<prompt> True about great cerebral vein of galenThalamostriate vein and choroidal vein form the great cerebral vein of galenIt forms superficial venous drainage system of brainGreat cerebral vein of galen drains into sigmoid sinusBasal vein and deep cerebral vein unite beneath splenium of corpus callosum to form vein of galen  <response>: Great cerebral vein constitutes deep vein system of brain. It drains into straight sinus.Thalamostriate vein and choroidal vein join to form internal cerebral vein deep cerebral vein. 