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.
Roseman, L., Sereno, M. I., Leech, R., Kaelen, M., Orban, C., McGonigle, J., … & Carhart‐Harris, R. L. (2016). LSD alters eyes‐closed functional connectivity within the early visual cortex in a retinotopic fashion. Human Brain Mapping. http://dx.doi.org/10.1002/hbm.23224
N,N-dimethyltryptamine, more commonly known as DMT, is an exceptionally fast-acting and powerful psychedelic. DMT can be ingested by drinking the entheogenic brew ayahuasca, injected intravenously, intramuscularly or through inhalation. It is produced endogenously in a variety of plants and animals, including in humans. DMT exerts physiological effects that go beyond its mind-altering effects, as discussed in Jacob and Presti (2005). For example, DMT has been shown to induce anxiolytic and antidepressant effects (Sanches et al. 2016).
DMT is not only an agonist of serotonin 2A and 2C receptors (5-HT2A and 5-HT2C); it also binds to σ1 putative receptors and trace amine receptors (Vitale et al. 2011). In addition, its serotonergic analogues can influence immunoregulation, and may even prevent carcinogenesis (Frecska et al. 2012). DMT’s multifaceted interactions show that its effects are not limited to the central nervous system but may play a more crucial role in the body’s cellular protective mechanisms (Frecska et al. 2012).
Dr. Ede Frecska has published multiple papers on the effects of ayahuasca and DMT on creativity, tissue regeneration, and the interhemispheric fusion in altered states of consciousness (Frecska et al. 2016). With the recent discovery of DMT’s activation of the σ1 receptor , which plays a crucial role in protecting the body from undergoing oxidative stress, Dr. Frecska and his team are currently investigating DMT’s role in neuroprotection prior to clinical death (Frecska 2015).
σ1 receptors play a key role in neuroprotection by regulating both neuronal development and morphogenesis. This is done through the regulation and manipulation of oxidative stress and mitochondrial functions (Tuerxun et al. 2010). Agonists of σ1 receptors exacerbate neuroprotective effects by inhibiting intracellular calcium overload and by thwarting the activation of pro-apoptopic genes, as well as activating protective genes, as shown in stroke models (Zhang et al. 2012). This leads to the reduction of calcium neurotoxicity, prevents oxidative stress-induced cell death, and can stimulate neuronal plasticity (Kourrich et al. 2012). Most importantly, the constant activation of σ1 receptors during ischemia leads to a reduction of neurotoxicity (Katnik et al. 2006). Ultimately, this research suggests that DMT may have a role in reducing the hypoxic-anoxic damages such as local anoxia (e.g. stroke) or general hypoxia (e.g. cardiac arrest) (Kourrich et al. 2012).
DMT’s medicinal properties are not limited to neuroprotection, but can extend to immunoprotection as well. The 5HT2A receptors, as well as the sigma receptors, can profoundly influence the body’s immune system. Serotonin plays an important role in cellular immune functions, and more specifically in the elimination of pathogens and cancer cells (O’Connell et al. 2006). σ1 receptor agonists can increase the production of anti-inflammatory cytokines as well as reduce pro-inflammatory cytokines. Both these processes are important in reducing the cellular damage in case of injury or disease (Frecska et al. 2012).
Currently, there is only speculation that DMT is produced during near-death experiences, as there are few parallels between near-death experiences and DMT visions (Strassman 2001). However, based on limited information, one may conjecture the production of DMT during life-threatening situations. McEwen and Sober (1967) have demonstrated that when undergoing extreme environmental stress, rabbits produce vast quantities of DMT in the lungs, which are then released into the blood (McEwen & Sober 1967). DMT is then transported through the neural membranes within synaptic vesicles and delivered to the brain. Knowing the relationship between DMT and the σ1 receptors, it is hypothesised that DMT limits or reverses the accumulated oxidative stress. This serves as the foundation of Dr. Frecska’s hypothesis, and if evidence is found of DMT’s role in the neuroprotection of the human brain in the stages leading up to clinical death, then DMT would have the potential to be used as an emergency medicine. If successful, one could envision the use of DMT ampoules to be used intravenously in ambulances, operating rooms and in disaster zones. Clinical studies with humans are still necessary in order to define whether it is feasible or not.
