K. Nojima

Effect of the stimulus frequency and pulse number of repetitive transcranial magnetic stimulation on the inter-reversal time of perceptual reversal on the right superior parietal lobule

The aim of this study is to investigate the effect of the stimulus frequency and pulses number of repetitive transcranial magnetic stimulation (rTMS) on the inter-reversal time (IRT) of perceptual reversal on the right superior parietal lobule (SPL). The spinning wheel illusion was used as the ambiguous figures stimulation in this study. To investigate the rTMS effect over the right SPL during perceptual reversal, 0.25 Hz 60 pulse, 1 Hz 60 pulse, 0.5 Hz 120 pulse, 1 Hz 120 pulse, and 1 Hz 240 pulse biphasic rTMS at 90% of resting motor threshold was applied over the right SPL and the right posterior temporal lobe (PTL), respectively. As a control, a no TMS was also conducted. It was found that rTMS on 0.25 Hz 60 pulse and 1 Hz 60 pulse applied over the right SPL caused shorter IRT. In contrast, it was found that rTMS on 1 Hz 240-pulse applied over the right SPL caused longer IRT. On the other hand, there is no significant difference between IRTs when the rTMS on 0.5 Hz 120 pulse and 1 Hz 120 pulse were ap...

Predicting rTMS effect for deciding stimulation parameters

Repetitive transcranial magnetic stimulation (rTMS) is used in the medical field to modulate cortical excitability. However, when applied in this setting, rTMS stimulation parameters are not usually decided objectively. The aim of this study is to make a model that predicts the rTMS effect, allowing stimulation parameters (intensity and pulse number) to be easily determined before use. First, we investigated the relationship between stimulation condition and rTMS outcome. rTMS delivered at 1 Hz was applied with stimulation intensities of 85%, 100%, or 115% resting motor threshold (RMT) over the primary motor cortex in the left hemisphere. Motor-evoked potentials (MEPs) were measured before rTMS and after every 200 rTMS pulses. Eighteen hundred pulses were applied for each stimulation condition. Results showed that more pulses and stronger intensities lead to a larger decrease in MEP amplitude. An initial prediction model was then made by applying multiple regression analysis over the experimental data. We then adjusted the model depending on the size of the initial MEP amplitude before rTMS, and confirmed the improvement.

Effects of Transcranial Magnetic Stimulation and Transcranial Direct Current Stimulation on EEG Alpha Wave

Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) are painless technique for nerve stimulation. It’s possible to inhibit or excite neuron activity. For EEG alpha wave (8-14 Hz), it was affected to various brain activities. But, the most evident change was found when eyes closed and eyes opened.

Comparison of Influences on P300 Latency in the Case of Stimulating Supramarginal Gyrus and Dorsolateral Prefrontal Cortex by rTMS

The purpose of this study is to investigate influence of P300 latency in the case of stimulating SMG (Supramarginal Gyrus) and DLPFC (Dorsolateral Prefrontal Cortex). P300 of ERP (Event-Related Potentials) is induced by applying Odd-Ball task that is composed by the two sounds with different frequency. The Odd-Ball task was executed before and after magnetic stimulation by rTMS (100 stimuli with 1Hz). We compared the P300 latency before and after the rTMS magnetic stimulation. In the case of stimulating left and right SMG, P300 appeared earlier than in the case of no stimulating left and right SMG. In the case of stimulating left and right DLPFC, P300 appeared later than in the case of no stimulating left and right DLPFC.

Time change of perceptual reversal of ambiguous figures by rTMS

The aim of this study was to investigate the effect of stimulus frequency and number of pulses during rTMS (repetitive transcranial magnetic stimulation) on the phenomenon of perceptual reversal. Particularly, we focused on the temporal dynamics of perceptual reversal in the right SPL (superior parietal lobule), using the spinning wheel illusion. We measured the IRT (inter-reversal time) of perceptual reversal. To investigate whether stimulus frequency or the number of pulses is critical for the rTMS effect, we applied the following schedules over the right SPL and the right PTL (posterior temporal lobe): 0.25Hz 60pulses, 0.25Hz 120pulses, 0.5Hz 120pulses, and 1Hz 120pulses biphasic rTMS at 90% of the resting motor threshold. As a control, we included a No-TMS condition. The results showed that rTMS with 0.25Hz 60pulses over the right SPL caused shorter IRT. There were no significant differences between IRTs for rTMS with 0.25Hz 120pulses, 0.5Hz 120pulses or 1Hz 120pulses over the right SPL. Comparing these results with those of a previous study, we found that an rTMS condition with 60pulses causes shorter IRT; 240pulses causes longer IRT; and 120pulses does not change IRT. Therefore, when applying rTMS over the right SPL, the IRT of perceptual reversal is primarily affected by the number of pulses.

