The cerebrum or telencephalon together with the diencephalon constitute the forebrain. It is the most anterior or especially in humans most superior region of the vertebrate central nervous system. Telencephalon refers to the embryonic structure from which the mature cerebrum develops. The dorsal telencephalon or pallium develops into the cerebral cortex and the ventral telencephalon or subpallium becomes the basal ganglia. The cerebrum is also divided into symmetric left and right cerebral hemispheres.

With the assistance of the cerebellum the cerebrum controls all voluntary actions in the body. Contents 1 Development 2 Hemispheres 3 Structure 4 Composition 5 Functions 5.1 Movement 5.2 Sensory processing 5.3 Olfaction 5.4 Language and communication 5.5 Learning and memory 6 Cell regeneration in Xenopus laevis 6.1 Larval stage 6.2 Developed stage 6.3 Effects of abnormality 7 Variation among species 8 See also 9 References 10 External links Development

During vertebrate embryonic development the prosencephalon the most anterior of three vesicles that form from the embryonic neural tube is further subdivided into the telencephalon and diencephalon. The telencephalon then forms two lateral telencephalic vesicles which develop into the left and right cerebral hemisphere Hemispheres left side controls right side of body right side controls left side of body Structure

The cerebrum is composed of the following sub-regions: Cerebral cortex or cortices of the cerebral hemispheres Basal ganglia or basal nuclei Limbic System Composition Location of the human cerebrum (red).

The cerebrum comprises what most people think of as the "brain." It lies in front or on top of the brainstem and in humans is the largest and most well-developed of the five major divisions of the brain. The cerebrum is the newest structure in the phylogenetic sense with mammals having the largest and most well-developed among all species. In larger mammals the cerebral cortex is folded into many gyri and sulci which has allowed the cortex to expand in surface area without taking up much greater volume.

In humans the cerebrum surrounds older parts of the brain. Limbic olfactory and motor systems project fibers from the cerebrum to the brainstem and spinal cord. Cognitive and volitive systems project fibers from the cerebrum to the thalamus and to specific regions of the midbrain. The neural networks of the cerebrum facilitate complex behaviors such as social interactions thought judgement learning working memory and in humans speech and language. Functions

Note: As the cerebrum is a gross division with many subdivisions and sub-regions it is important to state that this section lists the functions that the cerebrum as a whole serves. See main articles on cerebral cortex and basal ganglia for more information. Movement

The cerebrum directs the conscious or volitional motor functions of the body. These functions originate within the primary motor cortex and other frontal lobe motor areas where actions are planned. Upper motor neurons in the primary motor cortex send their axons to the brainstem and spinal cord to synapse on the lower motor neurons which innervate the muscles. Damage to motor areas of cortex can lead to certain types of motor neuron disease. This kind of damage results in loss of muscular power and precision rather than total paralysis. Sensory processing

