Effect of Islamic fasting on visualattention by event-related potential analysis

Abstract

Fasting can the psychological and mental state of a person. Previous studies conducted on evaluating the effects of Islamic fasting on visual spatial attention mechanism found no significant effects; however, the temporal mechanism of brain activities was not investigated in those studies. Thus, in this research we study the effect of Islamic fasting on visual spatial attention through the temporal mechanism of brain activities. This will give us the means to better understand the internal processes of the brain with regard to visual spatial attention. This is done by the process of motivation and emotion using images of food and dynamic facial expression as a realistic source of intervention. There are two major tasks utilized in this study. In the first task, the dot probe method was adopted on 26 participants to investigate the effect of food on visual spatial attention. The second task focused on facial expression using modified Posner method with 40 subjects. Both experiments were conducted before, during and after the month of Ramadan. The reaction time and the event related potential (ERP) components, extracted from recorded EEG during both tasks were measured as the output features of visual attention system. Findings of this study showed that spatial attention is affected by food and facial expression stimuli due to Islamic fasting. Furthermore, the facial expression task showed significant effect of gaze and its interaction with the emotional stimuli. Moreover, according to the findings of the reaction time and ERP analysis, the neural activity showed faster and preference for emotional input rather than gazing input. Besides, the happy facial expression stimuli produce faster results than neutral expression. These results indicated that ERP component coming from the right hemisphere of the brain has more effect than left side. This is consistent with the emotional lateralization concept of emotional processing rather than the valence concept. This is a significant finding since previous researches were not able to resolve these differences.