Neurochemical and molecular mechanisms underlying the retrieval-extinction effect

Extinction within the reconsolidation window, or retrieval-extinction', has received much research interest as a possible technique for targeting the reconsolidation of maladaptive memories with a behavioural intervention. However, it remains to be determined whether the retrieval-extinction effecta long-term reduction in fear behaviour, which appears resistant to spontaneous recovery, renewal and reinstatementdepends specifically on destabilisation of the original memory (the reconsolidation-update' account) or represents facilitation of an extinction memory (the extinction-facilitation' account). We propose that comparing the neurotransmitter systems, receptors and intracellular signalling pathways recruited by reconsolidation, extinction and retrieval-extinction will provide a way of distinguishing between these accounts.