Psychological Explorations of the Magic Mushroom (Psilocybin) Experience, Part II : Neuropsychological Measures José Arturo Costa Escobar & Antonio Roazzi, 2011

Psychological Explorations of the Magic Mushroom (Psilocybin) Experience, Part II : Neuropsychological Measures

José Arturo Costa Escobar, M.S., Antonio Roazzi, Ph.D.

Neurobiologia, 2011, 74, (3-4), 99-112.



Some investigations conducted with psilocybin and mushrooms of the Psilocybe genus on the human mind point to a peculiarity of these substances to promote a special state of consciousness. The present study measured the effects of dehydrated magic mushrooms on human visual processes and memory utilizing tasks in a pre- and post-test form. We observed defi cits in visual working memory and these results were consistent with other, recent psilocybin studies. However this and other visual mechanisms were not affected as measured according to the functions of the Motor-Free Visual Perception Test, suggesting an important role for unconscious attentional process in working memory tasks. Participants’ performances on a manual line bisection task suggested a dominant activity of the left brain hemisphere during its realization, or synchronization of brain hemisphere activity, and seem to differ from the performance of schizophrenia subjects. In conclusion, magic mushrooms showed to be a potential tool in investigation of the psychological processes and basic functional aspects of general human cognition.

KEY WORDS : Perception; Memory; Hallucinogens; Psychedelics; Psychotomimetic; Cognition.



The genus Psilocybe constitutes an important group of Fungi called magic mushrooms due to their psychoactive effects. They have been widely used as entheogens by Indians of Central America and ritual use continues until today as well and as new modes of use like hedonistic (1-3). In Brazil there are some species which occur throughout the territory (4-6).

Psilocybe are rich in the compounds psilocybin and psilocin. These compounds act primarily on the
serotonergic brain system, promoting a complex altered state of consciousness characterized by modifications in perception, cognition, volition, sometimes accompanied by a sense of mystical-like experiences and believed to resembled schizophrenia and psychosis (7-12).

Current knowledge demonstrates that psilocybin is capable of interfering with cognitive mechanisms
(e.g., memory processing, visual perception, perception of time, language, attention, etc.) as well in brain substrates, with particular action on limbic structures, the reptilian complex and neo-cortex (12- 20). Some of these studies have revealed similarities with mental and cerebral functioning usually found
in schizophrenic patients. This resemblance has led some investigation on psychopharmacology since
psychedelic substances discovery by modern science about one hundred years ago are now recognized as important tools in psychosis research (10, 11, 21).

Understanding what mechanisms function in the altered states of consciousness induced by psychedelics represents an important fi eld that seeks to explain its resemblance with schizophrenia and psychosis, as well as its psychotherapeutic potential as pointed out by some contemporary research (20, 22-28).

The present study had the objective of exploring the action of the consumption of magic mushrooms
on human cognition. In this second part of our study, we present the results of neuropsychological tests, with particular attention to a discussion of the Model Psychosis Paradigm for psychedelic substances.