Psychedelic spurs growth of neural connections lost in depression

Psilocybin is a natural compound that can be found in mushrooms and has been used as a treatment for depression for many years. It is not clear how the brain reacts to it and how long the benefits might last.Yale researchers have shown that mice receiving a single dose psilocybin resulted in a significant and lasting increase in the number of neurons. These findings were published in Neuron on July 5.Alex Kwan, Yale's associate professor of neuroscience and psychiatry, said that there was a 10% increase in neuronal connections. Also, they were about 10% larger on average, so the connections were also stronger." He is the senior author of the paper.Previous laboratory studies had demonstrated that psilocybin and the anesthetic, ketamine, could decrease depression. Yale researchers found that these compounds increased the density of dendritic spinal spines. These are small protrusions on nerve cells that aid in information transmission between neurons. These neuronal connections are less common in depression and chronic stress.Kwan and Ling-Xiao Shao (a postdoctoral associate at Yale School of Medicine), imaged dendritic spinal cells in high resolution. They then tracked them in live mice for several days using a laser scanning microscope. After administering psilocybin, they found an increase in dendritic spine count and increased size. These changes remained a month later. After being administered psilocybin, mice that had been subject to stress experienced behavioral improvements and higher neurotransmitter activity.Psilocybin (an active component in "magic mushrooms") can provide a deep mystical experience for some people. The popular recreational drug psychedelic is also used in religious ceremonies.Kwan suggested that it may be the unique psychological effects of psilocybin that stimulate the growth of neuronal links.He said, "It was quite surprising to see such lasting changes after just one dose of pilocybin." "These connections could be structural changes that the brain uses in order to store new experiences."###