Article Figures & Data
Figures
- Figure 1.
Diagram of the DPDT. After initiating the trail with a trough entry, rats chose between two levers, one lever delivering one pellet reward and the other delivering three pellets accompanied by a delayed foot shock (0, 4, 8, 12, 16 s). There was no shock associated with reward in the final block. Lever identity was counterbalanced across subjects.
- Figure 2.
DPDT. a, On average, rats shifted behavior toward the punished reward as the delay increased, indicative of underestimation of delayed punishment. Each marker represents mean choice of the large reward ± SEM. b, Individual differences in DPDT performance, with each line representing a single subject. c, Percentage time spent performing locomotion during the delay period after punished and safe levers were pressed and reward was delivered. Locomotion significantly decreased after choice of the punished relative to safe reward, suggesting that rats anticipated impending shock.
- Figure 3.
Sex differences in delayed punishment discounting. a, Mean percentage of male versus female selection of the punished lever through blocks 1–6 of DPDT. Males discounted punishment significantly more than females as delay increased. Asterisks denote significant differences between sexes at individual time points. b, Both females and males showed reduced locomotion during the delay preceding punishment compared with unpunished trials. Data displayed as mean ± SEM
- Figure 4.
a, Appearance of nucleated epithelial cells, cornified epithelial cells, or leukocytes was used to determine stage of estrous cycle. b, Female rats did not differ in percentage choice of the punished lever during the DPDT across proestrus, estrus, metestrus, and diestrus stages of the estrous cycle. Data depicted as mean ± SEM
- Figure 5.
Cued DPDT. a, Mean percentage of male versus female selection of the punished lever through blocks 1–6 of DPDT and cued DPDT. b, There was no significant cue × sex interaction, indicating that addition of a cue light attenuated choice of the punished lever for (b) male and (c) female rats. Each marker represents mean ± SEM.
- Figure 6.
Comparing delayed reward and punishment discounting. a, Rats shifted preference toward the immediate reward as the delay increased, indicative of delay discounting. b, Individual differences in delay discounting, with each curve representing an individual rat. c, AUC for discounting of delayed rewards was not significantly correlated with AUC during discounting of delayed punishment. d, Slope of percentage choice of the punished reward lever during DPDT and percentage choice of the delayed reward lever during delay discounting were not correlated. e, There was no differences in discounting curve slope between reward and punishment discounting. f, When animals were separated by sex, females demonstrated a higher slope for delayed reward than delayed punishment, indicating more rapid discounting of delayed rewards versus punishments. No task difference was observed in males. a, e, and f display mean ± SEM; b, c, and d display individual scores.
Tables
Delay Sex Mean SEM t df p 0 s Male 17.611 8.98 −0.882 18 0.389 Female 8.722 4.56 4 s Male 28.933 12.87 −0.303 18 0.766 Female 23.677 11.644 8 s Male 42.933 14.081 −0.53 18 0.603 Female 32.727 13.155 12 s Male 60.711 11.934 −1.428 18 0.17 Female 36.122 12.414 16 s Male 78.514 9.491 −2.311 18 0.033* Female 41.501 12.905 No Male 82.755 9.446 −2.389 18 0.028* shock Female 45.042 12.65 - Table 2.
Bivariate correlations were conducted to compare slope, AUC, and mean percentage choice of the punished reward for each delay block between DPDT and the delay discounting task
Measure r All rats p All rats r Female p Female r Male p Male Slope −0.173 0.508 0.207 0.623 −0.237 0.539 AUC −0.049 0.852 0.008 0.985 −0.098 0.802 Mean: 0 s 0.386 0.126 0.658 0.076 0.409 0.274 Mean: 4 s −0.134 0.608 0.009 0.984 −0.199 0.608 Mean: 8 s −0.269 0.296 −0.201 0.632 −0.347 0.361 Mean: 12 s 0 0.999 −0.021 0.961 −0.082 0.833 Mean: 16 s 0.068 0.796 −0.098 0.818 0.052 0.895 There were no significant correlations between tasks in any measure for all rats, nor for individual sexes.
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