Studying Of Transcranial Magnetic Stimulation’s Effects On Verbal Working Memory

This paper in order to detect the effect of verbal working memory is by transinical magnetic stimulator stimulate the subjects brainsThis paper use E-Prime software design verbal woring memory tasks and TMS Brainsight system in order to make the stimulate position accurately. The former three groups experiment change three parameters of stimulator to stimulate the subject and record the behavioral datas.The three parameters include the stimulate part,the stimulate time and the stimulate frequency. The fourth set of experiments record the EEG under two conditions that5Hz high frequency and no stimulate then analysis the EEG The behavior results show that the main duration affects the verbal working memory is in the rest time of the6s, the main part affects the verbal working memory is the left dorsolateral prefrontal cortex, the reaction of the high frequency magnetic stimulation was less than no stimulation. By use the coherence average ways to extract the latency of P300shows that the latency under the high frequency magnetic stimulation is less than under the no stimulation. The latency represents the time from accepting the letters stimulation to reacting.The latency shorten means that the reaction time of subjects tail off The results instruct that high frequency can improve the subjects verbal working memory by exciting the brain parts.In order to reveal the process of information transfer,this paper use the time frequency analysis and correlation analysis of EEG. The results show that after the lower-case letter appear which from300ms to500ms, β band energy improve significantly and time of high energy focuse on a band is longer,the activity of β band is more severely in frontal lobe than in parietal lobe after the subjects accept magnetic stimulation.These results represent that magnetic stimulation effect the subjects verbal working memory.Contract the ITC under two conditions find that after magnetic stimulation β band s ITC value tails off,this result represent that the magnetic stimulation influence the energy distribution of frontal lobe and parietal lobe. The time after the lower-case letter appear from300ms to500ms, β band s correlation coefficient of Cz and Fpz become bigger that represent for the activity of parietal lobe to frontal lobe become severly after magnetic stimulation. The time after the lower-case letter appear from400ms to500ms,the phase difference of a band become bigger shows that the direction of information transfer in parietal lobe change a lot after magnetic stimulation.After magnetic stimulation the positive of phase difference of β band become negative shows that the direct of information transfer in frontal lobe change a lot. Base on the analysis of above,obtain the conclusion is that the verbal working memory of subjects could be improved by using high frequency stimulation to act on the left dorsolateral prefrontal cortex of subjects in the rest time of the6s.