LYON, FRANCE — After being in a vegetative state for 15 years, a French man is showing some signs of consciousness after neurosurgeons implanted a vagus nerve stimulator in his chest, according to a study published Monday in Current Biology.

The man, now 35, was involved in a car accident when he was 20 that left him unconscious,

The vagus nerve extends from the brain to other parts in the body, including the heart, lungs and gut.

Vagus nerve stimulation is already used to treat people with epilepsy and depression.

Researchers wanted to test the ability of vagus nerve stimulation to restore consciousness in a person in a vegetative state.

Patients in a vegetative state show no signs consciousness, mental activity or motor function, according to CNN.

People in a vegetative state can occasionally open their eyes, however this is just a random physiological response.

Vagus nerve stimulation begins with implanting a device in the chest and running a wire under the skin. This wire connects the vagus nerve and the device. The device sends electrical pulses along the nerve to the brainstem, which in turn transmits these impulses to certain brain areas.

Researchers found that after one month of stimulation, the patient’s attention, movements and brain activity significantly improved.

The scientists are now planning a larger study to confirm and extend the potential of vagus nerve stimulation.