cerebrum
Meaning of cerebrum: Each half controls the opposite side of the body, so the site of an injury predicts which side loses function.
Definition of cerebrum
The cerebrum is the large upper part of the brain, split into left and right hemispheres joined by the corpus callosum, a thick bundle of nerve fibers. Its folded outer layer, the cerebral cortex, handles voluntary movement, sensation, language, reasoning and memory, and deeper structures within it help start and smooth movement.
What do the lobes do?
| Lobe | Main responsibilities |
|---|---|
| Frontal | Voluntary movement, planning, judgment, personality, and speech production |
| Parietal | Touch, position sense, temperature, and awareness of space and the body |
| Temporal | Hearing, understanding of language, and the formation of memories |
| Occipital | Vision, from raw signal through to recognition |
| Insula | Taste, internal body sensation, and part of the response to pain |
The map is real but not rigid. Complex tasks recruit several regions at once, and areas can take on some of the work of a damaged neighbor, particularly in children.
How is it different from the cerebellum and the brainstem?
The cerebrum is by far the largest of the three and carries out the deliberate work. The cerebellum sits beneath and behind it and does not initiate movement; it coordinates and times movement that has already been ordered, so damage there causes clumsiness and unsteadiness rather than weakness. The brain stem connects the brain to the spinal cord and runs breathing, heart rate, blood pressure, swallowing and consciousness itself, which is why very small injuries there can be devastating. Nerve fibers from all of it pass through the brainstem on their way down.
Why does location matter after an injury?
Each hemisphere controls movement and receives sensory information from the opposite side of the body, because the pathways cross in the brainstem. Damage to the left side of the cerebrum therefore weakens the right arm and leg, and in most people it also affects language, since the language areas usually sit on the left. Damage to the right side more often disturbs attention to the left side of space, spatial judgment and awareness of the deficit itself. A stroke in one artery produces a recognizable pattern because that artery supplies a known territory, so the pattern of loss points back to the site before any scan confirms it.
Used in a sentence
Imaging identified an area of abnormality within the right cerebral hemisphere of the cerebrum.
Good to know
Symptoms following an injury to the cerebrum often correspond to the specific region affected, which is why the location of damage, not only its presence, is considered when assessing the likely effects of a brain injury.
Word origin
Where “cerebrum” comes from
From Latin cerebrum, meaning brain.