You may well find this a rather hideous notion and just thinking about it makes my imagination cause my brain to feel funny… Back in the late 60s and early 70s research was conducted on people who had agreed to have their corpus callosum surgically severed. The corpus callosum is the bit which connects the two hemispheres of the brain…. I know, I know, thinking about it makes your brain feel funny, as I said… *Attempts to think of something else*

In 1968 a study by Sperry published in the American Psychologist journal entitled Hemispheric disconnection and unity in conscious awareness and then in 1970, a study by Gazzaniga entitled The bisected Brain both attempted to explain hypnosis in terms of the brains hemispheres.

These studies were then built upon by Watzlawick in 1978 in the book The language of change.

Without any evidence, it proposed the idea that hypnosis blocked the left hemisphere of the brain while  using language patterns that were engaging the right side of the brain. At the time, many proponents of this notion also suggested that the ‘unconscious’ (whatever that might be) was also to be found in the right side of the brain.

This has since been proven to be untrue and lots of research and modern information indicates that our brain functions are very much shared across the full range of locations in our brains; you can look at the work entitled A midstream view of the neuropsychophysiology of hypnosis: Recent research and future directions which features in the book I am holding up here in my office by Fromm and Shor entitled Hypnosis: research developments and perspectives.  Which evidences the notion that both hemispheres are engaged with so-called conscious and unconscious processes.

As of today though, there are still many people who believe that one hemisphere of the brain dominates hypnosis. Is there evidence that supports this? Well, lots of research does tend to suggest that a hypnotized brain responds much the same to a non-hypnotised brain when responding to certain tasks when it comes to the dominant hemisphere – the nature of the task tends to indicate which side of the brain dominates.

That said, there are a number of studies which seem to indicate that people deemed as ‘highly hypnotizable individuals’ (often a controversial topic in and of itself due to interpretation differences) often display higher and faster arousal emotionally and the EEGs indicate more activity in the right side of the brain.

These studies include Crawford, Clarke and Kitner-Triolo (1996) Self-generated happy and sad emotions in low and highly hypnotizable persons during waking and hypnosis featured in the International Journal of Psychophysiology as well as  Gruzelier (1998) The neuropsychology of hypnosis in Michael Heap’s Hypnosis: Current clinical, experimental, and forensic practices as well as the 1993 work by Heller entitled Neuropsychological mechanisms of individual differences in emotion, personality, and arousal in the journal Neuropsychology.

In fact, the Gruzelier chapter suggests and shows there are three stages of brain activity when anyone is hypnotised. The initial stage shows the frontal lobe having more activity when the individual concentrates and tunes in to the voice of the hypnosis professional.  The next stage is whereby the individual starts to go through a process of letting go, the with the third stage there is much more activity in the right side of the brain (in particular the posterior cortical area on the right side) in those considered to be highly hypnotisable.

There are other studies to suggest that the left hemisphere was more active initially and going through the hypnosis induction and then the right side of the brain seems more active and the left side of the brain seemed to be less active.

As with all of the explorations, it does seem that we need to continue studying it to really know more about the nature of the biology of hypnosis. I’ll be looking at some other facets of the brain, biology and technology when it comes to the brain and hypnosis throughout the week.