【作者】 吕静；

【导师】 苗丹民；

【作者基本信息】 第四军医大学 ， 应用心理学， 2008， 博士

【摘要】 不同形式导致的脑力疲劳(Mental fatigue, MF)在很多职业中存在,并对个体的生理和心理活动造成严重影响,军事及特殊职业领域均对此进行了相关研究。研究表明,疲劳后唤醒水平降低,认知功能下降,以注意力下降最为显著,同时还伴有情绪情感状态的改变。但是以往研究多采用主观评定,受到了一些局限。本研究以ERP技术为手段,应用经典和创新模式,对疲劳后的注意加工特征进行逐步探讨;并研究疲劳状态对情绪的影响。自愿参加实验的32名正常青年男性被试,根据不同的认知负荷任务建立脑力疲劳模型并分为两组(驾驶组,VDT组),在疲劳前与疲劳后分别进行实验,得到疲劳前后各实验指标与量表分数,以客观指标与主观评定来对疲劳前后的认知与情绪特征进行研究。实验分为三部分:第一,首先进行主观评定,应用疲劳量表-14,POMS量表,VAS量表对被试的疲劳状态与情绪状态进行评估。第二,应用ERP技术研究脑力疲劳状态下的注意特征,采用传统MMN模式、优化MMN模式、新异Oddball模式、一级CNV模式,通过对脑自动信息加工——非随意注意——注意选择——注意保持的典型成分:传统MMN、优化MMN、P3a、P3b、CNV的波幅和潜伏期分析,探讨疲劳状态对非意识-意识转换时注意能力的影响。第三,应用ERP技术研究脑力疲劳对情绪变化的影响,采用GO-NOGO模式以及与情绪内容无关的反应要求的面孔加工模式,对所诱发出的NOGO-N2、NOGO-P3、N170进行分析,以探讨疲劳状态的情绪变化。本研究的主要结果及结论:1.脑力疲劳状态下,脑的自动信息加工受到影响,即疲劳后出现“前注意”能力受损;此外,疲劳前额叶右半球的优势效应,在疲劳后未见,或许与疲劳后额叶右半球功能减弱有关。支持该结论的指标有:两组被试无论是传统MMN还是优化MMN的波幅均在疲劳前后有差异,疲劳后明显减小;优化MMN波幅显示了两组被试在疲劳前右半球大于左半球,但是疲劳后左右半球无差异。2.脑力疲劳状态下,脑的额叶执行功能减弱,非随意注意与选择注意能力下降。朝向反应的削弱提示脑力疲劳后可能会对危险信号的觉察判断能力下降,自我保护能力缺乏。同时选择注意能力的下降说明疲劳后机体对相关任务做出反应的能力受到损害。支持该结论的指标有:两组被试疲劳后的P3a与P3b的波幅均较疲劳前减小。P3a波幅最高点出现在额叶,疲劳前可见明显的额叶优势,但是疲劳后未见,P3a波幅减小可提示疲劳后额叶执行能力下降。3.脑力疲劳状态下,注意的保持能力受损,期待行为减弱以及与认知相关的运动能力下降。支持该结论的指标有:两组被试在疲劳前后的CNV平均波幅以及CNV晚成分平均波幅均有差异,即疲劳后CNV与CNV晚成分的波幅均降低。4.脑力疲劳状态下,对负性情绪刺激的注意偏向消失,对外界威胁进行自我保护的能力变差。下列指标支持此结论:与高兴面孔相比,疲劳前对愤怒面孔反应的N170幅值增强,但是疲劳后对高兴面孔与愤怒面孔加工时N170波幅并未出现差异。5.脑力疲劳状态下,对于冲突信息监测和抑制反应准备的能力下降,即情绪调节能力障碍;疲劳后对负性情绪信息抑制能力的障碍,说明疲劳后机体负性情绪增强。支持该结论的指标包括:疲劳后NOGOO-N2波幅下降,NOGO-P3波幅减小;疲劳后对愤怒面孔反应的NOGO-N2波幅增大。6.脑力疲劳状态下,主观评定显示了被试在完成任务后疲劳感加重,各疲劳因子分均增高。情绪状态有所改变负性情绪增加,POMS量表显示疲劳后,愤怒-敌意(A)、疲乏-惰性(F)、紧张-焦虑(T)因子分值增加。VAS量表结果提示警觉/能够集中注意(Alert/concentrate)、焦虑(Anxious)和易怒(Irritable)3项指标疲劳前后分数有差异。更多还原