Although Dr. Frescka’s studies focus on rats (pre-clinical studies), his studies have looked beyond DMT’s mere hallucinogenic relevance and have opened avenues into further studying DMT’s neuroprotective role. The potential medical ramifications are vast. The applications of DMT may be beyond what we can imagine, and certainly deserve to be systematically studied.
References
Frecska, E., 2015. What role does the ‘spirit molecule’ DMT play in the brain?. [fusion_builder_container hundred_percent=”yes” overflow=”visible”][fusion_builder_row][fusion_builder_column type=”1_1″ background_position=”left top” background_color=”” border_size=”” border_color=”” border_style=”solid” spacing=”yes” background_image=”” background_repeat=”no-repeat” padding=”” margin_top=”0px” margin_bottom=”0px” class=”” id=”” animation_type=”” animation_speed=”0.3″ animation_direction=”left” hide_on_mobile=”no” center_content=”no” min_height=”none”][Online] Available at: http://walacea.com/campaigns/dmt
Frecska, E., Bokor, P. & Winkelman, M., 2016. The Therapeutic Potentials of Ayahuasca: Possible Effects against Various Diseases of Civilization. Frontiers in Pharmacology, p. 10.3389.
Frecska, E. et al., 2012. A possibly sigma-1 receptor meditated dole of dimethyltryptamine in tissue protection, regeneration and immunity. Translational Neuroscience, pp. 1-18.
Jacob, M. & Presti, D., 2005. Endogenous psychoactive tryptamines reconsidered: an anxiolytic role for dimethyltryptamine.. Medical Hypotheses, 64(5), pp. 930-7.
Katnik, C. et al., 2006. Sigma-1 receptor activation prevents intracellular calcium dysregulation in cortical neurons during in vitro ischemia. Journal of Pharmacology and Experimental Therapeutics, Band 319, pp. 1355-1365.
Kourrich, S., Tsung-Ping, S., Fujimoto, M. & Bonci, A., 2012. The sigma-1 receptor: roles in neuronal plasticity and disease. Trends Neuroscience, 35(12), pp. 762-771.
McEwen, C. & Sober, A., 1967. Rabbit serum monoamine oxidase. The Journal of Biological Chemistry, Band 242, pp. 3068-3078.
O’Connell, P. et al., 2006. A novel form of immune signaling revealed by transmission of the inflammatory mediator serotnin between dendritic cells and T cells. Blood, Band 107, pp. 1010-1017.
Sanches, R. F. et al., 2016. Antidepressant Effects of a Single Dose of Ayahuasca in Patients With Recurrent Depression: A SPECT Study. Journal of Clinical Psychopharmacology, 36(1), pp. 77-81.
Strassman, R., 2001. DMT: The Spirit Molecule. First Hrsg. Rochester: Park Street Press.
Strassman, R. & Qualis, C., 1994. Dose-response study of N,N-dimethyltryptamine in humans. I. Neuroendocrine, autonomic, and cardiovascular effects. Archives of General Psychiatry, pp. 85-97.
Tuerxun, T. et al., 2010. SA4503, a sigma-1 receptor agonist, prevents cultured cortical neurons from oxidative stress-induced cell death via suppression of MAPK pathway activation and glutamate receptor expression. Neuroscience Letters, Band 469, pp. 303-308.
Zhang, Y. et al., 2012. Sigma-1 receptor agonists provide neuroprotection against gp12- via a change in bel-2 expression in mouse neuronal cultures. Brain Research, Band 1431, pp. 13-22.
Since the wars in Iraq and Afghanistan, posttraumatic stress disorder (PTSD) has become a major area of research and development. The most widely accepted treatment for PTSD is prolonged exposure (PE) therapy, but for many patients it is intolerable or ineffective. ±3,4-methylenedioxymethamphetamine (MDMA)-assisted psychotherapy (MDMA-AP) has recently re-emerged as a new treatment option, with two clinical trials having been published and both producing promising results. However, these results have yet to be compared to existing treatments. The present paper seeks to bridge this gap in the literature. Often the statistical significance of clinical trials is overemphasized, while the magnitude of the treatment effects is overlooked. The current meta-analysis aims to provide a comparison of the cumulative effect size of the MDMA-AP studies with those of PE. Effect sizes were calculated for primary and secondary outcome measures in the MDMA-AP clinical trials and compared to those of a meta-analysis including several PE clinical trials. It was found that MDMA-AP had larger effect sizes in both clinician-observed outcomes than PE did (Hedges’ g=1.17 vs. g=1.08, respectively) and patient self-report outcomes (Hedges’ g=0.87 vs. g=0.77, respectively). The dropout rates of PE and MDMA-AP were also compared, revealing that MDMA-AP had a considerably lower percentage of patients dropping out than PE did. These results suggest that MDMA-AP offers a promising treatment for PTSD.
