A single session of rTMS over the left dorsolateral prefrontal cortex influences attentional control in depressed patients.

Depressed patients are impaired in the ability to shift their focus of attention. This attentional control process is related to dysfunctions in the dorsolateral prefrontal cortex (DLPFC). It has been proposed that a dorsal circuit plays an important role in the interaction between emotional and attentional information processing. However, because the different emphasis of fundamental cognitive neuroscience research and clinical research of repetitive transcranial magnetic stimulation (rTMS) over the DLPFC, little research has been done on the effects of rTMS on cognitive functioning after a single stimulation session to explore the neural systems underlying depression. This study was conducted as a double-blind, placebo-controlled, crossover, within subjects design. Sixteen depressed patients performed a modified task switching paradigm, before and after receiving high frequency (HF) versus placebo rTMS over the left DLPFC. One session of HF-rTMS over the left DLPFC had a specific beneficial effect on task-switching performance, whereas mood remained stable. Antidepressant effects of rTMS could be related to the same neurochemical changes that underlie cognitive functioning. Therefore, task switching performance may provide a unique window into the extent of antidepressant effects which can be considered as second-order long-term effects possibly related to primary alternations in cognitive functioning.

The impact of one session of HF-rTMS on salivary cortisol in healthy female subjects.

Previous studies in healthy volunteers reported a possible impact of high frequency repetitive transcranial magnetic stimulation (HF-rTMS) on stress hormones, like cortisol. In this sham-controlled, "single blind", crossover study, we examined whether HF-rTMS had an effect on the hypothalamic-pituitary-adrenal (HPA) axis, by analysing salivary cortisol levels. Two studies were conducted. First, HF-rTMS on the left dorsolateral prefrontal cortex (DLPFC) was performed in 28 young healthy female volunteers. Second, in a comparable, but different group of 26 healthy females, HF-rTMS was performed on the right DLPFC. Salivary cortisol levels were assessed before, immediately after and 30 min after real and sham HF-rTMS. We found no support for the hypothesis that one single session of HF-rTMS on the left or the right DLPFC has an immediate or delayed impact on the HPA-axis, as measured by salivary cortisol. Although we controlled for several methodological problems in HF-rTMS research, the hypothesis that one single session of HF-rTMS on the left or on the right DLPFC can influence the HPA-axis in healthy volunteers was not supported.

Possible association between 3,4-methylenedioxymethamphetamine abuse and valvular heart disease.

Valvular heart disease, inducing valvular regurgitation, has been described in users of drugs such as anorectic agents and ergot derivates. 3,4-Methylenedioxymethamphetamine (MDMA; "ecstasy") also leads in vitro to the proliferation of cardiac valvular interstitial cells by activation of the 5-hydroxytryptamine 2B receptor. The aim of this study was to determine the occurrence of valvulopathy in young adults taking MDMA. Twenty-nine subjects using or having used MDMA and 29 gender- and age-matched controls were blindly evaluated with echocardiography. Eight subjects (28%) who took MDMA had abnormal echocardiographic results using the United States Food and Drug Administration's criteria for appetite suppressant-induced valvular heart disease, compared with none in the control group (p = 0.0045). Six (21%) subjects had mitral regurgitation of 1/4 and 4 (14%) of > or =2/4, compared with none in the control group (p = 0.002). The mean mitral regurgitant area ratios (jet/atrium) were 12 +/- 9.8% and 5 +/- 1.3%, respectively (p = 0.007). Tricuspid regurgitation > or =2/4 was present in 13 MDMA users (45%) and absent in controls (p <0.001). The mean tricuspid regurgitant area ratios were 19 +/- 9.5% and 9 +/- 4.5%, respectively (p <0.001). Four MDMA users (14%) had mild aortic regurgitation (p = 0.11). Valvular "strands" were present in 6 MDMA users (21%) and in none of the controls (p = 0.02). In conclusion, MDMA may lead to mild to moderate valvular heart disease and valvular strands.

The influence of rTMS over the right dorsolateral prefrontal cortex on top-down attentional processes.

Repetitive Transcranial Magnetic Stimulation (rTMS) provides a unique opportunity to study causal relationships between activity in the dorsolateral prefrontal cortex (DLPFC) and executive functioning, by modulating brain activity in SHAM controlled designs. We devised a new Stroop task paradigm in which subjects must engage in both strategic and automatic attentional processes. In the current experiment, we manipulated subjects' expectancies for incongruent stimuli. Previous research demonstrated that when subjects have a high level of expectancy that a stimulus will be incongruent, they are able to strategically adjust the relative influence of word reading on color naming. The effect of high frequency (HF) rTMS on Stroop performance of 20 right-handed healthy female volunteers was tested using a double blind within subjects design by counterbalanced crossover sham (placebo) and active rTMS over the right DLPFC. Since mood remained unchanged after rTMS, the Stroop data could be evaluated independent of mood changes. Only in the high expectancy condition, we found a decreased response time to both congruent and incongruent trials on the Stroop task performance after HF rTMS. The SHAM placebo condition yielded no effects. We conclude that high frequency stimulation over the right DLPFC has an effect on top-down attentional processes by modulating the attentional set.

The influence of rTMS over the right dorsolateral prefrontal cortex on intentional set switching.

