Non-Conscious Brain Processes Revealed by Magnetoencephalography (MEG)

Abstract

Information processing in the human brain can happen fully conscious or in total absence of consciousness. Despite being far away from understanding consciousness in terms of being a subjective phenomenon based on neural activity we can at least imagine what it means to be consciously aware of a sensory perception or knowledge or ourselves. At the very moment we know that we know and what we know, the respective knowledge is consciously processed and can be verbally expressed, but what about information processing in the absence of consciousness? Can non-conscious information processing do the same just without consciousness? It is difficult to imagine what kind of information processing happens below the level of consciousness and what it actually means. What does non-conscious information look like? What does non-conscious information represent and what can it do? These are important questions to be answered in order to better understand consciousness itself. Among others a recent review reports about unconscious high-level processing in the human brain (van Gaal et al., 2011). In this review, the authors summarise scientific evidence to support the idea that decision making, an apparently conscious process, as well as other parts of highly sophisticated human behaviour can happen automatically without conscious control. This is exactly in line with the spirit of this book chapter that is written to support this notion with neuroimaging data collected via magnetoencephalography (MEG). For those who trust the well known iceberg analogy related to Sigmund Freud’s work about the human spirit the above mentioned questions must be very exciting, because according to this analogy non-conscious (in Freud’s terminology preand unconscious) information processing accounts for more than 80% of all information processing. This highlights the importance and the dominance of brain functions that happen in the absence of consciousness. According to my own view, the function of the brain is to produce controlled behaviour, besides managing basic body functions. The brain produces behaviour by processing information in three major steps. Step 1 is to process sensory input from outside and inside the body. In step 2 cognitionand emotion-related aspects of a stimulus are processed to make decisions. Finally, in step three the output of cognition and emotion is translated into motor programs that are then executed to elicit motor action which equals behaviour, at