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A new harmonic language decodes the effects of LSD - new publication in Scientific Reports.

MIB and Oxford professor Morten Kringelbach co-leads large international research team which has uncovered changes in whole-brain dynamics caused by LSD.

18.12.2017 | Hella Kastbjerg

LSD (lysergic acid diethylamide) was initially synthetized by Albert Hofmann in 1938 to stimulate the respiratory and circulatory systems. Yet, it was 5 years later that he accidentally discovered the profound effects of LSD on perception and consciousness, which led to its extensive use as a research and therapeutic tool in psychiatry in the 1950s. Today, LSD and related psychedelics are considered by some to be ‘microscopes’ or ‘telescopes’ for the psyche, because they reveal more of the mind than is normally accessible. However, the brain mechanisms underlying LSD’s profound effects have remained largely elusive.

Now, thanks to the efforts of a large international team, researchers have uncovered changes in whole-brain dynamics caused by LSD, according to a study published December 15, 2017 in the open-access journal Scientific Reports (published by the Nature publishing group), led by Dr Selen Atasoy, Prof Morten Kringelbach, Prof Gustavo Deco and Dr Robin Carhart-Harris from the Universities of Pompeu Fabra (Spain), Oxford (UK), Center for Music in the Brain, Aarhus (Denmark) and Imperial College London (UK).

To decode the effects of LSD in the brain, the team has used a novel harmonic language of brain activity, which was firstly introduced in a Nature Communications publication in January 2016. This harmonic decoding of fMRI data showed that LSD increases the total energy and enriches the repertoire of connectome harmonics - the basic elements of this harmonic language. The research also revealed that LSD selectively activated high-frequency connectome harmonics, which remarkably caused the brain activity to self-organize right at the edge of chaos.

Dr Selen Atasoy, the lead author of the study says: “The connectome harmonics we used to decode brain activity are universal harmonic waves, such as sound waves emerging within a musical instrument, but adapted to the anatomy of the brain. Translating fMRI data into this harmonic language is actually not different than decomposing a complex musical piece into its musical notes”.

 “What LSD does to your brain seems to be similar to jazz improvisation” says Atasoy, “your brain combines many more of these harmonic waves (connectome harmonics) spontaneously yet in a structured way, just like improvising jazz musicians play many more musical notes in a spontaneous, non-random fashion”.

“The presented method introduces a new paradigm to study brain function, one that links space and time in brain activity via the universal principle of harmonic waves. It also shows that this spatio-temporal relation in brain dynamics resides at the transition between order and chaos.” says Prof Gustavo Deco.

Dr. Robin Carhart-Harris adds: “Our findings reveal the first experimental evidence that LSD tunes brain dynamics closer to criticality, a state that is maximally diverse and flexible while retaining properties of order. This may explain the unusual richness of consciousness experienced under psychedelic drugs and the notion that they ‘expand consciousness’.”

Prof Morten Kringelbach notes: “By revealing the characteristic differences between LSD and normal awake state, the applied harmonic wave decomposition opens-up the possibility of extracting the signatures of various mental states, including sleep, anesthesia, and disorders of consciousness as well as psychiatric and neurological disorders.”.

For more information please contact Dr Selen Atasoy on selenatasoy@gmail.com.

 

ADDITIONAL INFORMATION:

* The paper “Connectome-harmonic decomposition of human brain activity reveals dynamical repertoire re-organization under LSD” is published in the high-impact journal Scientific Reports. The paper was published on Friday the 15th December and will be freely available on the journal website:   https://www.nature.com/articles/s41598-017-17546-0

* The paper “Human brain networks function in connectome-specific harmonic waves” was published in the high-impact journal Nature Communications and is available on the journal website at   https://www.nature.com/articles/ncomms10340.

* More information about connectome harmonics can be found in "Harmonic brain modes: a unifying framework for linking space and time in brain dynamics" in Neuroscience:   http://journals.sagepub.com/doi/abs/10.1177/1073858417728032

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