Objective Evaluation Approaches For Investigating Binocular Rivalry

The research on consciousness is a popular topic in many fields such as physiology, neurophysiology and neuroimaging. Binocular rivalry is a key to the research of consciousness, for it is a visual physiological phenomenon during which the external physical stimuli and the alternant perception are separated. For a long time, the investigation on binocular rivalry mainly depends on the subjects'manual report, which could be severely influenced by individual differentiae, thus applying objective approaches on research of binocular rivalry is much necessary.Frequency tagged binocular rivalry makes good use of the frequency features of steady state visual evoked potentials by tagging the two perceptual states with two frequencies and combines with other EEG analysis, to research on perception(awareness) and consciousness-related issues. Therefore, it is a new objective technique to investigate on perceptual states. The results shows that tagging frequencies in high frequency band can avoid the noise from background EEG, and can effectively reduce the visual fatigue during experiments.This paper presents a set of frequency-tagged objective method to investigate on perceptual alternation during binocular rivalry, which includes instantaneous detection, average detection and rate-index brain imaging. In objective detection of instant perceptual state, the pattern recognition technique is applied in the classification to identify the two perceptual states, which proved to be an effective way to observe the physiological process of binocular rivalry. To objectively and quantificationally estimate the speed of perceptual alternation, a new EEG analysis combining phase locking and cross power spectrum is presented to capture the alternation rate on average. It is proved to be robust and has good precision. It is of great importance both on clinical treatment and on scientific research. Based on the above method, this paper presents a parameter called rate-index, to evaluate the participation of perception-related activity during binocular rivalry, which helps to form a new brain mapping approach. Compared with the common used fMRI approach, it holds many advantages such as high temporal resolution, convenient experiment implementation and low cost.This paper also proposed a hypothesis about neural mechanism model of binocular rivalry. Based on this model, we provide possible explains for several controversial issues about mechanism of binocular rivalry.In this paper, the set of objective detection method makes a breakthrough, which avoids the limitation of subjective research means. No subjective information is needed and therefore is especially applicable to the cases of non-verbal infants and the elders, and therefore can achieve the objective evaluation to consciousness during binocular rivalry. Based on the rate-index imaging result, a hypothesis is proposed by creating a model for mechanism of binocular rivalry.