Analysis of EEG Signals in Memory Guided Saccade Tasks

We have been researching relationship between saccadic eye movements and EEG signals before saccadic eye movements in order to develop the Brain-Computer Interface (BCI). In previous studies, we confirmed sharply changed EEG signals were recorded just before saccade. The EEG signals in right occipital lobe have low potential in the case of saccade to the right side and the EEG signals in left occipital lobe have low potential in the case of saccade to the left side. However, these EEG signals were recorded with the visually guided saccade task and the saccade in the visually guided saccade task is not voluntary movements perfectly. Involuntary movements are not suitable for inputs of BCIs. Therefore, in this research, we record EEG signals with the memory guided saccade task and compare EEG signals in the visually guided saccade task with EEG signals in the memory guided saccade task. In this research, we instructed subjects to perform following tasks. First, a visual stimulus (LED) on the right side or a LED on the left side is turned on and subjects memorize which LED is turned on. Secondly, after a few second, beep sound is turned on and subjects move their eyes to LED position where subjects memorized. As results, we obtained sharply changed EEG signal in occipital lobe just before eye movements. The EEG signals have sharp changes in right occipital lobe when subjects move their eyes to the right, and in the case of eye movements to the left, left occipital lobe have sharp changes. These results are similar to results in visually guided saccade tasks. Therefore, in the voluntary and the involuntary saccadic eye movements, sharply changed EEG signals in occipital lobe are observed just before eye movements and sharply changed EEG signals are suitable for inputs of BCIs.