청각자극 제시에 의한 인간의 뇌파 특성에 관한 연구

Abstract

In this paper, we make measurements and an analysis of EEG (Electroencephalography) is elicited by the auditory organ among the five sensory organ. It is aimed to examine the new information of human cognitive activities. Firstly, we detected P300 to be elicited by auditory stimuli like auditory information. The P300 is an ERP(Event-Related Potential) to obtain via the EEG. We used 4 stimuli with 3-tone and 2-volume. This is a method to use two target stimuli with th same frequency but different volume. The experimental results approved that the 4-stimulus oddball paradigm can elicit P300 component clearly. It was supposed that the task to concentrate attention on two features (frequency and volume) was more difficult than that on one feature(frequency) although discriminating new feature was very easy task. Secondly, we carried out experiment on two ways. Those were to present designated targets and choice targets. We detected P300s from the experiments using the ways and showed the experiments results to analyze the P300s due to target choice in oddball paradigm. 3 tone( 2000Hz, 1000Hz, 500Hz) is mostly used stimuli in oddball paradigm. The experiment results showed similar features both the target choice case and the designated targets case in the first experiment. In the second experiment, we could not observe the similar relations in the results of the first experiment. This finding suggested that characteristics of stimuli is more related to cognitive process than choice of auditory stimuli. Thirdly, we detected the P300 from the experiments according to the direction of stimuli. We analyzed the experiment results to find different facts about cognitive process. The brain mapping can be obtained using the ICA(Independent Component Analysis) method when subjects recognized the auditory stimuli. As the results, latency of the P300 was shorter on the left direction than on the right direction. According to the channel of each task, the P300 amplitude was large at the Fz, Cz, Pz electrode. The P300 peak latency was short when stimuli were presented on left direction and both direction. We can observe the EEG signals clearly at mid-line electrodes and at the opposite site of presenting stimuli using the ICA analysis method. Lastly, we carried out the experiments to measure the EEG of the subjects when the interior noises of the KTX and the Saemaul-ho were presented like stimuli and analyzed the variation of the β waves in the EEG. In the result 80% of subjects have the large relative β power of interior noises by the KTX. It could be assumed that most of people felt more discomfort in the KTX than in the Saemaul-ho from the relative βpowers of experiment results. As mentioned above, it could be estimated to human cognitive activities among human brain activity using EEG analysis with all kinds of informations through the human auditory organ.