Impairment of executive performance after transcranial magnetic modulation of the left dorsal frontal‐striatal circuit

The dorsal frontal‐striatal circuit is implicated in executive functions, such as planning. The Tower of London task, a planning task, in combination with off‐line low‐frequency repetitive transcranial magnetic stimulation (rTMS), was used to investigate whether interfering with dorsolateral prefrontal function would modulate executive performance, mimicking dorsal frontal‐striatal dysfunction as found in neuropsychiatric disorders. Eleven healthy controls (seven females; mean age 25.5 years) were entered in a cross‐over design: two single‐session treatments of low‐frequency (1 Hz) rTMS (vs. sham rTMS) for 20 min on the left dorsolateral prefrontal cortex (DLPFC). Directly following the off‐line rTMS treatment, the Tower of London task was performed during MRI measurements. The low‐frequency rTMS treatment impaired performance, but only when the subjects had not performed the task before: we found a TMS condition‐by‐order effect, such that real TMS treatment in the first session led to significantly more errors (P = 0.032), whereas this TMS effect was not present in subjects who received real TMS in the second session. At the neural level, rTMS resulted in decreased activation during the rTMS versus sham condition in prefrontal brain regions (i.e., premotor, dorsolateral prefrontal and anterior prefrontal cortices) and visuospatial brain regions (i.e., precuneus/cuneus and inferior parietal cortex). The results show that low‐frequency off‐line rTMS on the DLPFC resulted in decreased task‐related activations in the frontal and visuospatial regions during the performance of the Tower of London task, with a behavioral effect only when task experience is limited. Hum Brain Mapp, 2013. © 2011 Wiley Periodicals, Inc.     

Fast Left Prefrontal rTMS Reduces Post-Gastric Bypass Surgery Pain: Findings From a Large-Scale,Double-Blind,Sham-Controlled Clinical Trial

BackgroundA single session of left prefrontal rTMS has been shown to have analgesic effects, and to reduce post-operative morphine use. We sought to test these findings in a larger sample, and try and see if multiple sessions had additive analgesic benefit.Methods108 patients undergoing laparoscopic gastric bypass surgery received two sessions of 10 Hz rTMS (110% of motor threshold) over the left dorsolateral prefrontal cortex (one immediately following surgery and one 4 h later). Participants were randomly assigned to receive 2 sessions of real rTMS, 2 sessions of sham, 1 real then 1 sham, or 1 sham then 1 real rTMS treatments. Patients and study staff were blind to rTMS conditions.ResultsUnlike previous rTMS trials for post-operative pain, no differences emerged between groups with respect to total patient-controlled analgesia usage (IV hydromorphone). However, despite no difference in IV analgesic usage, subjects that received 2 real rTMS sessions rated both the affective and sensory dimensions of their pain significantly lower than those in the sham–sham group at several time points during the post-surgical/post-rTMS period.ConclusionsThis study suggests that left prefrontal rTMS may produce significant analgesic effects in the perioperative setting. However, further work is needed to understand this effect and attempt to make it clinically useful in light of the lack of effect on PCA hydromorphone use.     

Right prefrontal repetitive transcranial magnetic stimulation in obsessive-compulsive disorder: a double-blind, placebo-controlled study.

OBJECTIVE: The efficacy of repetitive transcranial magnetic stimulation (rTMS) of the right prefrontal cortex for patients with obsessive-compulsive disorder (OCD) was studied under double-blind, placebo-controlled conditions. METHOD: Patients were randomly assigned to 18 sessions of real (N=10) or sham (N=8) rTMS. Treatments lasted 20 minutes, and the frequency was 1 Hz for both conditions, but the intensity was 110% of motor threshold for real rTMS and 20% for the sham condition. RESULTS: No significant changes in OCD were detected in either group after treatment. Two patients who received real rTMS, with checking compulsions, and one receiving sham treatment, with sexual/religious obsessions, were considered responders. CONCLUSIONS: Low-frequency rTMS of the right prefrontal cortex failed to produce significant improvement of OCD and was not significantly different from sham treatment. Further studies are indicated to assess the efficacy of rTMS in OCD and to clarify the optimal stimulation characteristics.     

