Effect of Intermittent Theta Burst Stimulation on the Neural Processing of Emotional Stimuli in Healthy Volunteers.

BACKGROUND: Intermittent theta burst stimulation (iTBS) is a form of repetitive transcranial magnetic stimulation that has shown to be effective in treatment-resistant depression. Through studying the effect of iTBS on healthy subjects, we wished to attain a greater understanding of its impact on the brain. Our objective was to assess whether 10 iTBS sessions altered the neural processing of emotional stimuli, mood and brain anatomy in healthy subjects. METHODS: In this double-blind randomized sham-controlled study, 30 subjects received either active iTBS treatment (10 sessions, two sessions a day) or sham treatment over the left dorsolateral prefrontal cortex. Assessments of mood, structural magnetic resonance imaging (MRI) and functional MRI (fMRI) were performed before and after iTBS sessions. During the fMRI, three different categories of stimuli were presented: positive, negative and neutral photographs. RESULTS: This study showed that, during the presentation of negative stimuli (compared with neutral stimuli), 10 sessions of iTBS increased activity in the left anterior insula. However, iTBS did not induce any change in mood, regional gray matter volume or cortical thickness. CONCLUSIONS: iTBS modifies healthy subjects' brain activity in a key region that processes emotional stimuli. (AFSSAPS: ID-RCB 2010A01032-37).

Gender-Related Brain Activations during an Emotional Task: An fMRI Study.

BACKGROUND: Women have twice the rate of depression and anxiety disorders as men. Some studies suggest that this could be caused by women's greater sensitivity to negative emotions. Few brain imaging studies have compared the brain activity of men to women during a presentation of emotional stimuli. Our objective was to investigate brain activations in men and women during an emotional task. We hypothesized that the pattern of brain activations would differ by gender and valence of the stimuli. METHODS: We conducted a functional magnetic resonance imaging study in 30 healthy participants (15 men and 15 women). Positive, negative and neutral photographs were presented to the subjects. Participants subjectively rated the valence and intensity of the stimuli. RESULTS: No significant gender-by-category interaction effect was observed for the intensity or valence of the stimuli. We found that, during the presentation of negative photographs, there was a higher activity in women's right fusiform gyrus compared to men's. CONCLUSION: Given the involvement of the fusiform gyrus in anxiety disorders, this study yields promising findings in order to better understand women's vulnerability to anxiety disorders.

Unexpected Improvement of Hand Motor Function with a Left Temporoparietal Low-Frequency Repetitive Transcranial Magnetic Stimulation Regime Suppressing Auditory Hallucinations in a Brainstem Chronic Stroke Patient.

We here report paradoxical hand function recovery in a 61-year-old male tetra-paretic chronic patient following a stroke of the brainstem (with highly degraded right and abolished left-hand finger flexion/extension disabling him to manipulate objects) who experienced insidious auditory hallucinations (AHs) 4 years after such event. Symptomatic treatment for AHs was provided with periodical double sessions of low-frequency repetitive transcranial magnetic stimulation (rTMS) (daily 1 Hz, 2 × 1,200 pulses interleaved by 1 h interval) delivered to the left temporoparietal junction across two periods of 5 and 3 weeks, respectively. At the end of each stimulation period, AHs disappeared completely. Most surprisingly and totally unexpectedly, the patient experienced beneficial improvements of long-lasting impairments in his right-hand function. Detailed examination of onset and offset of rTMS stimulation regimes strongly suggests a temporal relation with the remission and re-appearance of AHs and also with a fragile but clinically meaningful improvements of right (but not left) hand function contingent to the accrual of stimulation sessions. On the basis of post-recovery magnetic resonance imaging structural and functional evidence, mechanistic hypotheses that could subtend such unexpected motor recovery are critically discussed.

Repetitive Transcranial Magnetic Stimulation to Supplementary Motor Area in Refractory Obsessive-Compulsive Disorder Treatment: a Sham-Controlled Trial.

BACKGROUND: Repetitive transcranial magnetic stimulation has been explored in patients with obsessive-compulsive disorder, but with negative or conflicting results. This randomized double-blind study was designed to assess the efficacy of 1-Hz repetitive transcranial magnetic stimulation over the presupplementary area. METHODS: Forty medication-resistant patients were assigned to 4 weeks of either active or sham repetitive transcranial magnetic stimulation targeting the presupplementary area with the help of a neuronavigation system. RESULTS: According to the Yale-Brown obsessive-compulsive scale, the baseline-week 4 evolution showed no significant differences between groups. Responder rates at week 4 were not different between groups (repetitive transcranial magnetic stimulation 10.5% vs sham 20%; P=.63). CONCLUSION: Low-frequency repetitive transcranial magnetic stimulation applied to the presupplementary area seems ineffective for the treatment of obsessive-compulsive disorder patients, at least in severe and drug-refractory cases such as those included in this study. Further research is required to determine profiles of responder patients and appropriate repetitive transcranial magnetic stimulation parameters for obsessive-compulsive disorder.

Effect of repetitive transcranial magnetic stimulation on mood in healthy subjects.

BACKGROUND: High frequency repetitive transcranial magnetic stimulation (rTMS) of the left dorsolateral prefrontal cortex (DLPFC) has shown significant efficiency in the treatment of resistant depression. However in healthy subjects, the effects of rTMS remain unclear. OBJECTIVE: Our aim was to determine the impact of 10 sessions of rTMS applied to the DLPFC on mood and emotion recognition in healthy subjects. DESIGN: In a randomised double-blind study, 20 subjects received 10 daily sessions of active (10 Hz frequency) or sham rTMS. The TMS coil was positioned on the left DLPFC through neuronavigation. Several dimensions of mood and emotion processing were assessed at baseline and after rTMS with clinical scales, visual analogue scales (VASs), and the Ekman 60 faces test. RESULTS: The 10 rTMS sessions targeting the DLPFC were well tolerated. No significant difference was found between the active group and the control group for clinical scales and the Ekman 60 faces test. Compared to the control group, the active rTMS group presented a significant improvement in their adaptation to daily life, which was assessed through VAS. CONCLUSION: This study did not show any deleterious effect on mood and emotion recognition of 10 sessions of rTMS applied on the DLPFC in healthy subjects. This study also suggested a positive effect of rTMS on quality of life.

Effect of two weeks of rTMS on brain activity in healthy subjects during an n-back task: a randomized double blind study.

BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) has shown significant efficiency in the treatment of several psychiatric disorders. In depressive disorders, the dorsolateral prefrontal cortex (DLPFC) is the main target for rTMS, but the effects of this stimulation on cognitive functions and their neural correlates are not well known. Previous works have established that the left DLPFC is reliably activated during the n-back working memory task. OBJECTIVE: The aim of this randomized double-blind study was to determine the impact of rTMS applied to the DLPFC on brain activity during an n-back task in healthy subjects. METHODS: After randomization, twenty subjects received either active treatment (10 sessions; 1 session a day; frequency = 10 Hz; intensity = 110% of motor threshold) or placebo treatment (sham coil). Subjects performed an n-back task during two functional magnetic resonance imaging sessions (one before stimulation, and one after 10 active or sham rTMS sessions). RESULTS: No significant changes, neither in mood nor in performance in the n-back task, were shown. A significant group-by-time interaction effect was found in the bilateral middle frontal gyrus and in the left caudate nucleus. CONCLUSIONS: These results show that rTMS applied on the left DLPFC had close and remote effects on brain areas involved in working memory.