Effect of light illumination factors on brain activity as measure of event related potential using EEGLAB

Abstract

Quality of illumination causes alertness and mental activity. Research has shown that the behavioral aspects of living species are significantly affected by type of illumination, level of intensity and Correlated Colour Temperature (CCT). Continuous Electroencephalograph (EEG) is electrical activity of brain and it is a complex signal, detected with the help of several electrodes on scalp. EEG data consists of low frequency signals and main five different rhythmus - delta, theta, alpha, beta, and gamma. Stimulus brain activity is the Event Related Potential (ERP). EEG and ERP are the main tools to study the role of brain in different activities. Present study examines the effect of intensity of light and CCT of a LED source on the subject with the help of EEGLAB a software tool available for MATLAB toolbox. The signal processing is carried out for time- frequency analysis and independent component analysis (ICA). Experiments are conducted on five different subjects in age group from 25 to 50 years. EEG measurements are carried out in dark scene, and in an enlightened scene with the help of NeXus-10 physiological monitoring system. It is observed that event related potential rises and shows a peculiar pattern when light intensity and CCT change. Subjective response shows that cool white light and neutral white light are more comfortable. Alertness is more in warm white light.