功能磁共振成像研究睡眠剥夺36小时对健康男性工作记忆的影响

目的 利用功能磁共振成像(functional magnetic resonance imaging,fMRI)技术研究睡眠剥夺36 h对健康男性工作记忆的影响及可能机制.方法 10名健康男性受试者连续36 h睡眠剥夺,睡眠剥夺前后分别接受工作记忆任务测试,同时进行fMRI扫描.fMRI扫描采用2项工作记忆任务,收集获得的行为学结果和fMRI图像,用SPM2软件进行图像分析.比较睡眠剥夺前后工作记忆任务测试及fMRI扫描结果.结果 剥夺后LTR任务的反应时间为(866±102)ms,比剥夺前(754±91)ms]明显延长(t=2.59,P<0.01),准确率为84.78%±8.71%,比剥夺前(95.31%±3.56%)明显降低(t=3.52,P<0.01);剥夺后PLUS任务的反应时间为(848±94)ms,比剥夺前(756±79),ms]明显延长(t=2.37,P<0.05),准确率为84.22%±9.66%,比剥夺前(95.70%±4.72%)明显降低(t=3.38,P<0.01);剥夺前在额顶叶、前扣带回和丘脑等工作记忆相关性脑区被激活.PLUS任务较LTR任务激活脑区范围更广,强度更显著.剥夺后顶叶激活降低,前额叶和丘脑的激活增强.结论 睡眠剥夺能够导致工作记忆能力受损.fMRI显示睡眠剥夺后完成工作记忆任务时,在相应脑区顶叶激活降低,前额叶和丘脑激活增强,这可能是睡眠剥夺导致认知功能损害的机制之一.

Functional magnetic resonance imaging study of working memory changes in healthy male volunteers after 36 hours sleep deprivation

Objective To observe changes in the working memory and brain functional imaging on functional magnetic resonance imaging(fMRI) after 36 hours sleep deprivation (SD) in healthy volunteers and to explore the possible mechanism of the changes.Methods FMRI scannings were performed in ten male healthy young volunteers before and after 36 hours SD and results were analyzed using SPM2 software.Subjects were also tested LTR and PLUS task to measure the persistence and operation of working memory before and after 36 hours SD.Results The reaction time of LTR task after 36 hours SD ( (866 ± 102) ms)was significantly longer than that before SD ( (754 ± 91 ) ms, t = 2.59, P < 0.01 ).The reaction time of PLUS task after SD ( (848 ± 94) ms) was significantly longer ( t = 2.37, P < 0.05 ) than that before SD ( (756 ± 79) ms).The error rate of LTR task after SD (95.3% ± 3.56% ) was significantly higher (t=3.52,P < 0.01 ) than that before SD (84.8% ± 8.71% ).The error rate of PLUS task after SD (95.7% ±4.72% ) was significantly higher (t =3.38 ,P <0.01 ) than that before SD (84.2% ±9.66% ).There were no significant differences between the two tasks.The frontal and parietal lobes, anterior cingulate gyrus and thalamus were activated during memory tasks testing before SD.Brain activation was broader and stronger in PLUS task than in LTR task.After SD, activation in parietal lobe was decreased and activation in prefrontal and thalamus was increased significantly.Conclusions The working memory performance decreased after SD.Both LTR and PLUS tasks of working memory activate frontal and parietal lobes, anterior cingulate gyrus and thalamus.The activation of parietal lobe decreased and the activation of prefrontal lobe and thalamus increased after 36 hours SD.This is the possible mechanism of SD to causes the cognition decline.