The Doctor's mind

The Doctor's mind was the inner consciousness within the Eleventh Doctor;s brain.

The Cyber-Planner, Mr Clever, attempted to take over the Doctor's mind when trying to convert him into a Cyberman. The mind was subsequently split into two halves; 49.881% in the Doctor's control and 49.881% under Mr Clever's influence. The two sides differentiated, with Mr Clever's half coloured silver and blue with circuitry scattered around while the Doctor's was orange with Gallifreyan symbols covering it. (Tv: Nightmare in Silver)

Within the mind, the Doctor could apply a mental block to prevent intruders from seeing things he desires them not to see. (TV: Nightmare in Silver) However, if the Doctor was purposefully connecting with another, namely Jeanne-Antoinette Poisson with the Tenth Doctor, they could see into his memories, so long as the Doctor maintained the connection. (TV: The Girl in the Fireplace) Sometimes, the Doctor would rapidly connect his mind with another's to speedily shares information although the process resulted in a mild headache. (TV: The Lodger)