Blinding success of rTMS applied to the dorsolateral prefrontal cortex in randomised sham-controlled trials: A systematic review

Abstract

Objectives. The lack of a suitable sham condition for repetitive transcranial magnetic stimulation (rTMS) research may compromise the success of blinding procedures. The aim of this systematic review was to examine the reporting of blinding success in randomised sham-controlled trials (RCTs) of rTMS applied to the dorsolateral prefrontal cortex. Methods. A literature search using Pubmed and Web of Science was conducted to identify RCTs of rTMS. Regression analyses were used to investigate whether participants in the real and sham rTMS groups differed in (1) their ability to correctly guess to which intervention they had been randomised, and (2) how likely they were to think they had received real rTMS. Results. Thirteen out of 96 (13.5%) RCTs reported blinding success. Available data from 9/13 studies showed that participants in real and sham rTMS groups were not significantly different in their ability to correctly guess their intervention allocation, but with a trend for participants in the real group to more often guess correctly. However, people in the real rTMS groups were significantly more likely to think they had received real rTMS compared with those in sham rTMS groups. Conclusions. Few RCTs in rTMS report on blinding success. As current sham methods may inadequately mimic real rTMS, this could result in only partial success of blinding and bias estimations of treatment effects.     

重复经颅磁刺激治疗精神分裂症阴性症状的随机双盲研究

目的探讨重复经颅磁刺激（rTMS）治疗精神分裂症阴性症状的疗效。方法 30例精神分裂症患者被随机分为rTMS真刺激组（治疗组,15例）和rTMS伪刺激组（对照组,15例）,采用θ短阵快速脉冲刺激（TBS）模式刺激左侧前额叶背外侧皮质（DLPFC）,每周5次,共干预20次。于基线、治疗2周及治疗4周时应用阳性与阴性症状量表（PANSS）的阴性因子分和阴性症状量表（SANS）进行疗效评定。结果共有27例患者完成研究,对照组有3例脱落。经rTMS干预4周后,治疗组与对照组的PANSS阴性因子分减分值分别为（4.67±2.47）分和（2.33±1.87）分,两组比较有统计学差异（z=-2.41,P=0.016）;SANS总分减分值分别为（11.87±8.04）分和（5.92±6.47）分,两组比较有统计学差异（z=2.08,P=0.038）。根据PANSS阴性因子分评定,治疗组的有效率达到46.7%,对照组的有效率为16.7%;根据SANS总分评定治疗组的有效率达到46.7%,而对照组的有效率为8.3%;阴性症状的组间疗效差异有统计学意义（P〈0.05）。除了轻微的一过性头痛和入睡困难,未见有其他严重不良反应。结论 TBS模式可改善精神分裂症患者的阴性症状。     

Improving the antidepressant efficacy of transcranial magnetic stimulation: maximizing the number of stimulations and treatment location in treatment-resistant depression

Objective: To assess the efficacy of increasing the number of fast left repetitive transcranial magnetic stimulations (rTMS) (10 Hz @ 120% of motor threshold (MT) over the left dorsolateral prefrontal cortex (DLPFC)) needed to achieve remission in treatment‐resistant depression (TRD). And, to determine if patients who do not remit to fast left will remit using slow right rTMS (1 Hz @ 120% MT over the right DLPFC). Method: Patients were part of a multicenter sham‐controlled trial investigating the efficacy of fast left rTMS. Patients who failed to meet minimal response criteria in the sham‐controlled study could enroll in this open fast left rTMS study for an additional 3–6 weeks. Patients who failed to remit to fast left could switch to slow right rTMS for up to 4 additional weeks. The final outcome measure was remission, defined as a HAM‐D score of <3 or 2 consecutive HAM‐D scores less than 10. Results: Forty‐three of 141 (30.5%) patients who enrolled in the open phase study eventually met criteria for remission. Patients who remitted during fast left treatment received a mean of 26 active treatments (90,000 pulses). Twenty‐six percent of patients who failed fast left remitted during slow right treatment. Conclusion: The total number of rTMS stimulations needed to achieve remission in TRD may be higher than is used in most studies. TRD patients who do not respond to fast left rTMS may remit to slow right rTMS or additional rTMS stimulations. Depression and Anxiety, 2011. © 2011 Wiley Periodicals, Inc.     

