Effects of 30 Hz Theta Burst Transcranial Magnetic Stimulation on the primary motor cortex
Division of Pediatric Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.Journal of Neuroscience Methods (Impact Factor: 2.05). 05/2012; 208(2):161-4. DOI: 10.1016/j.jneumeth.2012.05.014
Theta Burst Stimulation (TBS) is a relatively new form of repetitive Transcranial Magnetic Stimulation (TMS) used to probe neuroplasticity in the human cortex. Thirty-Hz TBS, a variation of the originally described 50Hz TBS, has been shown to induce cortical changes in several nonmotor regions. However, its effects over the primary motor cortex have not been examined. Due to TMS device mechanical properties, 30Hz TBS is advantageous over 50Hz TBS in that it can be delivered at higher stimulation intensities. The goal of this pilot study is to examine the neurophysiologic effects of 30Hz TBS on the primary motor cortex (M1) of healthy adults. Eighteen right-handed adults (33±9.0 years; M:F=8:10) completed intermittent TBS (iTBS) or continuous TBS (cTBS) over left M1. TBS was performed with Magstim® SuperRapid2 with stimulation bursts (3 pulses at 30Hz) repeating every 200ms. For iTBS, each 2-s stimulation train was separated by 8s but there was no pause between trains for cTBS. Each TBS consisted of a total of 600 pulses delivered at an intensity of 90%*Resting Motor Threshold. Motor-Evoked Potentials (MEP) in the right first dorsal interosseous muscle were measured before, and one and ten minutes after TBS. Pre/post-TBS MEP amplitudes were compared using repeated-measures ANOVA. MEP amplitudes increased after 30Hz iTBS and decreased after 30Hz cTBS (TBS-Type*Time effect p=0.009). In conclusion, 30Hz TBS induced similar neurophysiologic effects over M1 as conventional 50Hz TBS.
- Brain Stimulation 02/2013; 6(4). DOI:10.1016/j.brs.2013.01.006 · 4.40 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Neuro-imaging studies have suggested that the ability to imitate meaningless and meaningful gestures may differentially depend on superior (SPL) and inferior (IPL) parietal lobule. Therefore, we hypothesized that imaging-guided neuro-navigated continuous theta burst stimulation (cTBS) over left SPL mainly affects meaningless and over left IPL predominantly meaningful gestures. Twelve healthy subjects participated in this study. High resolution structural MRI was used for imaging guided neuro-navigation cTBS. Participants were targeted with one train of cTBS in three experimental sessions: sham stimulation over vertex and real cTBS over left SPL and IPL, respectively. An imitation task, including 24 meaningless and 24 meaningful gestures, was performed 'offline'. cTBS over both left IPL and SPL significantly interfered with gestural imitation. There was no differential effect of SPL and IPL cTBS on gesture type (meaningless versus meaningful). Our findings confirm that left posterior parietal cortex plays a predominant role in gestural imitation. However, the hypothesis based on the dual route model suggesting a differential role of SPL and IPL in the processing of meaningless and meaningful gestures could not be confirmed. Left SPL and IPL play a common role within the posterior-parietal network in gestural imitation regardless of semantic content.Clinical neurophysiology: official journal of the International Federation of Clinical Neurophysiology 09/2013; 125(3). DOI:10.1016/j.clinph.2013.07.024 · 3.10 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Brain injury to the dorsal frontoparietal networks (FPNs), including the posterior parietal cortex (PPC) and dorsolateral prefrontal cortex (DLPFC), commonly cause spatial neglect. However, the interaction of these different regions in spatial attention is unclear. The aim of the present study was to investigate whether hyperexcitable neural networks can cause an abnormal interhemispheric inhibition. The Attention Network Test (ANT) was used to test subjects following intermittent theta burst stimulation (iTBS) to the left or right FPNs. During the ANT task, all subjects tolerated each conditioning iTBS without any obvious iTBS-related side effects. Subjects receiving real-right-PPC iTBS showed significant enhancement in both alerting and orienting efficiency compared with those receiving either sham-right-PPC iTBS or real-left-PPC iTBS. Moreover, subjects exposed to the real right DLPFC iTBS exhibited significant improvement in both alerting and executive control efficiency, compared with those exposed to either the sham-right-DLPFC or real-left-DLPFC conditioning. Interestingly, compared with subjects exposed to the sham-left-PPC stimuli, subjects exposed to the real-left-PPC iTBS had a significant deficit in the orienting index. The present study indicates that iTBS over the contralateral homologous cortex may induce the hypoactivity of the right PPC through interhemispheric competition in spatial orienting attention.Journal of Neurophysiology 09/2013; 110(12). DOI:10.1152/jn.00369.2013 · 2.89 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.