Telencephalon (Cerebral Hemisphere)
OUTLINE The Cortex - Lobes, Sulci & Gyri - Functional Subdivisions - Limbic Lobe & Limbic System The Subcortex - Basal Ganglia - White Matter (Internal Capsule) - Relations of Lateral Ventricle
The Location of Telencephalon Cerebral Falx & Cerebellar Tentorium
Longitudinal Fissure Development & Overview Lateral Fissure
External Features frontal lobe parietal lobe temporal lobe occipital lobe insular lobe longitudinal fissure lateral fissure central sulcus parieto-occipital sulcus
Corpus Callosum rostrum, genu, trunk & splenium Insular Lobe Lateral Fissure Central Sulcus Parieto-occipital Sulcus
IMPOTRANT Sulci & Gyri of Cerebral Hemisphere (Lateral Aspect)
IMPOTRANT Sulci & Gyri of Cerebral Hemisphere (Medial Aspect)
precentral gyrus postcentral gyrus superior, middle & inferior frontal gyri Lateral Aspect intraparietal sulcus: - superior parietal lobule - inferior parietal lobule (supramarginal & angular gyri)
Medial Aspect paracentral lobule cingulate gyrus corpus callosum cuneus precuneus parahippocampal gyrus uncus lingual gyrus
short gyri of insula: - anterior, middle & posterior gyri Insular central sulus of insula Lobe long gyri of insula: - anterior (superior) & posterior (inferior) gyri Transverse Temporal Gyrus (Transverse Gyri of Heschl)
The Cerebral Cortex
Normal & Alzheimer s The Cerebral Cortex Histological Layers
Brodmann s Map
Primary Somatomotor Area Primary Somatosensory Area Visual Area Auditory Area Gustatory Area Gustatory Area & Olfactory Area
postcentral gyus & posterior portion of paracentral lobe receives sensory information from contralateral somatic sensroy organs Primary SomatoSensory Cortex Motor Association Area Primary Somatomotor Cortex precentral gyus & anterior portion of paracentral lobe controls contralateral movements
Primary Somatomotor Cortex & Primary Somatosensory Cortex
Visual Cortex calcarine sulcus & (stria of gennari)
Auditory Cortex transverse temporal gyrus Gustatory Cortex inferior portion of postcentral gyus uncus & insula (olfactory area)
Conscious Motor & Sensory Cortexes & Association Areas
motor speech area (Broca s area): talk The Speech Areas writing speech center (cheirokinesthetic center): write the speech areas are located in the dominant hemisphere (usually the left one of right-handed individuals) sensory speech areas visual speech area: read auditory speech area: hear
Wernicke s area (auditory speech area): - supramarginal gyrus visual speech area: - angular gyrus Arcuate Fasciculus Broca s area (motor speech area): - posterior part of inferior frontal gyrus writing speech center: - posterior part of middle frontal gyrus
Speech Areas & their Functional Related Areas Areas of Increased Cortical Blood Flow during Reading Aloud
Hippocampus Limbic Lobe & Limbic System Limbic Lobe on the medial wall of the hemisphere, principally the subcallosal, cingulate and parahippocampal gyri Limbic System limbic lobe, hippocampus, fornix, dentate gyrus & amygdala
Corpus Callosum Fornix & Dentate Gyrus Hippocampus
Hippocampus & Parahippocampal Gyrus
Relations of Fornix, Hippocampus, Parahippocampal Gyrus & Lateral Ventricle
Coronary Section through Hippocampus
Limbic System & its Function Main Functions emotional brain memory visceral action olfactory reflex
Parahippocampal Gyrus Hippocampus The Papez Circuit Fornix Mamillary Bodies memory formation emotions Anterior Thalamic Nuclei Cigulate Gyrus
olfactory bulb & tract gyrus rectus olfactory sulcus Inferior Aspect of the Brain (right temporal pole has been displaced laterally) Orbital Gyri Olfactory Triangle & Anterior Perforated Substance
The Subcortex of Cerebrum basal nuclei white matter Internal Capsule lateral ventricle
Locations of Basal Nuclei & Thalamus caudate nucleus lentiform nucleus - putamen - globus pallidus amygdaloid body claustrum The Basal Nuclei / Ganglia masses of gray matter found deep within the white matter components of the extrapyramidal system
Basal Nuclei & Thalamus Basal Ganglia Corpus Striatum Amygdala Neostriatum (Striatum) Paleostriatum Caudate Nucleus Putamen Globus Pallidus Lentiform Nucleus
Case horizontal MRI slice at the level of the corpus striatum from a 2-year-old girl suffering from severe choreoathetosis as a result of intrauterine damage to her basal ganglia by toxoplasmosis Overview of Basal Nuclei Projections all regions of cerebral cortex project to the basal nuclei output of basal ganglia is directed towards the frontal lobe, particularly, pre-motor & supplementary motor cortex no direct projections to spinal cord
Projections & Functions of Basal Nuclei assist the pattern & rhythm of movement regulate the movement - influence muscle activity (muscle tone) - inhibit antagonistic and unnecessory movement regulate attention & cognition
White Matter Internal Capsule commissural fibers association fibers (long & short) projection fibers
connect the left & right cerebral hemispheres Commissural Fibers corpus callosum ant. commissure post. commissure fornix / hippocampal commissure interthalamic adhesion
Association Fibers short association fibers (U fibers) long association fibers superior longitudinal fasciculus inferior longitudinal fasciculus perpendicular fasciculus uncinate fasciculus cingulum
Association Fibers ARC: arcuate fasciculus; CLA: claustrum; CR: corona radiata; HRZ: horizontal segment; IFO: inferior fronto-occipital fasciculus; ILF: inferior longitudinal fasciculus; PT: putamen; AR: auditory radiation; SLF: superior longitudinal fasciculus; SS: sagittal stratum; UNC: uncinate fasciculus; U: U fibers; GCT: geniculocalcarine tract; CST: corticospinal tract; PP = parietopontine fibers; FP = frontopontine fibers
Projection Fibers & Internal Capsule ascending and descending fibers conveying impulses to and from the entire cortex of cerebral hemisphere are called projection fibers
the projection fibers a compact band Internal Capsule medially: caudate nuc. & thalamus laterally: lentiform nuc.
Internal Capsule
Internal Capsule ant. limb post. limb genu
Conscious Tracts anterior limb genu - corticobulbar / corticonuclear tract posterior limb - corticospinal tract (motor) - thalamocortical fibers / center thalamic radiations (sensory) - optic radiations - auditory radiations Subconscious Tracts anterior limb: frontopontine tract, anterior thalamic radiation posterior limb: parietooccipitotempropontine fibers / corticopontine fibers
Arrangement of Posterior Limb Descending fibers: face, arm & leg (F, A, L) Ascending fibers: face, arm & leg (f, a, l)
Damage to Internal capsule CLINICAL NOTE Arterial Supply to Internal Capsule
Limbs & Genu of Internal Capsule
Cerebral Ventricles Development & Overview
a pair of C-shaped lateral ventricles third ventricle lies between two diencephalons fourth ventricle exists dorsally to the pons Ventricles of the Brain Interventricular Foramen & Cerebral Aqueduct Septum Pellucidum
Lateral Ventricle 3 horns: - anterior / frontal, - posterior / occipital - inferior / temporal ventricular body
Important Relations of Lateral Ventricle
Sections through the Lateral Ventricle thalamus nuclei basal nuclei hippocampus Amygdala interventricular foramen third ventricle cerebral aquduct