Brain A brain was the central area for thought in most sentient biological entities . All animals had brains of some sort . ( TV : " Invasion of the Dinosaurs " ) The Fourth Doctor claimed that a machine as efficient as the human brain would have to be bigger than London and powered by the entire Europe an grid . A Time Lord ' s brain was even more complex . ( TV : " The Invisible Enemy " ) Richard Harries experimented with brainwaves . He had sibling rat s transfer knowledge through the waves and complete tasks the other had learnt . ( PROSE : " The Banquo Legacy " ) The Fifth Doctor created an anti - dreaming device that stopped the brainwaves associated with dream ing . ( TV : " Snakedance " ) While most brains were natural , the Rani once constructed a giant brain to absorb the mental energies of various individuals and compute the equations for a Time Manipulator . ( TV : " Time and the Rani " ) In certain circumstances , the brain could be transplanted out of the biological entity into another vessel . This was done with Morbius ' brain after his body was destroyed . His ally , Mehendri Solon , had to find a head large enough to fit the brain and only found the right match when he met the Fourth Doctor . ( TV : " The Brain of Morbius " ) On Thoros Beta , the surgeon Crozier accomplished significant results in this field , with the brain of the Mentor Kiev . ( TV : " Mindwarp " ) On Pete ' s World , the Cybermen there were created by having the brain transplanted from the human form into the cybernetic suit . ( TV : " Rise of the Cybermen " ) The Ood had two brains . One was carried in their hands . There was also a giant brain on the Ood Sphere . ( TV : " Planet of the Ood " ) The Eleventh Doctor claimed to have twenty - seven brains when chatting with Clara , although it was a lie . ( TV : " The Bells of Saint John " ) The Morpho were a race of disembodied brains . ( TV : " The Velvet Web " ) The Masters of Dorada were a race of disembodied brains . ( PROSE : " The Dream Masters " ) The Shoal of the Winter Harmony resembled disembodied brains in their natural form . ( TV : " The Return of Doctor Mysterio " ) K9 Mark 2 told Starkey that the second planet in the Montoon system had an " ocean of brains " . ( TV : " Curse of Anubis " ) Lady Cassandra O ' Brien . Δ17 was able to survive the destruction of the sheet of skin which formed her " body " because her brain was undamaged , allowing her to constitute a new skin body with another skin sheet from her old human body — this one taken from her backside . ( TV : " The End of the World " , " New Earth " ) Miranda Cleaves had a blood clot in her brain , as did her ganger . Cleaves was cured by a poultice the Eleventh Doctor gave her . ( TV : " The Almost People " ) The Judoon had rather small brains ; a Judoon brain was able to fit in a box that could easily be held in a humanoid palm . ( WC : " Prequel ( A Good Man Goes to War ) " ) The Mechanistrian s were Korad s who had their brains placed in machines . ( PROSE : " Peril in Mechanistria " ) The Clockwork Repair Droids of the 51st century spaceship SS " Madame de Pompadour " thought they could use the brain of their ship ' s namesake , Madame de Pompadour herself , to help repair their ship ; to this end they opened up time window s back to 18th century France to stalk Madame de Pompadour . ( TV : " The Girl in the Fireplace " ) Mordrega needed to consume human brains to survive . ( AUDIO : " The Ghosts of Gralstead " ) The Great Power increased the power of Dalek brains , but it killed them shortly afterwards . ( PROSE : " Doctor Who and the Daleks " )