The primary sensory areas of the cerebral cortex receive and process visual auditory somatosensory gustatory and olfactory information. Together with association cortical areas these brain regions synthesize sensory information into our perceptions of the world around us. Olfaction Main article: Olfaction The olfactory bulb in most vertebrates is the most anterior portion of the cerebrum and makes up a relatively large proportion of the telencephalon. However in humans this part of the brain is much smaller and lies underneath the frontal lobe. The olfactory sensory system is unique in the sense that neurons in the olfactory bulb send their axons directly to the olfactory cortex rather than to the thalamus first. Damage to the olfactory bulb results in a loss of the sense of smell. Language and communication Main article: Language Speech and language are mainly attributed to parts of the cerebral cortex. Motor portions of language are attributed to Broca's area within the frontal lobe. Speech comprehension is attributed to Wernicke's area at the temporal-parietal lobe junction. These two regions are interconnected by a large white matter tract the arcuate fasciculus. Damage to the Broca's area results in expressive aphasia (non-fluent aphasia) while damage to Wernicke's area results in receptive aphasia (also called fluent aphasia). Learning and memory Main article: Memory Explicit or declarative (factual) memory formation is attributed to the hippocampus and associated regions of the medial temporal lobe. This association was originally described after a patient known as HM had both his hippocampuses (left and right) surgically removed to treat severe epilepsy. After surgery HM had anterograde amnesia or the inability to form new memories. Implicit or procedural memory such as complex motor behaviors involve the basal ganglia. Cell regeneration in Xenopus laevis Larval stage In a study of the telencephalon conducted in Hokkaido University on African clawed frogs (Xenopus laevis)1 it was discovered that during larval stages the telencephalon was able to regenerate around half of the anterior portion (otherwise known as partially truncated) after a reconstruction of a would-be accident or malformation of features. The regeneration and active proliferation of cells within the clawed frog is quite remarkable regenerated cells being almost functionally identical to the ones originally found in the brain after birth despite the lack of brain matter for a sustained period of time. This kind of regeneration depends on ependymal layer cells covering the cerebral lateral ventricles within a short period before or within the initial stage of wound-healing. This is observed within the stages of healing within larvae of the clawed frog. Developed stage The regeneration within the developed stage of the clawed frog is different from that in the larval stage. Because the cells adhere to one another they are unable to form an entity that can cover the cerebral lateral ventricles. Thus the telencephalon remains truncated and the loss of function becomes permanent. Effects of abnormality After removing over half of the telencephalon in the developed stage of the clawed frog the lack of functions within the animal was apparent manifesting with obvious difficulties in movement nonverbal communication between other species as well as other difficulties thought to be similar to those seen in humans. This kind of regeneration is still relatively unknown in regard to regeneration within larval stages similar to the human fetal stage. Variation among species In the most primitive living vertebrates the hagfishes and lampreys the cerebrum is a relatively simple structure receiving nerve impulses from the olfactory bulb. In cartilaginous and lobe-finned fishes and also in amphibians a more complex structure is present with the cerebrum being divided into three distinct regions. The lowermost (or ventral) region forms the basal nuclei and contains fibres connecting the rest of the cerebrum to the thalamus. Above this and forming the lateral part of the cerebrum is the paleopallium while the uppermost (or dorsal) part is referred to as the archipallium. The cerebrum remains largely devoted to olfactory sensation in these animals despite its much wider range of functions in amniotes.2 In ray-finned fishes the structure is somewhat different. The inner surfaces of the lateral and ventral regions of the cerebrum