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“Ayahuasca turned on my mind’s eye”: Enhanced visual imagery after ayahuasca intake in a man with “blind imagination” (aphantasia)

  • Ribeirão Preto Medical School, University of São Paulo, Brazil
  • International Center for Ethnobotanical Education, Research and Service (ICEERS)


Background and aims: Aphantasia (“blind imagination”) is a poorly described condition with an uncertain etiology, characterized by reduced or lack of voluntary visual imagery. Preliminary evidence in humans suggests that hallucinogenic or psychedelic drugs that act as agonists of cortical 5-HT2A receptors [lysergic acid diethylamide, psilocybin, and dimethyltryptamine (DMT)] enhance visual imagery. Methods: Interview and description of the case are presented in this study. Results: A man self-diagnosed with long-lasting aphantasia that he attributed to a traumatic separation from his father when he was young and to a difficult relationship with him described sustained improvements in his visual imagery following ingestion of a single dose of the South American botanical hallucinogen ayahuasca, which is rich in DMT. Although improvements were modest, they were sustained and significative for the subject. Conclusions: It is suggested that the described improvements were possibly attributed to biological and psychological processes, including stimulation of cortical 5-HT2A receptors, subsequent increased activity in the visual cortex, enhanced imaginative and imagery capacities, and psychosomatic resolution of a previous psychological trauma. Further trials could elucidate the role of 5-HT2A agonists, especially ayahuasca, in aphantasia.
Ayahuasca turned on my minds eye: Enhanced visual imagery after
ayahuasca intake in a man with blind imagination(aphantasia)
Faculdade de Medicina de Ribeirão Preto, Departamento de Neurociências e Ciências do Comportamento,
Hospital das Clínicas, Universidade de São Paulo, Ribeirão Preto, Brazil
National Institute of Science and Technology Translational Medicine, Ribeirão Preto, Brazil
ICEERS Foundation (International Center for Ethnobotanical Education, Research and Services), Barcelona, Spain
The Enyart Group, Los Angeles, CA, USA
(Received: April 12, 2018; revised manuscript received: June 14, 2018; accepted: June 18, 2018)
Background and aims: Aphantasia (blind imagination) is a poorly described condition with an uncertain etiology,
characterized by reduced or lack of voluntary visual imagery. Preliminary evidence in humans suggests that
hallucinogenic or psychedelic drugs that act as agonists of cortical 5-HT
receptors [lysergic acid diethylamide,
psilocybin, and dimethyltryptamine (DMT)] enhance visual imagery. Methods: Interview and description of the
case are presented in this study. Results: A man self-diagnosed with long-lasting aphantasia that he attributed to a
traumatic separation from his father when he was young and to a difcult relationship with him described sustained
improvements in his visual imagery following ingestion of a single dose of the South American botanical hallucinogen
ayahuasca, which is rich in DMT. Although improvements were modest, they were sustained and signicative for the
subject. Conclusions: It is suggested that the described improvements were possibly attributed to biological and
psychological processes, including stimulation of cortical 5-HT
receptors, subsequent increased activity in the visual
cortex, enhanced imaginative andimagery capacities, and psychosomaticresolution of a previous psychological trauma.
Further trials could elucidate the role of 5-HT
agonists, especially ayahuasca, in aphantasia.
Keywords: aphantasia, visual imagery, psychedelics, hallucinogens, ayahuasca
Visual imagery is usually experienced by humans in mem-
ory processes, day-dreaming/mind-wandering, dreaming,
imagination, and creativity. Some techniques, such as
breathing exercises, imagery training, and psychoactive
drugs, can and have been used to stimulate visual imagery
and creativity (Schultes & Hofmann, 1992). The neural
basis of voluntary imagery involves activation of frontal
and parietal brain regions associated with memory and
executive functions and of occipital regions related to visual
processing (Zeman, Dewar, & Della Sala, 2015).
Aphantasia is a term proposed by Zeman et al. (2015)to
describe a rarely recognized phenomenon characterized by
reduced or absent voluntary imagery.The neural basis of
this apparently rare condition is not well-understood but
seems to involve decits of information processing in the
same brain regions that are involved in visual imagery,
i.e., frontoparietal and occipital cortices. Moreover, decits
in visual memory and other cognitive functions also seem to
be involved (Zeman et al., 2015;Zeman, Dewar, & Della
Sala, 2016). Some authors have suggested that aphantasia
may have a psychological origin, instead of an organic basis
(de Vito & Bartolomeo, 2016). Consistent with this perspec-
tive, aphantasia is often associated with depressive, anxious,
and dissociative disorders. Thus, several possible interacting
factors may contribute to this condition. To the best of the
authorsknowledge, there are no treatments for this condition.
