Rudolf Magnus Institute of Neuroscience, Department of Neurology and Neurosurgery, University Medical Center Utrecht, Utrecht, The Netherlands.
PLoS One. 2013 Jul 31;8(7):e70074. doi: 10.1371/journal.pone.0070074. Print 2013.
Evidence is increasing for involvement of the endocannabinoid system in cognitive functions including attention and executive function, as well as in psychiatric disorders characterized by cognitive deficits, such as schizophrenia. Executive function appears to be associated with both modulation of active networks and inhibition of activity in the default mode network. In the present study, we examined the role of the endocannabinoid system in executive function, focusing on both the associated brain network and the default mode network. A pharmacological functional magnetic resonance imaging (fMRI) study was conducted with a placebo-controlled, cross-over design, investigating effects of the endocannabinoid agonist Δ9-tetrahydrocannabinol (THC) on executive function in 20 healthy volunteers, using a continuous performance task with identical pairs. Task performance was impaired after THC administration, reflected in both an increase in false alarms and a reduction in detected targets. This was associated with reduced deactivation in a set of brain regions linked to the default mode network, including posterior cingulate cortex and angular gyrus. Less deactivation was significantly correlated with lower performance after THC. Regions that were activated by the continuous performance task, notably bilateral prefrontal and parietal cortex, did not show effects of THC. These findings suggest an important role for the endocannabinoid system in both default mode modulation and executive function. This may be relevant for psychiatric disorders associated with executive function deficits, such as schizophrenia and ADHD.
越来越多的证据表明，内源性大麻素系统参与认知功能，包括注意力和执行功能，以及以认知缺陷为特征的精神疾病，如精神分裂症。执行功能似乎与主动网络的调节和默认模式网络的活动抑制都有关。在本研究中，我们研究了内源性大麻素系统在执行功能中的作用，重点关注相关的脑网络和默认模式网络。我们进行了一项药理学功能磁共振成像 (fMRI) 研究，采用安慰剂对照、交叉设计，使用具有相同配对的连续表现任务，调查内源性大麻素激动剂 Δ9-四氢大麻酚 (THC) 对 20 名健康志愿者执行功能的影响。在 THC 给药后，任务表现受损，表现为假警报增加和检测到的目标减少。这与一组与默认模式网络相关的脑区的去激活减少有关，包括后扣带回皮质和角回。去激活减少与 THC 后表现下降显著相关。被连续表现任务激活的区域，特别是双侧前额叶和顶叶皮质，没有显示出 THC 的作用。这些发现表明内源性大麻素系统在默认模式调节和执行功能中都起着重要作用。这可能与以执行功能缺陷为特征的精神疾病有关，如精神分裂症和 ADHD。