A randomized, controlled trial of sequential bilateral repetitive transcranial magnetic stimulation for treatment-resistant depression

OBJECTIVE: High-frequency left-side repetitive transcranial magnetic stimulation (rTMS) and low-frequency stimulation to the right prefrontal cortex have both been shown to have antidepressant effects, but doubts remain about the magnitude of previously demonstrated treatment effects. The authors evaluated sequentially combined high-frequency left-side rTMS and low-frequency rTMS to the right prefrontal cortex for treatment-resistant depression. METHOD: The authors conducted a 6-week double-blind, randomized, sham-controlled trial in 50 patients with treatment-resistant depression. Three trains of low-frequency rTMS to the right prefrontal cortex of 140 seconds' duration at 1 Hz were applied daily, followed immediately by 15 trains of 5 seconds' duration of high-frequency left-side rTMS at 10 Hz. Sham stimulation was applied with the coil angled at 45 degrees from the scalp, resting on the side of one wing of the coil. The primary outcome variable was the score on the Montgomery-Asberg Depression Rating Scale. RESULTS: There was a significantly greater response to active than sham stimulation at 2 weeks and across the full duration of the study. A significant proportion of the study group receiving active treatment met response (11 of 25 [44%]) or remission (nine of 25 [36%]) criteria by study end compared to the sham stimulation group (two of 25 [8%] and none of 25 respectively). CONCLUSIONS: Sequentially applying both high-frequency left-side rTMS and low-frequency rTMS to the right prefrontal cortex, has substantial treatment efficacy in patients with treatment-resistant major depression. The treatment response accumulates to a clinically meaningful level over 4 to 6 weeks of active treatment.     

低频重复经颅磁刺激对难治性精神分裂症的增效作用

目的评价低频重复经颅磁刺激(r TMS)对难治性精神分裂症的疗效和认知功能的影响及其安全性。方法将52例幻听症状突出的难治性精神分裂症患者随机分为真刺激组和伪刺激组,刺激频率为1Hz,部位为背外侧前额叶皮质。在基线期、2周(治疗10次)、6周(治疗20次)和治疗结束后1个月采用阳性和阴性症状量表(PANSS)、幻听量表(AHRS)、临床总体印象量表(CGIS)评价精神症状,采用可反复测查的成套神经心理状态评估工具(RBANS)评价认知功能,采用副反应量表(TESS)评定不良反应。结果 r TMS治疗10次、20次及随访1个月时,真刺激组和伪刺激组相比,PANSS幻觉、CGI评分、AHRS频率及RBANS总评分比较差异均有统计学意义(P0.05或0.01);r TMS治疗20次及随访1个月时,AHRS总评分、影响、痛苦、RBANS视觉广度、言语功能及注意力评分差异有统计学意义(P0.05或0.01);随访1个月时,PANSS阳性症状、一般病理症状评分、RBANS即刻记忆评分差异有统计学意义(P0.05或0.01)。r TMS治疗后未发现明显不良反应。结论低频r TMS可改善精神分裂症的幻听、阳性症状和认知功能且安全性好。     

Induction and quantification of prefrontal cortical network plasticity using 5 Hz rTMS and fMRI

