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We may owe some of our unique intelligence to a generous supply of a signalling chemical called dopamine in brain regions that help us think and plan. Our brains produce far more dopamine in these regions than the brains of other primates like apes.
Dopamine is a brain signalling chemical that is vital for our control of movement. It is depleted in people with Parkinson’s disease, leading to mobility problems, tremors and speech impairments. But it also plays a pivotal role in many cognitive abilities at which humans excel, including learning, concentrating, pleasure-seeking and planning ahead.
Nenad Sestan and André Sousa of the Yale School of Medicine in New Haven, Connecticut and their colleagues measured the activity of individual genes in tissue samples from 16 brain regions, taken from six humans, five chimpanzees and five macaque monkeys.
They found elevated activities of two enzymes that make