Raclopride PET Study Research Articles

Relationship between subjective well-being and aripiprazole: an [11C]raclopride PET study

The dopamine blockade by antipsychotics trigger subjective dysphoria. Compared with D2 antagonists, aripiprazole, a D2 partial agonist, was expected to produce a different experience. Indeed, a previous study reported no relationship between the D2 receptor occupancy by aripiprazole and subjective dysphoria, while the D2 receptor occupancy by antagonists was associated with negative subjective experiences. This study revisited the relationship in patients treated with aripiprazole by using an inhibitory Emax model, which enables the individual drug-free binding potential and D2 receptor occupancy to be properly estimated. Eight patients with schizophrenia who have been clinically stable on aripiprazole were enrolled. Assessments including Positive and Negative Syndrome Scale (PANSS) and Subjective Well-being under Neuroleptics Scale (Kv-SWN) were administered. [11C]raclopride PET scan were conducted 2, 26, and 74 h after aripiprazole administration. Regression analysis showed a significant negative association between the D2 receptor occupancy by aripiprazole in the striatum and the Kv-SWN (R2 = 0.55, p = 0.036), but the PANSS total score was not associated with the Kv-SWN (R2 = 0.42, p = 0.080). The negative association between D2 receptor occupancy by aripiprazole and subjective well-being implies that clinicians should find the lowest effective doses of aripiprazole for clinically stable patients to improve their subjective experiences and clinical outcomes.

The Interplay Between Postsynaptic Striatal D2/3 Receptor Availability, Adversity Exposure and Odd Beliefs: A [11C]-Raclopride PET Study

Between unaffected mental health and diagnosable psychiatric disorders, there is a vast continuum of functioning. The hypothesized link between striatal dopamine signaling and psychosis has guided a prolific body of research. However, it has been understudied in the context of multiple interacting factors, subclinical phenotypes, and pre-postsynaptic dynamics. This work investigated psychotic-like experiences and D2/3 dopamine postsynaptic receptor availability in the dorsal striatum, quantified by in vivo [11C]-raclopride positron emission tomography, in a sample of 24 healthy male individuals. Additional mediation and moderation effects with childhood trauma and key dopamine-regulating genes were examined. An inverse relationship between nondisplaceable binding potential and subclinical symptoms was identified. D2/3 receptor availability in the left putamen fully mediated the association between traumatic childhood experiences and odd beliefs, that is, inclinations to see meaning in randomness and unfounded interpretations. Moreover, the effect of early adversity was moderated by a DRD2 functional variant (rs1076560). The results link environmental and neurobiological influences in the striatum to the origination of psychosis spectrum symptomology, consistent with the social defeat and diathesis-stress models. Adversity exposure may affect the dopamine system as in association with biases in probabilistic reasoning, attributional style, and salience processing. The inverse relationship between D2/3 availability and symptomology may be explained by endogenous dopamine occupying the receptor, postsynaptic compensatory mechanisms, and/or altered receptor sensitivity. This may also reflect a cognitively stabilizing mechanism in non-help-seeking individuals. Future research should comprehensively characterize molecular parameters of dopamine neurotransmission along the psychosis spectrum and according to subtype profiling.

Dopamine dysregulation in psychotic relapse after antipsychotic discontinuation: an [18F]DOPA and [11C]raclopride PET study in first-episode psychosis.

