The brain - but not as you know it! This week it's all about astrocytes - the most numerous cells in our brain but also the most mysterious. Ali Jennings also shares his lab experiences, from crazy Russian scientists, to what the emotional challenge of working with rats. Plus Matilda and Ali challenge each other with temperature perception experiments! If you eat mint leaves and chilli at the same time, do the hot and cold perceptions cancel each other out? Tune in to find out.