Amoroso, T., & Workman, M. (2016). Treating posttraumatic stress disorder with MDMA-assisted psychotherapy: A preliminary meta-analysis and comparison to prolonged exposure therapy. Journal of psychopharmacology (Oxford, England). http://dx.doi.org/10.1177/0269881116642542
N,N-Dimethyltryptamine (DMT) is an indole alkaloid widely found in plants and animals. It is best known for producing brief and intense psychedelic effects when ingested. Increasing evidence suggests that endogenous DMT plays important roles for a number of processes in the periphery and central nervous system, and may act as a neurotransmitter. This paper reviews the current literature of both the recreational use of DMT and its potential roles as an endogenous neurotransmitter. Pharmacokinetics, mechanisms of action in the periphery and central nervous system, clinical uses and adverse effects are also reviewed. DMT appears to have limited neurotoxicity and other adverse effects except for intense cardiovascular effects when administered intravenously in large doses. Because of its role in nervous system signaling, DMT may be a useful experimental tool in exploring how brain works, and may also be a useful clinical tool for treatment of anxiety and psychosis.
Carbonaro, T. M., & Gatch, M. B. (2016). Neuropharmacology of N, N-Dimethyltryptamine. Brain Research Bulletin. http://dx.doi.org/10.1016/j.brainresbull.2016.04.016
Evidence suggests that hallucinogens may have therapeutic potential for addressing a variety of problem behaviors related to the externalizing spectrum of psychopathology, such as substance misuse and criminality. Intimate partner violence (IPV) is a prevalent form of criminal violence that is related to externalizing pathology. However, the association between hallucinogen use and IPV has not been comprehensively examined. In this prospective study, we examined the association between IPV and naturalistic hallucinogen use among 302 inmates at a US county jail. Cox regression analyses indicated that hallucinogen use predicted reduced arrest for IPV independently (β=−0.54, SE=0.20, χ2=7.19, exp(B)=0.58, p<0.01) and after accounting for covariates (β=−0.48, SE=0.23, χ2=4.44, exp(B)=0.62, p<0.05). These results add to a growing literature suggesting distinct therapeutic potential for hallucinogens to assist in the attenuation of problematic behavior.
Walsh, Z., Hendricks, P. S., Smith, S., Kosson, D. S., Thiessen, M. S., Lucas, P., & Swogger, M. T. (2016). Hallucinogen use and intimate partner violence: Prospective evidence consistent with protective effects among men with histories of problematic substance use. Journal of psychopharmacology (Oxford, England). http://dx.doi.org/10.1177/0269881116642538 Link to full text
Repeated drug consumption may progress to problematic use by triggering neuroplastic adaptations that attenuate sensitivity to natural rewards while increasing reactivity to craving and drug cues. Converging evidence suggests a single sub-anesthetic dose of the N-methyl-D-aspartate receptor antagonist ketamine may work to correct these neuroadaptations and restore motivation for non-drug rewards. Using an established laboratory model aimed at evaluating behavioral shifts in the salience of cocaine now vs money later, we found that ketamine, as compared to the control, significantly decreased cocaine self-administration by 67% relative to baseline at greater than 24 h post-infusion, the most robust reduction observed to date in human cocaine users and the first to involve mechanisms other than stimulant or dopamine agonist effects. These findings signal new directions in medication development for substance use disorders.
