英國(guó)研究人員日前報(bào)告說(shuō)已探清了迷幻蘑菇導(dǎo)致幻覺(jué)的原因，即迷幻蘑菇含有的一種物質(zhì)會(huì)導(dǎo)致大腦某些部位的活動(dòng)性減弱,，這項(xiàng)發(fā)現(xiàn)或許有助治療抑郁癥等精神疾病,。
英國(guó)帝國(guó)理工學(xué)院等機(jī)構(gòu)研究人員在新一期美國(guó)《國(guó)家科學(xué)院學(xué)報(bào)》上報(bào)告說(shuō),，迷幻蘑菇中含有的致幻物質(zhì)是“二甲-4-羥色胺磷酸”，研究人員為一些健康志愿者注射了這種物質(zhì),，同時(shí)利用磁共振成像技術(shù)對(duì)他們大腦進(jìn)行掃描,，觀察大腦中出現(xiàn)的變化。
結(jié)果發(fā)現(xiàn)，與以前人們猜測(cè)這種物質(zhì)致幻是因?yàn)樵黾恿舜竽X的活動(dòng)性不同,，它減弱了大腦中一些部位的活動(dòng)性,，如內(nèi)側(cè)前額葉皮層、后帶皮層等,。這些部位在大腦中起著“連接中樞”的作用,，能夠協(xié)調(diào)各個(gè)功能部位的感受，研究人員因此認(rèn)為,，這些“連接中樞”活動(dòng)性的降低,，導(dǎo)致了大腦各個(gè)功能部位之間信息互相傳遞的脫節(jié)，從而引起各種奇怪的幻覺(jué),。
研究人員羅賓·卡哈特-哈里斯說(shuō),，這項(xiàng)發(fā)現(xiàn)還說(shuō)明或許可以用從迷幻蘑菇中提取出的物質(zhì)來(lái)幫助治療抑郁癥。過(guò)去曾有研究發(fā)現(xiàn),，許多抑郁癥患者大腦中的相關(guān)部位活動(dòng)性過(guò)高,，也有一些醫(yī)生基于經(jīng)驗(yàn)而使用迷幻蘑菇來(lái)幫助治療抑郁癥，但其背后的科學(xué)原理一直不太清楚,，本次研究結(jié)果為此提供了支持,，說(shuō)明迷幻蘑菇的藥用價(jià)值值得進(jìn)一步研究。(生物谷 Bioon.com)
doi:10.1073/pnas.1119598109
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Neural correlates of the psychedelic state as determined by fMRI studies with psilocybin
Robin L. Carhart-Harris, David Erritzoe, Tim Williams, James M. Stone, Laurence J. Reed, Alessandro Colasanti, Robin J. Tyacke, Robert Leech, Andrea L. Malizia, Kevin Murphy, Peter Hobden, John Evans, Amanda Feilding, Richard G. Wise, and David J. Nutt
Psychedelic drugs have a long history of use in healing ceremonies, but despite renewed interest in their therapeutic potential, we continue to know very little about how they work in the brain. Here we used psilocybin, a classic psychedelic found in magic mushrooms, and a task-free functional MRI (fMRI) protocol designed to capture the transition from normal waking consciousness to the psychedelic state. Arterial spin labeling perfusion and blood-oxygen level-dependent (BOLD) fMRI were used to map cerebral blood flow and changes in venous oxygenation before and after intravenous infusions of placebo and psilocybin. Fifteen healthy volunteers were scanned with arterial spin labeling and a separate 15 with BOLD. As predicted, profound changes in consciousness were observed after psilocybin, but surprisingly, only decreases in cerebral blood flow and BOLD signal were seen, and these were maximal in hub regions, such as the thalamus and anterior and posterior cingulate cortex (ACC and PCC). Decreased activity in the ACC/medial prefrontal cortex (mPFC) was a consistent finding and the magnitude of this decrease predicted the intensity of the subjective effects. Based on these results, a seed-based pharmaco-physiological interaction/functional connectivity analysis was performed using a medial prefrontal seed. Psilocybin caused a significant decrease in the positive coupling between the mPFC and PCC. These results strongly imply that the subjective effects of psychedelic drugs are caused by decreased activity and connectivity in the brain's key connector hubs, enabling a state of unconstrained cognition.