Although antipsychotic drugs are effective for relieving the psychotic symptoms of first-episode psychosis (FEP), psychotic relapse is common during the course of the illness. While some FEPs remain remitted even without medication, antipsychotic discontinuation is regarded as the most common risk factor for the relapse. Considering the actions of antipsychotic drugs on presynaptic and postsynaptic dopamine dysregulation, this study evaluated possible mechanisms underlying relapse after antipsychotic discontinuation. Twenty five FEPs who were clinically stable and 14 matched healthy controls were enrolled. Striatal dopamine activity was assessed as Kicer value using [18F]DOPA PET before and 6 weeks after antipsychotic discontinuation. The D2/3 receptor availability was measured as BPND using [11C]raclopride PET after antipsychotic discontinuation. Healthy controls also underwent PET scans according to the corresponding schedule of the patients. Patients were monitored for psychotic relapse during 12 weeks after antipsychotic discontinuation. 40% of the patients showed psychotic relapse after antipsychotic discontinuation. The change in Kicer value over time significantly differed between relapsed, non-relapsed patients and healthy controls (Week*Group: F = 4.827, df = 2,253.193, p = 0.009). In relapsed patients, a significant correlation was found between baseline striatal Kicer values and time to relapse after antipsychotic discontinuation (R2 = 0.518, p = 0.018). BPND were not significantly different between relapsed, non-relapsed patients and healthy controls (F = 1.402, df = 2,32.000, p = 0.261). These results suggest that dysfunctional dopamine autoregulation might precipitate psychotic relapse after antipsychotic discontinuation in FEP. This finding could be used for developing a strategy for the prevention of psychotic relapse related to antipsychotic discontinuation.

Simultaneous scanning of two mice in a small-animal PET scanner: a simulation-based assessment of the signal degradation

In PET imaging, research groups have recently proposed different experimental set ups allowing multiple animals to be simultaneously imaged in a scanner in order to reduce the costs and increase the throughput. In those studies, the technical feasibility was demonstrated and the signal degradation caused by additional mice in the FOV characterized, however, the impact of the signal degradation on the outcome of a PET study has not yet been studied. Here we thoroughly investigated, using Monte Carlo simulated [18F]FDG and [11C]Raclopride PET studies, different experimental designs for whole-body and brain acquisitions of two mice and assessed the actual impact on the detection of biological variations as compared to a single-mouse setting. First, we extended the validation of the PET-SORTEO Monte Carlo simulation platform for the simultaneous simulation of two animals. Then, we designed [18F]FDG and [11C]Raclopride input mouse models for the simulation of realistic whole-body and brain PET studies. Simulated studies allowed us to accurately estimate the differences in detection between single- and dual-mode acquisition settings that are purely the result of having two animals in the FOV. Validation results showed that PET-SORTEO accurately reproduced the spatial resolution and noise degradations that were observed with actual dual phantom experiments. The simulated [18F]FDG whole-body study showed that the resolution loss due to the off-center positioning of the mice was the biggest contributing factor in signal degradation at the pixel level and a minimal inter-animal distance as well as the use of reconstruction methods with resolution modeling should be preferred. Dual mode acquisition did not have a major impact on ROI-based analysis except in situations where uptake values in organs from the same subject were compared. The simulated [11C]Raclopride study however showed that dual-mice imaging strongly reduced the sensitivity to variations when mice were positioned side-by-side while no sensitivity reduction was observed when they were facing each other. This is the first study showing the impact of different experimental designs for whole-body and brain acquisitions of two mice on the quality of the results using Monte Carlo simulated [18F]FDG and [11C]Raclopride PET studies.

Relation of dopamine receptor 2 binding to pain perception in female fibromyalgia patients with and without depression – A [11C] raclopride PET-study

