Effects of repetitive transcranial magnetic stimulation (rTMS) on the physiological regulation of cortical excitability (original) (raw)
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Brazilian Journal of Psychiatry, 2019
Objective: The medial prefrontal cortex (mPFC) is a highly connected cortical region that acts as a hub in major large-scale brain networks. Its dysfunction is associated with a number of psychiatric disorders, such as schizophrenia, autism, depression, substance use disorder (SUD), obsessive-compulsive disorder (OCD), and anxiety disorders. Repetitive transcranial magnetic stimulation (rTMS) studies targeting the mPFC indicate that it may be a useful therapeutic resource in psychiatry due to its selective modulation of this area and connected regions. Methods: This review examines six mPFC rTMS trials selected from 697 initial search results. We discuss the main results, technical and methodological details, safety, tolerability, and localization strategies. Results: Six different protocols were identified, including inhibitory (1 Hz) and excitatory (5, 10, and 20 Hz) frequencies applied therapeutically to patient populations diagnosed with major depressive disorder, OCD, autistic spectrum disorder, SUD, specific phobia, and post-traumatic stress disorder (PTSD). In the OCD and acrophobia trials, rTMS significantly reduced symptoms compared to placebo. Conclusion: These protocols were considered safe and add interesting new evidence to the growing body of mPFC rTMS literature. However, the small number and low methodological quality of the studies indicate the need for further research.
Journal of psychiatry & neuroscience : JPN, 2009
Repetitive transcranial magnetic stimulation (rTMS) applied over the dorsolateral prefrontal cortex (DLPFC) is a new treatment procedure that holds promise of more insight into the pathophysiology of depression because the DLPFC may play an important role in the interplay between emotional and attentional information processing. We sought to investigate whether acute neurocognitive effects of rTMS are related to antidepressant outcomes. Between January 2005 and May 2007, we examined the effects of a single session compared with 2 weeks of rTMS over the left DLPFC on cognition and mood in therapy-resistant patients with depression. We used a crossover placebo-controlled double-blind design and differentiated rTMS treatment responders and nonresponders. We used a task-switching paradigm to measure cognitive function. After 2 weeks of high-frequency rTMS over the left DLPFC, depressive symptoms improved in more than half (53%) of our therapy-resistant population. After a single session...
Journal of psychiatric …, 2006
Transcranial magnetic stimulation has evolved into a powerful neuroscientific tool allowing to interfere transiently with specific brain functions. In addition, repetitive TMS (rTMS) has long-term effects (e.g. on mood), probably mediated by neurochemical alterations. While long-term safety of rTMS with regard to cognitive functioning is well established from trials exploring its therapeutic efficacy, little is known on whether rTMS can induce changes in cognitive functioning in a time window ranging from minutes to hours, a time in which neurochemical effects correlated with stimulation have been demonstrated. This study examined effects of rTMS on three measures of executive function in healthy subjects who received one single rTMS session (40 trains of 2 s duration 20 Hz stimuli) at the left dorsolateral prefrontal cortex (DLPFC). Compared to a sham condition one week apart, divided attention performance was significantly impaired about 30–60 min after rTMS, while Stroop-interference and performance in the Wisconsin Card Sorting Test was unaffected after rTMS. Repetitive TMS of the left DLPFC, at stimulation parameters used in therapeutic studies, does not lead to a clinically relevant impairment of executive function after stimulation. However, the significant effect on divided attention suggests that cognitive effects of rTMS are not limited to the of acute stimulation, and may possibly reflect known neurochemical alterations induced by rTMS. Sensitive cognitive measures may be useful to trace those short-term effects of rTMS non-invasively in humans.
