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Measuring the subjective: revisiting the psychometric properties of three rating scales that assess the acute effects of hallucinogens

Written by: José Carlos Bouso, Eduardo José Pedrero-Pérez, Sam Gandy, Miguel Ángel Alcázar-Córcoles

Objective: In the present study we explored the psychometric properties of three widely used questionnaires to assess the subjective effects of hallucinogens: the Hallucinogen Rating Scale (HRS), the Mystical Experience Questionnaire (MEQ), and the Addiction Research Center Inventory (ARCI).

Methods: These three questionnaires were administered to a sample of 158 subjects (100 men) after taking ayahuasca, a hallucinogen whose
main active component is N,N-dimethyltryptamine (DMT). A confirmatory factorial study was conducted to check the adjustment of previous
data obtained via theoretical proposals. When this was not possible, we used an exploratory factor analysis without restrictions, based on tetrachoric and polychoric matrices and correlations.

Results: Our results sparsely match the theoretical proposals of the authors, perhaps because previous studies have not always employed
psychometric methods appropriate to the data obtained. However, these data should be considered preliminary, pending larger samples to
confirm or reject the proposed structures obtained.

Conclusions: It is crucial that instruments of sufficiently precise measurement are utilized to make sense of the information obtained in the study of the subjective effects of psychedelic drugs. Copyright © 2016 John Wiley & Sons, Ltd.

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October 6, 2016 0 Comments

Serotonin Receptor Signaling and Hallucinogenic Drug Action

An oldie but a goodie. This article is of interest because it helps elaborate on the concept that 5-MeO-DMT has high affinity for the serotonin 5-HT1A receptor, and it is 4- to 10-fold more potent than N,N-dimethyltryptamine (DMT) in human subjects” (Shen, H.-W., Jiang, X.-L., Winter, J. C., & Yu, A.-M.). In this article, we can take a look at how various “hallucinogens” also known as psychedelics, entheogens, or medicines affect the serotonergic system in the brain. The article takes a look at the structures of tryptamine, serotonin, psilocin, 5-MeO-DMT, and LSD and also talks about DOI as “hallucinogenic” substances.

From article:
“There are seven known families of serotonin receptors, named 5-HT1 through 5-HT7, encompassing at least 15 subtypes. The classification of receptors relies upon sequence similarity as well as second messenger pathways coupled to receptor activation (reviewed in Gerhardt and Heerikhuizen, 1997). Hallucinogens all have a high affinity for certain serotonin receptor subtypes, namely, the 5-HT2A and 5-HT2C receptor subtypes (Glennon et al, 1984; Sanders-Bush et al, 1988). The relative hallucinogenic potencies of various drugs can be extrapolated by their affinities for these receptors (Glennon et al, 1984).”

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Shen, H.-W., Jiang, X.-L., Winter, J. C., & Yu, A.-M. (2010). Psychedelic 5-Methoxy-N,N-dimethyltryptamine: Metabolism, Pharmacokinetics, Drug Interactions, and Pharmacological Actions. Current Drug Metabolism, 11(8), 659–666.

Posted by: Rafael Lancelotta

September 17, 2016 0 Comments

The serotonergic hallucinogen 5-Methoxy-N,N-dimethyltryptamine disrupts cortical activity in a regionally-selective manner

Authored by: Maurizio S. Riga, Bc, Analia Bortolozzi, PhD, Letizia Campa, Bc, Francesc Artigas, PhD, Pau Celada, PhD