Dopamine D2/D3 receptor availability at rest and its association with individual pain perception was investigated using the [11C] raclopride PET-method in 24 female Fibromyalgia (FMS) participants with (FMS+, N=11) and without (FMS−, N=13) comorbid depression and in 17 healthy women. Thermal pain thresholds (TPT) and pain responses were assessed outside the scanner. We compared the discriminative capacity, i.e. the individual׳s capacity to discriminate between lower and higher pain intensities and the response criterion, i.e. the subject׳s tendency to report pain during noxious stimulation due to psychological factors. [11C] raclopride binding potential (BP), defined as the ratio of specifically bound non-displaceable radioligand at equilibrium (BPND) was used as measure of D2/D3 receptor availability. We found significant group effects of BPND in striatal regions (left ventral striatum, left caudate nucleus and left nucleus accumbens) between FMS+ and FMS− compared to healthy subjects. Correlational analysis showed negative associations between TPT and D2/D3 receptor availability in the left caudate nucleus in FMS-, between TPT and D2/D3 receptor availability in the right caudate nucleus in FMS + and positive associations between TPT and D2/D3 receptor availability in the left putamen and right caudate nucleus in healthy controls. The response criterion was positively associated with D2/D3 receptor availability in the right nucleus accumbens in FMS − and negatively with D2/D3 receptor availability in the left caudate nucleus in healthy controls. Finally, no significant associations between D2/D3 receptor availability and discriminative capacity in any of the groups or regions were determined. These findings provide further support for a disruption of dopaminergic neurotransmission in FMS and implicate DA as important neurochemical moderator of differences in pain perception in FMS patients with and without co-morbid depression.

Dopamine D2/3 receptor availability in the striatum of antipsychotic-free older patients with schizophrenia—A [11C]-raclopride PET study

BackgroundNo study has examined dopamine D2/3 receptor (D2/3R) availability in antipsychotic-free older patients with schizophrenia. MethodsWe included patients with schizophrenia 50years or older who were antipsychotic-free for at least 3months. We compared non-displaceable binding potential (BPND) of [11C]-raclopride in the caudate, putamen, ventral striatum, and globus pallidus between patients and age- and sex-matched healthy controls. ResultsTen patients participated (antipsychotic-naive=4). No differences in BPND were found between patients and controls in any ROIs (F(1, 72)=.42, p=.52). ConclusionThe preliminary results suggest no differences in D2/3R availability between antipsychotic-free older patients with schizophrenia and controls.

Striatal dopamine function during gambling in pathological gamblers: Interim analysis of ongoing [11C]raclopride PET study

Striatal dopamine function during gambling in pathological gamblers: Interim analysis of ongoing [11C]raclopride PET study

Individual differences in extraversion and impulsiveness are associated with striatal dopamine D2 receptor availability: a [11C]raclopride PET study

Individual differences in extraversion and impulsiveness are associated with striatal dopamine D2 receptor availability: a [11C]raclopride PET study

Striatal and Extrastriatal D2/D3-Receptor-Binding Properties of Ziprasidone

To elucidate the "atypicality" of ziprasidone, its striatal and extrastriatal D2/D3-receptor binding was characterized in patients with schizophrenia under steady-state conditions. These data were compared with striatal receptor occupancy values after single-dose ziprasidone ingestion in healthy controls. [F]fallypride positron emission tomography (PET) recordings were obtained in 15 patients under steady-state ziprasidone treatment at varying time points after the last dose. Binding potentials were calculated for striatal and extrastriatal regions. D2/D3-receptor occupancies were expressed relative to binding potentials in 8 unmedicated patients. In a parallel [C]raclopride-PET study, striatal D2/D3-receptor occupancy was measured in healthy subjects after single oral doses of 40 mg ziprasidone or 7.5 mg haloperidol. Ziprasidone plasma concentrations correlated significantly with D2/D3-receptor occupancies in all volumes of interests. Occupancy in extrastriatal regions was approximately 10% higher than in striatal regions. Half maximal effective concentration values were consistently higher in striatal than in extrastriatal regions (temporal cortex: 39 ng/mL; putamen: 64 ng/mL), irrespective of the time between last dosing and scan. Single ziprasidone doses resulted in higher occupancies exceeding the 95% prediction limits of the occupancy versus plasma concentrations for chronic dosing. Ziprasidone shares moderate preferential extrastriatal D2/D3-receptor binding with some other atypicals. D2/D3-receptor occupancy is rapidly attuning to the daily course of ziprasidone plasma levels, suggesting relatively high intraday variations of D2/D3-receptor binding. The discrepancies between single-dose and steady-state results are important for the future design of dose-finding PET occupancy studies of novel antipsychotics. Single-dose studies may not be totally relied on for final dose selection.

