1. DEVELOPMENT OF PROSENCEPHALON

3. PROSENCEPHALON (FOREBRAIN)
Telencephalon: Rostral part of forebrain
Cerebral Hemispheres
Diencephalon: Caudal & median part
optic cup & stalk
Hypophysis/Pituitary
Thalmus
Hypothalmus
Epiphysis

4. DIENCEPHALON
Roof plate
Alar plates = 2
Absent floor & basal plates

5. ROOF PLATE & EPIPHYSIS Roof plate Choroid plexus of 3rd ventricle
Most caudal part of roof plate develops into epiphysis/ pineal body

6. Pineal body
Appears as epithelial thickening in the midline, but by 7th week it begins to evaginate
Eventually it becomes a solid organ on the roof of mesencephalon
Function: Respond to light and darkness & affect the endocrine and behavioral rhythms
In adults calcium is frequently deposited in the epiphysis and then serve as land marks on radiographs of skull.

8. ALAR PLATES Forms lateral wall of diencephalon
A groove hypothalamic sulcus divides it into:
Thalamus
Hypothalamus

9. THALAMUS
Thalamus gradually projects into the lumen of diencephalon due to proliferation of cells
Frequently the expansion is so great that two thalami fuse in mid line forming massa Intermedia or Interthalamic connexus

10. HYPOTHALMUS Forms the lower portions of alar plate
Differentiate into number of nuclear masses that regulate visceral functions
Mammillary body forms a distinct protuberance on the ventral surface of hypothalamus on each side of midline

12. Hypophysis/Pituitary Gland-Ectodermal
Develops from two sources:
An ectodermal outpocketing of the stomodeum---- Rathke’s pouch
Downward extension of diencephalon---- the infundibulum

13. Cont…
At 3 weeks Rathke’s pouch appear as evagination that grows dorsally towards infundibulum.
By the end of 2nd month it loses its connection with the oral cavity
Comes to lie in close contact with infundibulum

15. Cont…
Cells in the anterior wall rapidly proliferate and form the ---- anterior lobe/ adenohypophsis.
A small extension of the lobe is pars tuberalis that surrounds the infundibulum
The posterior wall of pouch forms the --- pars Intermedia
Infundibulum give rise to stalk & pars nervosa----posterior lobe/Neurohypophysis

16. Hypophysis/Pituitary Gland-Ectodermal

17. HYPOPHYSEAL DEFECTS CRANIOPHARYNGIOMAS
Remnant of Rathke’s pouch

18. Cerebral Hemispheres
Arise by 5th week as bilateral evaginations of lateral wall of forebrain
Interventricular foramen

19. CEREBRAL HEMISPHERES
Middle of 2nd month the basal part/floor of hemispheres begins to grow & bulges into lumen of lateral ventricle & into floor of foramen of Monro
In T.S this rapidly growing region has striated appearance therefore called Corpus striatum
C.H become C-shaped
Choroid plexus develop in the region where wall of hemisphere is attached to roof of diencephalon

20. CORPUS STRIATUM
As the cerebral cortex differentiates the axons passing to & from the cortex (Internal capsule) break the nuclear masses into:
dorsomedial portion caudate nucleus
ventrolateral portion the lentiform nucleus
Medial wall of C.H fuse with lateral wall of diencephalon

21. CHOROID FISSURE
The Lateral ventricle become C-shaped due to growth & curvature of C.H
The caudal end of each C.H turns ventrally & then rostrally, forming the temporal lobe & in so doing it carries the ventricle (forming temporal horn) & Choroid fissure with it.

22. CHOROID PLEXUS
Choroid plexus protrude in the lateral ventricle along the choroid fissure
The thin medial wall of the C.H is invaginated along the choroid fissure by vascular pia matter to form choroid plexus of temporal horn

24. Growth of cerebral hemispheres
C.H grow in anterior, posterior & inferior directions resulting in formation of frontal, occipital & temporal lobes.
As growth in the region of corpus striatum slows the region b/w frontal & temporal lobes depressed & is called insula
This region is later overgrown by other lobes Which completely covers it at birth.

26. COMMISSURES Anterior commissure- 1st to appear Hippocamphal commissure
Corpus callosum- 10th week
Habenular commissure
Posterior commissure
Optic chiasma

30. Congenital anomalies

31. Cranium Bifidum

32. Holoprosecrphaly

33. Schizencephaly

34. Anencephaly

35. Hydrocephalus

36. Arnold Chiari Malformation

37. THANK YOU