A study at Yale University has shown that blocking a single molecule can defeat chronic fear in adulthood. Researchers believe the study could be an avenue for the treatment for patients with anxiety disorders and post-traumatic stress disorder (PTSD) who have difficulties recovering from pervasive fear memories.
According to the paper published in the journal Molecular Psychiatry, the team examined the effect of Nogo Receptor 1 (NgR1) on nerve and brain cells of adult mice and tested if disabling the receptor could extinguish induced fear behaviors. To induce fear memories in animals, like the ones that are associated with PTSD, researchers used classical fear conditioning – the coupling of a tone with a mild foot shock.
Induced fear on mice stays even shocks are discontinued for months and the sound of a tone triggers extreme anxiety-like behavior in conditioned mice. Repeatedly introducing to the tone without the shocks lessens the fear response for a while, but it does not completely eliminate it. The team reports that with time the fear returns. However, mice bred without Nogo Receptor showed no residual fear behavior – but only in those mice that had fear extinction training.
“Training when Nogo Receptor is blocked seems to have the potential to eliminate damaging fear responses,’’ said Stephen Strittmatter, the lead author of the study in a news release. “The elimination of Nogo Receptor seemed to allow training to rewire their brains to produce a long-lasting effect on behavior.”
Researchers hope to develop pharmacological tools to block Nogo Receptor specifically during and after extinction training. They plan to investigate whether Nogo Receptor limits the ability of training to reduce other inappropriate appetitive memories involved in drug-seeking.