Tieteelliset julkaisut

Tulokset kategoriasta aihe hakusanalla Aivotutkimus. Takaisin

Psilocybin for treatment-resistant depression: fMRI-measured brain mechanisms. (Carhart-Harris RL, Roseman L, Bolstridge M, Demetriou L, Pan.., 2017)
Julkaisu:Scientific Reports
Tiivistelmä: Psilocybin with psychological support is showing promise as a treatment model in psychiatry but its therapeutic mechanisms are poorly understood. Here, cerebral blood flow (CBF) and blood oxygen-level dependent (BOLD) resting-state functional connectivity (RSFC) were measured with functional magnetic resonance imaging (fMRI) before and after treatment with psilocybin (serotonin agonist) for treatment-resistant depression (TRD).

Quality pre and post treatment fMRI data were collected from 16 of 19 patients. Decreased depressive symptoms were observed in all 19 patients at 1-week post-treatment and 47% met criteria for response at 5 weeks. Whole-brain analyses revealed post-treatment decreases in CBF in the temporal cortex, including the amygdala. Decreased amygdala CBF correlated with reduced depressive symptoms. Focusing on a priori selected circuitry for RSFC analyses, increased RSFC was observed within the default-mode network (DMN) post-treatment. Increased ventromedial prefrontal cortex-bilateral inferior lateral parietal cortex RSFC was predictive of treatment response at 5-weeks, as was decreased parahippocampal-prefrontal cortex RSFC.

These data fill an important knowledge gap regarding the post-treatment brain effects of psilocybin, and are the first in depressed patients. The post-treatment brain changes are different to previously observed acute effects of psilocybin and other 'psychedelics' yet were related to clinical outcomes. A 'reset' therapeutic mechanism is proposed.
Aihe:Yleiset vaikutukset, aivotutkimus
URL: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5640601/

Neural correlates of the LSD experience revealed by multimodal neuroimaging (Carhart-Harris RL, Muthukumaraswamy S, Roseman L, Kaelen M, .., 2016)
Julkaisu:Proceedings of the National Academy of Sciences of the United States of America
Tiivistelmä: LSD:n vaikutuksia aivoissa tutkittiin kolmen aivokuvantamismenetelmän avulla. Kohderyhmänä olivat terveet koehenkilöt. Tutkimuksessa todettiin, että LSD vähentää oletushermoverkostoon luettujen aivoalueiden välistä integraatiota ja toisaalta lisää eri aivoalueiden välistä kytkeytyneisyyttä.

Näköaivokuoren voimistunut verenkierto, näköaivokuoren vaimentuneet alfa-aallot ja primäärisen näköaivokuoren toiminnallisten yhteyksien laajeneminen korreloivat vahvasti koehenkilöiden visuaalisista hallusinaatiosta tekemien arvioiden kanssa.

Lisäksi parahippokampuksen ja retrospleniaalisen aivokuoren välisten yhteyksien vaimeneminen korreloi koehenkilöiden arvioimien egon hälvenemisen ja merkityskokemuksen muuttumisen kanssa.

Myös eri kuvantamismenetelmien välillä havaittiin merkittäviä korrelaatioita.
Menetelmät:Aivokuvantaminen, fMRI, MEG
Tagit: aivot, default mode network, LSD, tietoisuus
URL: http://www.pnas.org/content/113/17/4853.full

Classical hallucinogens and neuroimaging: A systematic review of human studies: Hallucinogens and neuroimaging. (Dos Santos RG, Osório FL, Crippa JAS, Hallak JEC, 2016)
Julkaisu:Neuroscience and Biobehavioural Reviews
Tiivistelmä: 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.
Yhdiste:Psykedeelit yleisesti, ayahuasca, psilosybiini, LSD
Aihe:Aivotutkimus, yleiset vaikutukset, farmakologia
URL: https://www.sciencedirect.com/science/article/pii/S01497634163023...

The current state of research on ayahuasca: A systematic review of human studies assessing psychiatric symptoms, neuropsychological functioning, and neuroimaging. (Dos Santos RG, Balthazar FM, Bouso JC, Hallak JE, 2016)
Julkaisu:Journal of Psychopharmacology
Tiivistelmä: RATIONALE:
In recent decades, the use of ayahuasca (AYA) - a β-carboline- and dimethyltryptamine-rich hallucinogenic botanical preparation traditionally used by Northwestern Amazonian tribes for ritual and therapeutic purposes - has spread from South America to Europe and the USA, raising concerns about its possible toxicity and hopes of its therapeutic potential. Thus, it is important to analyze the acute, subacute, and long-term effects of AYA to assess its safety and toxicity.

The purpose of this study was to conduct a systematic review of human studies assessing AYA effects on psychiatric symptoms, neuropsychological functioning, and neuroimaging.

Papers published until 16 December 2015 were included from PubMed, LILACS and SciELO databases following a comprehensive search strategy and pre-determined set of criteria for article selection.

The review included 28 full-text articles. Acute AYA administration was well tolerated, increased introspection and positive mood, altered visual perceptions, activated frontal and paralimbic regions and decreased default mode network activity. It also improved planning and inhibitory control and impaired working memory, and showed antidepressive and antiaddictive potentials. Long-term AYA use was associated with increased cortical thickness of the anterior cingulate cortex and cortical thinning of the posterior cingulate cortex, which was inversely correlated to age of onset, intensity of prior AYA use, and spirituality. Subacute and long-term AYA use was not associated with increased psychopathology or cognitive deficits, being associated with enhanced mood and cognition, increased spirituality, and reduced impulsivity.

Acute, subacute, and long-term AYA use seems to have low toxicity. Preliminary studies about potential therapeutic effects of AYA need replication due to their methodological limitations.
Aihe:Yleiset vaikutukset, aivotutkimus, farmakologia
URL: http://journals.sagepub.com/doi/abs/10.1177/0269881116652578

Antidepressant Effects of a Single Dose of Ayahuasca in Patients With Recurrent Depression: A SPECT Study. (Sanches RF, de Lima Osório F, Dos Santos RG, Macedo LR, Mai.., 2016)
Julkaisu:Journal of Clinical Psychopharmacology
Tiivistelmä: 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.
Aihe:Masennus, yleiset vaikutukset, aivotutkimus
Menetelmät:Open label, seuranta, SPECT
URL: https://www.ncbi.nlm.nih.gov/pubmed/26650973

Decoding the signaling of a GPCR heteromeric complex reveals a unifying mechanism of action of antipsychotic drugs. (Fribourg M, Moreno JL, Holloway T, Provasi D, Baki L, Mahaja.., 2011)
Tiivistelmä: Klassiset serotonergiset psykedeelit aktivoivat 5-HT2A serotoniinireseptorin tavalla, joka heteromerisöi sen metabotrooppisen glutamaattisereptorin (mGluR2) kanssa, salvaten sen toiminnan. Reseptorikompleksin muodostuminen on olennainen psykedeelisille vaikutuksille, koska 5-HT2A agonistit, jotka eivät samalla salpaa mGlu-reseptoreita eivät myöskään tuota psykedeeleille tyypillisiä vaikutuksia.
Yhdiste:psykedeelit yleisesti
Menetelmät:In vitro
Tagit: 5-HT2A, psykedeelit, toimintamekanismi
URL: https://www.cell.com/cell/fulltext/S0092-8674(11)01272-4