人们常用“愤怒得失去理智”来形容一个人发怒的样子,其实这时并不一定是其大脑中没有理智,而可能是大脑中负责理智的部分缺乏一种信号物质——血清素的帮助,因此难以控制与愤怒相关的大脑部位活动。
英国剑桥大学等机构的研究人员在美国新一期《生物精神病学》(Biological Psychiatry)杂志上报告了这项研究成果。专家解释说,神经细胞需借助血清素传递信息,人体通常用食物中的色氨酸来合成血清素。研究人员请一些志愿者在不同日子里分别进食富含或缺少色氨酸的食物,随后用一些图片来激起他们大脑中的愤怒情绪,用磁共振成像技术来观察大脑内部的反应。
结果显示,在缺少色氨酸并因此导致血清素含量较低时,大脑的愤怒反应更难被抑制。而对大脑活动的观察发现,在血清素含量低的时候,大脑中额叶部位和杏仁核部位之间的信号联系就会减少。杏仁核部位与愤怒情绪有关,而额叶部位发出的信号可以帮助控制这种愤怒。因此,在缺少作为“信使”的血清素时,“理智”的额叶就难以控制“愤怒”的杏仁核。
研究人员莫利·克罗克特说,以前研究者就知道血清素含量与愤怒情绪有关,但直到最近才有技术手段来探测大脑内部的相关活动特点,本次研究最终发现了血清素在负责理智和愤怒的大脑部位之间充当信使的机制。
因此,如果你是一个易于发怒的人,不妨在日常生活中多吃一些富含色氨酸的食物,以增加大脑中血清素的含量。通常蛋白质含量较高的食物中都含有不少色氨酸,如大豆、鸡蛋和鸡肉等。(生物谷 Bioon.com)
doi:10.1016/j.biopsych.2010.12.037
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The Importance of Serotonin for Orbitofrontal Function
Angela C. Roberts
The orbitofrontal cortex (OFC) receives a dense serotonin (5-hydroxytryptamine, or 5-HT) innervation from the dorsal raphe nucleus, with a smaller contribution from the median raphe nucleus. The reciprocal innervation from the OFC enables the OFC to regulate not only its own 5-HT input but the 5-HT input to the rest of the forebrain. This article reviews the evidence from studies in rodents and primates that implicate 5-HT in the OFC in the ability of animals to adapt their responding to changes in reward contingencies in the environment. A consensus is emerging that reductions in orbitofrontal 5-HT, whether the result of localized infusions of 5,7-dihydroxytryptamine (5,7-DHT), peripheral treatment with parachloroamphetamine (PCA) or para-chlorophenylalanine (PCPA), or chronic cold stress impairs this ability. Genetic variation in the 5-HT transporter can also affect this ability. An explanation regarding insensitivity to reward loss is ruled out by the finding that marmosets with 5-HT reductions in the OFC display a decline of responding as rapid as that of control animals when reward is withheld during extinction of a two-pattern discrimination task. The failure of these same animals to explore alternative stimuli during extinction, along with the recent electrophysiological evidence that dorsal raphe nucleus neurons encode future motivational outcomes, implicates orbitofrontal 5-HT in the process by which animals either exploit current resources or explore alternative resources based on current reward expectations.