EDITOR'S CHOICE IN NEUROSCIENCE
L.D. de Voogd et al., “Eye-movement intervention enhances extinction via amygdala deactivation,” J Neurosci, 38:8694–706, 2018.
EYEING THE PROBLEMS
Some psychotherapists coach patients to recall traumatic memories as they make back-and-forth eye movements, tracking the therapist’s hand. The procedure, eye movement desensitization and reprocessing (EMDR), helps lessen the power of those memories, but how it works “has been kind of unknown,” says psychologist Joseph Dunsmoor of the University of Texas at Austin.
Lycia de Voogd of Radboud University in the Netherlands and her colleagues sought to integrate EMDR and a form of conditioning known as fear extinction, a way of lessening fear through repeated exposure to a stimulus. They gave 24 healthy subjects electric shocks to their fingers as the participants looked at blocks of color on a screen. The next day, the participants simply looked at the blocks, with or without tracking a moving dot with their eyes for 10 seconds. On the third day, the researchers reapplied the shock to subjects as they looked at the color blocks again in order to reinstate the fear response.
EMDR in tandem with fear extinction dampened skin conductance, a measure of fear, more than extinction alone. Additionally, fMRI scans of participants revealed that reduced fear recovery corresponded with less activation in the fear-processing amygdala. Both a working memory task, which involved keeping track of a number sequence, and guided eye movements independently tamped down activity in the amygdala while activating brain pathways involved in controlling emotion.
Dunsmoor, who was not involved in the study, notes that knowing the mechanism underlying EMDR could help identify other techniques to help patients deal with trauma.