Dakwar, E., Hart, C. L., Levin, F. R., Nunes, E. V., & Foltin, R. W. (2016). Cocaine self-administration disrupted by the N-methyl-D-aspartate receptor antagonist ketamine: a randomized, crossover trial. Molecular Psychiatry. http://dx.doi.org/10.1038/mp.2016.39 Link to full text
Social ties are crucial for physical and mental health. However, psychiatric patients frequently encounter social rejection. Moreover, an increased reactivity to social exclusion influences the development, progression, and treatment of various psychiatric disorders. Nevertheless, the neuromodulatory substrates of rejection experiences are largely unknown. The preferential serotonin (5-HT) 2A/1A receptor agonist, psilocybin (Psi), reduces the processing of negative stimuli, but whether 5-HT2A/1A receptor stimulation modulates the processing of negative social interactions remains unclear. Therefore, this double-blind, randomized, counterbalanced, cross-over study assessed the neural response to social exclusion after the acute administration of Psi (0.215 mg/kg) or placebo (Pla) in 21 healthy volunteers by using functional magnetic resonance imaging (fMRI) and resting-state magnetic resonance spectroscopy (MRS). Participants reported a reduced feeling of social exclusion after Psi vs. Pla administration, and the neural response to social exclusion was decreased in the dorsal anterior cingulate cortex (dACC) and the middle frontal gyrus, key regions for social pain processing. The reduced neural response in the dACC was significantly correlated with Psi-induced changes in self-processing and decreased aspartate (Asp) content. In conclusion, 5-HT2A/1A receptor stimulation with psilocybin seems to reduce social pain processing in association with changes in self-experience. These findings may be relevant to the normalization of negative social interaction processing in psychiatric disorders characterized by increased rejection sensitivity. The current results also emphasize the importance of 5-HT2A/1A receptor subtypes and the Asp system in the control of social functioning, and as prospective targets in the treatment of sociocognitive impairments in psychiatric illnesses.
Preller, K. H., Pokorny, T., Hock, A., Kraehenmann, R., Stämpfli, P., Seifritz, E., … & Vollenweider, F. X. (2016). Effects of serotonin 2A/1A receptor stimulation on social exclusion processing. Proceedings of the National Academy of Sciences, 201524187. http://dx.doi.org/10.1073/pnas.1524187113
Psychedelic drugs such as lysergic acid diethylamide (LSD) were used extensively in psychiatry in the past and their therapeutic potential is beginning to be re-examined today. Psychedelic psychotherapy typically involves a patient lying with their eyes-closed during peak drug effects, while listening to music and being supervised by trained psychotherapists. In this context, music is considered to be a key element in the therapeutic model; working in synergy with the drug to evoke therapeutically meaningful thoughts, emotions and imagery. The underlying mechanisms involved in this process have, however, never been formally investigated. Here we studied the interaction between LSD and music-listening on eyes-closed imagery by means of a placebo-controlled, functional magnetic resonance imaging (fMRI) study. Twelve healthy volunteers received intravenously administered LSD (75 µg) and, on a separate occasion, placebo, before being scanned under eyes-closed resting conditions with and without music-listening. The parahippocampal cortex (PHC) has previously been linked with (1) music-evoked emotion, (2) the action of psychedelics, and (3) mental imagery. Imaging analyses therefore focused on changes in the connectivity profile of this particular structure. Results revealed increased PHC–visual cortex (VC) functional connectivity and PHC to VC information flow in the interaction between music and LSD. This latter result correlated positively with ratings of enhanced eyes-closed visual imagery, including imagery of an autobiographical nature. These findings suggest a plausible mechanism by which LSD works in combination with music listening to enhance certain subjective experiences that may be useful in a therapeutic context.
Kaelen, M., Roseman, L., Kahan, J., Santos-Ribeiro, A., Orban, C., Lorenz, R., … & Wall, M. B. (2016). LSD modulates music-induced imagery via changes in parahippocampal connectivity. European Neuropsychopharmacology. http://dx.doi.org/10.1016/j.euroneuro.2016.03.018 Link to full text
Opnieuw hebben onderzoekers van het Psychedelic Research Programme, opgezet in samenwerking tussen de Beckley Foundation en het Londense Imperial College, baanbrekend onderzoek gepubliceerd naar de effecten van psychedelica op de hersenen. Deze trendsettende studies zijn de eerste waarbij multimodale neuro-beeldvorming is toegepast op deelnemers die met LSD waren geïnjecteerd. Gebruikmakend van fMRI BOLD, arterial spin labelling en magnetoencephalografie (MEG), hebben dr. Carhart-Harris en zijn collega’s van het Imperial College London de effecten van lysergeenzuurdi-ethylamide (LSD) op de netwerkcommunicatie, bloeddoorstroming en elektrische activiteit van de hersenen onthuld (Carhart-Harris et al., 2016).
