![Ratio of naturally retained 15N to 13C in rat brain regions as a marker of brain function and activity - ScienceDirect Ratio of naturally retained 15N to 13C in rat brain regions as a marker of brain function and activity - ScienceDirect](https://ars.els-cdn.com/content/image/1-s2.0-S0168010219304006-ga1.jpg)
Ratio of naturally retained 15N to 13C in rat brain regions as a marker of brain function and activity - ScienceDirect
![PETA on Twitter: "It's a fact that rats and mice are emotionally complex and intelligent animals. They don't deserve to be tortured in cruel experiments. Take action if you agree: https://t.co/0ZcSKhTmEv https://t.co/MeclmldbqV" / PETA on Twitter: "It's a fact that rats and mice are emotionally complex and intelligent animals. They don't deserve to be tortured in cruel experiments. Take action if you agree: https://t.co/0ZcSKhTmEv https://t.co/MeclmldbqV" /](https://pbs.twimg.com/media/EwyzxRYXMAApkiI.jpg)
PETA on Twitter: "It's a fact that rats and mice are emotionally complex and intelligent animals. They don't deserve to be tortured in cruel experiments. Take action if you agree: https://t.co/0ZcSKhTmEv https://t.co/MeclmldbqV" /
![The intelligence of rats is getting higher and higher, one day they will become more than human existence | Earth The intelligence of rats is getting higher and higher, one day they will become more than human existence | Earth](https://res.cloudinary.com/jerrick/image/upload/f_jpg,fl_progressive,q_auto,w_1024/631c55b487ebed001f4d5cbd.jpg)