Number of Pulses of rTMS Affects the Inter-reversal Time of Perceptual Reversal

In this study, we applied repetitive transcranial magnetic stimulation (rTMS) to investigate the effects of number of pulses of rTMS on the phenomenon of perceptual reversal. It has been known that the right SPL (superior parietal lobule) has a role in perceptual reversal of the spinning wheel illusion. We measured the IRT (inter-reversal time) of perceptual reversal. We compared the effects of 1Hz 60pulses, 1Hz 120pulses and 1Hz 240pulses rTMS. The results showed that when 1Hz 60pulses of rTMS was applied over the right SPL, the IRT was significantly smaller. On the other hand, when 1Hz 240pulses of rTMS was applied over the right SPL, the IRT was significantly longer IRT. When 1Hz 120pulses of rTMS was applied over the right SPL, there were no significant differences. Moreover, to investigate whether these effects are affected by the rTMS condition with stimulus frequency, or not, we compared the effects of 0.25Hz 60pulses, 0.5Hz 60pulses, 0.25Hz 120pulses and 0.5Hz 120pulses of rTMS. When 0.25Hz 60pulses or 0.5Hz 60pulses of rTMS was applied over the right SPL, the IRT was significantly smaller. When 0.25Hz 120pulses or 0.5Hz 120pulses of rTMS was applied over the right SPL, there were no significant differences. Therefore, it was found that the IRT of perceptual reversal primarily affected by the number of pulses and doesn’t affect the stimulus frequency of rTMS.

Relationship between pulse number of rTMS and inter reversal time of perceptual reversal

The aim of this study is to investigate the stimulus parameter which affects the repetitive Transcranial Magnetic Stimulation (rTMS) effect. It is said that the condition under 1Hz rTMS induces the inhibition effect. On the other hand, the condition over 1Hz rTMS induces the facilitation effect. However the number of pulses of rTMS is also important factor. In this study, we focused on the number of pulses. We used the cognitive task of perceptual reversal and compared the rTMS effects of different condition under 1Hz which is the inhibition condition. It has been known that the right superior parietal lobule (SPL) has a role in perceptual reversal. We applied rTMS over the SPL and measured the inter-reversal time (IRT) of perceptual reversal. The results showed that when 0.25Hz 60pulses, 0.5Hz 60pulses and 1Hz 60pulses of rTMS was applied over the right SPL, the IRT was significantly smaller. On the other hand, when 1Hz 240pulses of rTMS was applied over the right SPL, the IRT was significantly longer. When 0.25Hz 120pulses, 0.5Hz 120pulses and 1Hz 120pulses of rTMS was applied over the right SPL, there were no significant differences. Furthermore, to investigate the rTMS effects, when rTMS are applied over the motor area, we measured the motor evoked potential (MEP). The more pulses of rTMS was applied, the smaller the amplitude of MEP became. From these results, it was found that the IRT of perceptual reversal and the amplitude of MEP primarily affected by the number of pulses of rTMS.

The effect of TMS to supramarginal gyrus on event-related potential P300

In this study we investigated the effect of the single pulse transcranial magnetic stimulation (TMS) and repetitive TMS (rTMS) to the supramarginal gyrus (SMG) on an event related potential (ERP) which is called P300. By applying the Oddball task which gives 2 easily distinguishable types of stimuli, the P300, one of the ERP can be observed. Former studies reported that left SMG is related to the origin of P300. In Experiment 1, TMS is applied to the SMG after 150ms, 200ms, and 250ms from presentation of audio-stimuli. By comparing the P-values, the effect of the TMS applied to the left SMG was larger. In Experiment 2, rTMS (100 stimuli with 1Hz) is applied to the SMG. We measured the P300 response before and after rTMS. By comparing the latency and amplitude of P300, latency was confirmed to increase when applied to the left SMG. However, there was no difference of amplitude of P300.

Relationship between rTMS effects and MEP features before rTMS

Repetitive transcranial magnetic stimulation (rTMS) is a promising method for use in the clinical field, as it can induce modulation of cortical excitability. Generally, rTMS inhibits the motor cortex when delivered at less than 1 Hz. However, it has been indicated that a facilitative effect is induced by 1 Hz rTMS, depending on the stimulation parameters and the individual. Therefore, the aim of this study was to investigate the features of the subject that could affect the 1 Hz rTMS effect when rTMS stimulus conditions change. First, motor evoked potentials (MEP) were measured under rTMS conditions with a variety of stimulus intensities and numbers of pulses. The MEP features before rTMS and the MEP modulation by the rTMS were then analyzed. Furthermore, correlations between the MEP features and the rTMS effect were investigated. It was found that the MEP amplitude and MEP onset before rTMS can influence the rTMS effect. Furthermore, negative correlations were found between these MEP features and the rTMS effect. MEPs with a small amplitude and early latency were little influenced by the inhibitive effect of 1 Hz rTMS, while MEPs with a large amplitude and late latency were readily affected by the inhibitive effect of 1 Hz rTMS. In this study, we focused on the MEP features before rTMS and identified the features of the subject that could influence the rTMS effect when the rTMS stimulus condition was changed.

Modulation of mu wave by repetitive transcranial magnetic stimulation and transcranial direct current stimulation to the motor cortex

rTMS (repetitive transcranial magnetic stimula- tion) is a method which stimulus cerebral nerve by induced current in the brain. It is possible to inhibit or facilitate neu- ronal activity in the brain. tDCS (transcranial direct current stimulation) can also modulate cortical activity just as rTMS. tDCS is a method which stimulate the brain with the direct current generated at electrodes attached on the subject’s scalp. Depending on the current polarity, duration or strength, tDCS can induce after effects selectively. Mu wave is traditionally defined as an 8-12Hz wave recorded over sensorimotor cortex that decreases or desynchronizes with imagination of move- ment. However the rTMS and tDCS effects to the mu wave are still unclear. The aim of this study is to investigate the effects of rTMS and tDCS on mu wave.