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Biomedical subjects

M L Paillère-Martinot

Publications and source records attributed to M L Paillère-Martinot.

At least 19 recordsLinked to original sources
PubMed2005

Modulation of language areas with functional MR image-guided magnetic stimulation.

Repetitive transcranial magnetic stimulation (rTMS) can interfere with linguistic performance when delivered over language areas. At low frequency (1 Hz), rTMS is assumed to decrease cortical excitability; however, the degree of TMS effect on cortical language areas may depend on the localization of the stimulation coil with respect to the inter-individual anatomo-functional variations. Hence, we aimed at investigating individual brain areas involved in semantic and phonological auditory processes. We hypothesized that active rTMS targeted over Wernicke's area might modify the performance during a language-fragment-detection task. Sentences in native or foreign languages were presented to 12 right-handed male healthy volunteers during functional magnetic resonance imaging (fMRI). 3D-functional maps localized the posterior temporal activation (Wernicke) in each subject and MRI anatomical cortical landmarks were used to define Broca's pars opercularis (F3Op). A frameless stereotaxy system was used to guide the TMS coil position over Wernicke's and F3Op areas in each subject. Active and placebo randomized rTMS sessions were applied at 1 Hz, 110% of motor threshold, during the same language-fragment-detection task. Accuracy and response time (RT) were recorded. RT was significantly decreased by active rTMS compared to placebo over Wernicke's area, and was more decreased for native than for foreign languages. No significant RT change was observed for F3Op area. rTMS conditions did not impair participants' accuracy. Thus, low-frequency rTMS over Wernicke's area can speed-up the response to a task tapping on native language perception in healthy volunteers. This individually-guided stimulation study confirms that facilitatory effects are not confined to high-frequency rTMS.

Adult↗
PubMed2001

Temporal order and spatial memory in schizophrenia: a parametric study.

Spatial working memory has been shown to be impaired in schizophrenia. In contrast, memory for temporal order has been poorly studied in patients with schizophrenia. The aim of this study was to compare and to further characterize spatial working memory and sequence reproduction deficits in patients with schizophrenia under stable medication by manipulating cues (pattern versus sequence), delay, set-size and response type in various recall and recognition tasks. This allowed us to dissociate processes as encoding, retention and retrieval and to compare the performance of patients with schizophrenia to the performance of patients with prefrontal lesions, who have been previously tested in the same tasks. Our results show that increase of the set-size and of the delay decreased performance of both groups, and that these factors had larger detrimental effects in patients with schizophrenia than in controls. Furthermore, comparison between tasks revealed retention and retrieval deficits in schizophrenia. Finally, patients with schizophrenia showed impairments not only in recall but also in sequence recognition tasks with delay. This is in contrast to patients with prefrontal lesions, who have previously been shown to have intact recognition of sequences after a delay. These results suggest that the working memory deficit in schizophrenia cannot be restricted to a prefrontal dysfunction.

Adult↗
PubMed2001

In vivo extrastriatal and striatal D2 dopamine receptor blockade by amisulpride in schizophrenia.

Amisulpride, a substituted benzamide with high affinity for dopamine D2 and D3 receptors only, has been reported to have therapeutic effects on both negative and positive schizophrenic symptoms, although at distinct dose ranges (50-300 mg/day vs. 400-1,200 mg/day). The purpose of this study was to investigate the binding of amisulpride to extrastriatal (i.e., thalamus and temporal cortex) and striatal D2 dopamine receptors with respect to plasma amisulpride determinations. Ten patients with schizophrenia treated with amisulpride over a wide range of doses (25-1,200 mg/day) were studied. Positron emission tomography images were acquired by using 76Br-FLB-457, a highly specific antagonist of the D2 and D3 dopamine receptors. Binding indexes (BI) in the regions studied were estimated with reference to values from six healthy subjects. A curvilinear relationship was demonstrated between plasma concentration of amisulpride and the BI in extrastriatal regions. The BI also varied as a function of plasma concentration in striatum. Furthermore, the data provide evidence for different binding profiles: low plasma concentrations (28-92 ng/mL) induced marked extrastriatal binding and low striatal binding, whereas higher plasma concentrations (>153 ng/mL) induced marked binding both in extrastriatal and striatal regions. Dose-dependent differential binding profiles of amisulpride to D2 receptors in extrastriatal and striatal regions were demonstrated, and two therapeutic ranges of plasma concentrations for negative and positive schizophrenic symptoms, respectively, are suggested.