Ayahuasca is a psychoactive botanical preparation with
a long history of ritual and therapeutic uses in the
northwestern Amazon. It is prepared by the decoction of
the stalks of the harmine-rich liana Banisteriopsis caapi
together with the leaves of the Psychotria viridis bush, which
contains dimethyltryptamine (DMT; Schultes & Hofmann,
1992). Harmine and related beta-carbolines are reversible
inhibitors of monoamine oxidase, and DMT acts as an
agonist at cortical 5-HT
receptors. Open-label and
controlled studies showed that a single ayahuasca dose
was associated with signicant reductions in depressive
symptoms in patients with treatment-resistant depression
(Palhano-Fontes et al., 2018;Sanches et al., 2016). Interest-
ingly, ayahuasca as other agonists of cortical 5-HT
receptors, such as lysergic acid diethylamide (LSD)
* Corresponding author: Rafael G. dos Santos, PhD; Faculdade de
Medicina de Ribeirão Preto, Departamento de Neurociências e
Ciências do Comportamento, Hospital das Clínicas, Universidade
de São Paulo, Terceiro Andar, Av. Bandeirantes, 3900, Ribeirão
Preto, São Paulo, Brazil; Phone/Fax: +55 16 3602 2703; E-mail:
This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License,
which permits unrestricted use, distribution, and reproduction in any medium for non-commercial purposes, provided the original author and
source are credited, a link to the CC License is provided, and changes if any are indicated.
© 2018 The Author(s)
CASE REPORT Journal of Psychedelic Studies
DOI: 10.1556/2054.2018.008
and psilocybin enhances visual imagery (Carhart-Harris
et al., 2016;de Araujo et al., 2012;dos Santos, Os´orio,
Crippa, & Hallak, 2016;Roseman et al., 2016).
In October 2016, the authors were contacted by a
39-year-old man, Scotty Enyart (SE), who claimed that
ayahuasca improved his aphantasia.
SE believed that his symptoms began early in his life, since
he recalls from an early age that his inner experiences were
different from others.According to SE, he was diagnosed
with poor visual imagery in elementary, middle, and high
schools. For instance, reading never evoked visual imagery
and at the age of 16, he could not visualize the patterns of
words, and he described his spelling ability as: was that of
an eleven-year-old and my reading comprehension was
even more delayed than my spelling.Moreover, during
this period, he had low self-esteem and had to receive
special education classes and extended hours of practicing
tasks, including typing: Looking back at my life it became
clear that my spelling ability developed to an age appro-
priate level only when I learned how to type. A component of
being a good speller is remembering patterns of words; so,
when someone cant recall how to spell a word they will
visualize the word. Learning how to type allowed me to
understand words through touch, so if I cant recall a word I
will use my ngers, muscle memory, to feel the word out.
At that time, in the mid 1990s, there was not a formal
diagnosis of aphantasia since the term had not been pro-
posed yet. SE rst noticed that he had aphantasia in 2001,
during a cognitive psychology course in his undergraduate
program, when he was 24 years old: The professor asked us
students to close our eyes and recall an image of a clock.
Once we identied an image he then asked us to draw that
image on a piece of paper. The other students began to draw
detailed clocks. I closed my eyes several times trying to
bring forth an image of a clock, yet nothing came.He self-
diagnosed his aphantasia in 2015 after watching a BBC
special report on a man with the same diagnosis (Gallagher,
2015). SE explained to us that: When I close my eyes I
cannot see my wifes face, I cannot see my children. If I close
my eyes and think about my wife or kids I sense physical
space, facial features that are unique to my wife and kids are
not seen but the feeling of these features is there. I can sense
my emotional attachment to them deeply. I can hear their
voices, I can sense their touch, but I cannot see them.
Moreover, he told us that he does not see anything in his
dreams: My dreams are felt spatially and emotionally but
the visual doesnt exist. When dreaming about being chased
by a monster I can feel I am moving through space and I
experience intense fear, but the monster has no form, it is a
terrifying felt presence that is coming after me.