NeuroReport, 2005
In a double-blind, controlled study, we examined the therapeutic effects of high-frequency left prefrontal repetitive transcranial magnetic stimulation (rTMS) on schizophrenia symptoms. A total of 22 chronic hospitalized schizophrenia patients were randomly assigned to 2 weeks (10 sessions) of real or sham rTMS. rTMS was given with the following parameters: 20 trains of 5-second 10-ELz stimulation at 100 percent motor threshold, 30 seconds apart Effects on positive and negative symptoms, self-reported symptoms, rough neuropsychological functioning, and hormones were assessed. Although there was a significant improvement in both groups in most of the symptom measures, no real differences were found between the groups. A decrease of more than 20 percent in the total PANSS score was found in 7 control subjects but only 1 subject from the real rTMS group. There was no change in hormone levels or neuropsychological functioning, measured by the MMSE, in either group. Left prefrontal rTMS (with the used parameters) seems to produce a significant nonspecific effect of the treatment procedure but no therapeutic effect in the most chronic and severely ill schizophrenia patients.
Psychiatry and clinical psychopharmacology, 2018
OBJECTIVES: The aim of the present study was to examine the impact of 25 Hz high-frequency repetitive transcranial magnetic stimulation (rTMS) on neuropsychological testing in treatmentresistant depression patients who were receiving no other concomitant medications for the treatment. METHODS: A total of 19 patients with treatment-resistant depression and 20 healthy controls were included in the study. A 25 Hz, 1000 pulse stimulation was set at 100% of the motor threshold and delivered 20 times for 2 s with 30 s intervals as 20 sessions to the depression group, and sham treatment was applied to the control group. Brief Psychiatric Rating Scale (BPRS), Stroop task, trail-making test (TMT), and Wisconsin card sorting test (WCST) were performed both before and 3 days after the rTMS treatment. Seventeen-item Hamilton Depression Rating Scale (HAMD) and Beck Depression Inventory (BDI) were obtained at baseline and after the rTMS treatment, as well. RESULTS: After the rTMS treatment, 52.6% (10 of 19 patients) met the response criteria (>50% improvement in HAMD score), with 5 (26.3%) patients meeting the criteria for remission of depression (HAMD score ≤ 8). None of the patients had a worsened HAMD score at the end of treatment. Reflecting the antidepressant effect of rTMS treatment, the mean BDI score, BPRS score, and Stroop task scores significantly differed following the treatment (p < .001, p < .001, and p = .017, respectively). TMT score difference did not reach statistical significance, whereas WCST scores showed significance in "correct responses" and "perseverative errors" categories (p < .05, and p < .05, respectively). None of the test scores at the end of rTMS treatment showed a significant difference when compared to baseline scores for the control group (p > .05, for all). CONCLUSIONS: Results suggest that rTMS can be used as a beneficial treatment option to ameliorate cognitive functions, especially executive functions. Patients had an improvement in depressive symptoms with the rTMS treatment without any concomitant medication, as well. Therefore, improvement in cognitive performance might be associated with improvement in depressive symptoms.
Left Prefrontal Repetitive Transcranial Magnetic Stimulation in Schizophrenia
Schizophrenia Bulletin, 2004
In a double-blind, controlled study, we examined the therapeutic effects of high-frequency left prefrontal repetitive transcranial magnetic stimulation (rTMS) on schizophrenia symptoms. A total of 22 chronic hospitalized schizophrenia patients were randomly assigned to 2 weeks (10 sessions) of real or sham rTMS. rTMS was given with the following parameters: 20 trains of 5-second 10-ELz stimulation at 100 percent motor threshold, 30 seconds apart Effects on positive and negative symptoms, self-reported symptoms, rough neuropsychological functioning, and hormones were assessed. Although there was a significant improvement in both groups in most of the symptom measures, no real differences were found between the groups. A decrease of more than 20 percent in the total PANSS score was found in 7 control subjects but only 1 subject from the real rTMS group. There was no change in hormone levels or neuropsychological functioning, measured by the MMSE, in either group. Left prefrontal rTMS (with the used parameters) seems to produce a significant nonspecific effect of the treatment procedure but no therapeutic effect in the most chronic and severely ill schizophrenia patients.
