Experimental Studies in the Effects of Psilocybin on Binocular Depth Inversion, Binocular Rivalry, Neuropsychology and Synaesthesias

Investigators: Torsten Passie M.D., M.A.; Jürgen Seifert M.D., Udo Schneider M.D., Hinderk M. Emrich M.D., Ph.D.

Torsten Passie M.D. This is a study in 12 healthy physicians using medium doses of psilocybin to examine the effects of psilocybin on neuropsychological measures, changes in perception, and some subjective effects.

In our department, we conduct a lot of research the nature and neurophysiology of synaesthesias. In the psilocybin study, we are trying to explore the synaesthesias specific for psilocybin. We also study the alterations of some neuropsychological functions (attention, reaction time etc.), and other parameters.

For ethical reasons (to reduce the psychological discomfort of the subjects), the experiment as a whole was designed to leave most of the time free of experimental procedures, so the subjects could experience the psilocybin state in their individual ways. The room is specially furnished, and subjects have the opportunity to lie down and relax for several hours. This may help participants to look at themselves and have some valuable insights or healing experiences.

This protocol includes research with the newly designed hollow-mask paradigm, with subjects looking alternately into a mask from the outside and from the inside. If all the shading and colors are identical from inside and outside, the subject's mind will change the view of the hollow mask to that of the "normal" mask's view because this view is more plausible. This implies that the mind's top-down conceptualization dominates the evaluation of reality more than the use of bottom-up data from our senses, especially when the thing being seen is ambiguous.

Another unusual paradigm is binocular rivalry. This paradigm offers two opposing perceptions to the eyes and mind. [That is, a series of rightward slanting crosshatches may be presented in one eye and a series of leftward slanting crosshatches in the other.] Because of the ambiguous nature of the perceptions, the mind will change steadily between them. The frequency of these alterations may have some basic implications for the understanding of the communication between the two hemispheres of the brain and for altered states of consciousness in general.

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