Burst TMS Research Articles

Parietal theta burst TMS does not modulate bistable perception.

The role of the parietal cortex in perceptual awareness and in resolving perceptual ambiguity is unsettled. Early influential transcranial magnetic stimulation studies have revealed differences in conscious perception following parietal stimulation, fuelling the notion that parietal cortex causally contributes to resolving perceptual ambiguity. However, central to this conclusion is the reliability of the method employed. Several prior studies have revealed opposing effects, such as shortening, lengthening, or no effect on multistable perceptual transitions following parietal stimulation. Here we addressed the reliability of continuous theta-burst stimulation (cTBS) on parietal cortex on the perception of bistable stimuli. We conducted three cTBS experiments that were matched to prior experiments in terms of stimuli, stimulation protocol, and target site, and used a higher number of participants. None of our cTBS experiments replicated prior cTBS results. The only experiment using individual functional localizers led to weak effects, while the two others led to null results. Individual variability of motor cortex cTBS did not predict parietal cTBS effects. In view of recent reports of highly variable cTBS effects over motor cortex, our results suggest that cTBS is particularly unreliable in modulating bistable perception when applied over parietal cortex.

Neuronavigated 20hz theta burst TMS for OCD comorbid with depression and anxiety sequentially targeting RDLPFC, LDLPFC, and ROFC

Neuronavigated 20hz theta burst TMS for OCD comorbid with depression and anxiety sequentially targeting RDLPFC, LDLPFC, and ROFC

Neuronavigated 20hz theta burst TMS of the right orbitofrontal cortex in the treatment of obsessive compulsive disorder

Neuronavigated 20hz theta burst TMS of the right orbitofrontal cortex in the treatment of obsessive compulsive disorder

Targeting Presupplementary Motor Area in OCD With tDCS and Continuous Theta Burst TMS

The pre-supplementary motor area (pSMA) is linked to structures implicated in obsessive-compulsive disorder (OCD), placing it in a position to influence behaviors central to the disorder. We assessed effects of pSMA tDCS and TMS on symptoms and brain function in OCD individuals.

The Role of Continuous Theta Burst TMS in the Neurorehabilitation of Subacute Stroke Patients: A Placebo-Controlled Study.

Objectives: Transcranial magnetic stimulation, in particular continuous theta burst (cTBS), has been proposed for stroke rehabilitation, based on the concept that inhibition of the healthy hemisphere helps promote the recovery of the lesioned one. We aimed to study its effects on cortical excitability, oscillatory patterns, and motor function, the main aim being to identify potentially beneficial neurophysiological effects.Materials and Methods: We applied randomized real or placebo stimulation over the unaffected primary motor cortex of 10 subacute (7 ± 3 days) post-stroke patients. Neurophysiological measurements were performed using electroencephalography and electromyography. Motor function was assessed with the Wolf Motor Function Test. We performed a repeated measure study with the recordings taken pre-, post-cTBS, and at 3 months' follow-up.Results: We investigated changes in motor rhythms during arm elevation and thumb opposition tasks and found significant changes in beta power of the affected thumb's opposition, specifically after real cTBS. Our results are consistent with an excitatory response (increase in event-related desynchronization) in the sensorimotor cortical areas of the affected hemisphere, after stimulation. Neither peak-to-peak amplitude of motor-evoked potentials nor motor performance were significantly altered.Conclusions: Consistently with the theoretical prediction, this contralateral inhibitory stimulation paradigm changes neurophysiology, leading to a significant excitatory impact on the cortical oscillatory patterns of the contralateral hemisphere. These proof-of-concept results provide evidence for the potential role of continuous TBS in the neurorehabilitation of post-stroke patients. We suggest that these changes in ERS/ERD patterns should be further explored in future phase IIb/phase III clinical trials, in larger samples of poststroke patients.

Continuous theta burst TMS of area MT+ impairs attentive motion tracking.

