Neural processor

A neural processor is a device implanted in the nervous system of every Borg drone containing a record of all the information received from the Collective.

After the USS Enterprise (NCC-1701-E) traveled back in time from 2373 to 2063, Captain Jean-Luc Picard removed the neural processor implanted in the newly-assimilated Ensign Lynch, located in the abdomen. Attaching it to a tricorder, Picard was able to access the processor and discovered the Borg's plot to transform the Enterprise's deflector dish into an interplexing beacon with which to establish a link with the Borg living in the 21st century. 

Later that year, in the Delta Quadrant, a group of former Borg drones were able to activate their processors by using a portable neural transponder, re-linking their brain patterns. This allowed them to generate a neuro-electric field which, combined with a small neural transceiver attached to the base of the skull, was able to heal serious injuries sustained by Commander Chakotay, first officer of the USS Voyager, upon being fired upon by a particle weapon.