Grillon C, Davis M
Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA.
Psychophysiology. 1997 Jul;34(4):451-8. doi: 10.1111/j.1469-8986.1997.tb02389.x.
Conditioned fear in response to explicit and contextual cues was examined using the startle reflex in three groups of participants over two sessions separated by 4-5 days. The conditioned stimulus (CS) was paired with an aversive unconditioned stimulus (US) (shock) during conditioning in the paired but not in the unpaired group. In the reaction time (RT) group, the US was a nonaversive visual signal for an RT task. In the paired group, the CS potentiated startle in the postconditioning phase. This conditioned response was fully retained over the retention interval. There was no substantial change in baseline startle (startle delivered in the absence of CS). By contrast, startle was not potentiated by the CS in the unpaired group, but baseline startle was increased from Session 1 to Session 2. In the RT group, startle was not affected by the CS, and baseline startle was reduced from Session 1 to Session 2. These results suggest that paired presentations of a CS and an aversive US result in conditioned fear in response to the CS but little contextual fear, whereas unpaired presentations of a CS and US leads to poor explicit cue conditioning but substantial contextual fear.
在两组间隔4至5天的实验中，对三组参与者使用惊吓反射来检测对明确线索和情境线索的条件性恐惧。在配对组中，条件刺激（CS）在条件作用期间与厌恶非条件刺激（US）（电击）配对，而非配对组则不进行配对。在反应时间（RT）组中，非条件刺激是用于RT任务的非厌恶视觉信号。在配对组中，条件刺激在条件作用后阶段增强了惊吓反应。这种条件反应在保持间隔期内完全保留。基线惊吓（在无条件刺激时给予的惊吓）没有实质性变化。相比之下，在非配对组中，条件刺激并未增强惊吓反应，但基线惊吓从实验1到实验2有所增加。在RT组中，条件刺激未影响惊吓反应，且基线惊吓从实验1到实验2有所降低。这些结果表明，条件刺激与厌恶非条件刺激的配对呈现会导致对条件刺激的条件性恐惧，但情境性恐惧较少，而条件刺激与非条件刺激的非配对呈现会导致明确线索条件作用较差，但情境性恐惧较多。