SE reported that when he was a teenager, he experi-
mented with hallucinogens/psychedelics, such as LSD and
psilocybin, but according to him, these experiences were
externalwith visual effects experienced only with opened
eyes: The settings were with others walking around during
the day hours watching walls melt in public places or seeing
people with distorted faces pass by in the parks. We all sat
around laughing and watching the lines formed by our
hands as we waved them in front of our faces.According to
SE, these early experiences with hallucinogens brought
about meaningful experiences to him. However, there were
no eyes-closed effects on visual imagery.
While doing a PhD in psychology, he traveled to the
Amazon region to try ayahuasca. Thirty minutes after
ingesting a single dose, he began vomiting and described
the experience of being physically in the Amazon jungle,
but his mind was back in the city:I saw my life being
acted out in front of me as if I was watching a play from the
balcony.Suddenly his experience changed into fear, when
he felt spiraling through a colorful tunnel.The healer
started chanting and calmed him. With his eyes closed, he
saw his father, who had passed away years ago: I could see
him clearly, hear his voice, and even smell the distinct smell
that he picked up from working in the oil elds. I was seeing
in visual imagery for the rst time in my life as I laid there
with my eyes closed.
SE then described a complex scene involving the difcult
relationship that he had with his father, who left him when
he was very young. This early separation seemed to be quite
a traumatic and painful event to SE, who later developed a
difcult relationship with his father: My father left when I
was too young to remember. My rst memory of my father
was seeing him years later and of him getting upset at me
because I didnt know who he was. My brother and I used to
travel during the summer breaks to visit him. These visits
were pleasant but short and, as I grew older, confusing. My
father used to take me into grocery stores and put food into
my clothes and walk out of the store without paying. He
would tell me, my brother, and my step-brother to steal
televisions from the store while he distracted the store
clerk and if we got caught he would punish us in front
of the clerk. I have many similar stories, stories that made
no sense to me, but their importance lies not in the facts but
in the pain under the stories. We were never close, and when
he eventually moved back to be closer with us, I was an
angry teenager. This anger of course made me want to
reject him, and his response was to put as much blame back
on me as he could.
This difcult relationship persisted until the death of his
father some years: When I was 19 he was burned in a steam
re and developed a staph infection. We knew he was dying
and one day after my classes at the local city college I visited
him. I was alone with him and at this point he no longer was
breathing on his own, and he lay there unresponsive. The
nurse encouraged me to speak to him, saying that he could
hear me, but I couldnt say anything. I just sat there in the
corner of the room watching his chest go up and down with
the timing of the machine. I was young and didnt know
what to feel or how to process all of the mixed emotions. I
left without saying a word or even touching him. The next
day I was told that he had passed away.
SE then reported that he saw his grandfather in a
peaceful place, but his father was in a state of agony since
he could not visit my grandfather because I had not
released him from his guilt. My anger became evident to
me and I felt it in all cells in my body. I didnt realize it was
still there after all these years. I was convinced I had
dealt with it. But it was there, and it had control over me.
2|Journal of Psychedelic Studies
dos Santos et al.
My anger transformed into hurt, a feeling of abandonment
overcame me, and then the feeling of worthlessness
became stronger than ever.
The scene then developed into SE forgiving his father
and accepting their differences: My father pleaded for me,
not to forgive him, but to forgive myself. He wanted me to
know that none of what I felt was my fault and he opened
himself up to make it all clear to me. I began to cry, and my
father was nally able to move on to be with my grandfa-
ther. I had forgiven him; I had forgiven myself. A drum
started to beat lightly, and it gradually intensied deep in
my heart. This vibration overcame my entire body until I
was chanting strongly aloud. I felt worthy. I felt like a good
person. When I released my father from his guilt, he
released me from my feelings of not being good.
