The functions of the forebrain are wide-ranging, as the area is the largest part of the brain. Also known as the prosencephalon, the forebrain is mostly comprised of the cerebrum, which is divided into two hemispheres. The two main sections of the forebrain, however, are the telencephalon and the diencephalon. The telecephalon includes the cerebral cortex, the subcortical structures, and the corpus callosum, while the diencephalon includes the thalamus and the hypothalamus. Considering the many different parts of the forebrain and how each part is responsible for certain functions, it is understandable that its functions are extensive. In general, the forebrain processes cognitive, auditory, sensory, and visual information, as well as being involved in the forming and storage of memory and emotion.
Much of what the forebrain does is linked to the cerebrum. The cerebrum includes the cerebral cortex, which is made up of four lobes: frontal, temporal, parietal and occipital. Imagining, planning and reasoning are some of the functions of the frontal lobe. Hearing and smelling, as well as forming memories and retrieving them later, are functions of the temporal lobes. The parietal lobes handle senses such as taste, temperature and touch, and processing images and linking those images to the ones stored in the memory are functions of the occipital lobes.
The subcortical structures of the forebrain are located deeper in the brain and include the basal ganglia, hippocampus and amygdala. The basal ganglia, groups of nerve cells, are responsible for the coordination of movement. Both the hippocampus and amygdala are parts of the limbic system. The function of the hippocampus is the formation and retrieval of long-term memory, while the amygdala is the part of the forebrain responsible for the processing of emotions as well as autonomic and sexual behavior. The last part of the telencephalon is the corpus callosum, which connects the two hemispheres of the brain together.
The thalamus and hypothalamus make up the rest of the forebrain. The function of the thalamus is to distribute information to the cerebrum from the spinal cord. The thalamus controls what, as well as how much, information is sent and where in the cerebrum that information is sent, as well. The hypothalamus is responsible for metabolism and the regulation of sleeping and waking states. In addition, it also serves an important role in emotions, as it controls the molecules that make a person feel certain things.