Introduction to Neuroanatomy

1. Introduction to Neuroanatomy • Structure-function relationships • Localization of function in the CNS • Non-invasive brain imaging • CAT: structure, low resolution • MRI: structure, high resolution • PET: function, low resolution • fMRI: function, high resolution

2. Dual approach to learning neuroanatomy: • Functional anatomy • Neural structures that serve particular functions; e.g., pain path from skin to cortex for perception • Regional anatomy • Localization of structures in particular brain regions

3. Lecture objectives: • Overview of brain structures to “demystify” anatomical content in Neural Science lectures • Survey brain structure-function relations to provide background for first labs First half of lecture: • Quick review of basic CNS organization • Use development to understand principles of structural organization of CNS Second half: Functional localization

4. Introduction to Neuroanatomy I:Regional Anatomy

5. CNS Organizational Principles • 1) Tubular organization of central nervous system • 2) Columnar/longitudinal organization of spinal and cranial nerve nuclei • 3) Complex C-shaped organization of cerebral cortex and deep structures

6. Nuclei: locations of neuron cell bodies w/in the central nervous system Ganglia: locations of neuron cell bodies in the periphery Tracts: locations of axons w/in the central nervous system Nerves: locations of axons in the periphery Brief Overview of Mature CNS Neuroanatomy • Columnar/longitudinal organization of spinal and cranial nerve nuclei • Tubular organization of central nervous system

7. SC Dorsal surface Dorsalroot Ventralroot Gray matter White matter Spinal nerve Ventral surface NTA 1-4

8. Brief Overview of Mature CNS Neuroanatomy • 2) Columnar/longitudinal organization of spinal and cranial nerve nuclei • 1) Tubular organization of central nervous system • 3) Complex C-shaped organization of cerebral cortex and nuclei and structures located beneath cortex • Lateral ventricle • Basal ganglia • Hippocampal formation & Fornix

9. Neural Induction •Portion of the dorsal ectoderm becomes committed to become the nervous system: Neural plate

10. Neural tube wall: neurons & glia of CNS Neural tube cavity: ventricular system Neural crest: PNS neurons, etc White matter Gray matter Ectoderm Neuralplate Neuralgroove Neuraltube NTA 3-1

11. Brain vesicles: NT development Rostral Forebrain Midbrain Neural Tube Development Hindbrain Rostral neural tube forms the brain Caudal neural tube forms the spinal cord Spinal cord Caudal Cephalicflexure NTA 3-2

12. 3-vesicle stage 5-vesicle stage 3 & 5 ves stages Cerebralhemisphere Lateralventricle Forebrain Midbrain Diencephalon Midbrain 3rdventricle Hindbrain Pons &Cerebellum Cerebral aqueduct Medulla 4thventricle Spinal cord Centralcanal Cephalicflexure …by the 5 vesicle stage, all 7 major brain divisions are present NTA 3-2

13. Cephalicflexure The cephalic flexure persists into maturity MidsagBrain

14. axes NTA 1-13

15. Spinal cord & brain stem have a similar developmental plan • Segmentation • Nuclear organization: columnar

16. Dorsal horn SC dev Alar plate Sulcuslimitans Central canal Basal plate Ventral horn Dorsal horn Central canal Ventral horn NTA 3-7

17. Dorsal horn Dorsalroot Ventralroot Ventral horn

18. Similarities between SC and brain stem development •Sulcus limitans separates sensory and motor nuclei •Nuclei have columnar shape Key differences • 1) central canal enlargement motor medial and sensory lateral • 2) migration away from ventricle • 3) >> sensory and motor

19. BS dev Alar plate andmigrating neuroblasts Basal plate NTA 3-8

20. Striated/branchio. Striated/somite Autonomic. Vestibular/auditory. Somatic sensory. Taste/viscerosensory Alar plate Basal plate Medulla development 4th Vent Alar plate Sulcus limitans Basal plate Inferior olivarynucleus NTA 3-9

21. Pons development 4th Vent Striated/branchio. Alar plate Striated/somite Vestibular/auditory. Somatic sensory. Taste/viscerosensory Autonomic. Basal plate Pontine nuclei Sulcus limitans Alar plate Basal plate NTA 3-10

22. Midbrain development Cerebral aq. Alar plate Somatic sensory. Autonomic. Striated/somite Red nucleus Basal plate Sub. nigra Sulcus limitans More like spinal Cord b/c fewer nuclear classesand cerebral aqueduct Basal plate NTA 3-11

23. Similarities between forebrain and hindbrain/spinal development •Tubular Key differences • 1) CH more complex than BS/SC • 2) Cortical gyri more complex anatomy than nuclei • 3) Subcortical nuclei are C-shaped • Confusing: structure in two places on image

24. Diencephalon • Thalamus • Gateway to cortex • Hypothalamus • Control of endocrine and bodily functions • Circadian rhythms • Etc.

25. CH dev NTA 3-14

26. Parietal Occipital Frontal Temporal Cerebral Cortex Development

27. Forebrain Development & C-shaped Structures • Cerebral cortex (NTA 3-15) • Lateral ventricles (NTA 3-16) • Striatum (NTA 3-16) • Hippocampal formation and fornix (NTA 3-17)

28. Summary • 7 Major components of the central nervous system & Ventricles • All present from ~ 1st prenatal month • Longitudinal organization of SC and BS nuclei • Columns • Anatomical and functional divisions • C-shape organization of cerebral hemisphere structures and diencephalic • Cerebral cortex • Lateral ventricle • Striatum • Hippocampal formation and fornix