The sensory node is a cybernetic device implanted within each Borg drone. The sensory node is connected to both the ocular node and the cortical node, located within the Borg cortical array. (VOY: "Equinox, Part II")
In 2376, The Doctor was reprogrammed by the renegrade crew of the USS Equinox to perform an invasive surgical procedure and remove Seven of Nine's cortical array. (VOY: "Equinox, Part II") As he did so, he sang:
- The ocular node's connected to the...sensory node,
- The sensory node's connected to the...cortical node,
- The cortical node's connected to the...reticular node...