Neuronal plasticity is crucial for flexible interaction with a changing environment and its disruption is thought to contribute to psychiatric diseases like schizophrenia. High‐frequency repetitive transcranial magnetic stimulation (rTMS) is a noninvasive tool to increase local excitability of neurons and induce short‐time functional reorganization of cortical networks. While this has been shown for the motor system, little is known about the short‐term plasticity of networks for executive cognition in humans. We examined 12 healthy control subjects in a crossover study with fMRI after real and sham 5 Hz rTMS to the right dorsolateral prefrontal cortex (DLPFC). During scanning, subjects performed an n‐back working memory (WM) task and a flanker task engaging cognitive control. Reaction times during the n‐back task were significantly shorter after rTMS than after sham stimulation. RTMS compared with sham stimulation caused no activation changes at the stimulation site (right DLPFC) itself, but significantly increased connectivity within the WM network during n‐back and reduced activation in the anterior cingulate cortex during the flanker task. Reduced reaction times after real stimulation support an excitatory effect of high‐frequency rTMS. Our findings identified plastic changes in prefrontally connected networks downstream of the stimulation site as the substrate of this behavioral effect. Using a multimodal fMRI‐rTMS approach, we could demonstrate changes in cortical plasticity in humans during executive cognition. In further studies this approach could be used to study pharmacological, genetic and disease‐related alterations. Hum Brain Mapp 35:140–151, 2014. © 2012 Wiley Periodicals, Inc.     

Effect of repetitive transcranial magnetic stimulation on the cognitive impairment induced by sleep deprivation: a randomized trial

ObjectiveCurrently, an efficient method for improving cognitive impairment due to sleep deprivation (SD) is lacking. The aim of this study is to evaluate the effect of high-frequency repetitive transcranial magnetic stimulation (rTMS) during SD on reversing the adverse effects of SD.MethodsA total of 66 healthy people were randomized into the rTMS group and sham group. Both groups were deprived of sleep for 24 h. During SD, participants were asked to complete several cognitive tasks and underwent mood assessments. Saliva cortisol levels, plasma concentrations of brain-derived neurotrophic factor (BDNF), precursor BDNF (proBDNF), and tissue-type plasminogen activator (tPA), and frontal blood activation were detected before and after SD. The rTMS group received real rTMS stimulation for 2 sessions of 10 Hz rTMS (40 trains of 50 pulses with a 20-second intertrain interval) to the left dorsolateral prefrontal cortex and the sham group received sham stimulation during SD.ResultsTwenty-four hours of SD induced a reduced accuracy in the n-back task, increases in both anxiety and depression, increased cortisol levels, decreased frontal blood activation and decreased BDNF levels in healthy people. Notably, rTMS improved the hyperactivity of the hypothalamic-pituitary-adrenal axis and decreased frontal blood activation induced by SD, and reduced the consumption of plasma proBDNF.ConclusionsTwenty-four hours of SD induced a cognitive impairment. The administration of high-frequency rTMS during sleep deprivation exerted positive effects on HPA axis and frontal activation and might help alleviate cognitive impairment in the long term.     

An open-label study of adjunctive repetitive transcranial magnetic stimulation (rTMS) for partial remission in major depressive disorder

Abstract

Objective. This study aimed to evaluate the effect of adjunctive treatment with rTMS in patients with partial remission major depressive disorder. Method. Subjects were patients meeting DSM-IV-TR criteria for non-psychotic major depressive disorder who responded to 8 weeks of medication treatment but still had residual symptoms (HAM-D score between 7 and 18). All patients were assigned to receive 10 daily sessions (total of 12,500 magnetic pulses) of rTMS applied at the left dorsolateral prefrontal cortex as adjunctive treatment. The antidepressant effect was measured repeatedly at 6 days, and at 4 and 8 weeks after treatment with the Thai version of HAM-D scale as a primary outcome scale. Results. Seven of nine patients (78%) reached the stage of remission (HAM-D < 8) after being treated with adjunctive rTMS. There was a statistically significant difference in decreasing of the HAM-D score during the treatment, χ² (df 3) = 17.929, P < 0.001. There was no severe adverse event. One patient had vertigo after the first session of treatment and one patient had a scalp contraction feeling during treatment but full recovered in half an hour with no medical intervention. Conclusion. For patients with a major depressive disorder in partial remission, high frequency rTMS may provide benefits in adjunctive treatment which are tolerated well. However, the long term effects should be observed.     

The effect of one left-sided dorsolateral prefrontal sham-controlled HF-rTMS session on approach and withdrawal related emotional neuronal processes

Objective

Although repetitive Transcranial Magnetic Stimulation (rTMS) is frequently used to examine emotional changes in healthy volunteers, it remains largely unknown how rTMS is able to influence emotion.

