 These expansions may interact intimately with the astrocytic processes that are interconnected with the hypocellular layer (Layer II).The secondary layer (Layer II) provides for a hypocellular gap abutting the former and has been shown to contain a network of functionally correlated Glial Fibrillary Acid Protein (GFAP)-positive astrocytic processes that are linked to junctional complexes, yet lack cell bodies except for the rare neuronal somata.While the function of this layer is yet unknown in humans, it has been hypothesized that the astrocytic and ependymal interconnections of Layer I and II may act to regulate neuronal functions, establish metabolic homeostasis, and/or control neuronal stem cell proliferation and differentiation during development.