- The cerebrum is the largest and most developed part of the human brain, accounting for approximately 80% of its total volume.
- It is responsible for the higher-order functions that distinguish human intelligence and behavior, including conscious thought, voluntary movement, language, memory, emotion, perception, and decision-making.
- Located in the uppermost region of the central nervous system, the cerebrum is divided into two large cerebral hemispheres—right and left—separated by the longitudinal fissure but connected by a thick bundle of nerve fibers known as the corpus callosum, which enables communication between both sides.
- Each hemisphere of the cerebrum is further divided into four lobes: frontal, parietal, temporal, and occipital, each with specialized functions. The frontal lobe, located at the front of the brain, governs executive functions, such as reasoning, planning, problem-solving, voluntary motor activity, and speech production (via Broca’s area). The parietal lobe, positioned behind the frontal lobe, processes sensory input like touch, pressure, temperature, and pain, and contributes to spatial awareness and body orientation. The temporal lobe, situated beneath the frontal and parietal lobes, is involved in hearing, language comprehension (through Wernicke’s area), and aspects of memory and emotion. The occipital lobe, located at the back of the cerebrum, is dedicated to visual processing.
- The surface of the cerebrum is marked by gyri (ridges) and sulci (grooves), which increase the surface area and allow for a greater number of neurons to be packed into the limited volume of the skull. The outermost layer of the cerebrum is the cerebral cortex, composed of gray matter rich in neuronal cell bodies, dendrites, and synapses. Beneath the cortex lies the white matter, which consists mainly of myelinated axons that facilitate communication between different parts of the brain and between the brain and spinal cord.
- Functionally, the cerebrum is responsible for voluntary motor control, including the planning and execution of movement via the primary motor cortex (located in the precentral gyrus), and for interpreting sensory information in the primary somatosensory cortex (in the postcentral gyrus). It also supports cognitive abilities, such as attention, language, emotion, and creativity. Specific areas of the cerebrum are dedicated to language production (Broca’s area) and comprehension (Wernicke’s area), primarily in the left hemisphere for most right-handed individuals.
- The cerebrum also plays a significant role in memory formation and retrieval, particularly through the hippocampus, located in the temporal lobe. The amygdala, also within the temporal lobe, is crucial for emotional processing and linking emotions to memories. The cerebrum interacts extensively with subcortical structures like the thalamus and basal ganglia to coordinate sensory input and motor output, fine-tuning movement and contributing to motor learning.
- Damage to specific areas of the cerebrum can result in distinct neurological deficits. For example, injury to the frontal lobe may impair judgment, behavior, and voluntary movement, while damage to the occipital lobe may cause visual disturbances. Stroke, trauma, tumors, and degenerative diseases like Alzheimer’s and Parkinson’s can all affect cerebrum function.
