背景:L-茶氨酸是茶中发现的一种非蛋白质形成氨基酸。先前的研究表明,高剂量(100-400毫克)的茶氨酸可以增强注意力,主要是通过减少思维游移和分散注意力的处理。我们假设这些间接机制可以显着提高低级注意力任务的性能,而在需要主动的复杂注意力任务中,相对贡献可能较小,目标刺激的高阶处理。
方法:为了检验这一假设,我们进行了双盲,安慰剂对照,平衡,在32名健康年轻人中进行的四向交叉研究,我们比较了三种剂量的L-茶氨酸(100、200和400毫克)与安慰剂(蒸馏水)的效果,给药前和给药后50分钟给药,关于剑桥神经心理学测试自动电池的三个注意任务[即反应时间(RTI)-视觉运动速度,快速视觉信息处理(RVP)-持续关注,和停止信号任务(SST)-抑制控制]。以剂量×时间重复测量方差分析模型分析结果,与随后的成对比较。
结果:在RTI(100-200mg)和RVP(200-400mg)任务中,与基线相比,有效剂量显着改善了反应时间(p<0.05),但是一旦控制了安慰剂引起的基线变化,只有RTI简单反应时间显着改善,在100毫克(Δ=16.3毫秒,p=0.009)和200mg(Δ=16.9ms,p=0.009)的L-茶氨酸。
结论:与我们的假设一致,这些发现表明,L-茶氨酸在简单的视觉运动任务中显着提高注意力,但不是在更复杂的持续注意力任务中,或执行控制任务,需要自上而下抑制前主动反应。
BACKGROUND: L-
theanine is a non-protein-forming amino acid found in tea. Previous research shows high doses (100-400 mg) of L-
theanine enhances attention, mainly by reducing mind wandering and distracter processing. We hypothesized that these indirect mechanisms could significantly improve the performance of low-level attentional tasks, whereas the relative contribution could be less in complex attentional tasks that require active, higher-order processing of target stimuli.
METHODS: To test this hypothesis, we conducted a double-blind, placebo-controlled, counterbalanced, four-way crossover
study in 32 healthy young adults, where we compared the effects of three doses of L-
theanine (100, 200 and 400 mg) with a placebo (distilled water), administered before and 50 min after dosing, on three attentional tasks from the Cambridge Neuropsychological Test Automated Battery [viz. Reaction Time (RTI)-visuomotor speed, Rapid Visual Information Processing (RVP)-sustained attention, and Stop Signal Task (SST)-inhibitory control]. Results were analyzed in dose × time repeated measures ANOVA models, with subsequent pairwise comparisons.
RESULTS: Active doses significantly improved reaction times in the RTI (100-200 mg) and RVP (200-400 mg) tasks from baseline (p < 0.05), but once controlled for the change-from-baseline caused by placebo, only the RTI simple reaction times showed significant improvements, following 100 mg (Δ = 16.3 ms, p = 0.009) and 200 mg (Δ = 16.9 ms, p = 0.009) of L-theanine.
CONCLUSIONS: Consistent with our hypothesis, these findings suggest that L-
theanine significantly improves attention in simple visuomotor tasks, but not in more complex sustained attention tasks, or executive control tasks that require top-down inhibition of pre-active responses.