After the experience, SE developed the ability to visual-
ize: I can now bring forth faint pictures in my mind. They
fade quickly but they are there. When dreaming I now see
faint, quickly fading images. It feels like this experience with
ayahuasca has slightly opened up my minds eye and
allowed me to experience internal images like I have never
had before. Ayahuasca turned on my minds eye, even if it is
While the authors have never met him personally, he
approved and actively participated in the manuscript pro-
duction. Since we did not know SE before his experience
with ayahuasca, it was not possible to assess his imagery
skills before that time. Thus, to have an idea of his
experience, we asked SE to retrospectively answer the
Vividness of Visual Imagery Questionnaire used by Zeman
et al. (2015) in his research. SE answered the questionnaire
in December 2017 and his score was 30, which, according
to Zeman et al. (2015), would classify him in the minimal
imagerygroup (score >16, range: 1730), compared
with the no visual imagery(score =16) and control
(score >57) groups. Although his score was no more than
minimalgroup, SE felt that his imagery had improved, as
reported above.
Recent neuroimaging studies with LSD and psilocybin,
agonists of cortical 5-HT
receptors as DMT, sug-
gest that imagery is heightened by these drugs. It seems
that these drugs induce more parts of the brain to process
visual information, and that the brain interprets these
effects like realvisual perceptions (Carhart-Harris
et al., 2016;dos Santos et al., 2016;Roseman et al.,
2016). Regarding ayahuasca, an open-label study showed
that, during an imagery task, ayahuasca induced signicant
activation in the primary visual area comparable to the
activation levels of a natural image with the eyes open
(de Araujo et al., 2012).
It is interesting to note that SE reported previous use of
other hallucinogens that act as 5-HT
agonists, such
as LSD and psilocybin, but improvements in his aphantasia
were noticed only with ayahuasca. Although these drugs
share a common pharmacological mechanism, SE reported
that his previous experiences were meaningful but at the
same time were restricted to visual alterations with opened
eyes, and usually happened in public places, such as parks,
suggesting recreational use. Although ayahuasca also has
harmine and related beta-carbolines in its composition, the
main role of these compounds in the human pharmacology
of ayahuasca seems to be restricted to the reversible inhibi-
tion of peripheral monoamine oxidase, which renders oral
DMT active. Moreover, it is highly unlikely that a single
ayahuasca dose could have induced structural, permanent
changes in SEs brain.
Thus, another possible explanation could be related to
non-pharmacological or environmental factors, such as the
difference between the contexts where he had his experi-
ences. For instance, ayahuasca was used in a ritual and
therapeutic setting where SE experienced a meaningful
curative experience that was emotionally intense and appar-
ently cathartic. This experience was characterized not only
by visual perceptions, but also by emotionally charged
memories and insights, which seem to have caused a
psychological change in him. Those aspects were not
present in his experiences with LSD and psilocybin, which
were used in recreational contexts and did not cause mean-
ingful or emotionally intense feelings in him. Therefore, it is
plausible to speculate that his absence of voluntary imagery
was related to a confused relation with his father and thus to
a psychological origin, especially when we consider his
statement: I traveled back in time through my visual
memory and discovered the traumatic moment in which
the minds eye closed.Moreover, SE reported that ::: in
moments in which I feel most centered, most condent in
myself, the most sure of my path, is when the images are
The last possibility is that SE was depressed and/or had
posttraumatic stress disorder (PTSD), and ayahuasca could
have caused an antidepressant response in him (Palhano-
Fontes et al., 2018;Sanches et al., 2016). Thus, we could
speculate that the trauma could have induced a functional
decit that was resolved by ayahuasca. However, this is
unlikely because SE did not report depressive or PTSD
Considering that aphantasia has a low incidence but is
usually lifelong and no treatment is available, future re-
search should assess if people with aphantasia may improve
after using ayahuasca or other serotonergic hallucinogens.
Future studies should also assess whether aphantasia is due
to trauma or something else (such as functional changes in
brain dynamics), so that the theory proposed here can be
Acknowledgements: The authors would like to thank SE for
allowing us to report his case and for participating in the
manuscript production.
Conict of interest: RGdS is Fellow of the Brazilian
National Post-Doctorate Program (PNPD/CAPES) and
member of the ICEERS Advisory Board. JCB and OP
are ICEERS employees or collaborators. ICEERS is a
non-prot organization that promotes the scientic research
of ayahuasca. JECH receives a CNPq (Brazil) Productivity
Fellowship Award. For the remaining authors, none were
Journal of Psychedelic Studies |3
Ayahuasca and aphantasia
declared. None of the authors received any specic funding
for participating in this investigation. All authors had full
access to all the data and had nal responsibility for the
decision to submit for publication.
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4|Journal of Psychedelic Studies
dos Santos et al.
