of an attenuation of symptoms during adolescence in parallel with the emerging self-regulatory control during development suggests that plastic processes may play an important role in the development of tic symptoms. We conducted a systematic search to identify existing imaging studies (both anatomical and functional magnetic resonance imaging [fMRI]) in young persons under the age of 19 years with TS. The final search resulted in 13 original studies, which were reviewed with a focus on findings suggesting adaptive processes (using fMRI) and plasticity (using anatomical MRI). Differences in brain activation compared to healthy controls during tasks that require overriding of prepotent responses help to understand compensatory pathways in children with TS. Along with alterations in regions putatively representing the origin of tics, deviations in several other regions most likely represent an activity-dependent neural plasticity that help to modulate tic severity, such as the prefrontal cortex, but also in the corpus callosum and the limbic system. Factors that potentially influence the development of adaptive changes in the brain of children with TS are age, comorbidity with other developmental disorders, medication use, IQ along with study-design or MRI techniques for acquisition, and analysis of data. The most prominent limitation of all studies is their cross-sectional design. Longitudinal studies extending to younger age groups and to children at risk for developing TS hopefully will confirm findings of neural plasticity in future investigations.

  18. Simultaneous functional imaging using fPET and fMRI

    International Nuclear Information System (INIS)

    Villien, Marjorie

    2015-01-01

    Brain mapping of task-associated changes in metabolism with PET has been accomplished by subtracting scans acquired during two distinct static states. We have demonstrated that PET can provide truly dynamic information on cerebral energy metabolism using constant infusion of FDG and multiple stimuli in a single experiment. We demonstrate here that the functional PET (fPET-FDG) method accomplished simultaneously with fMRI, can enable the first direct comparisons in time, space and magnitude of hemodynamics and oxygen and glucose consumption. The imaging studies were performed on a 3T Tim-Trio MR scanner modified to support an MR-compatible BrainPET insert. Ten healthy subjects were included. The total PET acquisition and infusion time was 90 minutes. We did 3 blocks of right hand fingers tapping for 10 minutes at 30, 50 and 70 minutes after the beginning of the PET acquisition. ASL and BOLD imaging were acquired simultaneously during the motor paradigm. Changes in glucose utilization are easily observed as changes in the TAC slope of the PET data (FDG utilization rate) and in the derivative signal during motor stimuli in the activated voxels. PET and MRI (ASL, and BOLD) activations are largely colocalized but with very different statistical significance and temporal dynamic, especially in the ipsilateral side of the stimuli. This study demonstrated that motor activation can be measured dynamically during a single FDG PET scan. The complementary nature of fPET-FDG to fMRI capitalizes on the emerging technology of hybrid MR-PET scanners. fPET-FDG, combined with quantitative fMRI methods, allow us to simultaneously measure dynamic changes in glucose utilization and hemodynamic, addressing vital questions about neurovascular coupling.

  19. Hyaluronic acid-functionalized single-walled carbon nanotubes as tumor-targeting MRI contrast agent

    Directory of Open Access Journals (Sweden)

    Hou L

    2015-07-01

    Full Text Available Lin Hou,* Huijuan Zhang,* Yating Wang, Lili Wang, Xiaomin Yang, Zhenzhong ZhangSchool of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, People’s Republic of China*These authors contributed equally to this workAbstract: A tumor-targeting carrier, hyaluronic acid (HA-functionalized single-walled carbon nanotubes (SWCNTs, was explored to deliver magnetic resonance imaging (MRI contrast agents (CAs targeting to the tumor cells specifically. In this system, HA surface modification for SWCNTs was simply accomplished by amidation process and could make this nanomaterial highly hydrophilic. Cellular uptake was performed to evaluate the intracellular transport capabilities of HA-SWCNTs for tumor cells and the uptake rank was HA-SWCNTs> SWCNTs owing to the presence of HA, which was also evidenced by flow cytometry. The safety evaluation of this MRI CAs was investigated in vitro and in vivo. It revealed that HA-SWCNTs could stand as a biocompatible nanocarrier and gadolinium (Gd/HA-SWCNTs demonstrated almost no toxicity compared with free GdCl3. Moreover, GdCl3 bearing HA-SWCNTs could significantly increase the circulation time for MRI. Finally, to investigate the MRI contrast enhancing capabilities of Gd/HA-SWCNTs, T1-weighted MR images of tumor-bearing mice were acquired. The results suggested Gd/HA-SWCNTs had the highest tumor-targeting efficiency and T1-relaxivity enhancement, indicating HA-SWCNTs could be developed as a tumor-targeting carrier to deliver the CAs, GdCl3, for the identifiable diagnosis of tumor.Keywords: gadolinium, magnetic resonance, SWCNTs, hyaluronic acid, contrast agent

  20. Associations of resting-state fMRI functional connectivity with flow-BOLD coupling and regional vasculature.

    Science.gov (United States)

    Tak, Sungho; Polimeni, Jonathan R; Wang, Danny J J; Yan, Lirong; Chen, J Jean

    2015-04-01

    There has been tremendous interest in applying functional magnetic resonance imaging-based resting-state functional connectivity (rs-fcMRI) measurements to the study of brain function. However, a lack of understanding of the physiological mechanisms of rs-fcMRI limits their ability to interpret rs-fcMRI findings. In this work, the authors examine the regional associations between rs-fcMRI estimates and dynamic coupling between the blood oxygenation level-dependent (BOLD) and cerebral blood flow (CBF), as well as resting macrovascular volume. Resting-state BOLD and CBF data were simultaneously acquired using a dual-echo pseudocontinuous arterial spin labeling (pCASL) technique, whereas macrovascular volume fraction was estimated using time-of-flight MR angiography. Functional connectivity within well-known functional networks—including the default mode, frontoparietal, and primary sensory-motor networks—was calculated using a conventional seed-based correlation approach. They found the functional connectivity strength to be significantly correlated with the regional increase in CBF-BOLD coupling strength and inversely proportional to macrovascular volume fraction. These relationships were consistently observed within all functional networks considered. Their findings suggest that highly connected networks observed using rs-fcMRI are not likely to be mediated by common vascular drainage linking distal cortical areas. Instead, high BOLD functional connectivity is more likely to reflect tighter neurovascular connections, attributable to neuronal pathways.