Methods

In this sham-controlled, single-blind crossover study using fMRI, we examined in 20 right-handed healthy females whether a single high frequency (HF)-rTMS session applied to the left dorsolateral prefrontal cortex could influence emotional processing while focussing on blocks of positively and negatively valenced baby faces.

Results

While positive information was being processed, we observed after one active HF-rTMS session enhanced neuronal activity in the left superior frontal cortex and right inferior parietal cortex. After sham HF-rTMS, we found significant decreases in neuronal activity in the left superior frontal cortex, the left inferior prefrontal cortex, as well as in the right posterior cingulate gyrus. When negative information was processed, one active stimulation attenuated neuronal activity in the right insula only.

Conclusions

Our findings suggest that during the processing of positive information one active session enhanced the ability to empathize with the depicted emotional stimuli, while during the processing of negative information it resulted in decreased psychophysiological reactions.

Significance

These results provide new information on the working mechanism of left-sided HF-rTMS.     

The effects of repetitive transcranial magnetic stimulation on depressive symptoms and the P300 event-related potential

Changes in the Hamilton Depression Rating Scale and the P₃₀₀ auditory event-related potential were assessed in 10 patients with depression before and after a treatment course of five daily sessions of 10?Hz repetitive transcranial magnetic stimulation (rTMS) over the left prefrontal cortex. The patients were initially randomly allocated either to an active or a placebo rTMS treatment. All patients received both types of treatment separated by an interval of 4?weeks. The median Hamilton score decreased by 7 points following active rTMS and by 1?point after sham (p=0.075). Active rTMS was associated with a significant increase in the P₃₀₀ amplitude compared with sham (p=0.02). There was no correlation between changes in P₃₀₀ measurements and the Hamilton scores after active treatment. We conclude that five daily sessions of left prefrontal rTMS treatment is not of sufficient duration to make a significant improvement in depressive symptoms.     

Treatment of negative symptoms of schizophrenia using repetitive transcranial magnetic stimulation in a double-blind, randomized controlled study

OBJECTIVE: To verify whether high-frequency rTMS applied above the area of the left prefrontal cortex in 15 stimulation sessions with maximum stimulation intensity is able to modify negative symptoms of schizophrenia in a double-blind, randomized controlled study. METHODS: Twenty-two patients with schizophrenia stabilized on antipsychotic medication with prominent negative symptoms were included in the trial. They were divided into two groups: eleven were treated with effective rTMS and eleven with ineffective "sham" rTMS. The ineffectiveness of the sham rTMS was achieved through the stimulation coil position. Stimulation was applied to the left dorsolateral prefrontal cortex. The stimulation frequency was 10 Hz. Stimulation intensity was 110% of the motor threshold intensity. Each patient received 15 rTMS sessions on 15 consecutive working days. Each daily session consisted of 15 applications of 10-second duration and 30-second intervals between sequences. There were 1500 stimuli per session. RESULTS: During real rTMS treatment a statistically significant decrease of negative symptoms was found (approximately 29% reduction in the PANSS negative symptom subscale and 50% reduction in the SANS). No adverse events occurred during therapy except for a mild headaches. In sham rTMS treatment a decrease of negative symptoms was also identified, but to a lesser extent than in real rTMS (about 7% in negative subscale PANSS and 13% in SANS). The change in SANS achieved statistical significance. Mutual comparison revealed a greater decrease of negative symptoms in favor of real rTMS in contrast to sham rTMS. CONCLUSION: The augmentation of rTMS enabled patients to experience a significant decrease in the severity of the negative symptoms. Our results support the therapeutic potential of rTMS at higher frequency for negative symptoms of schizophrenia.     

