A Simple Plan: Hypnosis

The Science Behind Hypnosis

Time and time again, we hear the question, what exactly is hypnosis and is there science behind it? A brain signature of being hypnotized was first recognized in 2012 with functional MRI (fMRI), a type of MRI that showed brain . Parts of the brain connected with executive control and attention were proven to have a role.

More particularly, hypnotized subjects displayed greater co-activation between parts of the brain’s executive-control network (in-charge of basic cognitive functions) and the salience network (dictates which stimuli must be given attention). In their brains, these two networks reacted together. Those who were not hypnotized did not exhibit this connectivity.

What elevated these experiments to a higher league is the fact that researchers used fMRI to detect the parts of brain that responded when subjects analyzed colors. The color areas in both left and right hemispheres reacted when the subjects were told to look at colors. The researchers agreed that hypnosis is indeed a one-of-a-kind psychological state and definitely doesn’t come from adopting a role.
A Quick Rundown of Hypnosis

Another exciting observation from these trials were the hemispheric variances between the hypnotized and non-hypnotized brain. When non-hypnotized subjects were told to point out colors in a black-and-white image, only the right hemisphere responded. The left hemisphere, which deals with reason and logic, only responded under hypnosis.
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Another experiment used positron-emission tomography (PET) to examine cerebral blood flow in hypnosis. The hypnotic state was connected with activation of a lot of mostly left-sided cortical areas and some right-sided regions.

The trend of activation shared a lot of similarities with mental imagery, from which it showed differences by the relative deactivation of the precuneus (handles visuo-spatial imagery, episodic memory retrieval and self-processing operations of the brain). This activation trend proved to be similar with mental imagery, from which it differed with the relative deactivation of the precuneus, the area of the brain in charge of episodic memory retrieval, visuo-spatial imagery and self-processing operations. Some scientists believe that under hypnosis, the subjects simply activate, to a significant extent, the brain sections used in imagination, but without actual perceptual changes.
Another functional MRI study showed limited activity in both anterior cingulate cortex, which affects emotions, learning and memory, and visual areas under hypnosis. The results suggest that hypnosis influences cognitive control by limiting activity in specific brain regions.

In multiple studies, hypnotizable subjects exhibited substantially more brain activity in the emotion and behavior-affecting anterior cingulate gyrus, as compared to participants who are non-hypnotized. The anterior cingulate gyrus responds to mistakes and gauges emotional outcomes. Prefrontal cortex is related to with higher level cognitive processing and behavior.

Comparison of findings from various studies also show rather contradictory outcomes. Many regions of the brain seem to respond in different experiments. This could be related to multiple experimental techniques, both in terms of equipment and hypnotic approach used in the experiments.