Legend holds that "Kaffa", or coffee, was discovered in western Ethiopia by a man who noticed that his goats were more active after eating coffee beans.

據說 Kaffa (咖啡) 是一名住在伊索比亞西部的男人發現的，他留意到羊群在吃了咖啡豆後變得比平常亢奮。

Today, caffeine is the most widely-used brain stimulant in the world.

如今，咖啡因是世界上最廣泛使用的大腦興奮劑。

Caffeine works by blocking another chemical in your brain called adenosine from bonding to receptors on your neurons.

咖啡因能阻斷大腦中的化學物質「腺苷」與神經元上的接收器連結。

Adenosine is an inhibitor that keeps many brain regions in check, including one called the reticular activating system, which basically amplifies brain activity.

腺苷是一種抑制劑，會限制許多腦部區域運作，包括強化大腦活動的網狀刺激系統。

When adenosine is blocked, this region goes into overdrive, sending a wake-up call to the rest of your brain.

當腺苷停止作用，網狀刺激系統將全面啟動，向大腦其它區域發出「起床訊號」

So, actually, coffee doesn't stimulate your brain - it just suppresses the part that makes you drowsy!

所以，事實上咖啡不會刺激你的大腦，它只是阻擋了那些令你昏昏欲睡的化學物質！

Is caffeine addictive? Some scientists think so.

那麼咖啡因會上癮嗎？部分科學家認為會。

But it's not as bad as other drugs, because it doesn't strongly affect the dopamine pathways related to addiction.

但程度不像其他藥物強烈，因為咖啡不會嚴重影響與上癮有關的多巴胺路徑。

Your brain does learn to balance the caffeine, though, which is why stopping cold can be a real headache.

不過你的大腦也在學習與咖啡因抗衡，這是為什麼突然停止喝咖啡讓人如此頭痛。

And while the equivalent of 100 cups of coffee can kill you, studies have found that in moderation it may help protect against Alzheimers and Parkinsons disease.

雖然一次喝 100 杯咖啡可能會致命，但研究顯示適度飲用咖啡能預防阿茲海默症及帕金森氏症。

So perhaps our craving for coffee isn't all that BAAHHHD.

這樣一來，我們想喝咖啡的欲望似乎也沒那麼糟～嘛！(學羊叫)