High frequency (HF) repetitive transcranial magnetic stimulation (rTMS) has an excitatory effect on neurons of a specific brain area. The dorsolateral prefrontal cortex (DLPFC) has been associated with executive functions, such as task set switching. One important experimental paradigm for investigating such higher order cognitive control is the task-switching (TS) paradigm. A TS paradigm requires switching between two conditional response tasks with mutually incompatible response-selection rules. In the present study, the influence of HF rTMS over the right DLPFC in healthy female volunteers on a modified TS paradigm was investigated. As expected, reaction time on cued switching trials decreased significant after rTMS, as compared to non-cued switch trials. No changes emerged after the placebo sham condition. Mood remained unchanged after rTMS. These findings demonstrate the role of the right DLPFC in cued intentional set switch initiation.

The influence of rTMS over the left dorsolateral prefrontal cortex on Stroop task performance.

Several studies have demonstrated that repetitive transcranial magnetic stimulation (rTMS) can improve cognitive processing. Neuroimaging studies have shown the engagement of the left dorsolateral prefrontal cortex (DLPFC) in executive functioning, and more specifically during selective attention. In the present study, the influence of high-frequency rTMS over the left DLPFC on Stroop task performance in healthy female volunteers was investigated. As expected, reaction time on both the incongruent and congruent trials decreased significantly after stimulation, and there was no difference with regard to the Stroop interference effect. Mood remained unchanged after rTMS. Such a pattern is consistent with the role of the left DLPFC in implementing top-down attentional control.

Increased cerebral serotonin-2A receptor binding in depressed patients with myocardial infarction.

Serotonin (5-HT) has been implicated in the pathophysiology of depression. It is not known whether depression in post-myocardial infarction (MI) patients is also serotonin-mediated. In somatically healthy depressed persons, increased brain 5-HT(2A) receptor binding has been reported in some studies. In animal studies, decreased serotonin activity was found after induction of MI. In the present study, it was hypothesized that depressed post-MI patients would exhibit increased brain 5-HT(2A) receptor binding compared with non-depressed post-MI patients. Single photon emission computed tomography (SPECT) with the radioligand 123I-5-I-R91150, a 5-HT(2A) receptor antagonist, was used to study 5-HT(2A) receptor binding. SPECT scans were performed in nine depressed post-MI patients, 10 non-depressed post-MI patients and 10 healthy control subjects. Results were analysed using statistical parametric mapping. Depressed post-MI patients showed increased 5-HT(2A) receptor binding compared with non-depressed post-MI patients, and MI patients showed decreased 5-HT(2A) receptor binding compared with control persons. Both post-MI depression and MI seem to be associated with changes in 5-HT(2A) receptor binding.

A foreign speech accent in a case of conversion disorder.

OBJECTIVE: The aim of this paper is to report the psychiatric, neuroradiological and linguistic characteristics in a native speaker of Dutch who developed speech symptoms which strongly resemble Foreign Accent Syndrome. BACKGROUND: Foreign Accent Syndrome is a rare speech production disorder in which the speech of a patient is perceived as foreign by speakers of the same speech community. This syndrome is generally related to focal brain damage. Only in few reported cases the Foreign Accent Syndrome is assumed to be of psychogenic and/or psychotic origin. METHOD: In addition to clinical and neuroradiological examinations, an extensive test battery of standardized neuropsychological and neurolinguistic investigations was carried out. Two samples of the patient's spontaneous speech were analysed and compared to a 500,000-words reference corpus of 160 normal native speakers of Dutch. RESULTS: The patient had a prominent French accent in her pronunciation of Dutch. This accent had persisted over the past eight years and has become progressively stronger. The foreign qualities of her speech did not only relate to pronunciation, but also to the lexicon, syntax and pragmatics. Structural as well as functional neuroimaging did not reveal evidence that could account for the behavioural symptoms. By contrast psychological investigations indicated conversion disorder. CONCLUSIONS: To the best of our knowledge this is the first reported case of a foreign accent like syndrome in conversion disorder.

The ADP-IV questionnaire: differential validity and concordance with the semi-structured interview.

The Assessment of DSM-IV Personality Disorders questionnaire (ADP-IV) is a self-report measure of the DSM-IV Axis II personality disorders (PDs). The ADP-IV assesses for each DSM-IV criterion its typicality as well as the accompanying distress and impairment. This study investigates two important aspects of the construct validity of the ADP-IV: (a) the differential validity (i.e., the ability to differentiate between a sample of the general Flemish population ( n = 659) and a sample of psychiatric inpatients ( n = 487) with a high prevalence of clinical PD diagnoses, and patients with and without a PD in the psychiatric sample; (b) the convergent validity with the SCID-II semi-structured interview in a population of psychiatric inpatients ( n = 59). The results indicate a good differential validity: the dimensional scales and the categorical measures discriminated well between both groups and between patients with and without a PD diagnosis in the psychiatric sample. Concerning the concordance with the SCID-II, a decent level of agreement is exemplified by a correlation of.67 between the dimensional total scores of both instruments and by kappa coefficients for an "any" Axis II diagnosis at the.50 level. In conclusion, the results indicate that the ADP-IV is an efficient method for assessing PD in dimensional and categorical ways.