The cerebrum plays a role in many of the body's major functions, including determining personality and intelligence, understanding and producing language, interpreting sensory input, organizing, planning and overseeing motor functions. Also called the telencephalon, the cerebrum makes up about 70 percent of the mass of the brain, covering most of the brain's other structures. The cerebrum's outer portion has a covering of gray tissue known as the cerebral cortex, and it is split into left and right hemispheres joined at the corpus callosum.
Within the cerebrum, motor skills and movement begin inside the primary motor cortex and those parts of the frontal lobe where the brain plans actions. Upper motor neurons within the primary motor cortex send axons to the spinal cord and brain stem to send the muscles into motion.
The sensory portions of the cerebral cortex take in and interpret information from all five senses. Working with associative cortical regions, these areas of the brain turn sensory information into feedback that people understand.
One major difference between the human cerebrum and that of other vertebrates is the size of the olfactory bulb, which is in charge of the sense of smell. Most vertebrates feature a large bulb, but humans have one that is significantly smaller. This is reflected in the higher reliance that other species have on the sense of smell.