Cerebrum

The cerebrum is the largest part of the brain, consisting of two cerebral hemispheres separated by a longitudinal fissure and connected by the corpus callosum. It develops from the forebrain (prosencephalon) and contains a highly developed outer layer, the cerebral cortex, with underlying white matter and deep gray matter structures. It underpins most higher brain functions.

The hemispheres are divided into four lobes—frontal, parietal, temporal, and occipital—plus the insula beneath the cortex. The cortex is folded into gyri and sulci and has six layers in the neocortex. The primary motor cortex lies in the precentral gyrus, the primary somatosensory cortex in the postcentral gyrus, the primary visual cortex in the occipital lobe, and the primary auditory cortex in the temporal lobe. Language areas include Broca’s area in the frontal lobe and Wernicke’s area in the temporal lobe, connected by extensive association areas.

Deep gray matter includes structures like the basal ganglia (caudate, putamen, globus pallidus) and limbic components such as the amygdala and hippocampus. White matter tracts connect cortical regions within and between hemispheres via pathways including the corpus callosum; thalamic nuclei relay many cortical signals.

The cerebrum governs voluntary movement, perception, memory, thought, language, and emotion. Many functions are lateralized, with language often left-dominant in right-handed individuals. Blood supply arises from the internal carotid and vertebrobasilar systems, with the middle, anterior, and posterior cerebral arteries providing major cortical territories. Damage to specific regions produces characteristic deficits.