The Painfulness of Active,but not Sham,Transcranial Magnetic Stimulation Decreases Rapidly Over Time: Results From the Double-Blind Phase of the OPT-TMS Trial

BackgroundDaily left prefrontal repetitive transcranial magnetic stimulation (rTMS) over several weeks is an FDA approved treatment for major depression. Although rTMS is generally safe when administered using the FDA guidelines, there are a number of side effects that can make it difficult for patients to complete a course of rTMS. Many patients report that rTMS is painful, although patients appear to accommodate to the initial painfulness. The reduction in pain is hypothesized to be due to prefrontal stimulation and is not solely explained by accommodation to the stimulation.MethodsIn a recent 4 site randomized controlled trial (using an active electrical sham stimulation system) investigating the antidepressant effects of daily left dorsolateral prefrontal rTMS (Optimization of TMS, or OPT-TMS), the procedural painfulness of TMS was assessed before and after each treatment session. Computerized visual analog scale ratings were gathered before and after each TMS session in the OPT-TMS trial. Stimulation was delivered with an iron core figure-8 coil (Neuronetics) with the following parameters: 10 Hz, 120% MT (EMG-defined), 4 s pulse train, 26 s inter-train interval, 3000 pulses per session, one 37.5 min session per day. After each session, procedural pain (pain at the beginning of the TMS session, pain toward the middle, and pain toward then end of the session) ratings were collected at all 4 sites. From the 199 patients randomized, we had usable data from 142 subjects for the initial 15 TMS sessions (double-blind phase) delivered over 3 weeks (142 × 2 × 15 = 4260 rating sessions).ResultsThe painfulness of real TMS was initially higher than that of the active sham condition. Over the 15 treatment sessions, subjective reports of the painfulness of rTMS (during the beginning, middle and end of the session) decreased significantly 37% from baseline in those receiving active TMS, with no change in painfulness in those receiving sham. This reduction, although greatest in the first few days, continued steadily over the 3 weeks. Overall, there was a decay rate of 1.56 VAS points per session in subjective painfulness of the procedure in those receiving active TMS.DiscussionThe procedural pain of left, prefrontal rTMS decreases over time, independently of other emotional changes, and only in those receiving active TMS. These data suggest that actual TMS stimulation of prefrontal cortex maybe related to the reduction in pain, and that it is not a non-specific accommodation to pain. This painfulness reduction softly corresponds with later clinical outcome. Further work is needed to better understand this phenomenon and whether acute within-session or over time painfulness changes might be used as short-term biomarkers of antidepressant response.     

Repetitive transcranial magnetic stimulation of the right dorsolateral prefrontal cortex in posttraumatic stress disorder: a double-blind, placebo-controlled study

OBJECTIVE: The efficacy of repetitive transcranial magnetic stimulation (rTMS) of the right prefrontal cortex was studied in patients with posttraumatic stress disorder (PTSD) under double-blind, placebo-controlled conditions. METHOD: Twenty-four patients with PTSD were randomly assigned to receive rTMS at low frequency (1 Hz) or high frequency (10 Hz) or sham rTMS in a double-blind design. Treatment was administered in 10 daily sessions over 2 weeks. Severity of PTSD, depression, and anxiety were blindly assessed before, during, and after completion of the treatment protocol. RESULTS: The 10 daily treatments of 10-Hz rTMS at 80% motor threshold over the right dorsolateral prefrontal cortex had therapeutic effects on PTSD patients. PTSD core symptoms (reexperiencing, avoidance) markedly improved with this treatment. Moreover, high-frequency rTMS over the right dorsolateral prefrontal cortex alleviated anxiety symptoms in PTSD patients. CONCLUSIONS: This double-blind, controlled trial suggests that in PTSD patients, 10 daily sessions of right dorsolateral prefrontal rTMS at a frequency of 10 Hz have greater therapeutic effects than slow-frequency or sham stimulation.     

Transcranial magnetic stimulation accelerates the antidepressant effect of amitriptyline in severe depression: a double-blind placebo-controlled study.

