The answer is Walter Hess
Hess manipulated the diancephalon of the brain of cats by inserting metal rods in the hypothalamus regions of the brain, where the diencephalon is located, and passing electrical current through the rods to the brain region. He noticed that the cats, among other complex behavioral changes, would curl up and sleep. 
        
             
        
        
        
The physiology, behavior, and other qualities of a particular organism or class of organisms.
        
             
        
        
        
1. The separation of a substance into simpler substances or basic elements. 2. The process of decaying or rotting. Decomposition of dead organic matter is brought about by the activity of certain bacteria and fungi feeding on it.