Figure 2.

BLA Damage Leads to Over-potentiation of the ASR during Anticipation of Imminent yet Escapable Threat

(A) Participants in the TET saw pictures that could “attack” by a rapid approach, during which only a sufficiently fast button press could provide escape. Escape failure resulted in aversive shock stimulus (AS) presentation. Distance and attack speed were manipulated to be distant (easily escapable), imminent (with effort escapable at chance level), or inescapable, and all threat conditions (yellow pictures with shock hazard icon) were compared to an equivalent control condition (blue pictures with neutral icon) but without the threat of AS exposure. Note that this timing adjustment renders escape reaction time an uninformative behavioral measure, but it ensures that our measure of interest, acoustic startle reflex (ASR), is unaffected by the participant’s general ability in reaction speed.

(B) During the anticipation phase, ASR was measured. See STAR Methods and Figure S1.

(C) Estimated marginal means of the three-way—condition (threat and safe), distance (distant, imminent, and inescapable), group (BLA-damaged and healthy control)—interaction (Wald χ² = 10.023; p = 0.040) of ASR magnitudes in the TET (BLA damage, n = 5; HC, n = 14). This interaction reveals reliable threat potentiation in imminent (Wald χ² = 29.972; p < 0.001) and inescapable (Wald χ² = 42.270; p < 0.001), but not in distant (Wald χ² = 2.003; p = 0.157), conditions. Crucially, imminent threat potentiation was significantly stronger in BLA-damaged subjects (Wald χ² = 6.191; p = 0.013) and, although HCs showed significantly lower threat potentiation in imminent compared to inescapable conditions (Wald χ² = 4.670; p = 0.031), this was not the case in BLA-damaged subjects (Wald χ² = 0.196; p = 0.658). ^∗p < 0.05; ^∗∗p < 0.01; ^∗∗∗p < 0.001; see Table S2 for corresponding potentiation values and confidence intervals. Error bars represent standard error of the mean.