bulge up into the ventricles; these include both the basal nuclei and the various parts of the pallium and may be complex in structure especially in teleosts. The dorsal surface of the cerebrum is membranous and does not contain any nervous tissue.3 In the amniotes the cerebrum becomes increasingly large and complex. In reptiles the paleopallium is much larger than in amphibians and its growth has pushed the basal nuclei into the central regions of the cerebrum. As in the lower vertebrates the grey matter is generally located beneath the white matter but in some reptiles it spreads out to the surface to form a primitive cortex especially in the anterior part of the brain.4 In mammals this development proceeds further so that the cortex covers almost the whole of the cerebral hemispheres especially in more "advanced" species such as primates. The paleopallium is pushed to the ventral surface of the brain where it becomes the olfactory lobes while the archipallium becomes rolled over at the medial dorsal edge to form the hippocampus. In placental mammals a corpus callosum also develops further connecting the two hemispheres. The complex convolutions of the cerebral surface are also found only in higher mammals.5 The cerebrum of birds has evolved along different lines to that of mammals although they are similarly enlarged by comparison with reptiles. However this enlargement is largely due to the basal ganglia with the other areas remaining relatively primitive in structure. For example there is no great expansion of the cerebral cortex as there is in mammals. Instead an HVC develops just above the basal ganglia and this appears to be the area of the bird brain most concerned with learning complex tasks.6 See also List of regions in the human brain Cerebral cortex Basal ganglia References Levi-Montalcini R. (1949). Proliferation differentiation and degeneration in the spinal ganglia of the chick embryo under normal and experimental conditions. Pages 450502. Yoshino J Tochinai S. Successful reconstitution of the non-regenerating adult telencephalon by cell transplantation in Xenopus laevis. Dev Growth Differ. 2004;46(6):52334. PMID 15610142. Yaginuma H. Tomita M. Takashita N. McKay S. Cardwell C. Yin Q. Aminobuytric acid immunoreactivity within the human cerebral cortex. Pages 481500. Haydar T. F Kuan C. Y. Flavell R. A. & Rakic P. (1999) The role of cell death in regulating the size and shape of the mammalian forebrain. Pages 621626. Romer Alfred Sherwood; Parsons Thomas S. (1977). The Vertebrate Body. Philadelphia PA: Holt-Saunders International. pp. 536543. ISBN 0-03-910284-X.  External links Cerebrum Medical Notes on rahulgladwin.com NIF Search - Cerebrum via the Neuroscience Information Framework v d eNervous system (TA A14 GA 9) Central nervous system Meninges Spinal cord Brain: Rhombencephalon (Medulla oblongata Pons Cerebellum)  Mesencephalon  Prosencephalon (Diencephalon Telencephalon) Peripheral nervous system Somatic Sensory nerve  Motor nerve  Cranial nerves  Spinal nerves Autonomic Sympathetic  Parasympathetic  Enteric nervous system M: CNS anat(n/s/m/p/4/e/b/d/c/a/f/l/g)/phys/devp noco(m/d/e/h/v/s)/cong/tumr sysi/epon injr proc drug(N1A/2AB/C/3/4/7A/B/C/D) M: PNS anat(h r t c b l s)/phys/devp/prot/nttr/nttm/ntrp noco/auto/cong/tumr sysi/epon injr proc drug(N1B) v d eHuman brain: forebrain (cerebrum  cerebral cortex  cerebral hemispheres grey matter) (TA A14.1.09.002240 301320 GA 9.818826) Frontal lobe Superolateral Prefrontal Superior frontal gyrus (4l 6l 8l)  Middle frontal gyrus (9l 10l 46) Inferior frontal gyrus: 11l  47-Pars orbitalis  Broca's area (44-Pars opercularis 45-Pars triangularis) Superior frontal sulcus  Inferior frontal sulcus Precentral Precentral gyrus  Precentral sulcus Medial/inferior Prefrontal Superior frontal gyrus (4m 6m)  Medial frontal gyrus (8m 9m) Paraterminal gyrus/Paraolfactory area (12)  Straight gyrus (11m)  Orbital gyri/Orbitofrontal cortex (10m 11m 12)  Ventromedial prefrontal cortex (10m)  Subcallosal area (25) Olfactory sulcus  Orbital sulci Precentral Paracentral lobule (4)  Paracentral sulcus Both Primary motor cortex (4)  Premotor cortex (6)  Supplementary motor area (6)  Frontal eye fields (8) Parietal lobe Superolateral Superior parietal lobule (5l 7l)  Inferior parietal lobule (40-Supramarginal gyrus 39-Angular gyrus)  Parietal operculum (43) Intraparietal sulcus Medial/inferior Paracentral lobule (1m 2m 3m 5m)  Precuneus (7m) Marginal sulcus Both Postcentral gyrus/primary somatosensory cortex (1  2  3)  Secondary somatosensory cortex (5)  Posterior parietal cortex (7) Occipital lobe Superolateral Occipital pole of cerebrum  Lateral occipital gyrus (18 19)  Lunate sulcus  Transverse occipital sulcus Medial/inferior Primary visual cortex (17)  Cuneus  Lingual gyrus Calcarine fissure Temporal lobe Superolateral Transverse temporal gyrus/Primary auditory cortex (41 42)  Superior temporal gyrus (38 22/Wernicke's area)  Middle temporal gyrus (21)  Inferior temporal gyrus (20) Superior temporal sulcus  Inferior temporal sulcus Medial/inferior Fusiform gyrus (37) Medial temporal lobe (27  28  34  35  36) Inferior temporal sulcus Interlobar sulci/fissures Superolateral Central (frontal+parietal)  Lateral (frontal+parietal+temporal)  Parieto-occipital  Preoccipital notch Medial/inferior Medial longitudinal  Cingulate (frontal+cingulate)  Collateral (temporal+occipital)  Callosal sulcus Limbic lobe Parahippocampal gyrus anterior (Entorhinal cortex Perirhinal cortex)  Posterior parahippocampal gyrus  Prepyriform area Cingulate cortex/gyrus Subgenual area (25)  Anterior cingulate (24 32 33)  Posterior cingulate (23 31) Isthmus of cingulate gyrus: Retrosplenial cortex (26 29 30) Hippocampal formation Hippocampal sulcus  Fimbria of hippocampus  Dentate gyrus  Rhinal sulcus Other Supracallosal gyrus  Uncus Insular lobe Long gyrus of insula  Short gyri of insula  Circular sulcus of insula General Operculum  Poles of cerebral hemispheres Some categorizations are approximations and some Brodmann areas span gyri. M: CNS anat(n/s/m/p/4/e/b/d/c/a/f/l/g)/phys/devp noco(m/d/e/h/v/s)/cong/tumr sysi/epon injr proc drug(N1A/2AB/C/3/4/7A/B/C/D) v d eHuman brain cerebrum Interior of the cerebral hemispheres white matter: commissural fibers and septum (TA A14.1.09.241271 569571 GA 9.828 838840) Corpus callosum Genu  Splenium  Tapetum  Rostrum Archicortex: Indusium griseum Lamina terminalis Organum vasculosum of the lamina terminalis  Anterior commissure Fornix Columns of fornix  Crus of fornix  Commissure of fornix Septum pellucidum Septal nuclei (Medial septal nucleus Subfornical organ)  Cave of septum pellucidum M: CNS anat(n/s/m/p/4/e/b/d/c/a/f/l/g)/phys/devp noco(m/d/e/h/v/s)/cong/tumr sysi/epon injr proc drug(N1A/2AB/C/3/4/7A/B/C/D) v d eHuman brain cerebrum Interior of the cerebral hemispheres: Lateral ventricles (TA A14.1.09.272287 GA 9.829831) Ventricular system: Lateral ventricles Anterior horn Body: Lamina affixa  Stria terminalis  Collateral eminence Posterior horn: Calcar avis Inferior horn M: CNS anat(n/s/m/p/4/e/b/d/c/a/f/l/g)/phys/devp noco(m/d/e/h/v/s)/cong/tumr sysi/epon injr proc drug(N1A/2AB/C/3/4/7A/B/C/D) v d eHuman brain cerebrum Interior of the cerebral hemispheresRostral Basal ganglia and associated structures (TA A14.1.09.321552 GA 9.832837) Basal ganglia Grey matter Corpus striatum striatum: Putamen  Caudate nucleus lentiform nucleus: Putamen  Globus pallidus (GPe GPi) Ventral striatum Nucleus accumbens  Olfactory tubercle  Islands of Calleja Other Amygdala  Claustrum White matter Semioval center Internal capsule (Anterior limb  Genu  Posterior limb Optic radiation) Corona radiata  External capsule  Extreme capsule Pallidothalamic tracts: Thalamic fasciculus (Ansa lenticularis Lenticular fasciculus)  Subthalamic fasciculus Rhinencephalon Grey matter Anterior olfactory nucleus  Anterior perforated substance  Olfactory bulb White matter Olfactory tract (Medial olfactory stria Lateral olfactory stria)  Olfactory trigone Other basal forebrain Grey matter Substantia innominata (Basal optic nucleus of Meynert)  Nucleus of diagonal band White matter Diagonal band of Broca  Stria terminalis Archicortex: Hippocampal formation/ Hippocampus anatomy Grey matter Hippocampus proper: CA1  CA2  CA3  CA4 Dentate gyrus: Fascia dentata Subiculum White matter Alveus  Fimbria  Perforant path  Schaffer collateral M: CNS anat(n/s/m/p/4/e/b/d/c/a/f/l/g)/phys/devp noco(m/d/e/h/v/s)/cong/tumr sysi/epon injr proc drug(N1A/2AB/C/3/4/7A/B/C/D) v d eHuman brain cerebrum white matter: Association fibers (TA A14.1.09.553569 GA 9.843) Association fibers Uncinate fasciculus  Cingulum  Superior longitudinal fasciculus/Arcuate fasciculus  Inferior longitudinal fasciculus  Inferior occipitofrontal fasciculus M: CNS anat(n/s/m/p/4/e/b/d/c/a/f/l/g)/phys/devp noco(m/d/e/h/v/s)/cong/tumr sysi/epon injr proc drug(N1A/2AB/C/3/4/7A/B/C/D) ur