The document discusses the embryology of the brain, including: - The formation of the neural tube and its subdivisions into primary brain vesicles. - The development of the medulla, pons, midbrain, cerebellum, and cerebral hemispheres from the brain vesicles. - The formation of structures within each brain region like the cranial nerve nuclei in the medulla and pons. - The timeline of important developmental events from the formation of the neural plate to myelination.

1. DEPT OF NEUROLOGY, KING GEORGE HOSPITAL, VIZAG. EMBRYOLOGY OF THE BRAIN

2. EMBRYOLOGY OF THE BRAIN The neural tube and its subdivisions The neural crest Histological components of the CNS Development of medulla oblongata Development of pons Development of the midbrain Development of the cerebellum Development of the cerebral hemispheres

3. THE NEURAL TUBE AND ITS SUBDIVISIONS

4. FORMATION OF THE NEURAL TUBE

5. PRIMARY BRAIN VESICLES &THEIR SUB DIVISIONS

6. FLEXURES OF NEURAL TUBE

7. DEVELOPMENT OF EXTERNAL FORM OF BRAIN

8. DEVELOPMENT OF VENTRICLES OF BRAIN

9. THE NEURAL CREST

10. DERIVATIVES OF THE NEURAL CREST

11. HISTOLOGICAL COMPONENTS OF THE CNS

12. Layers Of Neural Tube Formation Of Neuroblast

13. DEVELOPMENT OF THE MEDULLA

15. Roof plate widens

16. Sulcuslimitansdivides Dorsal(lateral) alar lamina- caudal bulbopontine extension olivary nuclei Sensory nuclei of cranial n of medulla Ventral(medial) basal lamina- Motor nuclei of cranial n of medulla DEVELOPMENT OF MEDULLA OBLONGATA

17. CRANIAL NERVE NUCLEI OF MEDULLA OBLONGATA

18. MOTOR & SENSORY NUCLEI OF MEDULLA OBLONGATA

19. DEVELOPMENT OF THE PONS

21. Cranial bulbopontine extensionpontine nuclei

22. Axons of bulbopontine extensionMiddle cerebellar peduncle

23. Alar and basal laminacranial n nuclei

25. DEVELOPMENT OF MEDULLA&PONS

26. CRANIAL NERVE NUCLEI OF PONS

27. MOTOR &SENSORY CRANIAL NERVE NUCLEI OF THE PONS

28. DEVELOPMENT OF THE MIDBRAIN

32. Metencephalon

33. Cells migrate from mantle -marginal layerCortex

35. Middle- axons from pontine nuclei into cerebellum

37. DEVELOPMENT OF CEREBRAL HEMISPHERE

38. CEREBRAL HEMISPHERE&LATERAL VENTRICLE

39. FORMATION OF CHOROID FISSURE

40. FORMATION OF TELACHOROIDEA &CHOROID PLEXUS

41. DEVELOPMENT OF THALAMUS &HYPOTHALAMUS

42. EARLY DEVELOPMENT OF CORPUS STRIATUM

43. DEVELOPMENT OF CORPUS STRIATUM

44. DEVELOPMENT OF CEREBRAL CORTEX

45. FORMATION OF HIPPOCAMPUS

46. DEVELOPMENT OF COMMISURES

47. TIME TABLE OF IMPORTANT EVENTS Neural plate is formed at the beginning of the 3rd week. Neural folds begin to fuse in the 4th week. The anterior neuropore closes by 25th day and the posterior neuropore closes by 27th day. By the end of the 4th week, the neural tube is fully closed. In the 5th week, brain vesicles have formed and the flexures of neural tube are in progress. Corpus striatum appears in the 2nd month. Corpus callosum forms in the 10th week.

48. Myelination begins in the 4th month. Differentiation of cerebellum starts in the 8th week. The cerebellar cortex and Purkinje cells appear by the 12th week. Dentate nucleus is seen in the 15th week.

49. THANK YOU

50. The myelogenetic chronology.

55. LATERAL VIEWS OF THE FETAL BRAIN, FROM 10 TO 40 WEEKS OF GESTATIONAL AGE.