Theta burst stimulation-induced inhibition of dorsolateral prefrontal cortex reveals hemispheric asymmetry in striatal dopamine release during a set-shifting task: a TMS-[(11)C]raclopride PET study.

The prefrontostriatal network is considered to play a key role in executive functions. Previous neuroimaging studies have shown that executive processes tested with card-sorting tasks requiring planning and set-shifting [e.g. Montreal-card-sorting-task (MCST)] may engage the dorsolateral prefrontal cortex (DLPFC) while inducing dopamine release in the striatum. However, functional imaging studies can only provide neuronal correlates of cognitive performance and cannot establish a causal relation between observed brain activity and task performance. In order to investigate the contribution of the DLPFC during set-shifting and its effect on the striatal dopaminergic system, we applied continuous theta burst stimulation (cTBS) to left and right DLPFC. Our aim was to transiently disrupt its function and to measure MCST performance and striatal dopamine release during [(11)C]raclopride PET. A significant hemispheric asymmetry was observed. cTBS of the left DLPFC impaired MCST performance and dopamine release in the ipsilateral caudate-anterior putamen and contralateral caudate nucleus, as compared to cTBS of the vertex (control). These effects appeared to be limited only to left DLPFC stimulation while right DLPFC stimulation did not influence task performance or [(11)C]raclopride binding potential in the striatum. This is the first study showing that cTBS, by disrupting left prefrontal function, may indirectly affect striatal dopamine neurotransmission during performance of executive tasks. This cTBS-induced regional prefrontal effect and modulation of the frontostriatal network may be important for understanding the contribution of hemisphere laterality and its neural bases with regard to executive functions, as well as for revealing the neurochemical substrate underlying cognitive deficits.

Therapeutic effect of repetitive transcranial magnetic stimulation in Parkinson's disease: Analysis of [11C] raclopride PET study

Repetitive transcranial magnetic stimulation (rTMS) has been used as a potential therapeutic tool in Parkinson's disease (PD). However, the therapeutic value and/or the placebo effect of rTMS on PD remain to be elucidated. To investigate the therapeutic value and/or placebo effect of rTMS in PD, we compared the motor section of unified PD rating scale (UPDRS III) and the amount of extracellular dopamine concentration using [(11)C] raclopride PET before and after two sessions of rTMS in 9 PD patients. During a consecutive 2 days while off-medication, two series of 15 trains of 5 Hz-frequency rTMS (intensity, 90% of the resting motor threshold) were applied to the hand area of more severely symptomatic motor cortex (MC). After unilateral rTMS of MC, mean raclopride binding potentials (BPs) were reduced not only in putaminal and caudate areas on the stimulated side (-4.9% and -6.5%, respectively) (P > 0.05) but also in putaminal and caudate areas of nonstimulated hemispheres (-6.6%, P > 0.05 and -12.1%, P = 0.049, respectively). UPDRS III scores were significantly decreased (35.0 +/- 14.1 to 32.0 +/- 13.4, P = 0.049). A reduction of raclopride BP in nonstimulated ventral striatum by unilateral rTMS supports the placebo response during rTMS.

Lack of dopamine release in response to monetary reward in depressed patients: A [ 11C]raclopride PET study

Lack of dopamine release in response to monetary reward in depressed patients: A [ 11C]raclopride PET study

Stress-Induced Dopamine Release in Humans at Risk of Psychosis: a [11C]Raclopride PET Study