Adult↗
PubMed2001

Extrastriatal and striatal D(2) dopamine receptor blockade with haloperidol or new antipsychotic drugs in patients with schizophrenia.

BACKGROUND: Both traditional and atypical antipsychotics have been hypothesised to be effective in schizophrenia through limbic and cortical D(2) dopamine receptor blockade. AIMS: To investigate this hypothesis with the D(2)/D(3)-selective positron emission tomography (PET) probe [(76)Br]-FLB457. METHOD: PET scans were performed on 6 controls and 18 patients with schizophrenia treated with haloperidol or with risperidone, clozapine, amisulpride or olanzapine. RESULTS: The D(2) dopamine receptor blockade was high in the temporal cortex with both haloperidol and atypical antipsychotics. The atypicals, however, induced a significantly lower D(2) binding index than haloperidol in the thalamus and in the striatum. CONCLUSIONS: Results suggest that cortical D(2) dopamine receptors are a common target of traditional and atypical antipsychotics for therapeutic action. Higher in vivo binding to the D(2) receptors in the cortex than in the basal ganglia is suggested as an indicator of favourable profile for a putative antipsychotic compound.

Adult↗
PubMed2000

Altered hemispheric functional dominance during word generation in negative schizophrenia.

Functional brain imaging studies have reported decreased frontal activations in schizophrenia, but hemispheric dominance for language has rarely been assessed. To investigate regional activation and lateralization during word production, we determined normalized regional cerebral blood flow (rCBF) variations with positron emission tomography (PET) and H2(15)O (water labeled with the isotope oxygen 15) in 14 negative schizophrenia patients and 14 volunteers. Subjects were scanned during two trials of three conditions: rest, vocalized verbal fluency, and spontaneous word production. Images were analyzed using an anatomical volumes of interest method, and the two groups' changes were compared, using rest as a baseline. Differences in the lateralization of changes were detected in homologous frontal and inferior parietal regions. The lateralization effects in patients arose from lower activations in the left frontal regions, abnormal right inferior frontal activations, and weaker right inferior parietal deactivation, during the word production tasks. The right hemisphere changes correlated negatively with the performance in verbal fluency. Thus in negative schizophrenia patients, while the activations were less focused on the left hemisphere regions usually engaged in word generation, rCBF changes in the right hemisphere might reflect a compensatory functional pattern.

Adult↗
PubMed2000

A prognostic study of clinical dimensions in adolescent-onset psychoses.

Adolescent-onset psychoses often raise diagnostic difficulties because of the mixture of schizophrenic and affective features. This study examined prospectively which clinical dimensions contribute to difficulty in initial diagnosis and which clinical features have predictive value for outcomes of schizophrenia or affective disorders, and for eventual psychosocial functioning. Thirty-six adolescents consecutively admitted for a psychotic episode were followed up for 1 to 4 years. Symptoms were assessed at admission, at discharge, and once a year. DSM-III-R (APA 1989) diagnoses were assessed at admission and once a year. Comparisons were performed across initial and followup diagnostic groups. Positive symptoms did not differentiate the initial clinical pictures, while negative symptoms, manic symptoms, and disorganization differentiated the manic and depressive episodes in the acute phase. When initial positive symptoms (mainly delusions) were severe, they predicted a final diagnosis in the schizophrenia spectrum. Poor outcome was associated with more anhedonia-associality and lower functioning scores at admission. Results suggest (1) a higher vulnerability to positive symptoms in adolescents who will further develop schizophrenia and (2) the low specificity of affective symptoms at this age.

Acute Disease↗
PubMed2000

Working memory control in patients with schizophrenia: a PET study during a random number generation task.

OBJECTIVE: The authors' goal was to investigate brain regions involved in the deficiency of working memory control processes in patients with schizophrenia. METHOD: Regional cerebral blood flow was measured with positron emission tomography in eight men with stabilized schizophrenia and eight healthy men while they were performing a graded random number generation task. Twelve scans were made for each subject. Covariations between randomness of responses and regional activation were analyzed. RESULTS: The pattern of covariation between randomness of responses and activation in the anterior cingulate and superior parietal regions differed between patients and healthy subjects. CONCLUSIONS: These results suggest a cinguloparietal dysfunction underlying the impairment of working memory control processes during a random number generation task in patients with schizophrenia.