... While M.X. is a case of acquired aphantasia following a surgical procedure, the case of S.E. demonstrates that aphantasia could also develop independently of an organic cause and may be related to a psychological stressor (dos Santos et al., 2018). S.E. ...
... The way aphantasia is experienced differs between individuals, but some common aspects can be identified. Aphantasics refer to memory or conceptual knowledge rather than to imagery when retrieving information (Ross, 2016;dos Santos et al., 2018;Watkins, 2018;Zeman et al., 2010). The impairment of imagery may involve different modalities (Watkins, 2018;Ross, 2016) or specifically impede visual modality only (dos Santos et al., 2018). ...
... Aphantasics refer to memory or conceptual knowledge rather than to imagery when retrieving information (Ross, 2016;dos Santos et al., 2018;Watkins, 2018;Zeman et al., 2010). The impairment of imagery may involve different modalities (Watkins, 2018;Ross, 2016) or specifically impede visual modality only (dos Santos et al., 2018). Finally, aphantasic individuals report experiencing sensations of imagined physical space and ability to experience emotions in response to people or situations that are dear to them despite being unable to visualise them (dos Santos et al., 2018;Watkins, 2018). ...
Full-text available
Aphantasia is a relatively new term referring to the experience of lack of visual imagery. Here, we present a literature review on aphantasia in the context of memory as well as a case report of congenital aphantasia in a 24-year old female, A.B., who became aware of her particular condition only recently. The aim of this article is to draw attention to the concept of aphantasia and describe the patient’s experiences as well as her performance in mental imagery, memory, and intelligence tests. We believe that our paper may be useful for both research in psychology and clinical practice. Analysis of aphantasia may allow to assess the importance of mental imagery in other cognitive processes, like working memory or autobiographical memory. Moreover, the phenomenon of aphantasia emphasises the need to consider individual differences in mental imagery and inspires new research. Last but not least, we present a series of psychotherapeutic implications of aphantasia, such as deficits in autobiographical memory or difficulties with imagery-based techniques.
... In a recent article in this journal, Dos Santos, Enyart, Carlos Bouso, Pares, and Hallak (2018) report a case of ayahuasca use by a man with aphantasia, a condition characterized by reduced, or in this case, absence of visual mental imagery (Zeman, Dewar, & Della Sala, 2015). This account is the first such report of the use of a psychedelic agent by someone with aphantasia. ...
... In support of Dos Santos et al.'s (2018) favored psychological explanation and their suggestion that SE's aphantasia was acquired rather than congenital, this letter reports on a case study of an individual with apparent congenital aphantasia who has experienced no visual imagery, despite reporting having excessively smoked N,N-dimethyltryptamine (DMT)typically considered to be the most imagery-inducing chemical component of ayahuasca (e.g., McKenna, 2004). ...
... These findings cumulatively suggest that HE's condition is congenital (see also Zeman et al., 2015), not psychologically or otherwise acquired. Indeed, Dos Santos et al.'s (2018) case of "treatable" aphantasia appears to be novel in the literature on aphantasia, and probably belongs to the classification of acquired (Bartolomeo, 2002;de Vito & Bartolomeo, 2016;Zago et al., 2011) rather than congenital aphantasia. ...
... Thus, it can be assumed that the absence of visual imagery in aphantasics is a qualitative rather than a quantitative phenomenon and that it requires more effort (e.g. drug-induced imagery; dos Santos et al., 2018) to restore visual imagery in aphantasics than in poor imagers. Attentional guidance in aphantasics seems to be fundamentally impaired. ...
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Aphantasia is the condition of reduced or absent voluntary imagery. So far, behavioural differences between aphantasics and non-aphantasics have hardly been studied as the base rate of those affected is quite low. The aim of the study was to examine if attentional guidance in aphantasics is impaired by their lack of visual imagery. In two visual search tasks, an already established one by Moriya ( Attention, Perception, & Psychophysics , 80 (5), 1127-1142, 2018) and a newly developed one, we examined whether aphantasics are primed less by their visual imagery than non-aphantasics. The sample in Study 1 consisted of 531 and the sample in Study 2 consisted of 325 age-matched pairs of aphantasics and non-aphantasics. Moriya’s Task was not capable of showing the expected effect, whereas the new developed task was. These results could mainly be attributed to different task characteristics. Therefore, a lack of attentional guidance through visual imagery in aphantasics can be assumed and interpreted as new evidence in the imagery debate, showing that mental images actually influence information processing and are not merely epiphenomena of propositional processing.
