Taking LSD increases connectivity between different regions of the brain, scientists say. This leads individuals to experience a blur of the boundaries between their self and the environment around them, a phenomenon otherwise known as "ego dissolution".

The study, published in the journal Current Biology, is the second such report this week that examines LSD's effects on the brain, thanks to functional magnetic resonance imaging (fMRI).

While the first paper focused on discovering what areas were activated during hallucination, this latest research looks at connectivity in the brain under LSD, and how it explains ego dissolution.

Ego dissolution and proofs on the scans

The concept of ego dissolution itself is complex to define. "Normally we feel that we are beings separated from the environment, but this is lost under LSD. Simply put, consciousness is not lost, but self-consciousness is heavily impaired. It's obviously difficult to put into words since it is an experience outside the limits of how we normally feel," one of the authors, Enzo Tagliazucchi, told IBTimes UK.

He and his team, from the Royal Netherlands Academy of Arts and Sciences and Imperial College London, scanned the brain of 15 healthy volunteers, while they were either under the influence of LSD or a placebo.

When participants took LSD, scientists observed an increased global connectivity in many higher-level regions of the brain. These regions include the frontal, parietal and inferior temporal cortices – responsible for thoughts, actions and conciousness – as well as the bilateral thalamus.

Another finding was that the areas of increased connectivity identified overlapped with the parts of the brain where LSD receptors are known to be found.

Introspection and external world

More importantly, researchers showed that the feeling of ego dissolution increased proportionally with the connectivity in the brain. How do they explain this phenomenon?

"We know we are witnessing ego-dissolution because the participants – experienced psychedelic drug users – tell us so. This is the best proof we can get," says Tagliazucchi.

"Then, we discovered that some changes in the brain are in proportion to the intensity of ego-dissolution reported by the participants. We see increased communication between the network of regions associated with introspection and the network of regions associated with perceiving the external world".

As these connections are made between different parts of the brain, individuals progressively see barriers disappear between perceptions of their selves and of the environment.

Read more on IBTimes UK