The cerebrum is divided into two cerebral hemispheres, the right and the left. Each hemisphere is made of four cerebral lobes: frontal lobe, parietal lobe, temporal lobe and occipital lobe. Each cerebral lobe contains the gray matter and the white matter. The gray matter is the outer portion and it is made of neuron bodies; the gray matter is also known as the cerebral cortex. The white matter is the inner portion and it is white because it is in the region where axons of the cortical neurons pass.