The brain is composed of three parts: the brainstem, cerebellum, and cerebrum. The cerebrum is divided into four lobes: frontal, parietal, temporal, and occipital. 1  The cerebrum is the largest part of the brain and is composed of right and left hemispheres.It performs higher functions like interpreting touch, vision and hearing, as well as speech, reasoning, emotions, learning, and fine control of movement. The cerebellum is located under the cerebrum.he brain is composed of three parts: the brainstem, cerebellum, and cerebrum. The cerebrum is divided into four lobes: frontal, parietal, temporal, and occipital. 1  The cerebrum is the largest part of the brain and is composed of right and left hemispheres.