A neuro-electric field was an energy medium utilized by the Borg Collective capable of regenerating the damaged components of an injured Borg. Capable of healing both organic and inorganic body parts, the field was composed of neuro-electric energy, and was transmitted by hundreds, perhaps thousands of Borg drones.
After becoming separated from the Collective, the group of former drones known as "the Cooperative" constructed a portable neural transponder which allowed them to temporarily re-link their minds together, transmitting neuro-electric energy whenever it was needed. The performed this procedure on Commander Chakotay, first officer of the USS Voyager, in 2373, successfully healing serious injuries he had sustained after being fired upon by a particle weapon. Later, utilizing their residual neural link with Chakotay, they influenced him to reactivate the neuro-electric field generator of a derelict Borg cube, and redirect it towards the planet, allowing the Cooperative to forcibly establish a neural link amongst the planet's entire population. (VOY: "Unity")