Neurocircuitry of fear extinction in adult and juvenile rats.

•Juveniles and adults have comparable BLA projections to hippocampus.•Juveniles and adults have comparable BLA projections to infralimbic cortex.•Adults show activated BLA cells projecting to hippocampus after extinction.•Juveniles do not show activated BLA to hippocampus cells.•Activated BLA projections correlate with behavior in adults but not in juveniles.