Hypnosis induces a changed composition of brain oscillations in EEG: a case study

Abstract

Cognitive functions associated with the frontal lobes of the brain may be specifi cally involved in hypnosis. Thus, the frontal area of the brain has recently been of great interest when searching for neural changes associated with hypnosis. We tested the hypothesis that EEG during pure hypnosis would differ from the normal non-hypnotic EEG especially above the frontal area of the brain. The composition of brain oscillations was examined in a broad frequency band (1-30 Hz) in the electroencephalogram (EEG) of a single virtuoso subject. Data was collected in two independent data collection periods separated by one year. The 'hypnotic' and 'non-hypnotic' conditions were repeated multiple times during each data acquisition session. We found that pure hypnosis induced reorganization in the composition of brain oscillations especially in prefrontal and right occipital EEG channels. Additionally, hypnosis was characterized by consistent rightside-dominance asymmetry. In the prefrontal EEG channels the composition of brain oscillations included spectral patterns during hypnosis that were completely different from those observed during non-hypnosis. Furthermore, the EEG spectral patterns observed overall during the hypnotic condition did not return to the pre-hypnotic baseline EEG immediately when hypnosis was terminated. This suggests that for the brain, the return to a normal neurophysiological baseline condition after hypnosis is a time-consuming process. The present results suggest that pure hypnosis is characterized by an increase in alertness and heightened attention, refl ected as cognitive and neuronal activation. Taken together, the present data provide support for the hypothesis that in a very highly hypnotizable person (a hypnotic virtuoso) hypnosis as such may be accompanied by a changed pattern of neural activity in the brain.

The Existence of a Hypnotic State Revealed by Eye Movements

“…Hypnotic induction has been shown to involve changed patterns of activation in the same cortical areas [6]–[7], [9]. The putative role of these prefrontal areas in the hypnotic state is further elaborated by our previous results with TS-H. Two studies [26]–[27] utilizing EEG have revealed changes in the frontal areas of the brain. Fingelkurts et al [27] found that in the prefrontal EEG channels the composition of brain oscillations included spectral patterns during hypnosis that were significantly different from those observed during non-hypnosis.…”

A Preconscious Neural Mechanism of Hypnotically Altered Colors: A Double Case Study

“…She can be hypnotized and returned into a normal waking state by using a one-word induction (see [8] for a video-clip of the procedure). Her brain functioning [11]–[13] and automatic eye-movements [8] are immediately altered by hypnosis. It is unknown what proportion of highly hypnotizable participants are similar to TS-H, but they are very rare and difficult to find with the standard screening procedures [14].…”

Posthypnotic State Changes and Flashbacks: Analogous Processes?

“…The majority of recent studies of the neurophysiology of hypnosis used neuroimaging techniques such as positron emission tomography or functional magnetic resonance imaging and found hypnosis to be associated with activations of frontal and prefrontal areas of the brain, most frequently areas of the anterior cingulate cortex (ACC; Aleksandrowicz, Binder, & Urbanik, 2007;Casiglia et al, 2010;Faymonville et al, 2000Faymonville et al, , 2003Fingelkurts, Fingelkurts, Kallio, & Revonsuo, 2007a, 2007bGruzelier, 2006;Halligan, Athwal, Oakley, & Frackowiak, 2000 …”