预期错误与急性应激对不同强度恐惧记忆提取消退的影响

doi:10.3724/SP.J.1041.2021.00587

摘要/Abstract

摘要：

在条件性恐惧记忆再巩固模型下, 预期错误被证明是引发记忆不稳定的必要条件, 但其在不同强度恐惧记忆下的作用尚不明确。对于高强度可能导致的提取无效, 缺乏相应的探索以寻找解决办法, 而应激(stress)在其中发挥的作用值得探索。本研究考察人类被试中, 预期错误在不同强度恐惧记忆下的作用, 以及提取之后施加外源性应激对于消退进程的影响。结果发现, 对于较弱的恐惧记忆, 单个预期错误提取后消退可显著抑制恐惧自发恢复; 而对于较强恐惧记忆, 单个预期错误不能提取恐惧记忆进入再巩固, 已消退的记忆还会复发; 且在该种情况下, 如果在提取后施加外源性急性应激, 会进一步增大恐惧恢复。

关键词: 条件性恐惧, 提取消退, 预期错误, 急性应激, 记忆强度

Abstract:

Under the framework of Reconsolidation Interference of conditioned fear memory, Prediction Error (PE) has been demonstrated as a necessary condition of memory destabilization. However, the role of PE in destabilizing fear memories of different strengths is unclear. The degree of PE that is needed to effectively reactivate fear memories may be dependent on the strength of memory. It is unknown whether the PE used to reactivate weak memories is also effective in destabilizing stronger memories. Memory strength was proved to be an important boundary condition of memory reconsolidation; however, explorations of solutions to overcome the boundary are rare. Among factors that are possible to help to overcome the boundary condition, the effects of stress hormones are worth exploring. However, the manipulation of memory strength in human laboratory studies has not been well developed. Thus, the present study has three main aims: (1) to test the effect of fear memory strength in a human laboratory setting based on previous results in animal studies; (2) to examine the effect of PE during reactivation on destabilizing different strength memories and (3) to test the possible influence of post-reactivation exogenous stress to the retrieval-extinction of fear memories.

These results indicate that PE used to destabilize weak memories is insufficient to destabilize strong memories; and that post-reactivation acute stress cannot nullify this deficit which is due to boundary conditions (e.g., strength). We discuss possible interpretations of these results and the implications for the translation of retrieval-extinction to clinical practice.

The three days retrieval-extinction paradigm was adopted in the present study. We manipulated memory strength through two kinds of acquisition procedures on the first day, which varied the predictability of the unconditioned stimulus (US) occurrence after the conditioned stimulus (CS). Twenty-four hours later, a reminder containing a single PE was used to reactivate memories, which was followed by a stress task (Social Evaluate Cold Pressor test, SECPT) or not before extinction. After 24 hours, a test of spontaneous recovery and reinstatement was utilized to measure the return of fear in each condition. All participants were divided into three conditions: CS-Predictable US_no Stress Group, CS-Unpredictable US_no Stress Group and the CS-Unpredictable US_Stress Group. Skin conductance response (SCR) and fear-potentiated startle response (FPS) were used as measurements of conditioned fear.

The results showed that there was a relatively stronger increase in fear response (SCR) from Day 1 to Day 2 in the CS-Unpredictable US condition than the CS-Predictable US condition, which may suggest a difference in memory strength between conditions. And for the weak fear memory (CS-predictable US), the reactivation that involved a single PE and was followed by extinction training prevented the spontaneous recovery, especially on the SCR measurement. On the other hand, in the enhanced memory condition (CS-unpredictable US), the extinguished memory returned in the memory test on the third day, which suggests a failure of memory destabilization. Furthermore, when the post-reactivation acute stress task was adopted in the enhanced memory condition, the return of fear further increased, compared with the no stress manipulation conditions.

Key words: conditioned fear, retrieval-extinction, prediction error, acute stress, memory strength

中图分类号:

B845

李俊娇, 陈伟, 胡琰健, 曹杨婧文, 郑希付. (2021). 预期错误与急性应激对不同强度恐惧记忆提取消退的影响. 心理学报, 53(6), 587-602.

