The brain is a complex structure that is composed of different structures and tissues. According to the National Institutes of Neurological Disorders and Stroke (NINDS), the brain has three major parts: prosencephalon, mesencephalon and rhombencephalon. Each part can be further divided and has specialized functions, though they are interconnected and communicate with each other.
Prosencephalon
The prosencephalon, also called the forebrain, is the largest part of the brain, according to the Lundbeck Institute. The majority of the prosencephalon is the cerebrum, which contains the four lobes of the brain: occipital lobe, temporal lobe, parietal lobe and frontal lobe. The cerebrum is divided in half by the corpus callosum, and the two halves communicate through the fibers in the corpus callosum. The prosencephalon also contains multiple internal structures, like the thalamus, hypothalamus, basal nuclei, amygdala and hippocampus. This part of the brain is responsible for various functions, such as memory, perception, judgment, learning, motivation and concentration.
Mesencephalon
Also called the midbrain, the mesencephalon is about two centimeters square, according to the Lundbeck Institute. The mesencephalon is found behind the prosencephalon, and is a large part of the brain stem. This part of the brain contains the substantia nigra, which acts as a relay station for the basal nuclei and thalamus. The mesencephalon also has the tectum and tegmentum. The tectum is involved with visual and auditory responses, while the tegmentum deals with motor function.
Rhombencephalon
Joined with the mesencephalon, the rhombencephalon or hindbrain, forms the rest of the spinal cord. The Lindbeck Institute notes that the rhombencephalon also contains the cerebellum, pons and medulla oblongata. This part of the brain is responsible for important involuntary functions, such as breathing, swallowing and arousal. The rhombencephalon also controls some motor functions, such coordination and integration of visual information with movement.
