人们不能从历史中学到教训吗?

黑格尔关于人们不能在历史中学到任何教训的格言在我国一直流行,在危机时刻出现更是频繁。其实,这个论断带有天然的缺陷:一个全称否定判断只要碰到一个真实存在的事例就全盘崩溃,"言有易,言无难"说的就是这个道理。事实证明,无论是个人还是社会群体,都能从历史中学习教训,不过有些学习带有明显的局限性,也得不到什么好的结果。从前喻社会和人的大脑自发式工作系统的角度看,黑格尔的这句格言有它深刻的合理性。不过,在目前这个创新型时代,来自经验主义的危险无疑更大。

Central monoaminergic systems are a site of convergence of signals conveying the experience of exercise to brain circuits involved in cognition and emotional behavior

Physical activity can enhance cognitive function and increase resistance against deleterious effects of stress on mental health. Enhanced cognitive function and stress resistance produced by exercise are conserved among vertebrates, suggesting that ubiquitous mechanisms may underlie beneficial ef- fects of exercise. In the current review, we summarize the beneficial effects of exercise on cognitive function and stress resistance and discuss central and peripheral signaling factors that may be critical for conferring the effects of physical activity to brain circuits involved in cognitive function and stress. Additionally, it is suggested that norepinephrine and serotonin, highly conserved monoamines that are sensitive to exercise and able to modulate behavior in multiple species, could represent a conver- gence between peripheral and central exercise signals that mediate the beneficial effects of exercise. Finally, we offer the novel hypothesis that thermoregulation during exercise could contribute to the emotional effects of exercise by activating a subset of temperature-sensitive serotonergic neurons in the dorsal raphe nucleus that convey anxiolytic and stress-protective signals to forebrain regions. Throughout the review, we discuss limitations to current approaches and offer strategies for future re- search in exercise neuroscience.