Effects of emotion state on conditioned fear response and memory for conditioned fear cues / 中华行为医学与脑科学杂志

ABSTRACT

Objective:To explore the effects of emotion state on conditioned fear response and memory for conditioned fear cues.Methods:Forty-eight undergraduate students were recruited as subjects.On Day 1, forty-eight participants underwent a partial reinforcement fear conditioning paradigm, using fruit or animal visual pictures as conditioned stimulus (CS) and loud white noise as the unconditioned stimulus (US). On Day 2, all subjects were divided into the neutral( n=16), negative( n=16) and positive( n=16) emotion groups according to the principle of gender matching.The emotion state of each group was manipulated by watching a 5 minutes' emotional film clip respectively.Then the fear-conditioning session was conducted again.On Day 3, recognition memory tests were conducted for the conditioned neutral items which presented randomly together with some new picture items. Results:In the positive group, the skin conductance response(SCR) to conditioned fear cues after emotion induction ((0.091 ± 0.026) μs)was significantly lower than that before emotion induction((0.148 ± 0.027) μs), and the difference was statistically significant( P<0.05). The recognition rate of positive group (0.49±0.03) for CS+ presented on Day 2 was significantly lower than neutral group (0.61±0.04)( P<0.05). Under the negative emotional state, the recognition time of the subjects to the fear cues was higher than that of the positive group and the neutral group(the recognition time of Day 2 in neutral group, positive group and negative group were (914.17 ± 43.66) ms, (953.72 ± 37.76) ms, (1 483.49 ± 157.64) ms, respectively, P<0.01). Conclusion:Positive emotion can not only inhibit the conditioned fear responses but also decrease the recognition rate for the conditioned neutral cues.Inducted negative emotion only increase the time recognition for the conditioned neutral cues, but it has no effect on the SCR and recognition rate.