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As awareness of the phenomenon of aphantasia (= lack of voluntary imagery) has increased in recent years, many psychotherapists ponder its clinical implications. The present study investigates whether aphantasia meets the criteria for mental disorders, i.e. statistical rarity, impairment in activities of daily living, violation of social norms and inappropriate behavior and personal distress. Prevalence of aphantasia was determined meta‐analytically based on 3,543 participants. An international sample of 156 participants with aphantasia (58.3% male; Mage = 35.23) and 131 controls (65.6% male; Mage = 28.88) was assessed with the Reading the Mind in the Eyes Test, the Questionnaire for the Assessment of Everyday Memory Performance and the Aphantasia Distress Questionnaire, as well as measures of depression, anxiety and well‐being. The prevalence of aphantasia was estimated at 3.5 to 4.8%. Participants with aphantasia scored significantly lower than controls on every day and autobiographical memory, but not on theory of mind. A subgroup of 34.7% of participants with aphantasia reported distress significantly associated with lower well‐being and high levels of anxiety and depression. The level of distress increased with poorer performance in autobiographical memory and theory of mind. Although aphantasia meets the criterion of statistical rarity, the impact on activities of daily living and personal distress is too weak to justify a classification as a mental disorder. In a subgroup, however, distress can reach clinically relevant levels. In individual cases, it is therefore advisable to conduct a psychological assessment, for example by means of the Aphantasia Distress Questionnaire.
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Background and Aims Little is known about individual differences in Hallucinogen Persisting Perceptual Disorder (HPPD). This study investigated visual processing style and personality across two HPPD types (HPPD I and HPPD II) and a Non-HPPD group. Methods An online survey was delivered to participants sourced from online HPPD and psychedelic user groups and forums ( N = 117). Using one-way ANOVA, respondents were compared across four measures of individual difference. Using logistic regression, a range of visual symptoms and experiences were investigated as potential predictors of group categorisation. Results The HPPD I group had higher absorption and visual apophenia scores than the other groups and was predicted by higher drug use. The HPPD II group showed significantly higher trait anxiety than both other groups. Across the HPPD groups, HPPD II categorisation was also predicted by increased negative precipitating experiences, lack of prior knowledge and pre-existing anxiety diagnoses. Conclusions Anxiety, negative precipitating experiences and lack of prior knowledge are associated with negative experiences of persistent visual symptoms following hallucinogen use, whilst higher absorption and visual apophenia are associated with positive or neutral experiences. Together these findings indicate that differences in personality may play a role in determining an individual's experience of HPPD, highlighting the role of individual difference research in expanding knowledge around HPPD.
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Objective: Reports have indicated possible uses of ayahuasca for the treatment of conditions including depression, addictions, post-traumatic stress disorder, anxiety and specific psychoneuroendocrine immune system pathologies. The article assesses potential ayahuasca and N,N-dimethyltryptamine (DMT) integration with contemporary healthcare. The review also seeks to provide a summary of selected literature regarding the mechanisms of action of DMT and ayahuasca; and assess to what extent the state of research can explain reports of unusual phenomenology. Design: A narrative review. Results: Compounds in ayahuasca have been found to bind to serotonergic receptors , glutaminergic receptors, sigma-1 receptors, trace amine-associated receptors , and modulate BDNF expression and the dopaminergic system. Subjective effects are associated with increased delta and theta oscillations in amygdala and hippocampal regions, decreased alpha wave activity in the default mode network, and stimulations of vision-related brain regions particularly in the visual association cortex. Both biological processes and field of consciousness models have been proposed to explain subjective effects of DMT and ayahuasca, however, the evidence supporting the proposed models is not sufficient to make confident conclusions. Ayahuasca plant medicine and DMT represent potentially novel treatment modalities. Conclusions: Further research is required to clarify the mechanisms of action and develop treatments which can be made available to the general public. Integration between healthcare research institutions and reputable practitioners in the Amazon is recommended.
