Figure 2.

Proposed neuronal distribution of kinases and phosphatases (K&P) during memory acquisition and extinction. Blue circles: neurons participating in CS-US memory acquisition, requiring activation of kinases, and constrained by phosphatases. Yellow circles: “fear neurons” undergoing synaptic depotentiation, requiring the activity of phosphatases and constrained by kinase activities. Red circles: “extinction neurons” responsible for acquisition of the new CS-noUS memory through activation of various kinases.