人面孔照片诱发伴随负变化的初步研究

Preliminary research on contingent negative variation elicited by face photos

目的 研究熟悉和陌生人面照片与短声组成不同的刺激序列诱发伴随负变化（ＣＮＶ）。方法 ２０ 名１８～２６ 岁大学生为志愿受试者，完成４ 轮试验，Ａ 轮：Ｓ１ 和Ｓ２ 均为１ ５００ Ｈｚ 短声；Ｂ轮：Ｓ１为短声，Ｓ２ 为熟悉或陌生照片；Ｃ轮：熟悉或陌生照片为Ｓ１，短声为Ｓ２；Ｄ轮：序列编排同Ｃ轮。Ａ、Ｂ、Ｃ轮令受试者看到或听到Ｓ１，当Ｓ２ 呈现时迅速按键，Ｄ轮令受试者辨别Ｓ１ 是熟悉还是陌生照片，当Ｓ２呈现时分别按相应的键。试验中同时记录ＥＥＧ，分析ＣＮＶ的上升潜伏期、峰波潜伏期、峰波幅和波面积。结果 Ｃ、Ｄ轮ＣＮＶ的峰波幅和波面积显著小于Ａ轮和Ｂ轮，上升潜伏期和峰潜伏期则显著长于后者。Ｄ轮有面孔辨识任务与无辨识任务的Ｃ轮相比，ＣＮＶ 波面积和峰波幅减小，潜伏期则延长，辨别熟悉者照片时，ＣＮＶ波面积和波幅显著小于辨别陌生照片时，潜伏期则延长。ＣＮＶ较小时潜伏期相应延长，其前出现较大的Ｐ３ 波。结论 研究结果提示，反应注意、记忆、期待和准备等心理活动的ＣＮＶ，受到面孔辨别任务的影响，揭示了“分心效应”和复杂任务时ＣＮＶ减小的实质，即可能受认知过程（认知电位Ｐ３） 的影响。

Objective The contingent negative variation (CNV) elicited by different stimulus paradigms consisted of tones and face photos of familiar persons and strangers were studied. Methods The subjects were 20 students aged 18～26 years old as volunteers. Four trials were performed: A: The S1 and S2 were tones with 1 500 Hz;B: Tones as S1 and face photos of familiar persons or strangers as S2;C: Face photos of familiar persons or strangers as S1 and tones as S2;D:The paradigm was the same as that in trial C. In trial A,B and C,the subjects was asked to watch or listen the S1 and to press a butten immediately while the S2 occurred. In trial D, the subjects were asked to distinguish the person photo which is familiar or not and press different buttons respectively. EEG were recorded simultaneously. Onset latency,peak latency, peak amplitude and area of CNV were analyzed. Results It was found that the area and peak amplitude of CNV elicited in trial C,D were smaller and the onset and the peak latency were longer than that in trial A, B. When discrimination task was asked(D), the area and peak amplitude of CNV decreased and the latency of CNV prolonged when compared with those in trail C having no discrimnition task. In trial D,the area and peak amplitude of CNV elicited by face photos of familiar person was smaller and the latency was longer than those elicited by strangers. There seemed to be a rule that the smaller the area and peak amplitude of CNV was,the longer the lantencyes,preceding by bigger P3. Conclusions It suggests that CNV reflecting attention, memory, expectancy and preparation may be affected by the processing of face cognition and revealed the essence of distraction effect and complex task of CNV,that is,CNV is influenced by recognitive process(recognitive potential P3).