为什么人在春天想恋爱?
ipRGC细胞内含有黑视素(Melanopsin), 对光线产生一系列的化学反应[2],使ipRGC细胞在光照下放电[3]:
ipRGC的信号通过视神经直接传到到下丘脑(Hypothalamus)的节律控制核团suprachiasmatic nucleus(SCN)和其它神经核团, 以小鼠为例[1, 4-6]:
SCN在人脑中的位置和大小示意:
下丘脑是一个调节内分泌活动的高级神经中枢,它通过各种核团来控制各种神经递质的分泌,从而控制身体的多项功能。下丘脑的体积只有不到4cm^3,但是内部的核团很多,相互之间的关系非常复杂。SCN是下丘脑中功能最为重要的核团之一,它起到节律控制器的作用,调节人的昼夜周期和季节周期。春季到来的长日照通过此机理,会驱动动物和人的神经系统内分泌的变化[7]:
具体到人类,变化体现在褪黑素,甲状腺激素,和维生素D,从而分别影响人的睡眠(春眠不觉晓,更充足的睡眠)、精力(更充沛的精力)和身体感受(骨骼情况更好,感觉身体充满活力)。这提醒身体,春季是适合吃好,并且在食物充足的时候尽早找到伴侣的时机[8],这个时候,甚至男性身体的精子质量和数量都得到显著的增长,达到年度的最高水平[9]:
具体到一周之中,性行为最多发生在周五和周六——压力最低之时,周日发生率最低——周一恐惧。也就是说,我们身体感受到的压力水平跟性行为的欲望是负相关的。
总结春季日光时间变长驱动了我们大脑和身体的季节性节律,使我们身体和精神上都达年度最优水平,而我们的脑子不会区分由光照导致的感觉良好和由爱情导致的感觉良好春季丰富的新奇体验,驱动神经系统多巴胺分泌的爆发,而我们的脑子不会把它跟爱情的多巴胺爆发区分开由春季时间导致的1和2的良好感觉,使我们的脑子有轻度上瘾症状,驱使我们去寻找能促动多巴胺大量分泌的事物——爱情在神经科学构架下,所谓浪漫,便是充沛和丰富的新奇体验。因此所谓营造浪漫氛围,就是营造惊喜这种事物,这便是恋爱追求的法门。以上。
参考文献:
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[8] Murphy, Michelle, and Francis JP Ebling. "The role of hypothalamic tri-iodothyronine availability in seasonal regulation of energy balance and body weight."Journal of thyroid research2011 (2011).
[9] Yogev, L., et al. "Seasonal variations in pre‐and post‐thaw donor sperm quality."Human Reproduction19.4 (2004): 880-885.
[10] Legault, Mark, and Roy A. Wise. "Novelty‐evoked elevations of nucleus accumbens dopamine: dependence on impulse flow from the ventral subiculum and glutamatergic neurotransmission in the ventral tegmental area."European Journal of Neuroscience13.4 (2001): 819-828.
[11] Lisman, John E., and Nonna A. Otmakhova. "Storage, recall, and novelty detection of sequences by the hippocampus: elaborating on the SOCRATIC model to account for normal and aberrant effects of dopamine."Hippocampus11.5 (2001): 551-568.
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来源:搜狐
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