Out-of-Body Experiences Simulated by Stimulation of Portion of Brain

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During a week in which UFO’s were part of the Democratic debate, it only seemed to make sense that today’s issue of The New England Journal of Medicine would include an article on out-of-body experiences. The report shows the sensation of an out-of-body experience being simulated by stimulation of the posterior part of the superior temporal gyrus. Figure A (above) shows a three dimensional MRI reconstruction of the brain overlaid with clusters of significant increases in brain activity. From the discussion:

It has been suggested that an out-of-body experience results from a deficient multisensory integration at the temporoparietal junction on the right side.1 This hypothesis has been developed from data on lesions, the results of transcranial magnetic stimulation, and electrophysiological findings in healthy volunteers and patients with epilepsy,9 as well as from single-scan, ictal single-photon-emission computed tomographic imaging and interictal PET imaging in patients with epilepsy.1 We used functional neuroimaging with a controlled design to capture the regions of the brain that are engaged during an isolated, pure state of disembodiment. The consistency of the evoked out-of-body experience in our patient and its relatively long duration allowed for the use of PET scanning to visualize brain areas that were activated during the out-of-body experience.

The activation of the area at the junction of the angular gyrus and the supramarginal gyrus on the right side is probably related to the feeling of disembodiment and may be a consequence of disrupted somatosensory (mainly proprioceptive) and vestibular integration. The supramarginal gyrus on the right side of the brain in humans is involved in the processing of vestibular information for head and body orientation in space.10 Electrical stimulation of the angular gyrus on the right side induces vestibular and complex somatosensory responses,5 suggesting that the angular–supramarginal junction might be involved in the vestibular somatosensory integration of body orientation in space.

The general area of the superior temporal cortex has been thought to embody an internal map of self-perception, as one component of human self-consciousness.7 During disembodiment, self-perception is altered, but global self-consciousness is retained. In contrast, during depersonalization and derealization, both global self-consciousness and self-perception are retained, but the person feels dissociated from the surroundings.3 Imaging studies have revealed that dissociation and depersonalization scores in subjects with depersonalization disorder are significantly related to metabolic activity in the inferior parietal cortex (Brodmann’s area 7B), suggesting that spatial mislocalization of the self in relation to the physical body (disembodiment) is associated with activation of the angular–supramarginal junction, as we have shown, whereas spatial mislocalization of the self in the surrounding environment may be associated with somewhat more dorsally located inferior parietal activation.11

In addition, the precuneus has been implicated as part of a functional network generating reflective self-awareness as a core function of consciousness.12 PET imaging has shown that the angular gyrus, anterior cingulate gyrus, and precuneus are functionally connected and synchronously active during reflective self-awareness.12 The precuneus is reciprocally connected to both the posterior thalamus complex and the inferior parietal lobule–temporoparietal junction.13

For some reason I suspect that Deepak Chopra might have a different idea as to what causes out-of-body experiences.

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