Figure 2: Interaction of systemic TLR ligands with circumventricular organs and choroid plexus. (a) Schematic illustrating the anatomical location of choroid plexus and circumventricular organs (CVO) in the rat brain. (b) Depicted image of suggested transfer of inflammatory stimuli from circulating LPS via the epithelial cells of the choroid plexus and induction of inflammatory responses in the cerebrospinal fluid (CSF) of the brain. (c) The circumventricular organs of the brain lack a fully developed blood-brain barrier (BBB). This allows LPS to instigate interactions with inflammatory cells in these brain regions, which initiates an inflammatory response in brain parenchyma.