CEREBRUM & CEREBRAL CORTEX Seonghan Kim Dept. of Anatomy Inje University, College of Medicine
THE BRAIN ANATOMICAL REGIONS A. Cerebrum B. Diencephalon Thalamus Hypothalamus C. Brain Stem Midbrain Pons Medulla oblongata D. Cerebellum
MAJOR&ANATOMICAL®IONS&OF&THE&BRAIN&& Cerebrum& Diencephalon& Brain&Stem& Cerebellum&
The Cerebral Hemispheres and lobes 13 Figure 13.7b, c
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The Cerebral Hemispheres and lobes 14 Central sulcus Lateral sulcus! The FRONTAL LOBE and PARIETAL LOBE are separated by the CENTRAL SULCUS.! The TEMPORAL LOBE is between the parietal and frontal lobe, separated by the LATERAL SULCUS.! The OCCIPITAL LOBE does not have a real border; it s just a region.! These are the anatomical areas, but the functional areas are more important.
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! The CORPUS CALLOSUM is the area that connects the right and left halves of the brain. CORPUS CALLOSUM 16
Sheep brain Corpus callosum 17
This is the area that is responsible for the right half of the brain communicating with the left half of the brain. If the corpus callosum was cut, there would be no communication between the right and left halves of the brain. Autism is a neurological disease that includes problems with communication between the right and left cerebral hemispheres.
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INSIDE of CEREBRAL HEMISPHERE Cerebral cortex with gray matter Consists with lateral ventricle, basal ganglia, and nerve fibers which forms the white matter
White matter myelinated nerve fibers with glial cells Commissural fibers Association fibers Projection fibers
Commissural fibers - corpus callusum - anterior commissure - posterior commissure - fornix - habenacular commissure
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Association fibers short and long fibers long asso. fibers - cingulum - sup. longitudinal fasciulus - inf. longitudinal fasciculus - fronto-occipital fasciculus
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Projection fibers internal capsule; compact and flat white matter - anterior limb, posterior limb, genu - corona radiata - optic radiation
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Diencephalon
Diencephalon 1. Thalamus - process sensory information - major relay station for sensory impulse to cerebrum 2. Hypothalamus - make hormones which maintain the homeostasis of the body 3. Subthalamus 4. Epithalamus; Habenular nucleus, Pineal gland
Sits on the top of the brain stem Enclosed by the cerebral hemisphere Exposed only to the lower part
25 Figure 13.15
Thalamus 27 Hypothalamus Pituitary gland 28 Thalamus Hypothalamus Pituitary gland
Thalamus Gateway to cerebral cortex Most sensory stimuli project to the thalamus, which in turn project to the cerebrum Thalamus also influences moods and activities associated with strong emotion. Sensory integration Transfer impulses to the correct part of the cortex for localization and interpretation
HYPOTHALAMUS Under the thalamus Important autonomic nervous system center - helps regulates body temperature - controls water balance - regulates metabolism An important part of the limbic system (emotions) The pituitary gland is attached to the hypothalamus Endocrine system; hormone secretion
The hypothalamus synthesizes and secretes hormones, and these in turn stimulates or inhibits the secretion of pituitary hormones By secretion of hormones, the hypothalamus controls blood pressure, body temperature, hunger, thirst, fatigue, sleep, autonomic nervous reflexes, and circadian cycles.
Subthalamus Localizes inferior part of thalamus, adjacent to hypothalamus at anterior and medial parts red nucleus, substantia nigra connects to the corpus striatum and involves in muscular regulation
EPITHALAMUS Forms the roof of the third ventricle Consists of pineal body and Habenacular nucleus House the pineal body (pineal gland); an endocrine gland Includes choroid plexus - forms cerebrospinal fluid
PINEAL BODY (PINEAL GLAND) Consists of pinealocyte and glial cell The PINEAL BODY secretes melatonin. How much it secretes depends on the sensory information it receives from the eyes about how many hours of daylight are present. The amount of melatonin secreted and circulating in the blood then determines the circadian rhythm, or the 24- hour biological clock (cycles influenced by light). Therefore, the pineal body detects the number of hours of light and dark, and sets the body s 24-hour clock.