5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is a natural hallucinogen, acting as a non-selective serotonin 5-HT 1A /5-HT 2A -R agonist. Psychotomimetic agents such as the non-competitive NMDA-R antagonist phencyclidine and serotonergic hallucinogens (DOI and 5-MeO-DMT) disrupt cortical synchrony in the low frequency range (<4 Hz) in rat prefrontal cortex (PFC), an effect reversed by antipsychotic drugs. Here we extend these observations by examining the effect of 5-MeO-DMT on low frequency cortical oscillations (LFCO, <4 Hz) in PFC, visual (V1), somatosensory (S1) and auditory (Au1) cortices, as well as the dependence of these effects on 5-HT 1A -R and 5-HT 2A -R, using wild type (WT) and 5-HT 2A -R knockout (KO2A) anesthetized mice. 5-MeO-DMT reduced LFCO in the PFC of WT and KO2A mice. The effect in KO2A mice was fully prevented by the 5-HT 1A -R antagonist WAY-100635. Systemic and local 5-MeO-DMT reduced 5-HTU release in PFC mainly via 5-HT 1A -R. Moreover, 5-MeO-DMT reduced LFCO in S1, Au1 and V1 of WT mice and only in V1 of KO2A mice, suggesting the involvement of 5-HT 1A -R activation in the 5-MeO-DMT-induced disruption of V1 activity. In addition, antipsychotic drugs reversed 5-MeO-DMT effects in WT mice. The present results suggest that the hallucinogen action of 5-MeO-DMT is mediated by simultaneous alterations of the activity of sensory (S1, Au1, V1) and associative (PFC) cortical areas, also supporting a role of 5-HT 1A -R stimulation in V1 and PFC, in addition to the well-known action on 5-HT 2A -R. Moreover, the reversal by antipsychotic drugs of 5-MeO-DMT effects adds to previous literature supporting the usefulness of the present model in antipsychotic drug development.

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Posted by Rafael Lancelotta

September 15, 2016 0 Comments

5-Methoxy-N,N-Dimethyltryptamine Metabolism, Pharmacokinetics, Drug Interactions, and Pharmacological Actions

Research carried out by: Hong-Wu Shen, Xi-Ling Jiang, Jerrold C. Winter and Ai-Ming Yu

Abstract: 5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) belongs to a group of naturally-occurring psychoactive indolealkylamine drugs. It acts as a nonselective serotonin (5-HT) agonist and causes many physiological and behavioral changes. 5-MeO-DMT is O-demethylated by polymorphic cytochrome P450 2D6 (CYP2D6) to an active metabolite, bufotenine, while it is mainly inactivated through the deamination pathway mediated by monoamine oxidase A (MAO-A). 5-MeO-DMT is often used with MAO-A inhibitors such as harmaline. Concurrent use of harmaline reduces 5-MeO-DMT deamination metabolism and leads to a prolonged and increased exposure to the parent drug 5-MeO-DMT, as well as the active metabolite bufotenine. Harmaline, 5-MeO-DMT and bufotenine act agonistically on serotonergic systems and may result in hyperserotonergic effects or serotonin toxicity. Interestingly, CYP2D6 also has important contribution to harmaline metabolism, and CYP2D6 genetic polymorphism may cause considerable variability in the metabolism, pharmacokinetics and dynamics of harmaline and its interaction with 5-MeO-DMT. Therefore, this review summarizes recent findings on biotransformation, pharmacokinetics, and pharmacological actions of 5-MeO-DMT. In addition, the pharmacokinetic and pharmacodynamic drug-drug interactions between harmaline and 5-MeO-DMT, potential involvement of CYP2D6 pharmacogenetics, and risks of 5-MeO-DMT intoxication are discussed.

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Posted by: Rafael Lancelotta

September 9, 2016 0 Comments

Correcting Ocular Artifacts in EEG Signals

84_neuroeletrics_WIRED_00-81 February, 2016

All of us who deal with EEG signals know how important artifacts are. EEG is one of the biological potentials with lowest amplitude (typically a few microvolts), which makes it highly sensitive to be contaminated by undesired interferences, known as artifacts. We can find several artifacts sources such as be biological (recorded activity from other sources than the brain, i.e. the heart, muscles or eye movements), electromagnetic (interferences from other electronic equipment or mains noise) and others derived from head movements or changes in the skin-electrode interface. In general we can manage artifacts in two ways: detecting their appearance and remove the entire contaminated EEG sequence or cleaning artifacts interference from the recorded EEG signal, this last technique known as artifact correction.

