Cortex vault

The cortex vault was an additional electronic brain which was possessed by bronze Daleks such as Rusty. It contained memory banks and monitoring the Dalek's thoughts.

One of its primary functions was to keep a Dalek "pure". To achieve this it would stoke the fire of a Dalek's hatred whilst simultaneously extinguishing even the smallest glimmers of compassion, mercy or kindness. The Doctor saw this as possibly one of the most evil creations in the universe, describing it as "evil refined as engineering". (TV: Into the Dalek)