Electric shocks used to study fear, PTSD

Mina Kim

Shocks and pictures of animals are being used to learn more about PTSD, or post traumatic stress disorder. Graduate student Gus Hennings and research assistant Mason McClay lead this research at the Dunsmoor Lab.

The study is built on principles of Pavlovian conditioning, famously based on dogs learning to associate the sound of a bell with food, according to Scientific American. Hennings and McClay replaced bells and kibble with electric shocks and pictures of tools and animals.

Using this method, researchers can better understand why people with PTSD have a harder time forgetting their anxiety compared to others, said Joseph Dunsmoor, the principal investigator of the study and assistant professor of psychiatry at Dell Medical School.

“Basically, the pictures of animals and tools by themself aren’t scary in any way,” Dunsmoor said. “We introduce this electric shock right when the picture is presented. Over time, people learn to become anxious at the previously neutral pictures, but people also learn to forget that fear when the shocks stop happening the same time the picture is presented.”

While there are safety and ethical concerns regarding using electrical shocks to study PTSD, the shocks themselves are not painful, McClay said. And like every other active study at UT, this PTSD research has successfully passed the Institutional Review Board, McClay said.

“Our shocks themselves aren’t harmful at all, they just provide a stimulus strong enough for someone to associate a picture of a deer, for example, with a little anxiety that goes away easily — it’s very mild,” McClay said.

To evaluate whether the participant is experiencing anxiety during the experiment, the volunteers are placed in an fMRI machine. Dunsmoor said this machine indirectly reveals reactions to the pictures by measuring blood flow in the brain.

“A main part of conducting this study is using fMRI after we’ve given the patients some time to forget their fear,” Dunsmoor said. “Pavlovian conditioning isn’t our main focus here — it’s just a method through which we can learn more about how PTSD patients handle fear outside of their trauma.”

McClay said the research team still has to collect more data to expand the sample size. When they finish, there is potential the study will help people with PTSD alleviate their symptoms.

“People have been treating PTSD for a while now,” said Dunsmoor. “We’ve gotten pretty successful with it, but there are still many cases where people are unable to feel safe, and keep feeling afraid. Studying PTSD in this way could help us return that sense of safety everyone deserves.”