Fig. 3D reconstruction of subsurface (subplasmalemmal) cistern from neocortical pyramidal cell. Flat and extremely narrow subsurface cistern (magenta) is an integral part of endoplasmic reticulum (yellow), closely attached to plasma membrane (A, B - pm). Cisterns and channels of endoplasmic reticulum are confluent with perinuclear cistern (pc, nu) as visible from an opposite view (C, arrows; nuclear pores omitted ). (Neocortex, mouse. Series from Kasthuri et al., 2015 used for reconstructions.)