Non-rapid eye movement sleep 3D maze. Participants were then trained in the maze for 4 hours and later, during the various sleep cycles of nonREM sleep, REM sleep and wakefulness, they were scanned twelve times using a PET scan during the night. The PET scan demonstrated a higher blood flow in the hippocampus during SWS/non-REM sleep due to the training from the previous day while the control group exhibited no increased blood flow and they had not received the training the prior day. The brain activity during sleep, according to this study, would show the events of the previous day do make a difference.
Eye movement can make the photoreceptors or the ganglion cells become unresponsive; on the other hand a changing stimulus will not. Therefore, the random eye movement constantly changes the stimuli that fall on the photoreceptors and the ganglion cells, making the image more clear. Saccades are the rapid movement of eyes that is used while scanning a visual scene. In our subjective impression, the eyes do not move smoothly across the printed page during reading. Instead, our eyes make short and rapid movements called "saccades". During each "saccade" the eyes move as fast as they can and the speed cannot be consciously