In this thesis we present three main studies, two regarding the transition of reconsolidation to extinction of contextual fear memories (Chapters II and III), and one on the mechanisms of reconsolidation under the synaptic tagging and capture (STC) perspective (Chapter IV). On the transition of reconsolidation to extinction, we observed a “null point” period between the parameters that induce reconsolidation and extinction of contextual fear memories, at which memory was insensitive to disruption by the amnesic agent MK-801, and some evidence for underlying STC mechanisms in the process of memory destabilization and reconsolidation. These findings reinforce and expand the hypothesis of a three-phase transition between reconsolidation and extinction of episodic-like memories and bring new insights on the different ways memory might be affected by reactivation and the mechanistic process involve