The phrase “this is your brain on drugs” may conjure up images of eggs frying thanks to a classic anti-drugs ad campaign, but neuroscience has recently shown this is far from the truth.
A team of researchers led by Dr. David Nutt at Imperial College London recently published the first images of brains affected by the psychedelic drug lysergic acid diethylamide, better known as LSD, in the prestigious Proceedings of the National Academy of Sciences.
This is the first study to use modern techniques to visualize the effects of psychedelics on the human brain.
Conducting human trials with LSD is an achievement in itself.
It took the authors nine months to receive permission for the study because LSD is banned by both United Nations conventions and national laws in the United Kingdom.
Once the permissions were in place, the researchers found participants with prior experience of taking psychedelic drugs.
These participants were injected with either 75 micrograms of LSD — roughly equivalent to one or two “hits” of street LSD — or a drug-free placebo on two separate days.
After being dosed, the participants were put through a barrage of tests.
The scientists used functional magnetic resonance imaging, or fMRI, to visualize areas of the brain with increased blood flow.
They saw that blood flow to the visual cortex at the back of the brain was slightly increased, possibly helping drive the visual hallucinations that people on LSD experience.
The researchers also used a technique known as magnetoencephalography a non-invasive neuroimaging method to visualize the location of electrical activity in the patient’s brains.
They found changes in synchrony, the degree to which neurons in the brain fire together.
Regions that normally fire all their neurons together cease to do so while someone is on LSD, and regions that normally do not fire in synchrony may begin to do so.
This pattern matches the synchrony of patients given psilocybin, the active ingredient in psychedelic mushrooms.
After the imaging tests, scientists gave participants a questionnaire that documented the feelings they experienced while on LSD.
The researchers found ego-dissolution, a feeling of connection with the world around them rather than as a separate entity, is associated with a reduction of brain synchrony.
They also have evidence that brain regions that are usually disconnected suddenly begin communicating with each other during the psychedelic experience.
A region called the parahippocampus that is responsible for memory storage begins sending information to the visual cortex, which results in the experience of closed-eye imagery and revisiting vivid personal memories.
This LSD-enhanced cross-talk between brain regions may allow psychedelics to disrupt the brain’s default-signaling pathways, which are known to be exceptionally strong in patients suffering from depression.
This has led the group to begin looking into psychedelics as an aid for psychotherapy for cases of treatment-resistant depression and post-traumatic stress disorder.
These results are important in helping us better understand the subtle workings of the human brain and will assist in the development of new therapies for mental illness.