The Effects of LSD on Brain Scans

An experiment from a team at at Imperial College London studied the effects of LSD on the brain by giving the drug to 20 experienced volunteers and then scanning their brains. You might wonder why this hasn’t been done before. Imperial College neuropsychopharmacologist David Nutt, the lead researcher, explained how difficult it is to get approval for LSD research. Even in the UK where such research is legal, it can only be done as long as the aim is not therapeutic. The resources for this particular study was raised by crowdfunding. So what did they find?

In one study in the Proceedings of the National Academy of Sciences we looked at blood flow in different parts of the brain using functional magnetic resonance imaging, fMRI, and electrical activity using magnetoencephalography. We found that under LSD, compared to placebo, disparate regions in the brain communicate with each other when they don’t normally do so. In particular, the visual cortex increases its communication with other areas of the brain, which helps explain the vivid and complex hallucinations experienced under LSD, and the emotional flavour they can take.
On the other hand, within some important brain networks, such as the neuronal networks that normally fire together when the brain is at rest, sometimes called the ‘default mode network’, we saw reduced blood flow — something we’ve also seen with psilocybin — and that neurons that normally fire together lost synchronization. That correlated with our volunteers reporting a disintegration of their sense of self, or ego. This known effect is called ‘ego dissolution': the sense that you are less a singular entity, and more melded with people and things around you. We showed that this could be experienced independently of the hallucinatory effects — the two don’t necessarily go together.

There were other results you can read about at Nature. Scientists hope to someday run clinical trials to see if LSD can be use therapeutically for conditions such as PTSD, addiction, and treatment-resistant depression.