Catalepsaen Node: Part of the gene-seed implantation process. The Node is built into the back of a Space Marine's brain, and allows him to operate without sleep for prolonged periods. The Node allows the Marine to shut down portions of his brain, whilst maintaining activity in others, essentially allowing 'sleep cycles' for sections of the brain. Common uses of this implant are when setting watches with reduced numbers, when small numbers of Marines are guarding non-Marine units - as the Space Marine can remain awake throughout the night, unlike his companions. Lexandro D'arquebus used his Catalepsaen Node to watch over Grimm, Meh'Lindi and Jaq Draco whilst the four where travelling in the Eldar web-way.
The longest any Space Marine has ever been on active combat duty without rest is 328.7 hours, achieved by a squad of the Crimson Fists.
Source: Harlequin by Ian Watson, Rogue Trader by various
Submitter: Simguinus
Hive World Terra