Effect of Subliminal Auditory Stimulation on Components of Auditory Late Responses and Functional Magnetic Resonance Imaging Data in Adults with Normal Hearing

Abstract

Background and Aim: The use of subliminal stimulation for unconscious effects on the target population is of great importance. while several studies have generated proper visual and auditory stimuli for subliminal stimulation, no study was found on the long-term effects of it. Therefore, this study aims to investigate the long-term effects of auditory subliminal presentation on the central nervous system structures using fMRI and Auditory Late Responses (ALRs). Methods: Participants were 26 students with a mean age of 24.03±2.32 years. There was four group in study. First, fMRI was done and ALRs were recorded for all of them. Then, music files containing words embedded in them was presented subliminally to participants in groups A and B for 10 days, group C received music file without any subliminal stimuli and group D was control group. It was repeated after 10 days. Results: The subliminal stimuli had significant effects on the amplitudes of P1, N1, P2, and P3 waves (F3=25.03, 25.41, 39.11, and 14.60; p<0.001). Between-group comparison showed significant changes in groups A and B compared to groups C and D (p<0.05). The difference in the recorded potential mean values showed the highest change for recording electrodes in the prefrontal, frontal, and central regions and the lowest change in parietal and occipital regions. There was no significant change for a latency component. Conclusion: Subliminal stimuli, presented appropriately and continuously, can leave long- term effects on the central nervous system structure causing extensive changes in the people’s attitude to a certain subject. Keywords: Subliminal perception; unconscious perception; unconsciousness; subconsciousness; subliminal auditory stimulus