A neurolink was an emergency medical technique used for the stabilization of patients with brainstem injuries. Matching neural pads were used. One would be placed on a healthy individual, and a matching unit would be placed on the patient. These devices enabled a link to be established from the healthy person's autonomic nervous system to that of the injured patient.
When the Zalkonian named John Doe was discovered in the wreck of a Zalkonian escape pod in 2366, Dr. Beverly Crusher used a neurolink with Geordi La Forge to stabilize John's nervous system. (TNG: "Transfigurations")