Data establishes a neural link with Captain Picard
A neural link was the term used to describe the telepathic connection between Borg drones, allowing them the act as one mind in the Collective.
In 2367, Lieutenant Commander Data was able to establish a neural link with Captain Picard, who had been assimilated into the Collective. Utilizing this link, Data successfully planted a command into the Borg collective consciousness, misdirecting all the drones on a Borg cube attacking Earth to believe it was time to regenerate, effectively putting them all to sleep. (TNG: "The Best of Both Worlds, Part II")
In 2368, four drones of Unimatrix 01 crash landed on a planet in the Delta Quadrant, causing their link to the Collective to become severed. When three of the drones began expressing a desire to remain separate from the Collective, Seven of Nine injected them with nanoprobes, creating new interlink nodes in their brains, forming a new neural link between the three of them. This link remained active, even after they had been re-assimilated into the Collective. (VOY: "Survival Instinct")
In 2373, the group of former drones known as "the Cooperative" established a neural link with Commander Chakotay, first officer of the USS Voyager, in order to transmit neuro-electric energy with which to heal serious injuries he had sustained. Later, using the residual neural link they maintained with him, they influenced Chakotay to reactivate the neuro-electric field generator of a derelict Borg cube, and redirecting it towards their colony, forcibly establishing a new neural link amongst all of the inhabitants. (VOY: "Unity")
The next year, Chakotay utilized a neural transceiver to establish a link with Seven of Nine, who was attempting to assimilate Voyager. Chakotay was able to keep Seven distracted long enough for the Voyager crew to initiate a power surge, disabling her. (VOY: "Scorpion, Part II")