Endocrine organ for the regulation of the activities of parathyroid gland, adrenal gland, gonad, islet of LAngerhans
Pineal body Thalamus 51 52 Pineal body
ALZHEIMER S DISEASE
Functional Localization of Cerebral Cortex
Brodmann area
Brodmann areas for human & non-human primates Areas 3, 1 & 2 - Primary Somatosensory Cortex (frequently referred to as Areas 3, 1, 2 by convention) Area 4 - Primary Motor Cortex Area 5 - Somatosensory Association Cortex Area 6 - Premotor cortex and Supplementary Motor Cortex (Secondary Motor Cortex)(Supplementary motor area) Area 7 - Somatosensory Association Cortex Area 8 - Includes Frontal eye fields Area 9 - Dorsolateral prefrontal cortex Area 10 - Anterior prefrontal cortex (most rostral part of superior and middle frontal gyri) Area 11 - Orbitofrontal area (orbital and rectus gyri, plus part of the rostral part of the superior frontal gyrus) Area 12 - Orbitofrontal area (used to be part of BA11, refers to the area between the superior frontal gyrus and the inferior rostral sulcus) Area 13 and Area 14 * - Insular cortex Area 15 * - Anterior Temporal Lobe Area 17 - Primary visual cortex (V1) Area 18 - Secondary visual cortex (V2) Area 19 - Associative visual cortex (V3,V4,V5) Area 20 - Inferior temporal gyrus Area 21 - Middle temporal gyrus Area 22 - Superior temporal gyrus, of which the caudal part is usually considered to contain the Wernicke's area Area 23 - Ventral Posterior cingulate cortex Area 24 - Ventral Anterior cingulate cortex. Area 25 - Subgenual cortex (part of the Ventromedial prefrontal cortex)[4] Area 26 - Ectosplenial portion of the retrosplenial region of the cerebral cortex Area 27* - Piriform cortex
Area 28 - Posterior Entorhinal Cortex Area 29 - Retrosplenial cingulate cortex Area 30 - Part of cingulate cortex Area 31 - Dorsal Posterior cingulate cortex Area 32 - Dorsal anterior cingulate cortex Area 33 - Part of anterior cingulate cortex Area 34 - Anterior Entorhinal Cortex (on the Parahippocampal gyrus) Area 35 - Perirhinal cortex (on the Parahippocampal gyrus) Area 36 - Parahippocampal cortex (on the Parahippocampal gyrus) Area 37 - Fusiform gyrus Area 38 - Temporopolar area (most rostral part of the superior and middle temporal gyri) Area 39 - Angular gyrus, considered by some to be part of Wernicke's area Area 39 - Angular gyrus, considered by some to be part of Wernicke's area Area 40 - Supramarginal gyrus considered by some to be part of Wernicke's area Areas 41 & 42 - Primary and Auditory Association Cortex Area 43 - Primary gustatory cortex Area 44 - pars opercularis, part of Broca's area Area 45 - pars triangularis Broca's area Area 46 - Dorsolateral prefrontal cortex Area 47 - Inferior prefontal gyrus Area 48 - Retrosubicular area (a small part of the medial surface of the temporal lobe) Area 49 - Parasubiculum area in a rodent Area 52 - Parainsular area (at the junction of the temporal lobe and the insula) (*) Area only found in non-human primates.
CORTEX AND ASSOCIATION AREAS! Each area of the brain has a region where the sensory information comes in, and another area where the information is understood.! The area where the information comes in is a cortex, and the area where it is understood is the association area.! Therefore, there will be a visual cortex and association area, an auditory cortex and association area, and a somatic (sense of touch) cortex and association area. There is also a motor cortex and association area.
Func%onal)and)Structural)Areas)of)the) Cerebral)Cortex) Figure 13.11a 60
Pre-Central Gyrus! Within the primary motor area of the brain, there is a structure called the pre-central gyrus which contains a precise map of the different body parts.! This map is called a motor homunculus (Latin: little man)! All the neurons that innervate the lips would have their cell bodies in one particular region in this area. All the neurons that innervate the hands have their cell bodies in this area. All those that innervate the back have their cell bodies here.! However, we don t have as many neurons innervating the back as we do for the lips and hands.! The homunculus is drawn to represent how many neuron cell bodies we have that innervate each region of our body.
! Not all body parts are equally represented by cell density in the motor area in proportion to their size in the body.! Lips, parts of the face and hands are drawn large because there are many cells in the motor area that innervate those regions of the body.! The face region of the homunculus is large so we can have many facial expressions. The hands and tongue are large, indicating that we have many fine motor skills in those areas as well.! There is also a somatosensory homunculus.
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Accepted depiction of the homunculus 85 Perhaps this is a more accurate depiction of the homunculus?
Cortical area Frontal lobe - Abundant pyramidal cell with seldom granular layer - precentral area; sup. frontal gyrus, inf. frontal gyrus, middle frontal gyrus - premotor area (secondary motor area)/motor area (primary motor area) - supplementary motor area - frontal eye field; conjugate eye movement - motor speech area of Broca; nondominant hemisphere
prefrontal cortex; broad area connecting other cerebral cortex, hypothalamus, thalamus, corpus striatum, cerebellum - involved in the formation of personality and the deepness of emotions - affect personal creativity and decision
Parietal lobe - primary somesthetic area - the area of cortex is related to the numbers of sensory receptors - secondary somesthetic area
Occipital area - primary visual area - secondary visual area; surround pri. vis. area - occipital eye field; conjugate deviation, eye reflex
Temporal lobe - primary auditory area - secondary auditory area - sensory speech area of Wernicke; gateway of somesthetic, visual, and auditory
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taste area vestibular area ; posture, space, motor insula; not much known, phrasing? Association cortex
Cerebral domninance - hemisphere-dominance; - dmoninat hemisphere; handedness, speech, linguistics - non-dominant hemisphere; space recognition, face recognition, musicality
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