and the allocortex called the paralimbic cortex, where layers 2, 3 and 4 are merged. this area incorporates the proisocortex of the neocortex and the periallocortex of the allocortex. in addition, the cerebral cortex may be classified into four lobes: the frontal lobe, temporal lobe, the parietal lobe, and the occipital lobe, named from their overlying bones of the skull. blood supply and drainage main article: cerebral circulation arterial supply showing the regions supplied by the posterior, middle, and anterior cerebral arteries. blood supply to the cerebral cortex is part of the cerebral circulation. cerebral arteries supply the blood that perfuses the cerebrum. this arterial blood carries oxygen, glucose, and other nutrients to the cortex. cerebral veins drain the deoxygenated blood, and metabolic wastes including carbon dioxide, back to the heart. the main arteries supplying the cortex are the anterior cerebral artery, the middle cerebral artery, and the posterior cerebral artery. the anterior cerebral artery supplies the anterior portions of the brain, including most of the frontal lobe. the middle cerebral artery supplies the parietal lobes, temporal lobes, and parts of the occipital lobes. the middle cerebral artery splits into two branches to supply the left and right hemisphere, where they branch further. the posterior cerebral artery supplies the occipital lobes. the circle of willis is the main blood system that deals with blood supply in the cerebrum and cerebral cortex. cortical blood supply development