Brain Cognition And Information Transmission Mechanism Of Contour Detection And Integration

Contour detection is one of the most basic and important functionsin the advanced animal visual system.Contour integration is thought to be necessary for the perception of objects or situations. In this thesis, we combine the contour detection and the integration problem creatively through the research of eye movement behavior and fMRI together,in view of the bottom-up stimulus driven and top-down driven by two aspects of consciousness,the mechanism of brain cognition and the transmission of information is studied, and the research contents include the following two aspects:Firstly, the target in the visual scene is simple or complex. In this paper, a new stimulus is divided into three kinds of situations: no contour background(NC), obvious contour(OB) and unobvious contour(UO),the three stimuli were randomly presented in fixation, of people in different stimulation difficulty of integration correct rate and reaction time differences also observed the correct detection and error of eye movement trajectory, help us to understand the whole process of contour perception. The experimental results show that: the reaction time is from fast to slow in order: significant contour, no significant contour, no contour. The correct rate of reaction from high to low is: significant contour, no contour, no significant contour. In addition, the eye movement track found that there were significant differences in the contour detection of the eye movement in three cases.It shows that the integration process is different.Secondly, in order to further study on the contour integration, We designed the magnetic resonance experiment, and in the case of detection of contour error to join feed- back to subjects, and then analyzes the five areas of the brain fMRI signal through the sample T-test. The results show that when the contour is clear and the task is simple, the human V4 area is enough to complete the contour detection integration; when the task difficulty increases, the human FEF area and V4, V2 and other regions have a strong activation. When the task is difficult, the participants cannot complete the correct integration of contour detection, and receive specific feed- back, the prefrontal cortex(prefrontal cortex, the PFC) and temporal gyrus(inferotemporal cortex, IT) area increased activity, suggesting that contour detection related feedback may be originated in the PFC and reflux in the IT area or V4 area.Our evidence suggests that detection and contour integration need top-down and bottom-up mechanisms to work together. Contour detection is related to the higher brain area is located in PFC and FEF, and the effect of FEF is more early detection through eye movement control, while PFC by accepting external cues or memory. In addition, V1, V2, V4 interactions can complete the simple contour integration.When the task is more difficult, it needs the IT and LOC areas as the bridge connecting the high consciousness area and the occipital lobe of the visual cortical area to complete the contour detection integration.