cerebrum

cerebrum

 [ser´ĕ-brum]

the main portion of the brain, occupying the upper part of the cranial cavity; its two cerebral hemispheres, united by the corpus callosum, form the largest part of the central nervous system in humans. The term is sometimes extended to refer to the postembryonic forebrain and midbrain together or to the entire brain.

cer·e·brum

, pl.

ce·re·bra

,

cer·e·brums

(ser'ĕ-brŭm, sĕ-rē'brŭm; -bră; -brŭmz), [TA] Although the pronunciation of this word with stress on the first syllable is classically correct, the second syllable is often stressed in the U.S.

Term originally referring to the largest portion of the brain, including practically all parts within the skull except the medulla, pons, and cerebellum; it now usually refers only to those parts derived from the telencephalon and includes mainly the cerebral hemispheres (cerebral cortex and basal nuclei, also called basal ganglia).

[L., brain]

cerebrum

/cer·e·brum/ (ser´ĕ-brum) (sĕ-re´brum) the main portion of the brain, occupying the upper part of the cranial cavity; its two hemispheres, united by the corpus callosum, form the largest part of the central nervous system in humans. The term is sometimes applied to the postembryonic forebrain and midbrain together or to the entire brain.

cerebrum

(sĕr′ə-brəm, sə-rē′-)

n. pl. cere·brums or cere·bra (-brə)

The large rounded structure of the brain occupying most of the cranial cavity, divided into two cerebral hemispheres that are joined at the bottom by the corpus callosum. It controls and integrates motor, sensory, and higher mental functions, such as thought, reason, emotion, and memory.

cerebrum

[ser′əbrəm, sərē′brəm] pl. cerebrums, cerebra

Etymology: L, brain

the largest and uppermost section of the brain, divided by a longitudinal fissure into the left and right cerebral hemispheres. At the bottom of the groove, the hemispheres are connected by the corpus callosum. The internal structures of the hemispheres merge with those of the diencephalon and further communicate with the brainstem through the cerebral peduncles. The surface of the cerebrum is called gyri. Each lobe bears the name of the bone under which it lies. The cerebrum performs sensory functions, motor functions, and less easily defined integration functions associated with various mental activities. It generates a variety of electrical waves that may be recorded as an electroencephalogram to localize areas of brain dysfunction, to identify altered states of consciousness, or to establish brain death. See also cerebral cortex, cerebral hemisphere. cerebral, adj.

brain

The epicentre of the central nervous system, which is located within the cranial vault and divided into the right and left hemispheres. The brain functions as a primary receiver, organiser and distributor of information for the body; it is the centre of thought and emotion, co-ordinates and controls bodily activities and interprets sensory visual, auditory, olfactory, tactile and other information.

cer·e·brum

, pl. cerebra (ser'ĕ-brŭm, -bră) [TA]

Originally referred to the largest portion of the brain; it now usually refers only to the parts derived from the telencephalon and includes mainly the cerebral hemispheres (cerebral cortex and basal ganglia).

[L., brain]

cerebrum

(sĕr′ĕ-brŭm) (sĕr-ē′brŭm) [L.]

CEREBRUM)

The largest part of the brain, consisting of two hemispheres separated by a deep longitudinal fissure. The hemispheres are united by three commissures—the corpus callosum and the anterior and posterior hippocampal commissures. The surface of each hemisphere is thrown into numerous folds or convolutions called gyri, which are separated by furrows called fissures or sulci.

Embryology

The cerebrum develops from the telencephalon, the most anterior portion of the prosencephalon or forebrain.

Anatomy

Each cerebral hemisphere consists of three primary portions—the rhinencephalon or olfactory lobe, the corpus striatum, and the pallium or cerebral cortex. The cortex is a layer of gray matter that forms the surface of each hemisphere. The part in the rhinencephalon (phylogenetically the oldest) is called the archipallium; the larger nonolfactory cortex is called the neopallium. The cerebrum contains two cavities, the lateral ventricles (right and left) and the rostral portion of the third ventricle. The white matter of each hemisphere consists of three kinds of myelinated fibers: commissural fibers, which pass from one hemisphere to the other; projection fibers, which convey impulses to and from the cortex; and association fibers, which connect various parts of the cortex within one hemisphere.

Lobes: The principal lobes are the frontal, parietal, occipital, and temporal lobes and the central (the insula or island of Reil). Basal ganglia: Masses of gray matter are deeply embedded within each hemisphere. They are the caudate, lentiform, and amygdaloid nuclei and the claustrum. Fissures and sulci: These include the lateral cerebral fissure (of Sylvius), the central sulcus (of Rolando), the parieto-occipital fissure, the calcarine fissure, the cingulate sulcus, the collateral fissure, the sulcus circularis, and the longitudinal cerebral fissure. Gyri: These include the superior, middle, and inferior frontal gyri, the anterior and posterior central gyri, the superior, middle, and inferior temporal gyri, and the cingulate, lingual, fusiform, and hippocampal gyri.

Physiology

The cerebrum is concerned with sensations (the interpretation of sensory impulses) and all voluntary muscular activities. It is the seat of consciousness and the center of the higher mental faculties such as memory, learning, reasoning, judgment, intelligence, and the emotions. See: illustration

On the basis of function, several areas have been identified and located. Motor areas in the frontal lobes initiate all voluntary movement of skeletal muscles. Sensory areas in the parietal lobes are for taste and cutaneous senses, those in the temporal lobes are for hearing and smell, and those in the occipital lobes are for vision. Association areas are concerned with integration, analysis, learning, and memory.

cerebrum

The largest, and most highly developed, part of the brain. It contains the neural structures for memory and personality, cerebration, volition, speech, vision, hearing, voluntary movement, all bodily sensation, smell, taste and other functions.

cerebrum

that part of the forebrain which expands to form the CEREBRAL HEMISPHERES, found in all vertebrates except fishes.

cerebrum

cerebral hemispheres

cer·e·brum

, pl. cerebra (ser'ĕ-brŭm, -bră) [TA]

Cerebral parts derived from the telencephalon; includes mainly the cerebral cortex and basal ganglia.

[L., brain]

cerebrum (ser´əbrum, sərē´brum),

n the largest portion of the brain. Operating at the highest functional level and occupying the upper part of the cranium, it consists of two hemispheres united at the bottom by commissures of large bundles of nerve fibers. As with all parts of the nervous system, each part of it has highly specific functions (e.g., a specific outer cortical area controls voluntary mastication, whereas certain inner subcortical areas are involved in involuntary jaw posture).

cerebrum

the main portion of the brain, occupying the front part of the cranial cavity; its two cerebral hemispheres are united by the corpus callosum. The term is sometimes applied to the postembryonic forebrain and midbrain together or to the entire brain. See also brain.

Four major lobes of the cerebrum. By permission from Cunningham JG, Textbook of Veterinary Physiology, Saunders, 2002