Diencephalon: position & division (5parts) It lies between cerebrum & midbrain. The narrow space between the left & right diencephalons is the 3 rd ventricle. Dorsal thalamus is used as a center for judging the positions of the rest components of diencephalon. The part anteroinferior to it is hypothalamus;the portion behind it is metathalamus; the anterio--- posteriorly going & continuous structure superior to it is epithalamus,and the structure inferior to it (its base connecting midbrain) is subthalamus. Guo Ling, MD, PhD Department of Anatomy

Internal Structure of Thalamus Ventroposteriolateral nucleus(VPLN) is to relay the superficial and deep sensation informations from neck, trunk & limbs to the superior 2/3 part of the first sensory area(FSA) in crebrum. Ventroposteriomedial nucleus(VPMN) is to transmit facial sensation informations (including taste ) to the inferior 1/3part of FSA Smell information is not sent to the center through diencephophalon, but it is directly delivered to the gustatory area in cerebrum.

Ventral posteromedial N Ventral posterolateral N (Dorsal) Thalamus ( right ) Mediodorsal N Ant.nucleus group Medial geniculate body Lateral geniculate body

Thalamic Nuclei of Specific Afferents

Epithalamus thalamic medullary stria habenular trigone(nucleus) habenular commissure pineal body medial geniculate body lateral geniculate body Metathalamus Both contain the two nuclei relaying informations of sound and light(&color), respectively.

Subthalamus (subthalamic nucleus connecting the tegmentum of midbrain ) Hypothalamus External features (front to back) optic chiasma cinereous tuber mamillary body

Internal Structure of Hypothalamus supraoptic nucleus paraventricular nucleus infundibular(arcuate) nucleus supraopticochiasmatic nucleus Internal 4 nuclei& 3 tracts

Infundibular nucleus

Target tissue

Telencephalon ( rhinencephalon & 2 cerebral hemispheres ) sulcus -----downfolds on the surface of cerebra gyrus upfolds (appearance in 7-month-old fetus ) CEREBRUM

Front pole Occipital poleTemporal pole Dorsolateral surface Inf.surface Medial surface DIVISION 2 surfaces, 3 sulci 3 poles & 5 lobes

Cerebral Hemisphere :five lobes frontal lobe parietal lobe occipital lobe insula temporal lobe insula in

Four Gyri in Frontal Lobe precentral gyrus superior frontal gyrus middle frontal gyrus inferior frontal gyrus

Three Gyri &Two Lobules in Parietal Lobe postcentral gyrus, superior parietal lobule, inferior parietal lobule, supramarginal gyrus angular gyrus

superior temporal gyrus, middle temporal gyrus, inferior temporal gyrus, trasverse temporal gyrus. Four Gyri in Temporal Lobe

2 Gyri,2 Lobules,3 Sulci,1 Fornix,1 Septum & 1 Callosum in Medial Surface corpus callosum, fornix, cingulate gyrus, parahippocampal gyrus, transparent septum, cingulate sulcus, parietooccipital sulcus, calcarine sulcus, anterior part oparacentral lobule, posterior part of paracentral lobule.

olfactory bulb olfactory tract olfactory trigone anterior perforated substance Inferior Surface

cingulate gyrus parahippocampal gyrus uncus hippocampus dentate gyrus Limbic Lobe dentate gyrus Hippocampus Uncus Parahippocampal gyrus Cingulate gyrus

Functional Localization of Cerebral Cortex ( Brodmann`s map areas ) Primary motor area(areas 4, 6 ): precentral gyrus & anterior part of paracentral lobule

Functional Features of Primary Motor Area 1) Cross control 2) “upsidedown” control 3) paralysis following injury ( Skeletal muscles lose the ability to move voluntarily )

General sensory area : postcentral gyrus & posterior part of paracentral lobule

Functional Features of General Sensory Area 1) cross projection 2)“upsidedown” projection 3) lack of sensation after injury

Auditory area ( 41, 42 ): transverse temporal gyrus deafness after injury

Visual area(17): cortex on both sides of calcarine sulcus, blidness after injury

Language areas lie in the dominant (left) hemisphere and are 5 unique anatomical units for manipulating human languages. The animal cortex has no such areas. (Broca area) Motor speech area Writing area Visual language area Auditory language area

Internal Structures of Cerebral Hemispheres Cortex(surface pallium):6 layers of nerve cells(neocortex),3 layers ( paleocortex / archicortex ).26 billion neurons ， no new neuron increase after birth.

52 areas of Brodmann(1909):dorsolateral surface

52 areas of Brodmann (1909):medial surface

Internal Structure : imbedded deep in cerebrum basal nucleus & medulla Corpus striatum Basal nucleus (ganglia) (1)caudate nu (2)lentiform nu putamen globus pallidus (3)amygdaloid body (4)claustrum

a.Association fibers connect one cortex area with another only in one hemisphere(R/L). b.Commissural fibers connect the left hemispheric cortex with the right one. c.Projection fibres work as a connecting bridge between the cerebral cortex and subcortic structures Medulla--White matter consists of 3 kinds of nervous fibers.

Association Fibers (4 tracts ) superior longitudinal fasciculus arcuate fibers cingulum uncinate fasculus,

Commissural Fibres (4 tracts ) corpus callosum ant. & post. commissures fornix

Internal capsule is a gate to the passaage of projection fibers and is imbedded among dorsal thalamus,caudate & lentiform nuclei. head face upper limb Low limb acoustic radiation optic radiation Precentral gyrus 1.Composition & Position of Internal Capsule

2.DIVISION anterior limb genu posterior limb

ant. thalamic radiation frontopontine tract corticonuclear tract corticospinal tract central thalamic radiation optic radiation parieto-occipito-tempora-pontine tract acoustic radiation 3.Fiber Tracts Passing Internal Capsule

(lateral view)

1)Muscular paralysis on the opposite half side of body 2)Impairment of general sensation on opposite half side of body 3)Blindness on opposite half side of visual field 4.Typical Signs Following Injury 3 Opposite Symptoms

Ventricular System & Its Communication Left and right lateral ventricles  (interventricular  foramen) Third ventricle  (mesencephalic  aqueduct) Fourth ventricle  (median and lateral apertures of  fourth ventricle) Subarachnoid space