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Lysergic acid diethylamide (LSD) is a one of the most powerful chemicals that alters human behavior. LSD is a psychedelic drug which causes unusual psychological effects like altered consciousness, hallucinations, synesthesia, distortion of time and space and altered spiritual experiences. It belongs to the ergoline family but LSD drugs are not addictive, however psychiatric reactions like delusions, paranoia or anxiety can result from their usage.

LSD was first isolated from ergot sclerotia by Albert Hofmann in 1938; however, its psychedelic properties were unknown until 5 years later when Hofmann took a small dose in his lab. LSD’s effects on art, society and science were unprecedented in the decades after its discovery.  

However, a tremendous increase in recreational use and its revolutionary impacts in culture during late 1960s provoked laws against the usage of LSD making it illegal. Unfortunately, LSD human research was put on halt for half a century. Lately, numerous reports have been published on the psychological effects of LSD.

A new study, published in Proceedings of the National Academy of Sciences (PNAS), revealed the neural correlates of the LSD experience by multimodal neuroimaging.  Scientists have gained a glimpse into how the psychedelic drugs affect human brain activity using cutting-edge and complementary neuroimaging techniques. This study involved 20 healthy volunteers, who attended 2 scanning days (LSD and placebo) 20 weeks apart in a balanced order. Three complementary neuroimaging techniques were used: arterial spin labeling (ASL), blood oxygen level-dependent (BOLD) measures, and magnetoencephalography (MEG).  Sessions of scanning included an fMRI followed by a MEG scan, each lasting 75 min. Data were acquired during eye-closed, task-free, “resting state” conditions. Two resting state ASL scans totaling 16 min were completed 100 min after i.v. administration of LSD corresponding to the initial phase of the peak subjective effects of LSD (peak effects were reached ∼120–150 min post infusion). Two resting state BOLD scans totaling 14 min were completed 135 min post infusion, and two resting state MEG scans totaling 14 min were completed 225 min post infusion.13014982_1201514279860299_244780533_n

A major finding of the research was the discovery of what happens in the brain when people experience complex dreamlike hallucinations under LSD. Under normal conditions, information from our eyes is processed in a part of the brain at the back of the head called the visual cortex. However, when the volunteers took LSD many additional brain areas, not just the visual cortex, contributed to visual processing.

Dr Robin Carhart-Harris, from the Department of Medicine at Imperial, who led the research, explained: "We observed brain changes under LSD that suggested our volunteers were 'seeing with their eyes shut' — albeit they were seeing things from their imagination rather than from the outside world. We saw that many more areas of the brain than normal were contributing to visual processing under LSD – even though the volunteers' eyes were closed. Furthermore, the size of this effect correlated with volunteers' ratings of complex, dreamlike visions".

The results showed that psychedelics reduce the integrity and stability of well-established brain networks and at the same time minimize the degree of segregation or separation between them.  These results are consistent with the principle that psychedelics induce an “entropic” cortical brain activity. 

The results also support the therapeutic usage of psychedelics which mounts our need to understand how these drugs interact with our brain. In many psychiatric disorders, the brain may be viewed as having become entrenched in pathology, such that core behaviors become automated and rigid. Consistent with their “entropic” effect on cortical activity, psychedelics may work to break down such disorders by dismantling the patterns of activity on which they rest. Future work is required to test this hypothesis and the others that have been presented by this study as part of a broader initiative to properly utilize these valuable scientific tools.

 

References

●     Hofmann,A. (1980) LSD: My problem Child (McGraw-Hill, New York).

●     Robin L. Carhart-Harris, Suresh Muthukumaraswamy, Leor Roseman, Mendel Kaelen, Wouter Droog, Kevin Murphy, Enzo Tagliazucchi, Eduardo E. Schenberg, Timothy Nest, Csaba Orban, Robert Leech, Luke T. Williams, Tim M. Williams, Mark Bolstridge, Ben Sessa, John McGonigle, Martin I. Sereno, David Nichols, Peter J. Hellyer, Peter Hobden, John Evans, Krish D. Singh, Richard G. Wise, H. Valerie Curran, Amanda Feilding, and David J. Nutt. Neural correlates of the LSD experience revealed by multimodal neuroimaging. Proceedings of the National Academy of Sciences (PNAS), April 2016

●     Tagliazucchi and Roseman et al. Increased Global Functional Connectivity Correlates with LSD-Induced Ego Dissolution. Current Biology, 2016

●     Imperial College London. "Brain on LSD revealed: First scans show how the drug affects the brain." ScienceDaily. ScienceDaily, 11 April 2016. www.sciencedaily.com/releases/2016/04/160411153006.htm

●     Image imported from:

●     http://www.pnas.org/content/early/2016/04/05/1518377113.full

●     http://www.nature.com/news/brain-scans-reveal-how-lsd-affects-consciousness-1.19727