The idea that simple eye movements could help trauma victims reprocess emotional memories is the focus of research for Larry Stevens, psychological sciences professor.

Eye movement desensitization and reprocessing was first discovered by psychologist Francine Shapiro in 1987, and while many practitioners incorporate EMDR with their mental health patients, its reported success is not fully understood.

“One hypothesis is the Interhemispheric Coherence Model, that when we move our eyes back and forth we are stimulating both hemispheres of the brain so that we can better process the trauma,” said Stevens, who is building on this idea with research of his own.

While logical word-related memories are stored in the brain’s hippocampus, emotional memories, including fears and anxieties, are stored in the amygdala. Stevens said the stress hormone cortisol, which facilitates the storage of traumatic memories in the amygdala, also inhibits the storage of semantic memories in the hippocampus.

“We need therapies for this disconnection of different parts of the brain so people suffering from post-traumatic stress disorder don’t have traumatic memories continuing to reverberate in the amygdala. We need to integrate the words and the feelings,” Stevens said.

VisualPathways

Graphic of the brain showing the different hemispheres. Image courtesy of megagrip.co.uk

In one of Stevens’ studies, he attached 19 electrodes to the subjects’ scalps. Brain activity was measured in individuals as they processed memories and their eyes followed a light moving back and forth.

“We found significant increases in intra-hemispheric coherence for positive memories but we did not find statistically significant inter-hemispheric activity,” said Stevens, who reached similar findings on a subsequent experiment using negative memories.

With negative memories, added Stevens, there was more of an inter-hemispheric involvement. “Our prediction is that with more negative, traumatic memories, there will be more connections across hemispheres and greater access to information that will allow a healthy processing of the memories.”

Stevens and his team integrated findings into a new modified theory using cognitive psychology and their research on coherence. The two-stage cortical coherence model includes weakening the traumatic memory, immediately followed by connecting the original memory to a more positive outcome.

Stevens plans to use this science on military veterans suffering from PTSD to determine if the practice could bring relief to former soldiers that suffer from war trauma.