Walter Rudolf Hess
By stimulating the hypothalamus of cats with tiny electric currents, Hess induced behaviours. The behaviours ranged from excitement to apathy, depending on the position of the stimulation. He could induce different types of responses in the anterior (lateral) hypothalamus compared to stimulating the posterior ventromedial hypothalamus. When stimulating the anterior part, he could induce fall of blood pressure, slowing of breathing and responses such as wanting food, wanting water, needing to pee and needing to poop. On the other hand, stimulation of the posterior part led to extreme excitement and defensive behaviour.