One of the most relevant artifacts that pollute EEG recordings comes from interferences from eyes and eyelid movements. The closer to the eyes an electrode is placed, the more it is affected by these ocular artifacts. Among EOG artifacts the most relevant ones are eye-blinks. These interferences can be in the order of hundreds of micro-volts while artifact free EEG is the order of tens of micro-volts. Ocular artifacts contaminate the EEG in the band ranging from 0 to 15 Hz interfering with three of the most commonly used EEG bands, Delta, Theta and Alpha.

There are many techniques to correct artifacts, in this post I introduce three of the most commonly used. However none of them is perfect and researchers are still devoted to find mathematical methodologies to robustly subtract these interferences from EEG recordings. To this effect, EEG set-ups usually include electrodes to record EOG signals that are usually placed above/below eyes (Vertical EOG artifacts) and next to them (Horizontal EOG artifacts). These techniques are an example of currently accepted EOG correction techniques, however, there are many more such as neural networks, wavelet analysis…

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February 26, 2016 0 Comments

Brain Network Reconfiguration and Perceptual Decoupling During an Absorptive State of Consciousness

Trance is an absorptive state of consciousness characterized by narrowed awareness of external surroundings and has long been used—for example, by shamans—to gain insight. Shamans across cultures often induce trance by listening to rhythmic drumming. Using functional magnetic resonance imaging (fMRI), we examined the brain-network configuration associated with trance. Experienced shamanic practitioners (n = 15) listened to rhythmic drumming, and either entered a trance state or remained in a nontrance state during 8-min scans. We analyzed changes in network connectivity. Trance was associated with higher eigenvector centrality (i.e., stronger hubs) in 3 regions: posterior cingulate cortex (PCC), dorsal anterior cingulate cortex (dACC), and left insula/operculum. Seed-based analysis revealed increased coactivation of the PCC (a default network hub involved in internally oriented cognitive states) with the dACC and insula (control-network regions involved in maintaining relevant neural streams). This coactivation suggests that an internally oriented neural stream was amplified by the modulatory control network. Additionally, during trance, seeds within the auditory pathway were less connected, possibly indicating perceptual decoupling and suppression of the repetitive auditory stimuli. In sum, trance involved coactive default and control networks, and decoupled sensory processing. This network reconfiguration may promote an extended internal train of thought wherein integration and insight can occur.

  1. Cereb. Cortex (2015) doi: 10.1093/cercor/bhv137   

Full abstract here:

February 20, 2016 0 Comments

Recording brain waves in extreme situations: the psychoactivity of ayahuasca


Ayahuasca is an amerindian psychoactive sacrament used worldwide. Neuroscience studies have shown contradictory results regarding its effects in the brain (Don et al, 1998, Hoffmann et al, 2001, Riba et al, 2002, 2004, Stuckey et al, 2005, dos Santos et al, 2012). Combining EEG, plasma samples and robust statistics, we’ve uncovered biphasic effects in the brain which are related to many psychoactive compounds, not only N,N-dimethyltryptamine (DMT), as previously proposed.

To achieve this breakthrough, we had to deal with a series of technological and conceptual challenges. Since we faced a situation involving an altered state of consciousness, which makes remaining quiet and immobile very challenging, we anticipated noisy signals. Ayahuasca’s effects last at least four hours, possibly more. Thus, deciding which segments to analyze and how to best deal with a large multidimensional dataset was an additional challenge (channels, time, frequency, and subjects as its four dimensions, plus the plasmatic levels of chemical compounds over time)

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Or download the full PDF:  Brain Products Press Release – EEG in extreme situations like ayahuasca

