Brain cell
From Tardis Wiki, the free Doctor Who reference
Cho-Je noted that regeneration would "shake the brain cells a little." As a result, the resultant new incarnation would display somewhat erratic behaviour. (TV: Planet of the Spiders)
The Fourteenth Doctor, after regenerating from his predecessor, realised he had new braincells after remembering that the TARDIS had a custard-cream dispenser. (PROSE: A Letter from the Doctor 2024 [+]Loading...{"page":"6","1":"A Letter from the Doctor (DWAN 2024 short story)"})
