People who suffer trauma will, with few exceptions, never forget what happened to them, but a 91ֿ researcher may be able to offer them the hope of living withoutconstant fear and anxiety.
John Johnson, PhD, 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 who have horrible things happen to them are reliving them, and the memories are ingrained,” Johnson says. “Our question is: Can we reverse or block such strong memories from being made?”
He says it all comes down to the amygdala, a small area near the front of the brain that is responsible for processing emotions, including fear.
Among the cells the amygdala produces are microglia, the central nervous system’s first line of immunity defense. Microglia 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.
“Chronic stress can result in behavioral changes, like depression and anxiety,” Johnson says. “Our lab has shown previously that animals exposed to chronic stress have increased ability to form fear memories.”
In his new study, Johnson will use rodent models designed to mimic the conditions he hopes to treat in humans. “With exposure to chronic stress, we see an increased response in brain cytokines,” Johnson says. “We’re looking to see if these contribute to the formation of fear memories or enhance the consolidation of these memories.”
Animals exposed to chronic stress have increased ability to form fear memories.
The first stage of his 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, Johnson says he hopes to be able to use a virus to control the microglia in order to turn cytokine production off and on.
“That’s important, potentially, for anxiety and PTSD,” he says. “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 rodents.”