The Secret of Fear Memory Attenuation: Facing Fears
Exposure therapy, an effective treatment for fear disorders, requires memory retrieval of previous horror experiences in controllable environment. However, it remains unknown whether previous fear memories have been updated  or inhibited  during the formation of new memories, as well as the underlying neural mechanisms involved (e.g. the type of cells engaged in this process).
Memory traces or engrams represent learning-activated ensembles of neurons . Accumulating evidences have demonstrated that memory traces at certain stages can be visualized by dynamic labeling of neurons accurately with temporal precision [4, 5, 6]. A recent study published in Science by Khalaf et al.  demonstrated that the attenuation of a fearful memory depends on reactivation of the original fear memory trace. Using double transgenic TetTag mice (c-Fos::tTA/TRE::τ-LacZ), the authors first identified the ensembles of neurons (β-gal+neurons)involved in the recall of long-lasting memory....