H/T Reset.me:

During the experiment, mice were exposed to an auditory tone while receiving an electric shock, training them to fear the noise even when the shock was not administered.

Mice that received low doses of psilocybin, however, were quickly able to shed their aversion to the tone, while mice that did not take the substance took longer to return to normal. “They stopped freezing; they lost their fear,” study co-author Dr. Juan Sanchez-Ramos said to Live Science.

What’s more, the psychedelic mice showed growth in new brain cells, perhaps erasing memories of the fear response. Researchers think that the psilocybin is binding to brain receptors that stimulate growth and healing, acting on the hippocampus, a small part of the brain that is essential to learning and forming memories. Since PTSD is thought to result from a similar response in which patients cannot separate a stimulus from a traumatic event, psilocybin could perhaps help them heal their brains just like it did for the mice.

“Memory, learning, and the ability to relearn that a once threatening stimuli is no longer a danger absolutely depends on the ability of the brain to alter its connections,” study leader Dr. Briony Catlow of the Lieber Institute for Brain Development said to Real Clear Science. “We believe that neuroplasticity plays a critical role in psilocybin accelerating fear extinction.”

“It is highly possible that in the future we will continue these studies since many interesting questions have come up from these experiments,” Catlow said. “The hope is that we can extend the findings to humans in clinical trials.”