In 2377, a team from the USS Voyager gained access to the central plexus of a Class-4 tactical cube in an attempt to distribute a nanovirus to the entire Borg Collective, designed to nullify the cortical inhibitors of a community of drones who had been interacting with each other while regenerating, allowing them to retain their memories in the real world. As the central plexus of the tactical cube was protected by multi-regenerative security grids, the team allowed themselves to be assimilated, using a neural suppressant to retain their individuality.
The team initially experienced difficulty in gaining access to the plexus, as it would require shutting down the power grid for the entire section, an act which would have drawn unwanted attention. As such, they were forced to proceed to the primary access port, which was isolated from the main power grid. Gaining access to the chamber, they were successful in deploying the virus, allowing a number of liberated drones to begin mounting a resistance movement against the Collective. (VOY: "Unimatrix Zero", "Unimatrix Zero, Part II")