LI Junjiao, CHEN Wei, HU Yanjian, CAOYANG Jingwen, ZHENG Xifu. (2021). Effects of prediction error and acute stress on retrieval-extinction of fear memories of different strengths. Acta Psychologica Sinica, 53(6), 587-602.

图/表 8

表1 实验分组和样本量

变量	组别			p
变量	G1	G2	G3	p
提取阶段	单个PE	单个PE+SECPT	单个PE
N (SCR)	16	19	15
N (FPS)	15	21	23
年龄(岁)	20.88 ± 1.54	20.04 ± 1.80	21.44 ± 2.58	0.069
STAI-T	37.35 ± 10.88	41.83 ± 7.10	39.78 ± 7.92	0.266
BDI	6.94 ± 4.53	8.44 ± 5.96	7.26 ± 5.83	0.655

图2 第一天、第二天各生理指标与问卷测量的时间点注：BDI：贝克抑郁量表; STAI-T：特质焦虑问卷; PANAS：正性负性情绪量表; BP：血压; HR：心率; SF：主观感受; 各名称之后的数字代表测试的时间序号。

图1 实验程序示意图。A：总的实验流程图; B：习得阶段恐惧强度操作及提取阶段示意图。注：对恐惧强度的操纵为：在第一天使用CS呈现后半段不可预期时间点出现的两次电击(US), 形成CS-不可预知的US联合, 预期产生较高强度恐惧记忆(G1、G2); 使用在CS呈现时间的最后固定时间点(分别出现在第4800 ms和第5800 ms) 出现的两个US, 形成CS-可预知的US联合, 预期产生较低强度的恐惧记忆(G3)。对预期错误(PE)的操作为：在第二天对于所有组使用最后一个US (第5800 ms)进行提取, 在所有组造成电击次数上的预期错误, 即原本被试在习得阶段都是进行两次电击, 形成了对于每个CS都跟随两次US的预期。但在提取阶段CS呈现时, 只跟随1次US, 因此会形成单个预期错误(single PE)。

表2 各组在社会评价冰水应激/温水任务中心率变异性频率域参数值对比

实验分组	G1 不可预期US_无应激 n= 15	G2 不可预期US_应激 n= 20	G3 可预期US_无应激 n= 22	F	p
LF
前(pre)	71.70 ± 40.66	128.85 ± 108.95	120.87 ± 126.45	1.46	0.24
中(mid)	106.56 ± 145.84	227.76 ± 313.37	84.53 ± 82.59	2.29	0.11
后(post)	125.57 ± 109.65	130.52 ± 168.65	149.50 ± 181.47	0.12	0.89
HF
前(pre)	44.83 ± 38.65	96.02 ± 86.74	68.66 ± 65.67	2.43	0.10
中(mid)	73.57 ± 78.74	102.51 ± 100.09	74.11 ± 55.91	0.51	0.61
后(post)	55.46 ± 28.64	63.04 ± 40.96	88.76 ± 64.18	0.12	0.89

图3 SECPT任务过程中各组在心率变异性低频成分上的分值比较

图4 三组被试在恐惧记忆习得、提取、消退和测试阶段的皮肤电反应注：横坐标代表试次：1~6为第一天习得阶段, 8为第二天提取试次, 10~19为第二天消退阶段, 21~28为第三天自发恢复测试与消退阶段, 30~37为第三天重建测试与消退阶段。误差线表示标准误, 黄色闪电符号代表电击。图6同。

图5 各组在恐惧自发恢复量和重建量上的对比。A以皮肤电(SCR)为测量指标的恐惧恢复对比; B以惊跳反应(FPS)为测量指标的恐惧恢复对比。注：恐惧自发恢复量 = 再消退的第一个CS+试次的恐惧反应 - 消退训练最后一个CS+的恐惧反应; 恐惧重建量 = 最终消退的第一个CS+试次的恐惧反应 - 再消退最后一个CS+的恐惧反应。*p < 0.05, ** p < 0.01。

图6 三组被试在恐惧记忆习得、提取、消退和测试阶段的惊跳反应

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