Uit deze neuro-beeldvormingsonderzoeken hebben onderzoekers een nieuw en belangrijk inzicht gekregen in de basis van de ontbinding van het ego, de manier waarop ‘closed-eye visuals’ ontstaan en de effecten van de combinatie van LSD en muziek in het brein. De onderzoeken werden gedaan met 20 deelnemers die de ene keer 75µg LSD kregen ingespoten en de andere keer een placebo, met minstens twee weken er tussenin. Alle deelnemers hadden al ervaring met psychedelica.
Om de activiteit van verschillende hersengebieden en hun interconnecties gedurende LSD-invloed te evalueren, werd gebruik gemaakt van functional magnetic resonance imaging (fMRI), gebaseerd op de evaluatie van bloedzuurstofniveau-afhankelijk contrast (blood oxygen level dependent, ‘BOLD’). De scans werden uitgevoerd in een staat van rust, d.w.z. zonder externe stimuli of specifieke cognitieve taken. Daarna werden de niveaus van (des)integratie/(de)segregatie geëvalueerd, waarbij bepaalde interessante gebieden werden uitgelicht om hun interactie met de andere hersengebieden te analyseren.
Gemiddelde functionele connectiviteitsdichtheid (FCD) in corticale en subcorticale gebieden onder invloed van placebo en LSD – Tagliazucchi et al., 2016.
Een van de belangrijkste bevindingen uit het onderzoek was dat LSD een toename van geglobaliseerde communicatie tussen verschillende hersenregio’s bewerkstelligt. Door gebruik te maken van positron emissie tomografie (PET) ontdekten de onderzoekers dat het hoogste niveau van dergelijke communicatie plaatsvond in de gebieden met de hoogste dichtheid van serotonine-2A (5-HT2A) receptoren, aangezien LSD als een antagonist voor dit type receptoren werkt. Een interessant aspect hiervan is dat deze hogere interactie tussen hersengebieden overeenkomt met een lagere integratie binnen bepaalde netwerken. In totaal werden door de studie 12 ‘resting state networks’ geïdentificeerd die op deze manier door LSD werden beïnvloed, waarbij het defaultnetwerk (of default mode network, DMN) voor dit onderzoek het belangrijkste was.
Ontbinding van het ego
Het DMN is het netwerk in de hersenen dat geactiveerd wordt wanneer een persoon ruststaten zoals dagdromen ervaart, en gedeactiveerd raakt gedurende doelgerichte taken. Volgens het huidige onderzoek is de desintegratie binnen het DMN rechtstreeks gerelateerd aan het ontstaan van een bewustzijnstoestand die meestal wordt beschreven als een ontbinding van het ego. De ontbinding van het ego is de subjectieve ervaring van het verliezen van het gevoel van identiteit. Het wordt ook wel beschreven als eenheid met de buitenwereld of met het universum, voortgebracht door het vervagen van de grenzen van het autonome zelf. De vragenlijst over veranderde staten van bewustzijn die aan het eind van elke scandag werd gebruikt, onthulde dat de ontbinding van het ego gecorreleerd is aan de ervaring van veranderde betekenis, i.e. het hechten van belang aan objecten die eerder onbelangrijk werden geacht en het verlenen van een nieuwe, vreemde betekenis aan de omgeving. Ook andere hersengebieden, zoals het salience netwerk en de thalamus, werden in verband gebracht met de staat van ego-ontbinding.
Hersengebieden waar een significante correlatie werd gevonden tussen FCD en subjectieve meldingen van ego-ontbinding (LSD min placebo) staan rood gekleurd. Hersengebieden waar zich de meest selectieve correlaties voordoen tussen toenames van FCD en scores voor ego-ontbinding staan groen gekleurd – Tagliazucchi et al., 2016
De desintegratie van het DMN en andere rust-netwerken ging tevens gepaard met een verzwakking van de alfa hersengolven in gebieden zoals de cortex cingularis posterior (of posterior cingulate cortex / PCC). Over reguliere alfagolven bestaat de hypothese dat ze spontane neurale activiteit, d.w.z. die zonder blootstelling aan stimuli optreedt, tegenhouden (Tagliazucchi et al., 2016). Het bleek dat LSD de alfakracht doet afnemen en daarmee spontane activiteit in neuronen veroorzaakt, een effect dat de visuals bij gesloten ogen, die gepaard gaan met de LSD-ervaring, deels zou kunnen verklaren.
