ANATOMY OF CEREBRAL CORTEX LEVY MWANAWASA MEDICAL UNIVERSITY

About the cerebrum and the cerebral cortex

1. INTRODUCTION TO NEUROANATOMY & ANATOMY OF CEREBRAL CORTEX DR.P.PRAVEEN KUMAR LAMU

2. NEUROANATOMY • Study of morphological aspect of nervous system • NERVOUS SYSTEM • Central nervous system (CNS) • Peripheral nervous system (PNS) GROUP OF NEURONS • NUCLEUS – CNS • GANGLION – PNS GROUP OF FIBERS • TRACT – CNS • NERVE – PNS

3. DIVISIONS OF CENTRAL NERVOUS SYSTEM Central Nervous System • Brain o Brain stem – medulla, pons, midbrain o Diencephalon – thalamus & hypothalamus o Cerebellem o Cerebrum • Spine o Spinal Cord

4. PARTS OF BRAIN

5. DIVISIONS OF FORE BRAIN PARTS OF PROSENCEPHALON • Telencephalon – cerebrum • Diencephalons – Thalamus Hypothalamus Epithalamus Subthalamus Cerebrum – conscious activity including perception, emotion, thought, and planning Thalamus – Brain’s switchboard – filters and then relays information to various brain Hypothalamus – involved in regulating activities internal organs, monitoring information from the autonomic nervous system, controlling the pituitary gland and its hormones, and regulating sleep and appetite

6. BASIC STRUCTURAL ORGANISATION GREY MATTER – CELL BODIES OF NEURONS DENDRITES (PART CLOSE TO CELL) AXONS (PART CLOSE TO CELL) WHITE MATTER – MYELINATED AXONS NEUROGLIAL CELLS Blood vs. are seen in both

7. CEREBRUM Cerebrum • Is the largest portion of the brain encompasses about two-thirds of the brain mass – • It consists of two hemispheres divided by a fissure – corpus callosum • It includes the cerebral cortex, the medullary body, and basal ganglia • cerebral cortex is the layer of the brain often referred to as gray matter because it has cell bodies and synapses but no myelin o The cortex (thin layer of tissue) is gray because nerves in this area lack the insulation or white fatty myelin sheath that makes most other parts of the brain appear to be white . o The cortex covers the outer portion (1.5mm to 5mm) of the cerebrum and cerebellum o The cortex consists of folded bulges called gyri that create deep furrows or fissures called sulci o The folds in the brain add to its surface area which increases the amount of gray matter and the quantity of information that can be processed • Medullary body – is the white matter of the cerebrum and consists of myelinated axons o Commisural fibers – conduct impulses between the hemispheres and form corpus callosum o Projection fibers – conduct impulse in and out of the cerebral hemispheres o Association fibers – conduct impulses within the hemispheres • Basal ganglia – masses of gray matter in each hemisphere which are involved in the control of voluntary muscle movements

8. The cerebral cortex is the site of the highest order integration of sensory, motor and consciousness activities. Source Undetermined

9. Neocortex (90%) Meso- and Allo-cortex (10%) Source Undetermined

10. Lobes of the Cerebrum • Frontal – motor area involved in movement and in planning & coordinating behavior • Parietal – sensory processing, attention, and language • Temporal – auditory perception, speech, and complex visual perceptions • Occipital – visual center – plays a role in processing visual informatio

11. cerebellum Lateral fissure Temporal lobe Occipital lobe Central sulcus Parietal lobe Frontal lobe brainstem The cerebral hemispheres are divided into lobes: cortex and underlying white matter Source Undetermined

12. Association cortical areas surround the primary cortical areas, and can be divided into unimodal and multimodal regions. Unimodal association cortex relates to a single primary region only, whereas multimodal cortex intergrates information relating to multiple primary and unimodal regions. Source Undetermined

13. Cingulate gyrus Cingulate sulcus Calcarine sulcus Parieto-occipetal fissure Lingual gyrus Cuneate gyrus Further anatomical subdivisions of the medial surface of the cerebral hemisphere Source Undetermined

14. This dissected brain illustrates projection fibers, that innervate subcortical targets, e.g., thalamus, brainstem and spinal cord. corona radiata internal capsule Projection Fibers Source Undetermined

15. The corpus callosum is the largest of the two structures that contain commissural fibers. corpus callosum commissural fibers Commissural fibers interconnect both homologous and heterologous areas of the two hemispheres. Commissural Fibers Source Undetermined

16. CORPUS CALLOSUM splenium body genu ANTERIOR COMMISURE rostrum Commissural Fibers Source Undetermined

17. Regional cerebral blood flow - 0.5% difference in blood flow Language mapping in normal volunteers Imaging electrical activity in the brain with fMRI Source Undetermined Source Undetermined