Neural connection

Vader completed his meditation and opened his eyes. His pale, flame-savaged face stared back at him from out of the reflective black transparisteel of his pressurized meditation chamber. Without the neural connection to his armor, he was conscious of the stumps of his legs, the ruin of his arms, the perpetual pain in his flesh. He welcomed it. Pain fed his hate, and hate fed his strength. Once, as a Jedi, he had meditated to find peace. Now he meditated to sharpen the edges of his anger.

- Lords of the Sith, Chapter 1, Pg. 9