Head scans. Coloured computed tomography (CT) scans of axial sections through a healthy head. The sequence of scans (from left to right) starts at the base of the skull and moves in 1 centimetre slices to the top of the skull. The front of the head is at top. The dark spaces at the front of the head in the first 10 scans are the paranasal sinuses and the eye sockets (round). In the first four scans the brain tissue consists mostly of the brainstem and cerebellum, areas that control subconscious functions. The cerebrum, which is responsible for conscious thought and movement dominates the remainder of the scans.