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We reviewed the properties of mental imagery in aphantasia—a condition whereby individuals have difficulties in forming mental imagery, even though their visual perception is intact. Individuals with aphantasia have demonstrated lower priming effects regarding visual imagery in a binocular rivalry paradigm; however, these individuals could still complete visual short-term memory tasks normally via the use of verbal strategies (non-visual strategies). Few studies have provided clear evidence regarding its neurological basis, and future research is, thus, necessary to obtain evidence thereof. In considering object and spatial imagery, almost no differences were observed in spatial imagery between individuals with and without aphantasia in regard to rating scores of imagery questionnaires, although individuals with aphantasia show dysfunction in terms of object imagery. We review the imagery model and debate, in terms of aphantasia, which findings from studies on aphantasia may provide important suggestions for perceptual and imagery studies. We expect a better understanding of aphantasia to be promoted in society by developing studies that apply various approaches—including case studies, psychological tests, brain science, and educational support—following the present review article.
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Background: Recent open-label trials show that psychedelics, such as ayahuasca, hold promise as fast-onset antidepressants in treatment-resistant depression. Methods: To test the antidepressant effects of ayahuasca, we conducted a parallel-arm, double-blind randomized placebo-controlled trial in 29 patients with treatment-resistant depression. Patients received a single dose of either ayahuasca or placebo. We assessed changes in depression severity with the Montgomery-Åsberg Depression Rating Scale (MADRS) and the Hamilton Depression Rating scale at baseline, and at 1 (D1), 2 (D2), and 7 (D7) days after dosing. Results: We observed significant antidepressant effects of ayahuasca when compared with placebo at all-time points. MADRS scores were significantly lower in the ayahuasca group compared with placebo at D1 and D2 (p = 0.04), and at D7 (p < 0.0001). Between-group effect sizes increased from D1 to D7 (D1: Cohen's d = 0.84; D2: Cohen's d = 0.84; D7: Cohen's d = 1.49). Response rates were high for both groups at D1 and D2, and significantly higher in the ayahuasca group at D7 (64% v. 27%; p = 0.04). Remission rate showed a trend toward significance at D7 (36% v. 7%, p = 0.054). Conclusions: To our knowledge, this is the first controlled trial to test a psychedelic substance in treatment-resistant depression. Overall, this study brings new evidence supporting the safety and therapeutic value of ayahuasca, dosed within an appropriate setting, to help treat depression. This study is registered at (NCT02914769).
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The question of how spatially organized activity in the visual cortex behaves during eyes-closed, lysergic acid diethylamide (LSD)-induced "psychedelic imagery" (e.g., visions of geometric patterns and more complex phenomena) has never been empirically addressed, although it has been proposed that under psychedelics, with eyes-closed, the brain may function "as if" there is visual input when there is none. In this work, resting-state functional connectivity (RSFC) data was analyzed from 10 healthy subjects under the influence of LSD and, separately, placebo. It was suspected that eyes-closed psychedelic imagery might involve transient local retinotopic activation, of the sort typically associated with visual stimulation. To test this, it was hypothesized that, under LSD, patches of the visual cortex with congruent retinotopic representations would show greater RSFC than incongruent patches. Using a retinotopic localizer performed during a nondrug baseline condition, nonadjacent patches of V1 and V3 that represent the vertical or the horizontal meridians of the visual field were identified. Subsequently, RSFC between V1 and V3 was measured with respect to these a priori identified patches. Consistent with our prior hypothesis, the difference between RSFC of patches with congruent retinotopic specificity (horizontal-horizontal and vertical-vertical) and those with incongruent specificity (horizontal-vertical and vertical-horizontal) increased significantly under LSD relative to placebo, suggesting that activity within the visual cortex becomes more dependent on its intrinsic retinotopic organization in the drug condition. This result may indicate that under LSD, with eyes-closed, the early visual system behaves as if it were seeing spatially localized visual inputs. Hum Brain Mapp, 2016. © 2016 Wiley Periodicals, Inc.
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Significance Lysergic acid diethylamide (LSD), the prototypical “psychedelic,” may be unique among psychoactive substances. In the decades that followed its discovery, the magnitude of its effect on science, the arts, and society was unprecedented. LSD produces profound, sometimes life-changing experiences in microgram doses, making it a particularly powerful scientific tool. Here we sought to examine its effects on brain activity, using cutting-edge and complementary neuroimaging techniques in the first modern neuroimaging study of LSD. Results revealed marked changes in brain blood flow, electrical activity, and network communication patterns that correlated strongly with the drug’s hallucinatory and other consciousness-altering properties. These results have implications for the neurobiology of consciousness and for potential applications of LSD in psychological research.
