Figures & data
Figure 1. Timeline of events. (A) Timeline of events for animals that underwent effortful choice testing, shock stress, and were analyzed for PSA-NCAM. (B) Timeline of events for animals that underwent no behavioral training and were analyzed instead for plasma corticosterone after shock stress. (C) Timeline of events for animals that received shock stress and were tested for shuttle escape latencies. Red tick marks denote shock stress administration days. Blue tick marks denote testing or euthanasia days.
Figure 2. Effects of shock stress on shuttle escape performance and plasma corticosterone. (A) Shock stress significantly impaired shuttle escape performance, increasing escape latencies across all five trial blocks (1–5) each constituting five trials (25 trials total) on the FR-2 schedule. (B) Shock stress significantly increased plasma levels of free corticosterone. Error bars denote mean + SEM. ****p< .0001 and ****p <.00001.
Figure 3. Effects of shock stress on effortful choice behavior. (A) Rats were assessed on effortful choices before (pre) and after (post) shock stress. Shock stress had no effect on the pattern of HER, MER, and LER choices. (B) “High effort rats”, defined as HER preferring animals, and “Low effort rats”, defined as MER preferring animals, were not differentially affected by shock stress (pre = before shock stress; post = after shock stress). (C) Mean percent choice across 3 d prior to shock stress (Pre) and 3 d post shock stress (Post). Error bars denote mean + SEM.
Figure 4. Effects of shock stress and effortful choice testing on PSA-NCAM. Rats that had effortful choice experience and shock stress exhibited significantly higher levels of PSA-NCAM in both the amygdala and medial frontal cortex relative to rats with no effortful choice testing and no stress and those that received shock stress alone. Inset shows matched coronal sections with approximate dissection boundaries for amygdala (left) and medial frontal cortex (right). Error bars denote mean + SEM. ***p < .0001.