January 5, 2016 0 Comments



by Juan Acosta-Urquidi, PhD

ABSTRACT: Recent brain imaging studies in Psychedelic Brain Science are breaking new ground in our understanding of neurological substrate of biological consciousness in humans. The emerging field of inner experience and neuroscience is particularly well suited to the reexamination of the actions of psychedelics on subjective conscious experience. This approach is best understood as neurophenomenology. My work over the last few years has focused on the EEG correlates of the visionary tryptamine DMT action. I believe the researcher must also have the drug experience as part of the experimental protocol, in order to fully understand the richness of the phenomenon. The objective of this exploratory research was to examine the QEEG correlates of the psychoactive smoked inhalation of exogenous DMT action. Known as a potent visionary tryptamine, DMT is ubiquitous in nature and has also been localized in the brain and peripheral tissues of mammals, including humans. The exact function of this endogenous DMT is the subject of ongoing neuropharmacological research.

Three sources of DMT were tested: high purity synthetic 5-MeO- DMT, Bufo 5-MeO-DMT (an extract from the Sonoran desert toad venom, Bufo alvarius), and N,N- DMT from a natural extract of the Acacia tree Mimosa hostilis root bark.

The DMT was delivered by smoked inhalation (vaporization). The rapid onset (10-20 sec), short acting (5-15 min.), and reversible nature of the effects made such a QEEG study feasible. DMT dosage was adjusted to elicit an effective psychedelic experience (ca. 20-30 mg for N,N-DMT; 2-5 mg for synthetic 5-MeO-DMT, and 30-40 mg for the Bufo 5-MeO-DMT material). Healthy volunteers (age 25-60; N=15 men, N=8 women) were tested.

The protocol consisted of: 5-10 min. baseline control (resting eyes closed) was first acquired, followed by the DMT test condition, usually lasting 5-15 min. When subjects recovered from the DMT induced altered state, a report of their subjective experience was recorded on video and a post recovery EEG reading was made typically at 15-30 min. A statistical comparison (paired t-tests, correlated samples) of absolute power values for all EEG bands between baseline vs. DMT tests and post recovery conditions was carried out for all subjects. The DMT- induced profound alterations in consciousness were tracked with the shifts in the QEEG metrics analysed. The time course and intensity of the subjective experience correlated with the magnitude of the observed EEG effects.

published in Cosmos and History: The Journal of Natural and Social Philosophy, vol. 11, no. 2, 2015 

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QEEG Studies of the Acute Effects of the Visionary Tryptamine DMT. Cosmos and History 11(2), 2015

December 3, 2015 0 Comments


by Tania Re & Carlo Ventura

(With the collaboration of Giuseppe Vitiello, Mario Simoes and Jorge Martines)

ABSTRACT: The Unesco Chair “Anthropology of Health, biosphere and Healing System” inside the University of Genoa (IT) is a unique experience inside the University of Genoa that stems from a cultural necessity to fill and a wealth of knowledge to preserve health, environment and treatment strategies considered strictly connected in modern medicine. This new, integrated approach contradicts and overcomes the traditional separation between humanities and scientific medicine and treatments. Health and approach to treatment strategies are not uniform around the worlds; the universal baseline is quality assurance of investigation in science

The need to establish connections between Medicine, especially in the therapeutic aspect (healing), and all the information already obtained from the mind-matter phenomenology has led to much experimentation and theorizing in this border and transcultural area.

The research group formed by anthropologist who have studied altered states of consciousness in different cultures, medical doctors, quantum physicists and molecular biologists will try to define a transcultural perspective on consciousness merging anthropology, medicine and physics.

published in Cosmos and History: The Journal of Natural and Social Philosophy, vol. 11, no. 2, 2015 


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December 3, 2015 0 Comments

Alpha power increases during energy healing

Conference Paper

Alpha power increases during energy healing. EEG studies of healers, mystics and shamans.

