The November Scientific American (not yet available on line) has an article on "The Neurobiology of the Self", which describes some of the work being done using functional brain scans (PET scans, fMRI's) to elucidate the neuroanatomy and neurophysiology of consciousness and the determinants of the self-concept. Interestingly, and not surprisingly, there is much in the early evidence that supports a Psychoanalytic theory of the development of the self. I discussed the Psychoanalytic point of view in an earlier post, Narcissism, Malignant Narcissism, and Paranoia: Part I:
Early in life we take the various images we have developed of ourselves (our self representations, in Psychoanalytic terms) and merge them to form a relatively stable, and usually only moderately distorted, sense of who we are and how we fit into the world around us. If we had the good fortune to be raised by a "good enough" mother (D.W. Winnicott, again) part of our core self representation will be of the adored child, the "apple of the mother's eye" as Kohut once so elegantly put it. Many other self representations are added through the years, some positive, some negative, until we form a relatively stable, relatively realistic, core sense of who we are and what kind of person we want to be. One of Kohut's contributions was to show how the child's nascent sense of himself developed primarily in relation to the mother's sense of the child and how failures of attunement by the mother left the child at high risk for narcissistic disorders. In other words, how a mother looks at her child, especially her unconscious wishes and fears, are the most important influences on the child's developing self concept. A mother who experiences her two year old as demanding or defiant or a brat, rather than appreciating (not without some difficulty; 2 year olds have their reputation for a reason) her child's need for and push for independence, will one day discover they have a poorly behaved, impulse ridden, needy child on her hands.
Typically development is a rather complicated journey, and I do go into this in more detail in the rest of the post and several following posts, but the essential idea that multiple self-representations (ie, different images one has and develops about oneself) must be integrated to form a coherent and consistent sense of oneself has been bolstered by the finding of areas of the brain that appear to do just such integration.
Debra A. Gusnard of Washington University describes one such area, the medial prefrontal cortex, an area located in the cleft between the hemispheres of the brain , directly behind the eyes (where most people imagine their "self" to reside.) The medial prefrontal cortex may act as an integrating and synthesizing structure. Of note, this area of the brain has a high concentration of neurons called spindle cells, which are thought to be very involved in information processing. [Recent work suggesting the computational ability of single neurons may be more robust than we have recognized will need to be factored into the mix as time goes by.]
It is worth noting that there is a significant area of overlap between such a hypothesized brain structure and the psychoanalytic concepts of "object constancy", "ego structures" and "ego boundaries"; these concepts are relevant to determining the boundaries between self and not-self (or self and object.)
Furthermore, there appear to be specific areas of the brain that respond to our experiences and our traits and determines how they fit into our sense of ourselves. For example, a novel experience triggers areas of the brain that are self reflective, that is, they think about our self involved in the event. Another part of the brain appears to resemble a network which strengthens its associative connections over time; once the network has been established, the individual has an intuitive sense of what traits belong to him and what traits belong to others. We might think of this as akin to templates, models of the self, which have become stabilized and consistent over time. These kinds of models would be integrated in the medial prefontal cortex and would form the basis for the sense of self.
The discovery of "mirror neurons" is another piece of the puzzle. We have cells in our brains that react to seeing others having experiences as if they were happening to us. This would explain the familiar experience of suddenly discovering an itch when a person with you scratches, or of having an urge to yawn when the person you are with yawns. Of even greater significance would be the involvement of such cells in the psychological process of identification. In the youngest child, the distinction between self and not-self/other is more flimsy. It is likely their mirror cells are not well distinguished in their reactions from other, non-mirror cells. The mind of the child would be literally shaped by the reactions of the mother in the earliest days since the child's brain, and mind, would be unable to differentiate brain neural activity that has its genesis in its own experiences or in the mirrored experiences of its mother. In adults who have had trouble establishing a clearly demarcated sense of self, one could imagine their mirror cells are over developed or poorly integrated, their medial prefontal cortex is impaired, and/or perhaps their neural networks that correspond to the templates /self-representations are less defined and developed. Some of these people may have symptoms which fall under the rubric of porous ego boundaries, commonly seen in schizophrenia and, in attenuated form, in borderline personality states. In such conditions the ability to distinguish between one's own versus an other's thoughts and feelings is impaired. There is much more to say about this but that would bring us away from the neurobiology of the mind and will have to wait for another time.
The summary in Scientific American supports several key elements of the psychoanalytic theory of the development of the self concept, from early identification, to the elaboration of multiple self-representations, and finally to the stable integration of a host of self-representations into a unitary sense of self.
Psychiatrists often express the rueful wish, especially when talking about patients with impairments in their ego functions (especially our extremely challenging, borderline patients), that we could offer our patients an "ego transplant." It would not be out of the question to imagine that we will one day, by combining stem cell work to make more robust spindle cells to implant in the medial prefrontal cortex, be able to help some people who now have to rely on powerful medications and long term psychotherapy to maintain enough integrity of self to maintain relationships and functioning.
On another note, I have suggested in the past that one problem with the most rabid, most partisan ideologues (which I have found to be more of an issue on the left than the right in the recent past), might be that they have incorporated their politics into their self-representations. For such a person to change their political point of view would be nearly impossible because it would threaten to weaken their ego boundaries and cause severe regressive forces to be unleashed in their character. It would feel safer for such a person to believe fantastical, near delusional, fantasies, than to risk their self.
Freud always hoped to one day be able to attribute all mental processes to neurobiology; Ray Kurzweil, The Singularity is Near, imagines that we will one day be able to reverse engineer our brain and mind; those days are drawing closer, more rapidly than you might imagine.
Some of the ideas in this post are updated here: Consciousness and Conscious Robots.