Attentive motion tracking deficits measured using multiple object tracking (MOT) tasks have been identified in a number of neurodevelopmental disorders such as amblyopia and autism. These deficits are often attributed to the abnormal development of high-level attentional networks. However, neuroimaging evidence from amblyopia suggests that reduced MOT performance can be explained by impaired function in motion-sensitive area MT+ alone. To test the hypothesis that a subtle disruption of MT+ function could cause MOT impairment, we assessed whether continuous theta burst stimulation (cTBS) of MT+ influenced MOT task accuracy in individuals with normal vision. The MOT stimulus consisted of four target and four distractor dots and was presented at ±10° eccentricity (right/left hemifield). fMRI-guided cTBS was applied to left MT+. Participants (n = 13, age: 27 ± 3) attended separate active and sham cTBS sessions where the MOT task was completed before, 5-min post- and 30-min post-cTBS. Active cTBS significantly impaired MOT task accuracy relative to baseline for the right (stimulated) hemifield 5-min (10 ± 2% reduction) and 30-min (14 ± 3% reduction) post-stimulation. No impairment occurred within the left (control) hemifield after active cTBS or for either hemifield after sham cTBS. These results highlight the importance of lower level motion processing for MOT, suggesting that a minor disruption of MT+ function alone is sufficient to cause a deficit in MOT performance.

Cortical thickness changes following sound paired 20 Hz theta burst TMS therapy for tinnitus

Cortical thickness changes following sound paired 20 Hz theta burst TMS therapy for tinnitus

Anxiety and depression severity predicts depression outcome for bilateral neuronavigated 20HZ theta burst TMS

Anxiety and depression severity predicts depression outcome for bilateral neuronavigated 20HZ theta burst TMS

Bilateral neuronavigated 20HZ theta burst TMS in the treatment of anxiety

Objective: To assess the efficacy of bilateral neuronavigated 20Hz theta burst TMS (TBS-20Hz) for anxiety.

Continuous theta burst TMS of area MT impairs attentive motion tracking

Continuous theta burst TMS of area MT impairs attentive motion tracking

Continuous theta burst TMS as an add-on treatment for bipolar depression, design for a multicenter randomized sham-controlled trial.

Continuous theta burst TMS as an add-on treatment for bipolar depression, design for a multicenter randomized sham-controlled trial.

P232 Effects of inhibitory theta burst TMS to different brain sites involved in visuospatial attention – A combined neuronavigated cTBS and behavioural study

Purpose and methods The study sought to alter visual spatial attention in young healthy subjects by a neuronavigated inhibitory rTMS protocol (cTBS-600) to right brain areas thought to be involved in visual attentional processes, i.e. the temporoparietal junction (TPJ) and the posterior middle frontal gyrus (pMFG), and to test the reversibility of effects by an additional consecutive cTBS to the homologue left brain cortical areas. Results Healthy subjects showed a leftward bias of the egocentric perspective for both visual-perceptive and visual-exploratory tasks specifically for items presented in the left hemifield. cTBS to the right TPJ, and less systematically to the right pMFG reduced this bias for visuo-spatial and exploratory visuo-motor behaviour. Further, a consecutive cTBS to the left TPJ changed the bias again towards the left for a visual-perceptive task. Conclusions The evidence supports the notion of an involvement of the right TPJ (and pMFG) in spatial visual attention. The observations further indicate that inhibitory non-invasive brain stimulation (cTBS) to the left TPJ has a potential for reversing a rightward bias of spatial attention when the right TPJ is dysfunctional. Accordingly, the findings could have implications for therapeutic rTMS development for right brain damaged patients with visual neglect.

Continuous theta burst TMS as a tool to change decision-making in smokers

Continuous theta burst TMS as a tool to change decision-making in smokers

Effects of inhibitory theta burst TMS to different brain sites involved in visuospatial attention - a combined neuronavigated cTBS and behavioural study.

