The fissure separating the cerebral hemispheres is called the interhemispheric fissure or the longitudinal fissure. The two cerebral hemispheres are the upper part of the brain and together they are called cerebrum.
The cerebrum is the easiest part of human brain to spot. The outer layer of the cerebrum is gray in color and contains "gray matter": neurons and cells that support them. Below this, myelinated ascending and descending nerve fibers constitute the white matter. Within it, aggregates of gray neurons are found.
In the back lower side of the brain, a transverse fissure separates the cerebral hemisphere from the cerebellum, a smaller part of the brain. In the middle of the brain's interior, the two halves of the brain are connected by the corpus callosum. This is a group of nerve fibers that ensure exchange of information between the two hemispheres.
Gray matter is also known as the cortex. It contains millions of cells. Four lobes: the frontal, parietal, temporal and occipital, are outlined by grooves in the cortex. These four areas of the brain are each responsible for a specific activity. The frontal lobe controls learning and emotion. The parietal lobe is responsible for sensation of pressure and touch, as well as for reading and calculation. The temporal lobe's roles include hearing and understanding speech. It also contains hippocampus, which is instrumental in memory processes. The occipital lobe contains the primary visual cortex.