Dopamine neurons help the brain ignore befuddling stimuli

Dopamine-producing neurons in a region of the brain called the substantia nigra are activated to inhibit unwanted actions. This finding could help explain why people with Parkinson’s disease who have deficits in these nerve cells also have trouble with impulse control.

A team led by University of Tsukuba researchers trained two macaque monkeys to gaze at certain targets on a computer screen, but to avert their eyes from the visual mark when signalled to do so. The researchers simultaneously measured the monkeys’ brain activity at a single-neuron resolution.

The team found that the activity of nerve cells involved in transmitting dopamine spiked when the animals successfully resisted the urge to look at the target. The monkeys’ performance faltered, however, when treated with drugs that blocked dopamine signalling.