1. CNS development 1.A somewhat general overview of CNS development

2. In the beginning…… zygote – fertilized egg; – undergoes a number of divisions with overall size unchanged and divisions resulting in smaller and smaller cells (cleavage) to form the BLASTULA

5. blastula invaginates giving rise to 3 layers – called gastrulation and the structure is now called a gastrula

7. blastula invaginates giving rise to 3 layers – gastrulation – endoderm guts, lungs, liver, internal organs – mesoderm muscles, skeleton, connective tissue, cardiovascular system, urogenital system – ectoderm

8. neural groove flattens and forms the neural plate – this folds into a tubular structure called the neural tube

11. The 3 dimensions of the neural tube

12. longitudinal – caudal end – spinal cord rostral end – brain if neural tube fails to close caudal – spina bifida rostral – anencephaly

13. cavity of the neural tube forms the ventricular system

15. During neurula stage – see further specialization of neural tube cephalic end differentiates into 3 primary vesicles 1.

16. During neurula stage – see further specialization of neural tube 3 swellings at rostral end 1. prosencephalon – forebrain vesicle 2. mesencephalon – midbrain vesicle 3. rhombencephalon – hindbrain vesicle

17. After 3 vesicles are formed – we see 2 flexures: 1. cervical (sc and hindbrain) 2. cephalic (hindbrain and midbrain) when neurulation is complete – considered an embryo!

18. See further specialization of neural tube further divisions – 1. prosencephalon – forebrain vesicle telencephalon - cortex diencephalon – thalamus, hypothalamus 2. mesencephalon – midbrain vesicle 3.rhombencephalon – hindbrain vesicle metencephalon- pons and cerebellum myelencephalon - medulla

20. corticogenesis - develops from inside out

22. Axon and dendrite development When does dendritic growth occur? Environmental influence?

23. Synaptogenesis

24. general terms nerves tracts ganglion nucleus

25. myelination What is responsible for myelination? How long does myelination take?

26. Autonomic NS

28. Somatic NS 31 pairs of spinal nerves

31. label the diagram

33. sensory neurons – clustured in DRG – pseudo unipolar neurons bifurcated axon with central and peripheral branches

34. components of SC dorsal horn – – sensory relay neurons ventral horn – – motor nuclei white matter – – longitudinal tracts of myelinated axons

35. components of SC (con’t) white matter – – dorsal columns contains ascending axons carrying somatosensory info – lateral columns both ascending axons and descending axons – ventral columns ascending somatosensory and descending axons

37. corticospinal tract – humans - ~ 1,000,000 axons – originate in motor cortex; pyramidal motor system – makes monosynaptic connections with motor neurons

38. The corticospinal tract mostly contains motor axons. The rubrospinal tract – 2ndairy motor system - responsible for large muscle movement such as the arms and the legs (flexor and extension, muscle tone). The spinothalamic tract is a sensory pathway originating in the spinal cord that transmits information about pain, temperature, itch, some measures of touch to thalamus.

39. ways to determine region of spinal cord relative white to gray matter configuration of gray matter specific nuclei- clarkes nucleus

42. Cranial nerves primarily serve head and face

43. Brain hindbrain, midbrain and forebrain

45. hindbrain medulla pons cerebellum

46. hindbrain (con’t) medulla structure resembles SC contains: early relay nuclei in taste, hearing, maintenance of balance, neck and facial muscles pons – ventral portion – pontine nucleus – info about movement and sensation from cc to cerebellum – dorsal portion – respiration, taste, sleep

47. hindbrain medulla pons cerebellum – roles:

48. midbrain structures:

49. midbrain

51. diencephalon (part of the forebrain) thalamus – role: hypothalamus – role:

53. The thalamus communicates with much of the cerebral cortex - serving as a sensory and motor information relay.

54. components of the thalamus nuclei – relay or diffuse projections- classified based on location internal capsule – large bundle of fibers carrying most of axons running to and from cerebral hemispheres massa intermedia – connects left and right thalamus reticular nucleus – role – feedback to output nuclei of thalamus - GABA

55. telencephalon basal ganglia limbic system cerebrum (cerebral hemispheres)

58. telencephalon cerebrum (cerebral hemispheres) – SOME TERMS: – fissures – large grooves on cerebrum surface – gyrus – outswelling observed on cerebrum – sulci – smaller grooves on cerebrum

60. cerebral cortex layers distinctive laminar structure of certain cortices provides information regarding region of cortex – ex. Layer IV – main target of sensory info from thalamus

63. telencephalon cerebrum (cerebral hemispheres) – 4 lobes primary and association cortices – key differences in primary cortices

66. What do we know about the extent of innervation as it relates to sensory information? Explain the statement that functional systems are hierarchically organized.

67. Some questions….. Differentiate between unimodal association areas and multimodal association areas

68. Prefrontal association area functions of prefrontal cortex lesions – tests of frontal lobe function