Graeme Smith–Jan 2, 2010
In my memory model, the anterior cingulate cortex (ACC) is connected to many areas in the cerebral cortex, by a backbone network that seems to extend down both sides of the central fissure, as referenced in recent works on connectomics.
It's role, seems to be the selective suppression of processing in areas that are not of current interest to the brain. What this means, is that when the brain is idling, there is significant processing going on, but it is unselective, and chaotic in nature. Work such as David LaBerges Triangular Circuit theory of Attention, has suggested that it is the attention mechanism that limits processing and that therefore the ACC is an important part of the Attention system. As a proponent of Weak Attention, the idea that attention actually is used to guide information between processing centers to improve the signal to noise ratio, and the author of a Model, of memory that involves both bottom-up attention and Top-down attention at even the lowest levels of memory processing, I believe I understand a plausible mechanism for attention to direct processing in the implicit memory which lies at the bottom of the cerebral cortex circuits. If so the way that the ACC works, is likely to be in conjunction with other centers in the PFC, that direct it what clusters of inputs are best NOT to suppress, probably via some link to the Synchronous Activity in the cerebral cortex. Essentially, each process, is tagged with a different frequency, and the ventro-lateral PFC is thought to be sensitive to the frequencies, so that it can help the ACC decide which clusters are most likely to be useful, possibly in conjunction with the executive processes that are also thought to cluster in the PFC.
Recent MRI studies done on Hypnotism seem to suggest that the Idling processes of the brain are suppressed during Hypnotic states. This seems to suggest, that Hypnosis is a form of Attention, which involves significant activity in the ACC, (In order to suppress the natual idling processes) This should be visible if a comparative study, is done using an fMRI.
In my Memory Model, I have proposed a concept I call complicit attention, where the direction of processing in some centers of the brain, forms the equivalent of a processing command. I have also noted the utility of the cerebellum, for offering pseudo-sequences of these commands, in much the same way it produces pseudo-sequences of actions in Skill Memory. This being the basis of Automation and eventually what is sometimes called Intention, sub-conscious processing that is thought to determine what is consciously processed from 7 seconds before it is actually processed, to 500 milliseconds before it is processed depending on which model of sub-conscious processing you use.
What is important to realize is that this supports the idea that Consciousness is a control mechanism, rather than an executive function. What hypnosis seems to do is suppress the control mechanism of consciousness in order to replace it with default sub-conscious processing, during the trance.
The Idling processes are probably related to spontaneous attempts for the brain to make sense of ambiguities in the environment, and involves some conscious processing. The ACC is the location in the brain where ambiguities are isolated, so it makes sense that the ACC is controlling not only the data flowing into consciousness, but also the amount of conscious processing that occurs. If we train the ACC to shut down the speculative processing, it also throttles down consciousness, and with it the more abstract processes that act as barriers to suggestion. A clue that defenses against suggestion are in fact a form of abstract processing is suggested by the lateness in the development of the brain, to the susceptibility to hypnotism. It has been suggested that children before about 7 years of age, are not capable of supporting hypnotic trance states. This indicates to me that about the time of the development of an advanced theory of mind, people build defenses against suggestion.
Although there is still growth in the brain at this piont, I suggest that it is growth in the multi-modal Associative areas, that are the targets for my Complicit Attention, and as a result, the ACC can selectively suppress activity in these areas if the PFC is motivated to indicate it should. This might explain the apparrent conflict between the Hypnotic Communities statement that "You will not do anything that you do not want to" while under the influence, and the seemingly ethically questionable influence that the Mind Control sub-community of the hypnotic community has, in that it suggests that the YOU that decides is about as sophisticated as a 5 year old child, because it has suppressed the abstract defenses that are linked to Ethics and an advanced theory of mind.
