Fig 3. Differential firing in PL versus IL predicts freezing behavior.

(A) Freezing (circles) was similar across Days 1 (3 min post-shock period) and 2 (tones 4 and 5) in signaled rats, whereas it decreased markedly on Day 2 in unsignaled animals. Relative neural activity (PL minus IL) was similar in magnitude (and positive) across days for the same time periods in signaled rats, but also decreased in magnitude markedly on Day 2 in unsignaled animals. (B) Linear regression analysis showing the PL vs IL difference during tones 4 and 5 plotted against freezing levels for the same time period. This analysis revealed a strongly positive correlation between the two variables when including rats from both shock groups. All values are means ± SEM. *p < 0.01.