  • Juan Acosta-Urquidi
    Juan Acosta-Urquidi
Conference: ISSSEEM 22nd Conference. Research Symposium, At Holos University, MO


TITLE: Alpha power increases during energy healing. EEG studies of healers, mystics and shamans AUTHOR: Acosta-Urquidi, J. OBJECTIVE: This study addressed two questions: 1.What is the healer’s state of consciousness (ie. the EEG brainstate) during the act of healing? 2. Does the client that is receiving the healing treatment also exhibit a shift in brainstate, and does it share common features with the healer’s? The efficacy or the outcome of the healings were not investigated. MATERIALS/METHODS: This comparative QEEG (quantitative electroencephalography) study examined and 3 groups who volunteered to be tested: 1. A sample of bioenergy healer practitioners (N=20) from diverse traditions, including Reiki, Pranic, Johrei, Faith Healing, Shamanic, Spiritual, and Quantum Touch (healing state, HS group). 2. Clients who volunteered to receive a healing session (” receiving healing, RH group, N=11), were also tested and 3. A control group of non-healers (” sham healing ” , ShaH group, N=9) was also similarly examined. QEEG data (19 channels, 0.1-40 Hz bandwidth) was recorded from the 3 groups during a baseline (control) condition and during HS in the healers group, during RH condition for the client group and similarly for the ShaH group. A statistical within group comparison (paired correlated t-tests, P values) between the QEEG absolute power values before (baseline) and during HS, RH and ShaH was achieved. FFT spectral analysis, topographic brainmaps, numerical tables and a summary group comparison bar graph plot reveal the findings. RESULTS: During the healing state (HS), the healers and clients brainwaves exhibited some changes across all frequency bands: Delta (0.3-4 Hz),Theta (4-8 Hz), Alpha (812Hz) and Beta (13-40 Hz). However, only the most consistent, reproducible and statistically significant result is reported here, viz. a robust increase in global Absolute Alpha power. For group 1 (HS), the increased Alpha power was (mean % increase +-SEM): 98.05 +-15.10, N=20,P<.0032. For group 2 (RH), the increased Alpha power was also highly significant : 112.5 +-21.9; N=11, P<0.0002). 3. For group 3 (ShaH, N=9), there was no statistically significant change in Alpha power. CONCLUSION: This scientific comparative study provides objective data demonstrating that Energy Healers (Bioenergy Healers) from diverse traditions can shift their EEG to produce more Alpha power when engaged in the act of healing (local and distant). Moreover, clients receiving the healing also produced robust increased Alpha power. The unexpected finding that different healing traditions all share a common denominator, viz. increased Alpha power during HS, and that the Alpha power increase is also measured in the clients during RH is discussed.

Alpha power increases during energy healing. EEG studies of healers, mystics and shamans. (PDF Download Available). Available from: [accessed Nov 13, 2015].

ISSSEEM Abstr. 2014



November 13, 2015 0 Comments

Terra Incognita Public Launch/ Consciousness Hackers Meetup, April 13, 2015

The public launch of the Terra Incognita Project, presented Monday April 13th at the Palace Theater, Oakland. “Vegetal & Virtual Technologies: Using Neuroshamanic tools to map and integrate the Terra Incognita in the 21st Century”. Film maker Rak Razam, community member Dr. Juan Acosta, serial entrepreneur Joseph Winke, and licensed therapist Meriana Dinkova will host a discussion of their project exploring the merging of neuro-technology and the shamanic experience. Come along and join the discussion on ayahuasca culture, consciousness, and neuroscience technologies that can be used to help integrate the states of mind.  For more information visit: For more information visit:

July 20, 2015 0 Comments

Terra Incognita Soft Launch, Silicon Valley, April, 2015

The private launch of the Terra Incognita Project to the Silicon Valley EEG community, hosted at Joy Labz by Mikey Siegel, April 12, 2015. With Founder and Director Rak Razam, Founder Joe Winke, and neuroscientist Founder Dr. Juan Acosta.  With thanks and support from the Consciousness Hacking community: For more information visit: For more information visit:

July 20, 2015 0 Comments