De werking van visuals bij gesloten ogen
In het onderzoek naar door LSD opgeroepen closed-eye visuals werden opvallende resultaten binnengehaald. De onderzoekers keken zowel naar eenvoudige beelden zoals geometrische patronen, als naar complexe beelden, waaronder autobiografische scènes, die zich onder LSD voordeden. Het onderzoek toonde aan dat, ook al was er geen visuele input, de visuele cortex (VC) zich onder invloed van LSD toch gedroeg alsof die er wel was (Carhart-Harris et al., 2016). Deze observatie ondersteunt huidige theorieën die zeggen dat het verschijnen van geometrische beelden wellicht veroorzaakt wordt door de opgewekte instabiliteit van de VC (Butler et al., 2011).
Naast een toename in het niveau van bloeddoorstroming vertoonde de VC ook een toegenomen functionele connectiviteit met andere hersendelen, met name de cortex parahippocampalis (of PHC), die betrokken is bij het oproepen van herinneringen, door muziek veroorzaakte emoties, en mentale beeldvorming. De onderzoekers gebruikten een Dynamic Causal Modelling-analyse om een toegenomen effectieve connectiviteit tussen de VC en de PHC aan te tonen, waarbij de PHC de activiteit van de VC veroorzaakte. De verwevenheid van deze hersengebieden kan verantwoordelijk worden gehouden voor het ‘kleuren’ van persoonlijke herinneringen die de deelnemers onder LSD ervoeren. Naast de PHC werden andere hersenregio’s zoals die in de occipitale en inferiore frontale kwab ook geactiveerd, wat tot de conclusie leidt dat onder invloed van LSD een veel groter deel van de hersenen betrokken is bij het voortbrengen van beelden dan in de normale waaktoestand.
De invloed van muziek
Veder kwam het grote belang van muziek tijdens de psychedelische ervaring uit het onderzoek naar boven. Mendel Kaelen, promovendus aan het Imperial College London en directielid van Stichting OPEN, onderzocht de synergistische effecten van muziek tijdens de LSD-ervaring (Kaelen et al., 2016). Er werden drie fMRI-scans uitgevoerd, de eerste en derde zonder muziek, en de tweede terwijl de deelnemers naar muziek luisterden (twee fragmenten uit het album Yearning van de ambient artiest Robert Rich en de Indische klassieke muzikante Lisa Moscow).
Het onderzoek liet zien dat de PHC hevig geactiveerd raakt wanneer deelnemers aan muziek en LSD blootgesteld worden. Bovendien correspondeerde de toename van interactie tussen de PHC en de visuele cortex met de intensiteit van de closed-eye visuals, zowel de eenvoudige (geometrische patronen) als de complexe (bv. gebaseerd op persoonlijke herinneringen). Dit benadrukt het belang van het verwerken van muziek in LSD-ondersteunde therapie.
Kennis uitbreiden
De bevindingen van dit onderzoek met LSD verstevigen de basis van de kennis die vergaard is in experimenten met andere psychedelica. Van psilocybine is aangetoond dat het vergelijkbare effecten heeft op hersenactiviteit, met inbegrip van de desintegratie in bepaalde gebieden zoals het defaultnetwerk en het ontstaan van nieuwe verbindingen tussen netwerken die normaliter gesegregeerd zijn. Deze conclusies kwamen voort uit twee onafhankelijke onderzoeken, waarvan er één werd uitgevoerd door de auteurs van het onderhavige LSD-onderzoek (Carhart-Harris et al., 2012, Kometer et al., 2015). Weer een andere onderzoeksgroep ontdekte soortgelijke effecten op de menselijke hersenen van ayahuasca, een psychedelicum uit het Amazonegebied (Riba et al., 2002).
De resultaten van dit baanbrekende onderzoek hebben een aantal belangrijke implicaties. Ten eerste geven ze een begin van neurologisch inzicht in het therapeutisch potentieel van LSD. Door zijn ‘entropische’ effect op de hersenen – de toename van desintegratie binnen en tegelijkertijd toename van interactie tussen bepaalde hersengebieden – heeft LSD potentieel om pathologische patronen, die worden geassocieerd met bijvoorbeeld depressie, af te breken, en zo de effectiviteit van psychotherapie te vergroten.
