Figure 3.

Phenotypic extinction subgroups identified by cluster analysis. Each solid black line graph shows the individual longitudinal trajectory of freezing behaviour (Y-axis) for each subject across three critical phases of training (labelled on the X-axis). The horizontal dashed red line is a reference line indicating criterion for remission (37.5% freezing). Each panel indicates a homogeneous subgroup showing similar freezing trajectories. Subgroup 1: Mild initial fear with successful extinction and long-term fear reduction (n = 44). Subgroup 2: Severe initial fear with moderately successful extinction followed by return of fear (n = 42). Subgroup 3: Mild initial fear with largely successful extinction followed by return of fear (n = 33). Subgroup 4: Severe initial fear with largely successful extinction and long-term fear reduction (n = 27). Subgroup 5: Severe, persistent fear (n = 27). Subgroup 6: Fear incubation (n = 25). Subgroup 7: A more extreme version of Subgroup 2 (n = 17). (Online version in colour.)