Edwards Chad R, Skosnik Patrick D, Steinmetz Adam B, Vollmer Jennifer M, O'Donnell Brian F, Hetrick William P
Department of Psychological and Brain Sciences, Indiana University, 1101 E. 10th St., Bloomington, IN 47405, USA.
Neurosci Lett. 2008 Jul 18;439(3):264-8. doi: 10.1016/j.neulet.2008.04.102. Epub 2008 May 8.
While CB1 knockout mice exhibit striking impairments on a cerebellar-dependent task called delay eyeblink conditioning (dEBC), these animals demonstrate intact forebrain-dependent trace EBC (tEBC). Although heavy human cannabis users also show impaired delay EBC, their performance on tEBC is currently unknown. Therefore, 13 heavy cannabis users and 13 cannabis naive controls completed a tEBC procedure. The cannabis group exhibited similar rates of conditioned responding compared to controls in the acquisition and extinction phase. Consistent with reports of overt attentional abnormalities, the cannabis group exhibited decreased N100 ERP amplitudes to the tone CS that were unrelated to mean levels of conditioning across blocks during the acquisition phase. The lack of a significant effect of heavy cannabis use on tEBC reported here, combined with the previous report of impaired dEBC in such users, mirrors the findings observed in CB1 knockout mice, and suggests that the cannabinoid system differentially mediates forebrain- and cerebellar-dependent learning processes in both humans and animals.
虽然CB1基因敲除小鼠在一种名为延迟眨眼条件反射（dEBC）的小脑依赖性任务中表现出明显的损伤，但这些动物在依赖前脑的痕迹EBC（tEBC）方面表现正常。尽管重度大麻使用者在延迟EBC方面也表现出损伤，但其在tEBC上的表现目前尚不清楚。因此，13名重度大麻使用者和13名从未使用过大麻的对照者完成了一项tEBC程序。在习得和消退阶段，大麻组与对照组相比表现出相似的条件反应率。与明显的注意力异常报告一致，大麻组对音调条件刺激的N100事件相关电位振幅降低，这与习得阶段各块的平均条件化水平无关。此处报告的重度大麻使用对tEBC缺乏显著影响，与之前关于此类使用者dEBC受损的报告相结合，反映了在CB1基因敲除小鼠中观察到的结果，并表明大麻素系统在人类和动物中对依赖前脑和小脑的学习过程有不同的调节作用。