Drugs that increase dopamine levels in the brain can cause psychotic symptoms in healthy individuals and worsen them in schizophrenic patients. Psychological stress also increases dopamine release and is thought to play a role in susceptibility to psychotic illness. We hypothesized that healthy individuals at elevated risk of developing psychosis would show greater striatal dopamine release than controls in response to stress. Using positron emission tomography and [(11)C]raclopride, we measured changes in synaptic dopamine concentrations in 10 controls and 16 psychometric schizotypes; 9 with perceptual aberrations (PerAb, ie positive schizotypy) and 7 with physical anhedonia (PhysAn, ie negative schizotypy). [(11)C]Raclopride binding potential was measured during a psychological stress task and a sensory-motor control. All three groups showed significant increases in self-reported stress and cortisol levels between the stress and control conditions. However, only the PhysAn group showed significant stress-induced dopamine release. Dopamine release in the entire sample was significantly negatively correlated with smooth pursuit gain, an endophenotype linked to frontal lobe function. Our findings suggest the presence of abnormalities in the dopamine response to stress in negative symptom schizotypy, and provide indirect evidence of a link to frontal function.

The effect of nicotine on striatal dopamine release in man: A [11C]raclopride PET study

In common with many addictive substances and behaviors nicotine activates the mesolimbic dopaminergic system. Brain microdialysis studies in rodents have consistently shown increases in extrasynaptic DA levels in the striatum after administration of nicotine but PET experiments in primates have given contradicting results. A recent PET study assessing the effect of smoking in humans showed no change in [(11)C]raclopride binding in the brain, but did find that "hedonia" correlated with a reduction in [(11)C]raclopride binding suggesting that DA may mediate the positive reinforcing effects of nicotine. In this experiment we measured the effect of nicotine, administered via a nasal spray, on DA release using [(11)C]raclopride PET, in 10 regular smokers. There was no overall change in [(11)C]raclopride binding after nicotine administration in any of the striatal regions examined. However, the individual change in [(11)C]raclopride binding correlated with change in subjective measures of "amused" and "happiness" in the associative striatum (AST) and sensorimotor striatum (SMST). Nicotine concentration correlated negatively with change in BP in the limbic striatum. Nicotine had significant effects on cardiovascular measures including pulse rate, systolic blood pressure (BPr), and diastolic BPr. Baseline [(11)C]raclopride binding potential (BP) in the AST correlated negatively with the Fagerström score, an index of nicotine dependence. These results support a role for the DA system in nicotine addiction, but reveal a more complex relationship than suggested by studies in animals.

Striatal dopamine release during performance of executive functions: A [ 11C] raclopride PET study

To date, while the contribution of the striatum in executive processes is well documented, the role played by striatal dopamine during tasks requiring executive functions is still unknown. We used D2-dopamine receptor ligand [ 11C] raclopride PET in healthy subjects while performing the Montreal Card Sorting Task (MCST). We observed a striatal reduction in [ 11C] raclopride binding potential during planning of a set-shift when compared with matching according to an ongoing rule. These findings suggest that striatal dopamine neurotransmission increases significantly during the performance of specific executive processes confirming previous evidence of striatal activation during fMRI studies. The present observation may provide some insights on the origin of cognitive deficits underlying certain neurological disorders associated with dopamine dysfunction, such as Parkinson’s disease.

Corticostriatal functional interactions in Parkinson's disease: a rTMS/[11C]raclopride PET study

Several animal studies have shown that striatal dopamine can be released under direct control of glutamatergic corticostriatal efferents. In Parkinson's disease (PD), abnormalities in corticostriatal interactions are believed to play an important role in the pathophysiology of the disease. Previously, we have reported that, in healthy subjects, repetitive transcranial magnetic stimulation (rTMS) of motor cortex (MC) induces focal dopamine release in the ipsilateral putamen. In the present study, using [11C]raclopride PET, we sought to investigate early PD patients with evidence of unilateral motor symptoms. We measured in the putamen changes in extracellular dopamine concentration following rTMS (intensity, 90% of the resting motor threshold; frequency, 10 Hz) of the left and right MC. The main objective was to identify potential differences in corticostriatal dopamine release between the hemisphere associated with clear contralateral motor symptoms (symptomatic hemisphere) and the presymptomatic stage of the other hemisphere (asymptomatic hemisphere). Repetitive TMS of MC caused a binding reduction in the ipsilateral putamen of both hemispheres. In the symptomatic hemisphere, while the amount of TMS-induced dopamine release was, as expected, smaller, the size of the significant cluster of change in [11C]raclopride binding was, instead, 61.4% greater than in the asymptomatic hemisphere. This finding of a spatially enlarged area of dopamine release, following cortical stimulation, may represent a possible in vivo expression of a loss of functional segregation of cortical information to the striatum and an indirect evidence of abnormal corticostriatal transmission in early PD. This has potential implications for models of basal ganglia function in PD.

