Department of Psychology.
J Abnorm Psychol. 2013 Aug;122(3):756-69. doi: 10.1037/a0033407.
Research indicates that fear and anxiety are distinct processes with separable neurobiological substrates. Predictable versus unpredictable shock administration has been used to elicit fear versus anxiety, respectively. Recent research has demonstrated that alcohol may reduce anxiety but not fear. However, previous manipulations of predictability have varied both probability and temporal uncertainty of shock threat, leaving unresolved questions regarding which stimulus characteristics elicit anxiety and are sensitive to alcohol stress-response dampening (SRD). We developed a novel paradigm to closely parallel basic research in animals that systematically varied temporal uncertainty of threat while holding threat probability constant. Intoxicated (0.08% target blood alcohol concentration), placebo, and no-alcohol control participants viewed a series of visual threat cues. Certain cue duration (5 s) blocks were equivalent to predictable shock blocks eliciting fear in earlier research. Uncertain cue duration (5, 20, 50, or 80 s, intermixed) blocks introduced temporal uncertainty regarding impending shock to elicit anxiety. Startle potentiation relative to matched cue periods in no-shock blocks provided the primary measure of affective response. All threat cues produced robust startle potentiation. Alcohol reduced startle potentiation during the first 5 s of threat cue presentation in uncertain but not certain duration blocks. Alcohol also reduced startle potentiation at later times among longer uncertain duration cues, suggesting that alcohol SRD persisted. Trait negative emotionality and binge drinking status moderated alcohol SRD magnitude during uncertain threat. These translational findings corroborate previous reports regarding distinct substrates of fear versus anxiety and have implications for both alcoholism etiology and comorbidity with anxiety disorders.
研究表明，恐惧和焦虑是两个不同的过程，具有可分离的神经生物学基础。可预测和不可预测的休克管理分别被用来引发恐惧和焦虑。最近的研究表明，酒精可能会降低焦虑但不会降低恐惧。然而，以前的可预测性操纵既改变了休克威胁的概率，也改变了时间不确定性，这使得哪些刺激特征引发焦虑以及对酒精应激反应抑制（SRD）敏感的问题仍未解决。我们开发了一种新的范式，与动物的基础研究密切平行，该范式系统地改变了威胁的时间不确定性，同时保持威胁概率不变。醉酒（0.08%目标血液酒精浓度）、安慰剂和无酒精对照组参与者观看了一系列视觉威胁线索。某些线索持续时间（5 秒）块与之前研究中引发恐惧的可预测性休克块相当。不确定线索持续时间（5、20、50 或 80 秒，混合）块引入了关于即将到来的休克的时间不确定性，以引发焦虑。相对于无休克块中的匹配线索期，惊吓增强提供了情感反应的主要测量指标。所有威胁线索都产生了强烈的惊吓增强。在不确定持续时间的块中，酒精在威胁线索呈现的前 5 秒降低了惊吓增强，而在不确定持续时间的块中，酒精也降低了后期较长的不确定持续时间线索的惊吓增强，这表明酒精 SRD 持续存在。特质负性情绪和狂欢饮酒状态调节了不确定威胁期间酒精 SRD 的幅度。这些转化发现证实了先前关于恐惧与焦虑的不同基础的报告，并对酒精中毒的病因和与焦虑障碍的共病都有影响。
