People who suffer trauma will, with few exceptions, never forget what happened to them, but a 91ֿ researcher may be able offer them the hope of living without constant fear and anxiety.
John D. Johnson, Ph.D., associate professor of biological sciences in 91ֿ’s College of Arts and Sciences, received a three-year, $450,000 grant from the National Institutes of Health (NIH) for a study that could provide a better understanding of how we create deeply ingrained fear memories — and how to stop them.
“People have these horrible things that happen to them, and they’re reliving them, and the memories are so ingrained,” Dr. Johnson says. “Our question is, can we reverse those or block those from making such strong memories?”
Dr. Johnson says it all comes down to the amygdala, a small area near the front of the brain that is responsible for our response to and memory of emotions, namely fear.
Among the cells in the amygdala are microglia, the central nervous system’s first line of immunity defense.
Microglia, in turn, produce cytokines. Cytokines — which are also produced by other types of brain cells — are associated with neurological problems, including chronic anxiety, depression, and post-traumatic stress.
“We know chronic stress can result in a lot of behavioral changes, like depression and anxiety,” Dr. Johnson says. “Our lab has shown previously that animals that are exposed to chronic stress have this increased ability to form fear memories.”
In his new study, Dr. Johnson will use similar rodent models designed to mimic the conditions he hopes to be able to treat in humans.
“They are more prone to remembering fearful events,” Dr. Johnson says. “There’s this increased ability to form these fear memories. With exposure to chronic stress, we see an increased response in brain cytokines, and we’re looking to see if these contribute to the formation of these fear memories or enhance the consolidation of these memories.”
The first stage of Dr. Johnson’s project is to determine the role cytokines play in the formation of fear memories. The second is to determine if the cytokines come from the microglia. If they do, Dr. Johnson says, he hopes to be able to use a virus to control the microglia, in order to turn cytokine production off and on.
“We think that’s really important, potentially, for anxiety and PTSD,” Dr. Johnson says. “If you’re under chronic stress and you’re exposed to something bad, then you’re going to remember that and you’re going to contemplate that over and over again.
“We think that if we inhibit the microglia during the pairing of environmental cues and stress memory, then we can prevent the exaggerated anxiety that we see in these animals,” he says.
For more information about 91ֿ’s Department of Biological Sciences, visit www.kent.edu/biology.