Impact of the Spatial Normalization Template and Realignment Procedure on the SPM Analysis of [11C]Raclopride PET Studies

Background/Objectives: In this paper, we address the issue of how the preprocessing steps of a typical neuroreceptor PET study may influence the outcome of a statistical parametric mapping (SPM) analysis examining intercondition differences. Two preprocessing steps and their possible interaction were investigated: 1) the realignment of dynamic images to correct for patient's motion and 2) the effect of the template in the spatial normalization step required by SPM. Methods : The impact of different realignment methods was tested by performing the SPM analysis on a six patient-two conditions /sup 11/C-raclopride (RAC) study where the dynamic images of each subject were re-aligned with four methods. Once realigned, the images were spatially normalized to the standard cerebral blood flow (CBF) template, available in SPM, and to a RAC template. The SPM pattern showing the intercondition differences obtained in each case was compared with the expected one. The accuracy of the four realignment methods used was further tested using a set of motion-free RAC studies. Results/Conclusion: We found that: 1) different realignment methods may create different intercondition difference patterns; 2) such differences in the results may be due to a failure in accuracy of some realignment methods; and 3) the use of a template that closely matches the spatial distribution of the tracer under investigation can minimize these problems.

Reduction of Brain Dopamine Concentration With Dietary Tyrosine Plus Phenylalanine Depletion: An [11C]Raclopride PET Study

Extracellular dopamine concentrations were estimated through measurement of [(11)C]raclopride binding with positron emission tomography after dietary manipulation of the dopamine precursors tyrosine and phenylalanine. Healthy male subjects were scanned on two occasions: once after receiving a balanced amino acid drink and once after receiving a drink mixture from which tyrosine and phenylalanine were omitted. Dietary tyrosine and phenylalanine depletion increased [(11)C]raclopride binding in the striatum by a mean of 6%. The change in [(11)C]raclopride binding correlated significantly with the fall in the ratio of tyrosine and phenylalanine to large neutral amino acids. This is the first demonstration of an effect of a dietary manipulation on brain dopamine release in humans. This result provides support for the further investigation of the role of dietary manipulations in the treatment of neuropsychiatric disorders.

Pet Measurement of the Effect of Dietary Tyrosine Depletion on [11C]Raclopride Binding: An [11C]Raclopride Pet Study

Pet Measurement of the Effect of Dietary Tyrosine Depletion on [11C]Raclopride Binding: An [11C]Raclopride Pet Study

Striatal D2 dopamine receptor status in Parkinson's disease: an [18F]dopa and [11C]raclopride PET study.

