Figure 5.

At least two independent parameters influence extinction learning and the consolidation of an extinction memory. Model of how extinction learning and the formation of an extinction memory depend on three independent parameters. The sequence of US durations (constant, increasing, decreasing) and the number of retrieval trials are critical for extinction learning. The US duration, resulting in a difference in magnitude of the mismatch (mismatch US) between the experienced US during conditioning and the absence of the US during retrieval is critical for consolidation of an extinction memory.