The study sought to alter visual spatial attention in young healthy subjects by a neuronavigated inhibitory rTMS protocol (cTBS-600) to right brain areas thought to be involved in visual attentional processes, i.e. the temporoparietal junction (TPJ) and the posterior middle frontal gyrus (pMFG), and to test the reversibility of effects by an additional consecutive cTBS to the homologue left brain cortical areas. Healthy subjects showed a leftward bias of the egocentric perspective for both visual-perceptive and visual-exploratory tasks specifically for items presented in the left hemifield. cTBS to the right TPJ, and less systematically to the right pMFG reduced this bias for visuo-spatial and exploratory visuo-motor behaviour. Further, a consecutive cTBS to the left TPJ changed the bias again towards the left for a visual-perceptive task. The evidence supports the notion of an involvement of the right TPJ (and pMFG) in spatial visual attention. The observations further indicate that inhibitory non-invasive brain stimulation (cTBS) to the left TPJ has a potential for reversing a rightward bias of spatial attention when the right TPJ is dysfunctional. Accordingly, the findings could have implications for therapeutic rTMS development for right brain damaged patients with visual neglect.

Neuronavigated left temporal continuous theta burst stimulation in chronic tinnitus.

Clinical effects of repetitive transcranial magnetic stimulation (rTMS) in chronic tinnitus are moderate. More precise coil localisation strategies, innovative stimulation protocols, and identification of predictors for treatment response were proposed as promising attempts to enhance treatment efficacy. In this pilot study we investigated neuronavigated continuous theta burst TMS (cTBS). Twenty-three patients received neuronavigated cTBS over the left primary auditory cortex in a randomized sham-controlled trial (verum = 12; sham = 11). Treatment response was evaluated with tinnitus questionnaires and numeric rating scales. Immediate change in numeric rating scales during the first session was used as predictor for treatment response. Tinnitus was significantly reduced after treatment, but there were no superior effects between verum vs. sham treatment. Immediate change in the first treatment session predicted the response to treatment only in the verum group. In our study, verum cTBS was not superior to sham which highlights the persistent need for improving non-invasive brain stimulation techniques for the treatment of tinnitus. Future research should focus on the transfer of positive single session effects to daily treatment trials.

Bilateral prefrontal rTMS and theta burst TMS as an add-on treatment for depression: A randomized placebo controlled trial

Objectives. Repetitive transcranial magnetic stimulation (rTMS) of the left dorsolateral-prefrontal cortex (DLPFC) exerts antidepressant effects. In this randomised controlled clinical trial we aimed to test the safety and therapeutic efficacy of bilateral theta-burst stimulation (TBS) as an add-on therapy to standard treatment of major depression. Methods. Fifty-six patients diagnosed with a moderate to severe depressive episode received 15 daily treatments of either rTMS (110% motor-threshold; rightDLPFC, 1000 stimuli at 1 Hz + leftDLPFC, 1000 stimuli at 10 Hz), theta-burst stimulation (80% motor-threshold; rightDLPFC, continuous TBS, 1200 stimuli + leftDLPFC, intermittent TBS, 1200 stimuli), or sham TMS (N = 17, sham coil with the TBS protocol). Results. There was no significant effect in the primary outcome measures (change of the 21-item Hamilton Rating Scale for Depression). However, there was a tendency towards an increased responder rate at the end of the follow-up period for both active treatments as compared to sham, and this tendency was most pronounced for the TBS group. Conclusions. This pilot study did not reveal significant advantages of bilateral TBS or rTMS over sham treatment as an add-on treatment for major depression. A tendency towards a superior effect of bilateral TBS at the end of the follow-up period may warrant further studies.

Theta burst TMS increases cerebral blood flow in the primary motor cortex during motor performance as assessed by arterial spin labeling (ASL)

Theta burst stimulation (TBS) is a novel variant of repetitive transcranial magnetic stimulation (rTMS), which induces changes in neuronal excitability persisting up to 1h. When elicited in the primary motor cortex, such physiological modulations might also have an impact on motor behavior. In the present study, we applied TBS in combination with pseudo continuous arterial spin labeling (pCASL) in order to address the question of whether TBS effects are measurable by means of changes in physiological parameters such as cerebral blood flow (CBF) and if TBS-induced plasticity can modify motor behavior. Twelve right-handed healthy subjects were stimulated using an inhibitory TBS protocol at subthreshold stimulation intensity targeted over the right motor cortex. The control condition consisted of within-subject Sham treatment in a crossover design. PCASL was performed before (pre TBS/pre Sham) and immediately after treatment (post TBS/post Sham). During the pCASL runs, the subjects performed a sequential fingertapping task with the left hand at individual maximum speed. There was a significant increase of CBF in the primary motor cortex after TBS, but not after Sham. It is assumed that inhibitory TBS induced a "local virtual lesion" which leads to the mobilization of more neuronal resources. There was no TBS-specific modulation in motor behavior, which might indicate that acute changes in brain plasticity caused by TBS are immediately compensated. This compensatory reaction seems to be observable at the metabolic, but not at the behavioral level.

