MTOR and tuberous sclerosis: It has been shown that the mTOR pathway is both active in and critical for the development and differentiation of neural stem cells in both mouse and humans.21,22,86 Pathological increases in mTOR signalling, seen in tuberous sclerosis complex and somatic MTOR variants linked to hemimegancephaly,24,25 point to a significant input of the mTOR pathway in the control of neural stem cell expansion and differentiation.