Movement DisordersVolume 14, Issue 6 p. 1025-1030 Clinical/Scientific Note Striatal D2 dopamine receptor status in Parkinson's disease: An [18F]dopa and [11C]Raclopride PET study Christine Dentresangle, Christine Dentresangle CERMEP Cyclotron Unit, Hôpital Neurologique Pierre Wertheimer, Lyon, France CNRS UMR 55 42, Faculté de Médecine R.T.H. Laënnec, Université Claude Bernard, Lyon, FranceSearch for more papers by this authorLaurent Veyre, Laurent Veyre CERMEP Cyclotron Unit, Hôpital Neurologique Pierre Wertheimer, Lyon, FranceSearch for more papers by this authorDidier Le Bars PhD, Didier Le Bars PhD CERMEP Cyclotron Unit, Hôpital Neurologique Pierre Wertheimer, Lyon, FranceSearch for more papers by this authorChristian Pierre, Christian Pierre CERMEP Cyclotron Unit, Hôpital Neurologique Pierre Wertheimer, Lyon, FranceSearch for more papers by this authorFrank Lavenne, Frank Lavenne CERMEP Cyclotron Unit, Hôpital Neurologique Pierre Wertheimer, Lyon, FranceSearch for more papers by this authorPierre Pollak MD, Pierre Pollak MD Department of Clinical and Biological Neurosciences, Université Joseph Fourier, Grenoble, FranceSearch for more papers by this authorJeanine Guerin, Jeanine Guerin Laboratory of Neuropsychology, Cognitive Functions, Language and Memory, Hôpital Neurologique Pierre Wertheimer, Lyon, FranceSearch for more papers by this authorJean-Claude Froment MD, Jean-Claude Froment MD Department of Neuroradiology, Hôpital Neurologique Pierre Wertheimer, Lyon, FranceSearch for more papers by this authorEmmanuel Brousolle MD, PhD, Corresponding Author Emmanuel Brousolle MD, PhD CERMEP Cyclotron Unit, Department of Neurology, Hôpital Neurologique Pierre Wertheimer, Laboratory EA 1880, Université Claude Bernard, Lyon, FranceService de Neurologie, Hôpital Neurologique Pierre Wertheimer, 59, boulevard Pinel, 69003, Lyon, FranceSearch for more papers by this author Christine Dentresangle, Christine Dentresangle CERMEP Cyclotron Unit, Hôpital Neurologique Pierre Wertheimer, Lyon, France CNRS UMR 55 42, Faculté de Médecine R.T.H. Laënnec, Université Claude Bernard, Lyon, FranceSearch for more papers by this authorLaurent Veyre, Laurent Veyre CERMEP Cyclotron Unit, Hôpital Neurologique Pierre Wertheimer, Lyon, FranceSearch for more papers by this authorDidier Le Bars PhD, Didier Le Bars PhD CERMEP Cyclotron Unit, Hôpital Neurologique Pierre Wertheimer, Lyon, FranceSearch for more papers by this authorChristian Pierre, Christian Pierre CERMEP Cyclotron Unit, Hôpital Neurologique Pierre Wertheimer, Lyon, FranceSearch for more papers by this authorFrank Lavenne, Frank Lavenne CERMEP Cyclotron Unit, Hôpital Neurologique Pierre Wertheimer, Lyon, FranceSearch for more papers by this authorPierre Pollak MD, Pierre Pollak MD Department of Clinical and Biological Neurosciences, Université Joseph Fourier, Grenoble, FranceSearch for more papers by this authorJeanine Guerin, Jeanine Guerin Laboratory of Neuropsychology, Cognitive Functions, Language and Memory, Hôpital Neurologique Pierre Wertheimer, Lyon, FranceSearch for more papers by this authorJean-Claude Froment MD, Jean-Claude Froment MD Department of Neuroradiology, Hôpital Neurologique Pierre Wertheimer, Lyon, FranceSearch for more papers by this authorEmmanuel Brousolle MD, PhD, Corresponding Author Emmanuel Brousolle MD, PhD CERMEP Cyclotron Unit, Department of Neurology, Hôpital Neurologique Pierre Wertheimer, Laboratory EA 1880, Université Claude Bernard, Lyon, FranceService de Neurologie, Hôpital Neurologique Pierre Wertheimer, 59, boulevard Pinel, 69003, Lyon, FranceSearch for more papers by this author First published: 25 January 2001 https://doi.org/10.1002/1531-8257(199911)14:6<1025::AID-MDS1020>3.0.CO;2-PCitations: 37AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume14, Issue6November 1999Pages 1025-1030 RelatedInformation