Adult↗
PubMed1998

No serotonin 5-HT2A receptor density abnormality in the cortex of schizophrenic patients studied with PET.

To investigate putative abnormalities of cortical 5-HT2A receptor density in schizophrenia, we used positron emission tomography and [18F]setoperone, a high-affinity 5-HT2A receptor radioligand, in 14 neuroleptic-free or -naive schizophrenic patients and in 15 normal controls. No significant difference between the groups was observed in the whole or regional cortical binding potential of [18F]setoperone, indicating an absence of major 5-HT2A receptor cortical density abnormalities in schizophrenics.

Adult↗
PubMed1998

Binding of antipsychotic drugs to cortical 5-HT2A receptors: a PET study of chlorpromazine, clozapine, and amisulpride in schizophrenic patients.

OBJECTIVE: This study examined the binding to cortical serotonin 5-HT2A receptors of conventional doses of the typical neuroleptic chlorpromazine in comparison with clozapine, the prototype atypical antipsychotic, and amisulpride, a specific dopamine D2-D3 blocker. METHOD: Seventeen schizophrenic patients treated with chlorpromazine (75-700 mg/day), four treated with clozapine (200-600 mg/day), and five treated with amisulpride (200-1200 mg/day) were studied. Cortical 5-HT2A binding was estimated by reference to the values for 14 antipsychotic-free schizophrenic subjects with the use of positron emission tomography and [18F]setoperone, a high-affinity radioligand for cortical 5-HT2A receptors. RESULTS: A dose-dependent decrease in the number of available cortical binding sites for [18F] setoperone was demonstrated in the chlorpromazine group; for the highest dose, there was a virtual lack of sites available for binding. A very low percentage of available binding sites was also observed in the clozapine-treated patients at all doses. This suggests a high level of 5-HT2A blockade with both clozapine and high doses of chlorpromazine. No significant binding of amisulpride to 5-HT2A receptors was detected. CONCLUSIONS: A high level of 5-HT2A receptor blockade does not appear specific to clozapine in comparison with high doses of chlorpromazine, suggesting that the distinct clinical profiles of both drugs are unrelated to 5-HT2A blockade itself.

Adolescent↗
PubMed1997

Presynaptic dopaminergic function in the striatum of schizophrenic patients.

The dopaminergic hypothesis of schizophrenia postulates increased brain dopaminergic activity. Two previous studies reported increased 18F-DOPA uptake with positron emission tomography in schizophrenic patients (n = 5, n = 7). In the present study, striatal dopaminergic function was assessed in vivo in six untreated schizophrenics and seven control subjects, comparable for age and sex. The 18F-fluoro-L-DOPA (18F-DOPA) uptake rate constant Ki was determined in the caudate and putamen using coregistered positron emission tomography and magnetic resonance imaging. No difference between groups for mean Ki was found. The variability of the 18F-DOPA uptake values was higher in the caudate (p < 0.01) and in the putamen (p < 0.001) in schizophrenic patients than in control subjects, suggesting that schizophrenia is a disorder involving heterogeneous states of the striatal presynaptic dopaminergic function.

Adolescent↗
PubMed1997

Use of electroconvulsive therapy in adolescents.

Electroconvulsive therapy (ECT) is used in adolescent psychiatric practice, yet few studies have been conducted to assess its use for 13-19-year-olds. Efficacy, indications, side effects, technical characteristics, and outcome are uncertain. We retrospectively reviewed the medical records of 21 adolescents treated with bilateral ECT in our department from 1984 through 1995. In our series, ECT was effective in treating both maniac and depressive episodes, with a high rate of relapse at 1 year follow-up (approximately 40%). Clinical improvement was only partial and in schizophrenia and schizoaffective episodes. Seizure threshold was associated with gender, but not with the cumulative number of treatments. Adverse effects were frequent, but were usually transient with only moderate discomfort, even in patients with concomitant medical problems. We conclude that ECT is a safe and effective treatment for adolescents with severe and intractable mental illness, and it has the same indications and effects as in adults.

Adolescent↗
PubMed1996

In vivo characteristics of dopamine D2 receptor occupancy by amisulpride in schizophrenia.

