What is hypnosis? In hypnosis, which is a trance-like state that we are familiar with from stage performances, the practitioner gives commands and the person under suggestion acts accordingly. In hypnosis, the person is far from being sleepy. In fact, the opposite is true. This state helps the brain control sensation and behavior. Therefore, hypnosis can be used in pain management, controlling phobia, anxiety and stress. However, not everyone falls into hypnosis. It is estimated that about one-third of the population cannot be hypnotized.
We still don’t know exactly why some people can be hypnotized and the neurological mechanisms involved in the hypnotic state. However, some interesting data have been obtained over the years. Although these data offer clues in discovering the mechanism of hypnosis, it is a long way to go before reaching full understanding.
While there are many scientific and quasi-scientific theories about hypnosis, there is a remarkable shortage of reliable empirical evidence. The study of hypnosis is often an area that “serious” scientists stay away from. Hypnosis has long been viewed with suspicion because of its use in stage performances. Hypnosis has been seen as an “alternative” like meditation and acupuncture.
In addition to personal shyness, financial obstacles may also have limited hypnosis studies. Scientific funds are not very keen on funding such gray areas. However, some studies in recent years have increased the interest in hypnosis.
Neuroscientific Basis of Hypnosis
In a study conducted in 2012 using functional MRI, it was observed that the areas related to executive control and attention were activated in the hypnotized brain . More specifically, there is more co-activation between components of the executive control network (left dorsolateral prefrontal cortex) and attention network (dorsal anterior cingulate cortex). In the brains of hypnotizable people, two networks are activated sequentially. Such a connection has not been observed in persons who are difficult to hypnotize.
The person under hypnosis may perceive external and body-based sensory data differently. For example, it may be suggested that their arms become heavy and they cannot move, and the person may experience paralysis. Although skeptics question the authenticity of these demonstrations, neuroimaging studies support that brain activity changes under hypnosis.
The brain works differently under hypnotic suggestion. In an experiment in 2000, it was shown that under hypnosis, people could see vividly colored images in black and white or not see them completely. fMRI was used to determine which part of the brain was activated when the hypnotized individual was analyzing colors. When people were asked to perceive colors, the color fields in the right and left hemispheres were activated.
Scientists are convinced that hypnosis is not a role but a unique psychological state. However, the experiments only work on highly hypnotizable people, which is about 8% of the population.
Studies have shown that there are hemispheric differences in hypnotized and non-hypnotized brains. When people who are not in hypnosis are asked to perceive colors in a black and white photograph, only their right hemisphere is activated. The left hemisphere was activated only under hypnosis. The left hemisphere is related to reason and logic, so it may need the support of hypnosis to separate itself from real information from the senses.
During hypnosis, cerebral blood flow was examined by positron emission tomography (PET). Hypnotic state in left hemisphere occipital, parietal, precentral, premotor and ventrolateral prefrontal cortices; It is associated with activation in the occipital and anterior cingulate cortices in the right hemisphere. The activation pattern bears similarities to mental daydreaming, with the exception being the relative deactivation of the precuneus. There are also researchers who suggest that hypnosis consists of a larger activation of areas of the brain used for daydreaming.
In hypnosis, there may be decreased activity in the anterior cingulate cortex and visual areas. Cognitive control may be affected by regulating the activity of specific brain areas, including early visual modules, in hypnosis.
Several studies have found significantly greater activity in the anterior cingulate gyrus in hypnotizable subjects than in non-hypnotizable or weakly hypnotic subjects. The anterior cingulate gyrus responds to errors and evaluates emotional consequences. Hypnotizable people have more activity on the left side of the prefrontal cortex. The prefrontal cortex is involved in higher-order mental processing and behavior.
Comparing different studies may yield conflicting results. Different areas of the brain seem to be activated in different experiments. The difference in test methods may cause this. The conclusion from current studies is that hypnosis is a distinct psychological state. Understanding hypnosis can provide new approaches to the treatment of a variety of diseases and problems.