Neurons in the caudal pedunculopontine nucleus, an area of the brain that regulates motor coordination, switch neurotransmitters from acetylcholine to GABA as a result of exercise. The switch appears to provide feedback control that regulates motor coordination and skill learning.
Primates with larger brains can solve much more complex tasks using their hands than smaller-brained primates. However, improved dexterity comes at a cost. In humans and other large-brained primates, it takes longer for infants to learn the simplest hand and finger movements than our smaller-brained counterparts.