Fear extinction: from engrams to circuits

At the recent Federation of European Neuroscience Societies (FENS) meeting in Copenhagen, I chaired a session entitled “Fear extinction: from engrams to circuits”. In my talk, I reviewed what is known about the neural circuits responsible for extinction (or reduction) of learned fear associations that involve inhibition of the amygdala by the prefrontal cortex. A new approach is to study the extinction of active avoidance responses, which are excessive in anxiety disorders. Extinction of avoidance requires projections from the ventral hippocampus to the prefrontal cortex releasing the growth factor BDNF. Blocking BDNF production in hippocampal neurons with the CRISPR-Cas9 system impairs extinction. Clinical reduction of avoidance behaviors in patients would allow them to overcome their fears through fear extinction.

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Dr Greg Quirk

Associate Editor, npj Science of Learning; Head of the Quirk Laboratory, Department of Psychiatry, University of Puerto Rico

In our laboratory, we aim to increase understanding of how the brain overcomes fear, train effective scientific thinkers and increase neuroscience practice in historically underrepresented countries.