【Abstract】 There are different types of mental fatigue in different occupations, and the mental fatigue has tough impact on the individual activity physiologically and psychologically. There are many relative studies in military or other special fields that show that the level of arouse and cognition are reduced by fatigue, especially for the attention, in accompany with the shift of emotion and affection. There is much limitation in the past studies in which subjective evaluation was involved. ERP was employed in the present study in which the classical and creative modes were used to explore the processing characteristic of attention after fatigue, and the influence of fatigue upon emotion was also discussed in the study.32 male volunteers attended in the experiment, and the subjects were divided into two groups (driving group and VDT group) according to the different cognitive load. The experiment was employed before and after fatigue so as to get the grades of different scales and experiment data. The objective index and subjective evaluation were both used to assess the characteristic of cognition and emotion before and after fatigue. The experiment consisted of three parts: first, the Fatigue scale-14, POMS, and VAS were employed to evaluate the subjects’state of fatigue and emotion. Secondly, different ERP modes (classical MMN, optimal MMN, Novelty Oddball, CNV) were used to assess the features of attention in the mental fatigue. We discussed the amplitudes and latencies of classical MMN, optimal MMN, P3a, P3b, and CNV to probe into the ability of shift from unconsciousness to consciousness. Last, the modes of GO-NOGO and Face recognition were used to evaluate the changes of emotion in the fatigue by the analysis of N170, NOGO-N2, and NOGO-P3.The main conclusions of the present study are as follows:1. The automatic processing of information was influenced by the mental fatigue, and the pre-attention was impaired; in addition, the advantages of right hemisphere at front cortex disappeared after fatigue, which might be due to the reduction of performance in right hemisphere at front cortex. The reduction of the amplitudes of both classical and optimal MMN after fatigue occurred in both driving group and VDT group. The amplitudes of optimal MMN showed that the two groups had the advantages of right hemisphere over the left hemisphere; however, such difference disappeared after fatigue.2. The function of performance was damaged after fatigue, and the ability of involuntary attention and selective attention was impaired. The impairment of orient response indicated that the awareness and judgment of the signal of danger were damaged after fatigue, and the self-protection was also absent. Further, the reduction of selective attention demonstrated that the ability to respond to relative mission was declined after fatigue. The conclusion could be proved by the reduction of amplitudes of P3a and P3b in both groups after fatigue. The peak of P3a was located at frontal cortex, and the obvious advantages of the frontal cortex could be seen before fatigue, however, such advantages disappeared after fatigue. The decline of amplitudes of P3a showed the impaired function of performance after fatigue.3. Maintenance of attention was damaged after mental fatigue, and the expectation and cognitive motion were also reduced, which could be supported by the reduction of average amplitudes of CNV and CNV late component after fatigue, compared to the amplitudes before fatigue.4. Attentional preference to the negative emotion vanished after mental fatigue, and the response to the outside threat for self-protection was attenuated, which could be corroborated by the higher amplitude of N170 to angry faces than that of N170 to happy faces before fatigue, however, there was no significant difference between them after fatigue.5. The ability to supervise the conflict information and restrain the response was attenuated. The ability to restrain the information of negative emotion was declined by the fatigue, which demonstrated that fatigue gave rise to much more negative emotion. The conclusion could be proved by the decline of amplitude of NOGO-N2 and increased amplitudes of NOGO-N2 to the angry faces.6. The subjective evaluation showed the obvious sense of fatigue after mission, and each scale grade was significantly increased after fatigue, which indicated that the negative emotion was stimulated by fatigue. Scores of A, F, T in POMS were increased and the indexes of Alert, Anxious and Irritable were all different from those before fatigue.更多还原