The relationship between the daily oral dose of the benzamide amisulpride and the striatal D2-dopamine receptors occupancy was investigated in 11 schizophrenic patients using positron emission tomography with 76Br-bromolisuride. The patients were studied before and during chronic treatment with amisulpride over a wide range of doses. The test-retest variability of the method was estimated to be 5.8% in a group of four patients receiving placebo. A curvilinear relationship was demonstrated between the amisulpride doses and the D2-receptor occupancy. A range of 70-80% occupancy of the striatal D2 receptors, suggested as an optimal interval for therapeutic action on positive psychotic symptoms, was obtained with doses of amisulpride ranging between 630 and 910 mg per day, while an occupancy of 85%, suggested to be associated with pronounced extrapyramidal side-effects, was reached with 1,100 mg per day.

Adult↗
PubMed1996

[Persecution syndrome after the use of interferon: a case report].

The interferon has been used for fifteen years as a viral and carcinomatous pathology treatment, however it has some spychiatric secondary effects. In this paper we present a psychotic reaction in a patient without any psychiatric history. A depression with specific characteristics was also detected. It appears just after injection and goes away quickly forming an interesting "on-off" depression model.

Antiviral Agents↗
PubMed1995

Improvement of some schizophrenic deficit symptoms with low doses of amisulpride.

OBJECTIVE: The authors assessed the effects on primary negative symptoms of low doses of amisulpride, a substituted benzamide neuroleptic with high affinity for D2 and D3 dopamine receptors. METHOD: Young, drug-free schizophrenic patients with pure negative symptoms participated in a 6-week double-blind trial of placebo (N = 10) or low-dose amisulpride (N = 10). They were assessed with the Scale for the Assessment of Negative Symptoms. RESULTS: Amisulpride significantly improved negative symptoms. Improvement in avolition, attentional impairment, and retardation was significantly greater with amisulpride than with placebo. CONCLUSIONS: These findings suggest that some primary negative symptoms may be directly affected by low doses of benzamide neuroleptics.

Adult↗
PubMed1994

Delusional misidentification: a clinical, neuropsychological and brain imaging case study.

The case of a young woman with a disorder involving Capgras syndrome, Frégoli syndrome, intermetamorphosis, and the subjective-doubles syndrome is reported. Neuropsychological assessment showed a low efficiency in the complex visuospatial organization tasks and in non-verbal memory. MRI found a left lenticular hypodensity, and two PET scans performed in the symptomatic and recovered states showed significant changes and asymmetries in cerebral glucose metabolism in the frontal, parietal, and subcortical regions. These findings are discussed with respect to recent models of delusional misidentification syndromes.

Adult↗
PubMed1994

Central D2 receptors and negative symptoms of schizophrenia.

Most in vivo studies of striatal D2 receptor (SD2R) density with positron emission tomography in schizophrenia have attempted to relate this variable to the diagnosis of the illness. In the present study, a relationship between SD2R and clinical dimensions of this psychosis was searched for in a highly selected group of young negative schizophrenics (8 drug-naïve and 2 drug-free). The SD2R density index measured in vivo using 76Br-bromolisuride and PET correlated negatively (r = 0.80, P < 0.01) with a psychomotor dimension of schizophrenia involving blunted affect and alogia. The mean SD2R index of the patients did not differ from that of age-matched control subjects. Therefore, this behavioural dimension accounts for the variance of the SD2R, suggesting that the striatal dopamine system modulates symptoms such as flattened affect and alogia.

Adolescent↗
PubMed1991

The estimated density of D2 striatal receptors in schizophrenia. A study with positron emission tomography and 76Br-bromolisuride.

The striatal D2 receptors of 19 untreated schizophrenics and 14 normal control subjects were investigated with PET and 76Br-bromolisuride. The ratio of radioactivity in the striatum to that in the cerebellum was taken as an index of the striatal D2 receptor density. There was no significant difference between the control and the schizophrenic groups, nor any difference between subgroups of patients defined by clinical type or course of illness, and no relationship between the striatum:cerebellum activity ratio and SANS or SAPS ratings of symptoms. Unlike in the controls, this ratio was not correlated with age in schizophrenics. This study suggests that there is no quantitative abnormality of striatal D2 dopamine receptors in schizophrenia.

Adolescent↗