From the New Scientist:
“The team gave 20 volunteers infusions on two days, once containing 75 micrograms of LSD, the other a placebo. Then volunteers lay in a scanner and had their brains imaged with three different techniques, which together built up a comprehensive picture of neural activity, both with the drug and without.”
This work is yielding important findings:
“LSD also made the brain more unified in its activity, and there was more communication between regions that normally work separately. “The brain is functioning in a simpler way,” says Carhart-Harris.
The results also go some way to explaining how LSD causes dreamlike visual hallucinations. Although the primary visual cortex usually communicates mainly with other parts of the vision system, many other brain areas contributed to the processing of images in volunteers who received LSD.”