Serotonergic hallucinogens produce alterations of perceptions, mood, and cognition, and have anxiolytic, antidepressant, and antiaddictive properties. These drugs act as agonists of frontocortical 5-HT2A receptors, but the neural basis of their effects are not well understood. Thus, we conducted a systematic review of neuroimaging studies analyzing the effects of serotonergic hallucinogens in man. Studies published in the PubMed, Lilacs, and SciELO databases until 12 April 2016 were included using the following keywords: “ayahuasca”, “DMT”, “psilocybin”, “LSD”, “mescaline” crossed one by one with the terms “mri”, “fmri”, “pet”, “spect”, “imaging” and “neuroimaging”. Of 279 studies identified, 25 were included. Acute effects included excitation of frontolateral/frontomedial cortex, medial temporal lobe, and occipital cortex, and inhibition of the default mode network. Long-term use was associated with thinning of the posterior cingulate cortex, thickening of the anterior cingulate cortex, and decreased neocortical 5-HT2A receptor binding. Despite the high methodological heterogeneity and the small sample sizes, the results suggest that hallucinogens increase introspection and positive mood by modulating brain activity in the fronto-temporo-parieto-occipital cortex.
Ayahuasca is an Amazonian botanical hallucinogenic brew which contains dimethyltryptamine, a 5-HT2A receptor agonist, and harmine, a monoamine-oxidase A inhibitor. Our group recently reported that ayahuasca administration was associated with fast-acting antidepressive effects in 6 depressive patients. The objective of the present work was to assess the antidepressive potentials of ayahuasca in a bigger sample and to investigate its effects on regional cerebral blood flow. In an open-label trial conducted in an inpatient psychiatric unit, 17 patients with recurrent depression received an oral dose of ayahuasca (2.2 mL/kg) and were evaluated with the Hamilton Rating Scale for Depression, the Montgomery-Åsberg Depression Rating Scale, the Brief Psychiatric Rating Scale, the Young Mania Rating Scale, and the Clinician Administered Dissociative States Scale during acute ayahuasca effects and 1, 7, 14, and 21 days after drug intake. Blood perfusion was assessed eight hours after drug administration by means of single photon emission tomography. Ayahuasca administration was associated with increased psychoactivity (Clinician Administered Dissociative States Scale) and significant score decreases in depression-related scales (Hamilton Rating Scale for Depression, Montgomery-Åsberg Depression Rating Scale, Brief Psychiatric Rating Scale) from 80 minutes to day 21. Increased blood perfusion in the left nucleus accumbens, right insula and left subgenual area, brain regions implicated in the regulation of mood and emotions, were observed after ayahuasca intake. Ayahuasca was well tolerated. Vomiting was the only adverse effect recorded, being reported by 47% of the volunteers. Our results suggest that ayahuasca may have fast-acting and sustained antidepressive properties. These results should be replicated in randomized, double-blind, placebo-controlled trials.
The hallucinogenic brew Ayahuasca, a rich source of serotonergic agonists and reuptake inhibitors, has been used for ages by Amazonian populations during religious ceremonies. Among all perceptual changes induced by Ayahuasca, the most remarkable are vivid "seeings." During such seeings, users report potent imagery. Using functional magnetic resonance imaging during a closed-eyes imagery task, we found that Ayahuasca produces a robust increase in the activation of several occipital, temporal, and frontal areas. In the primary visual area, the effect was comparable in magnitude to the activation levels of natural image with the eyes open. Importantly, this effect was specifically correlated with the occurrence of individual perceptual changes measured by psychiatric scales. The activity of cortical areas BA30 and BA37, known to be involved with episodic memory and the processing of contextual associations, was also potentiated by Ayahuasca intake during imagery. Finally, we detected a positive modulation by Ayahuasca of BA 10, a frontal area involved with intentional prospective imagination, working memory and the processing of information from internal sources. Therefore, our results indicate that Ayahuasca seeings stem from the activation of an extensive network generally involved with vision, memory, and intention. By boosting the intensity of recalled images to the same level of natural image, Ayahuasca lends a status of reality to inner experiences. It is therefore understandable why Ayahuasca was culturally selected over many centuries by rain forest shamans to facilitate mystical revelations of visual nature. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.