Chapter 8. Dissociation and Neuroscience (1) the “Hidden Observer” (3)

Neural network theory attempts to understand human mind as a product of vast and complex networks consisting of neurons and neural fibers. Neural networks are subdivided into multiple modules, each in charge of different functions and operating in coordination with others. Dissociation occurs when this coordination fails.
This way of understanding dissociation from a neural network point of view is compatible with the definition of dissociation in current psychiatry. According to ICD-10（World Health Organization, 1991）, dissociation is explained as follows. "… Partial or complete loss of the normal integration between memories of the past, awareness of identity and immediate sensations, and control of bodily movements". It is obvious in this definition that there is an assumption that some neurological units exist, each of which in charge of different functions.
World Health Organization (1991) The ICD-10 classification of mental and behavioral disorders. Clinical descriptions and diagnostic guidelines. Geneva: World Health Organization.
Based on the neural network model, Cosolino (2002) describes the pathology of dissociation as follows. “Dissociation is a common symptom in reaction to traumatic experiences. It is characterized by disorientation and a disconnection among thoughts, behaviors, sensations, and emotions. Dissociation demonstrates to us that the neural networks organizing these functions are, in fact, separate. Because they are seamlessly interwoven during normal states of awareness, we fail to understand that their integration is an active, if unconscious, process. Dissociation reflects a pathological expression of the plasticity that organizes and integrates neural networks”. (p.24)
Cosolino L (2002) The Neuroscience of Psychotherapy, Building and Rebuilding the Human Brain. WW Norton & Company.
However, neural network model does not only explain dissociative phenomena, but also activities of human mind in general. There would be more detailed understanding of the modular nature of the brain function by the development of imaging technique and further neurological research (See Hawkins (2005) as such an example). However, there would be a very long way until the mechanism of dissociation is fully explained.
Hawkins J., Blakeslee, S. (2005) On Intelligence. Holt Paperbacks.
Once I elaborated on the issue of neuroscientific understanding of dissociation in a paper (Okano, 2008) and here is the gist of it. If we assume that our mental activities are the product of various different modules, there should be some switching mechanism operating among them. If connections of some modules are switched off for some reason, that might be how dissociation occurs. Although disconnection might be manifested as deficit of functions, i.e., negative symptoms, disconnected module might “free-run”, giving rise to some positive symptoms such as hallucination or creating of new identities.
Okano, K (2008) Memory disturbance in psychiatric practice; its understanding in the context of dissociation. Japanese Psychological Review. 51:120-133 (Japanese with English Review.)