BACKGROUND: Transcranial magnetic stimulation (TMS) is a noninvasive method to stimulate the cortex, and the treatment of depression is one of its potential therapeutic applications. Three recent meta analyses strongly suggest its benefits in the treatment of depression. The present study investigates whether repetitive TMS (rTMS) accelerates the onset of action and increases the therapeutic effects of amitriptyline. METHODS: Forty-six outpatients meeting DSM-IV criteria for nonpsychotic depressive episode were randomly assigned to receive rTMS (n = 22) or sham repetitive TMS (sham) (n = 24) during 4 weeks over dorsolateral prefrontal cortex (DLPFC) in this double-blind controlled trial. All patients were concomitantly taking amitriptyline (mean dose 110 mg/d). The rTMS group received 20 sessions (5 sections per week) of 5 Hz rTMS (120% of motor threshold and 1250 pulses per session). Sham stimulation followed the same schedule, however, using a sham coil. The efficacy variables were the Hamilton Depression Rating Scale-17 items (HAM-D/17), the Montgomery-Asberg Depression Rating Scale (MADRS), a Visual Analogue Scale (VAS), and the Clinical Global Impression (CGI). Tolerability was assessed by clinical examination and a safety screening of TMS side effects. RESULTS: Repetitive TMS had a significantly faster response to amitriptyline. There was a significant decrease in HAM-D/17 scores, already after the first week of treatment (p < .001 compared with baseline and p < .001 compared with sham). The decrease in HAM-D/17 scores in the rTMS group was significantly superior compared with the sham group throughout the study (p < .001 at fourth week). CONCLUSIONS: Repetitive TMS at 5 Hz accelerated the onset of action and augmented the response to amitriptyline.     

The right VLPFC and downregulation of social pain: A TMS study

Previous studies have demonstrated that the right ventrolateral prefrontal cortex (RVLPFC) is crucially involved in downregulating physical and social pain. However, it remains unclear whether the RVLPFC is more specific to either physical or social pain. The present study compares the role of RVLPFC in emotion regulation in physical‐ and social‐pain conditions using repetitive transcranial magnetic stimulation (rTMS). A total of 60 healthy participants underwent active (n = 30) or sham (n = 30) rTMS over the RVLPFC. Following each TMS session, participants performed a non‐reappraisal and then a reappraisal task to downregulate imagined physical or social pain evoked by pictures. Self‐reported negative emotional ratings and electroencephalogram data were recorded during the emotion regulation task. Participants were then required to rate the valence and arousal of those pictures 30 min after the task. It is found that rTMS‐activated RVLPFC led to reductions in subjective negative feelings and amplitudes of the late positive potential during reappraisal; however, these effects were found exclusively in the social‐pain condition. Participants also reported higher positive valence for socially, compared to physically, painful pictures after 30 min of the task. Behavioral and electrophysiological evidence both supported the functional specificity of RVLPFC in regulation of social pain. The prominent delayed effect of rTMS makes it possible to consider the potential application of rTMS‐VLPFC in clinical practice for social pain relief.     

Antidepressant efficacy of two different rTMS procedures

Background: This placebo-controlled study was designed to investigate the influence of two diffe-rent stimulation procedures of repetitive transcranial magnetic stimulation (rTMS) on depressive symptoms in patients with depressive disorders. Furthermore, effects on cognitive functions and psychomotor functioning were tested. Methods: Thirty patients with depression (22 females and 8 males; mean age of 56.4 years) were included. They were treated with a stable dosage of antidepressant medication. They received either high frequency rTMS (20 Hz) over the left dorsolateral prefrontal cortex (LDLPFC), low frequency rTMS (1 Hz) over the right dorsolateral prefrontal cortex (RDLPFC) or sham stimulations (10 patients in each group) as add on treatment at 10 days within 2 weeks. Depressive symptoms were registered by means of observer ratings (Hamilton Depression Rating Scale – HDRS) and self reports (Beck Depression Inventory – BDI). Psychomotor retardation was investigated by the Motor Agitation and Retardation Scale and cognitive function by d2 test. Results and conclusions: Differences between the rTMS procedures regarding depressive symptoms could not be found. Motor abnormalities, however, significantly improved exclusively after real stimulation procedures. Patients with less severe deficits in psychomotor speed and concentration responded more intensively than patients with severe deficits. Received: 10 October 2002 / Accepted: 18 March 2003 Correspondence to Dr. J. H?ppner