Het onderzoek heeft tevens aangetoond dat LSD potentieel heeft om van nut te zijn bij de studie naar de neurobiologie van het bewustzijn, gezien het feit dat het deelnemers in de zogenaamde ‘primitieve bewustzijnstoestand’ lijkt te brengen, die karakteristiek is voor de vroege stadia van bewustzijnsontwikkeling in kinderen, voor REM-slaap en voor de beginfase van psychose (Carhart-Harris et al., 2016). Dit betekent ook dat LSD zou kunnen worden toegepast in psychologische studies in het onderzoek naar pathologieën (Carhart-Harris et al., 2016).
Naast de korte-termijneffecten van LSD op de hersenchemie is tevens meer onderzoek nodig naar het potentieel van LSD-ervaringen om blijvende persoonlijkheidsveranderingen teweeg te brengen.
Butler T. C., Benayoun M., Wallace E., van Drongelen W., Goldenfeld N. and Cowan J. (2012). Evolutionary constraints on visual cortex architecture from the dynamics of hallucinations. Proceedings of the National Academy of Sciences of the United States of America, 606-609. https://dx.doi.org/10.1073/pnas.1118672109
Carhart-Harris R. L., Errizoe D., Williams T., Stone J. M., Reed L. J., Colasanti A., Tyacke R.J., Leech R., Malizia A.L., Murphy K., Hobden P., Evans J., Feilding A., Wise R.G. and Nutt D.J. (2012). Neural correlates of the psychedelic state as determined by fMRI studies with psilocybin. Proc. Natl. Acad. Sci. USA 109, 2138–2143. https://dx.doi.org/10.1073/pnas.1119598109
Carhart-Harris R. L., Muthukumaraswarmy S., Roseman L., Kaelen M., Droog W., Murphy K., Taggliazzuchi E., Schenberg E.E., Nest T., Orban C., Leech R., Williams, L., Williams T., Bolstridge M., Sessa B., McGoniglea J., Sereno M., Nichols D., Hellyer P.J., Hobden P., Evans J., Singh K.D., Wise R.G., Curran V., Feilding A. and Nutt D.J. (2016) Neural Correlates of the LSD Experience Revealed by Multimodal Neuroimaging. Proceedings of the National Academy of Sciences of the United States of America, 1-6. https://dx.doi.org/10.1073/pnas.1518377113
Kaelen M., Roseman L., Kahan J., Santos-Ribeiro A., Orban C., Lorenz R., Barett F.S., Bolstridge M., Williams T., Williams L., Wall M.B., Feilding A., Muthukumuraswamy S., Nutt D.J and Carhart-Harris, R. (2016) LSD modulates music-induced imagery via changes in the parahippocampal connectivity. European Neuropsychopharmacology, 1-10. http://dx.doi.org/10.1016/j.euroneuro.2016.03.018
Kometer M., Pokorny T., Seifritz E. and Vollenweider F.X. (2015) Psilocybin-induced spiritual experiences and insightfulness are associated with synchronization of neuronal oscillations. Psychopharmacology (Berl) 232(19):3663–3676. https://dx.doi.org/10.1007/s00213-015-4026-7
Tagliazucchi E., Roseman L., Kaelen M., Orban C., Muthukumaraswamy S. D., Murphy K., Laufs H., Leech R., McGonigle J., Crossley N., Bullmore E., Williams T., Bolstridge M., Feilding A., Nutt D.J. and Carhart-Harris R. (2016). Increased Global Functional Connectivity Correlates with LSD-Induced Ego Dissolution. Current Biology, 26, 1-8. http://dx.doi.org/10.1016/j.cub.2016.02.010
N,N-dimethyltryptamine, more commonly known as DMT, is an exceptionally fast-acting and powerful psychedelic. DMT can be ingested by drinking the entheogenic brew ayahuasca, injected intravenously, intramuscularly or through inhalation. It is produced endogenously in a variety of plants and animals, including in humans. DMT exerts physiological effects that go beyond its mind-altering effects, as discussed in Jacob and Presti (2005). For example, DMT has been shown to induce anxiolytic and antidepressant effects (Sanches et al. 2016).