Frontiers in Psychiatry, 2016
Introduction: Bipolar patients have abnormalities in cognitive functions and emotional processing. Two resting state networks (RSNs), the default mode network (DMN) and the sensorimotor network (SMN), play a decisive role in these two functions. Dorsolateral prefrontal cortex (DLPFC) is one of the main areas in the central executive network (CEN), which is linked to the activities of each of the two networks. Studies have found DLPFC abnormalities in both hemispheres of patients with bipolar depression. We hypothesized that the bilateral repetitive transcranial magnetic stimulation (rTMS) of DLPFC would produce changes in the activity of both the SMN and DMN as well as relevant cognitive function in patients with bipolar depression that responded to treatment. Methods: 20 patients with bipolar depression underwent 10 sessions of 1 Hz rTMS on right DLPFC with subsequent 10 Hz rTMS on left DLPFC. Changes in electroencephalography resting networks between pre and post rTMS were evaluated utilizing low-resolution electromagnetic tomography (eLORETA). Depression symptom was assessed using the Beck Depression Inventory (BDI-II) and cognitive function was assessed by Verbal Fluency Test (VFT), Rey Auditory Verbal Learning Test (RAVLT), Stroop Test, and Wisconsin Card Sorting Test (WCST). Results: Responders to rTMS showed significantly lower DMN activity at baseline and a significant decrease in SMN connectivity after treatment. Non-responders did not significantly differ from the control group at the baseline and they showed higher activity in the SMN, visual network, and visual perception network compared to control group following treatment. Bilateral rTMS resulted in significant changes in the executive functions, verbal memory, and depression symptoms. No significant changes were observed in selective attention and verbal fluency.
Schizophrenia Research: Cognition, 2020
Highlights • Despite their major effects on positive symptoms, antipsychotics do not have a significant effect on cognition in schizophrenia• Bilateral high frequency rTMS targeting dorsolateral prefrontal cortices has been effective on working memory• Bilateral 20 Hz rTMS improved attention and verbal working memory in schizophrenia patients,• It also improved the competence of switching the perceptional set up under a disruptive effect towards new instructions, in this study
Current Drug Abuse Reviewse, 2008
Recent studies support an association between substance use disorders (SUDs) and cortical excitability. Transcranial magnetic stimulation (TMS) is a non-invasive tool that can be used to assess cortical physiological processes (e.g., inhibition, excitation) and has proven to be a useful diagnostic tool in brain disorders associated with alterations in cortical excitability. In this manuscript, we review studies that employ TMS to evaluate cortical excitability in patients with SUDs. Furthermore, we discuss preliminary studies that examine repetitive TMS (rTMS) as a potential treatment for patients with SUDs. Although the use of TMS to evaluate and to treat those individuals with SUDs is in its early stages, these studies reveal significant alterations in both cortical inhibition and excitation. Specifically, elevated cortical inhibition was reported in both cocaine and nicotine dependent individuals, while one study demonstrated an increase in cortical excitability in those who use 3, 4-methylenedioxymethamphetamine (MDMA). Furthermore, three studies examining rTMS as a potential treatment in cocaine and nicotine addiction report decreases in the level of cravings and in the number of cigarettes smoked following rTMS administration to the dorsal lateral prefrontal cortex. Thus, TMS has provided early interesting findings vis à vis cortical excitability in SUDs. Moreover, preliminary evidence suggests that rTMS is efficacious in the treatment of cocaine and nicotine addiction. Further work is needed to enhance our understanding of the altered neurophysiology in SUDs as well as the ways in which rTMS treatment can be directed to optimize treatment.
Addiction, 2000
Transcranial magnetic stimulation (TMS) is a relatively noninvasive technique to interfere with the function of small cortical areas through currents induced by alternating magnetic fields emanating from a handheld coil placed directly above the targeted area. This technique has clear effects on a whole range of measures of brain function and has become an important research tool in neuropsychiatry. More recently, TMS has been studied in psychiatry mainly to assess its putative therapeutic effects in treatment refractory major depression.