Monash University researchers are part of a global team that has developed and applied world-first non-invasive computer technology to explore how the brain processes information when under the influence of hallucinogens, like LSD.



Using this new technology along with a carefully designed experiment, researchers have determined that when the brain is under the influence of psychedelic substances, the thalamus drops its guard and supplies an overabundance of information to the cortex. This is what causes us to ‘trip out’.



The research supports the common theory that attributes the ‘trippy effects’ of psychedelics to a breakdown of information processing in the brain that dictates how we react to internal and external stimuli.



“This sensory information overload results in alterations to our consciousness and perception of things around us, similar to a ‘dreamlike’ experience with perceived mental clarity,” Dr Adeel Razi, Senior Research Fellow at Monash Biomedical Imaging and the only Australian author, said.



“Psychedelics induce an altered state of consciousness that, on one hand, mimics the symptoms of schizophrenia, but on the other hand, may have beneficial therapeutic effects in mood and anxiety disorders.”



The study, led by researchers at the University of Zurich, monitored a neural pathway called the cortico-striato-thalamo-cortical (CSTC) loop using an MRI machine in 25 people administered with LSD. The CSTC loop determines which internal and external stimuli get our attention.



Results showed that LSD increased the amount of connectivity between the thalamus and certain regions of the cortex – ones that associate with changes in “self-experience” – which explains why psychedelics experience strange visuals and body sensations.



It first time that the CSTC model was tested in humans. Findings were published in the journal Proceedings of the National Academic of Sciences.



“An LSD trip is usually longer than the ones induced by other psychedelic substances. At the dose we administered, people usually felt sober after 10-12 hours. In a few cases, the effects of LSD can last for up to 24 hours,” Dr Katrin Preller from the University of Zurich said.



“Under the influence of LSD, we usually see an increase in blood pressure and a widening of the pupil. People also report higher levels of precision (like when playing the piano) alongside sharper and brighter images.”



This new computational method was developed by Dr Razi in conjunction with Professor Karl Friston at University College London and allows researchers to calculate the direction of information flow in the human brain using non-invasive imaging. This technique is now used in dozens of research labs across the world to understand how different brain regions communicate and how this communication is disrupted in disease.



“The development of such non-invasive neuro-technologies will allow for new treatments of brain disorders, such as schizophrenia, autism and dementia, as well as technological advances in neuroscience-inspired artificial intelligence and robotics,” Dr Razi, also the Deputy Lead of the Brain Mapping and Modelling Program at the Monash Institute of Cognitive and Clinical Neurosciences (MICCN), said.



Future studies will extrapolate on current findings to investigate other theories on why we ‘trip out’ and how the influence of LSD on the CSTC loop may help development treatments for mental health conditions.





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