Prolonged motor skill learning – a combined behavioural training and theta burst TMS study

To assess the behavioural effects of prolonged motor practice in healthy volunteers, and the specific impact of inhibiting different motor-related brain regions in the late phase of motor learning using continuous theta burst transcranial magnetic stimulation (cTBS). Twelve subjects trained their non-dominant arm in eight arm motor tasks (Arm Ability Training, AAT) once a day for three weeks (16 sessions). During the last four days, training was performed before and after applying cTBS to either M1, S1, SMA, or PMC. The AAT induced substantial and robust motor learning for the trained arm with variations across tasks. Considerable motor learning was also observed in the non-trained dominant arm with remarkably similar variations across tasks, suggesting that practise improved common underlying sensorimotor capacities (abilities) in addition to effector-specific effects. When applied after prolonged training, inhibitory cTBS showed no detrimental effects on motor performance/learning; M1 cTBS even improved performance in a labyrinth task. Prolonged training with the non-dominant arm led to profound motor learning across abilities with transfer to the non-trained dominant arm. Unlike during early stages of motor learning, no detrimental effect of cTBS over M1, S1, PMC, or SMA could be substantiated after prolonged motor practice.

Early stages of motor skill learning and the specific relevance of the cortical motor system – a combined behavioural training and theta burst TMS study

To examine whether motor performance and motor learning in healthy subjects can be segregated into a number of distinct motor abilities which are linked to intact processing in different motor-related brain regions (M1, S1, SMA, PMC) early during learning. Seven young healthy subjects trained in eight motor arm tasks (Arm Ability Training, AAT) once a day for 5 days using their left non-dominant arm. Except for day 1 (baseline), training was performed before and after applying an inhibitory form of repetitive transcranial magnetic stimulation (cTBS, continuous theta burst) to either M1, S1, SMA, or PMC. A principal component analysis of the motor behaviour data suggested four independent motor abilities: aiming, speed, steadiness, and visuomotor tracking. AAT induced substantial motor learning across abilities. Within session effects of cTBS revealed that activity in primary somatosensory cortex (S1) was relevant for motor performance and learning across all tasks whereas M1 was specifically involved in rapid tapping movements, PMC in ballistic arm navigation in extra-personal space; performance on a non-trained motor tasks was not affected by cTBS. Cortical sensory and motor areas including S1, M1, and PMC functionally contribute to early motor learning in a differential manner across motor abilities.

The Role of the Cerebellum in Sub- and Supraliminal Error Correction during Sensorimotor Synchronization: Evidence from fMRI and TMS

Our ability to interact physically with objects in the external world critically depends on temporal coupling between perception and movement (sensorimotor timing) and swift behavioral adjustment to changes in the environment (error correction). In this study, we investigated the neural correlates of the correction of subliminal and supraliminal phase shifts during a sensorimotor synchronization task. In particular, we focused on the role of the cerebellum because this structure has been shown to play a role in both motor timing and error correction. Experiment 1 used fMRI to show that the right cerebellar dentate nucleus and primary motor and sensory cortices were activated during regular timing and during the correction of subliminal errors. The correction of supraliminal phase shifts led to additional activations in the left cerebellum and right inferior parietal and frontal areas. Furthermore, a psychophysiological interaction analysis revealed that supraliminal error correction was associated with enhanced connectivity of the left cerebellum with frontal, auditory, and sensory cortices and with the right cerebellum. Experiment 2 showed that suppression of the left but not the right cerebellum with theta burst TMS significantly affected supraliminal error correction. These findings provide evidence that the left lateral cerebellum is essential for supraliminal error correction during sensorimotor synchronization.