Cerebrum

The cerebrum is the largest and most superior part of the human brain. It is divided into left and right hemispheres by a deep midline groove called the longitudinal fissure, with the two halves connected and communicating through a broad band of white-matter fibers, the corpus callosum.

Gross Structure and Location

The cerebrum occupies the front and top of the cranial cavity, sitting above the brainstem and cerebellum. Its outer surface, the cerebral cortex, is a roughly 2-mm-thick sheet of gray matter folded into ridges (gyri) and grooves (sulci) that vastly increase its surface area. Beneath the cortex lie white matter (myelinated connecting fibers) and deep gray-matter nuclei such as the basal ganglia. Each hemisphere is subdivided into four lobes by major landmarks: the central sulcus separates the frontal from the parietal lobe, the parieto-occipital sulcus marks off the occipital lobe, and the lateral (Sylvian) fissure separates the temporal lobe below.

Key Functions

Functions are broadly localized by lobe. The frontal lobe handles voluntary motor control, speech production, and executive abilities such as planning, attention, personality, and judgment. The parietal lobe integrates touch, temperature, and spatial information. The temporal lobe processes hearing, language comprehension, and memory, while the occipital lobe interprets vision. In most people the left hemisphere is dominant for language, and the right specializes in spatial and visual processing. Generally, each hemisphere controls the opposite side of the body.

Clinical Relevance

Because functions map to specific regions, damage produces predictable deficits. A stroke or tumor in the frontal motor cortex can cause weakness on the opposite side of the body, while injury to language areas can impair speech (aphasia). Occipital injury may cause partial blindness, and temporal-lobe disease is a common origin of epilepsy and memory disorders. Mapping symptoms back to cortical anatomy helps clinicians localize lesions before imaging.

This content is educational and is not a substitute for professional medical advice.