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Philosophy
Do Our Selves Always Travel With Us?
Neuroscience and Philosophy explain the mysteries of the self.
Posted November 3, 2015
You wake up in the morning. The first thing you become aware of is that it is you, yourself who just woke up. You feel tired and you are sure that it is you, yourself that is tired and did not sleep well. Then you get up and look into the mirror. You see a face, you feel and know that it is your face, the face of yourself. How do we know for sure that it is us, ourselves and not the self of another person? This feeling and knowledge of being one and the same self is even more mysterious given the fact that we change over time. Our body changes, our face gets wrinkled, our skin changes its colour, our hair becomes gray, etc. Despite all these changes, we still feel and know that it you are still you.
Where does the self come from? The discussion about the origin of the self has a long tradition that dwells deeply in philosophy. Early 18th Century philosophers like David Hume suggested that the self is not special at all but a mere collection or bundle of different stimuli. This was contradicted by his successor, the famous German philosopher Immanuel Kant who “located” the self in our cognitive functions, e.g., reason, as he said at his time. Other philosophers like the even earlier French philosopher Rene Descartes associated the self with a mind as distinguished from the body, including the brain.
Does the self exist in the mind? Current day philosophers argue that the assumption that the self is a separate mental entity is nothing but an illusion of the brain. Hence, some even go so far as to deny that there is any such thing as a self. That contradicts our daily experience though. We feel and experience a self, a sense of self as one may want to say. Where now does such sense of self come from? The brain is obviously a strong candidate in a time where everything including religious feelings and political decisions are traced back to the brain. Is the self nothing but the brain?
In my last blog, I discussed how environmental or better traumatic life events are encoded into our brain’s resting state or spontaneous activity. This suggests that the self is somewhat present in our brain’s spontaneous activity. This carries major implications. As long as there is spontaneous activity in the brain there is a self, at least a sense of self. Is the self really encoded and contained in our brain’s spontaneous activity?
Previous studies showed that personally relevant stimuli are processed mainly in regions in the middle of the brain, the so-called cortical midline structures (Northoff and Bermpohl 2004, Northoff et al. 2006). Most interestingly, the very same regions also show high activity levels in the resting state and thus spontaneous activity. How can we demonstrate that the spontaneous activity in the midline regions encodes personal relevance or self-relatedness?
A recent study from our group (Bai et al. 2015) tested whether the spontaneous activity predicts the degree of personal relevance or self-relatedness that subjects attribute to emotional stimuli. All the emotional stimuli subjects evaluated as highly self-related were compared with those that they assessed as low-self-related. Measuring electrical activity using electroencephalography (EEG), we then looked for neural activity changes prior to the onset of stimuli that were rated as high and low self-related.
Most interestingly, we observed that the power prior to stimulus onset, e.g., the pre-stimulus period in a particular frequency range, alpha (8-12Hz) was particularly high when the subjects assigned high personal relevance to the stimulus. In contrast, the pre-stimulus power was rather low in stimuli that subjects evaluated as low self-related. This suggests that frequency fluctuations in the range of 8-12Hz in the spontaneous activity encode and contain some personally relevant or self-related information.
These results show that the spontaneous activity seems to encode or contain personally relevant information. How such information is encoded and why the spontaneous activity is apparently very sensitive to especially self-related information remains unclear. What is clear though is that such encoding and containment of self-relatedness in our brain’s spontaneous activity implies that our self is always with us. In the same way our brain and its spontaneous activity are always with us, our self is with us. There is no way that we can ever detach us from our self and leave it behind as for instance when we move from one house or continent to another. We cannot just leave our self behind like an old suitcase. Why? Our brain encodes our self and without our brain and its spontaneous activity we could not travel (nor exist) at all. Henceforth, even if sometimes we would like to detach us from our self, our self nevertheless always travels with us.
What does this imply for our concept of self? Is the self located in the mind? Is the self the mind? Or is the self the brain? That will be discussed in the next blog.
References
Northoff G, Bermpohl F. (2004). Cortical midline structures and the self. Trends Cogn Sci. 8(3):102-7.
Northoff G, Heinzel A, de Greck M, Bermpohl F, Dobrowolny H, Panksepp J. (2006). Self-referential processing in our brain--a meta-analysis of imaging studies on the self. Neuroimage. 31(1):440-57.
Bai Y, Nakao T, Xu J, Qin P, Chaves P, Heinzel A, Duncan N, Lane T, Yen NS, Tsai SY, Northoff G. (2015). Resting state glutamate predicts elevated pre-stimulus alpha during self-relatedness: A combined EEG-MRS study on "rest-self overlap". Soc Neurosci. 21:1-15.
