1. CNS Anatomy: Brainstem & Spinal Cord Lecture 6

2. Mesencephalon n Surrounds cerebral aqueduct n Tectum l Superior Colliculi - vision l Inferior Colliculi - audition n Tegmentum ~

3. Thalamus Tectum Superior Colliculi Inferior Colliculi

4. Tegmentum n Periaqueductal Gray l analgesia n Reticular Formation – l sleep and arousal l attention n Red Nucleus and Substantia Nigra l motor system n Ventral Tegmental Area (VTA) l reinforcement ~

5. PAG Substantia Nigra Reticular formation Cross-section of Tegmentum Ventral Tegmental Area Dorsal Red Nucleus

6. Metencephalon n Surrounds fourth ventricle n Cerebellum l coordinates movements n Pons l Sleep and arousal l Reticular formation ~

7. Cerebellum Pons

8. n Medulla - “Vital Centers” n Reticular formation ~ Myelencephalon

9. Thalamus Medulla

10. Dorsal Ventral White Matter Gray Matter Central Canal Spinal Cord

11. Dorsal Ventral Dorsal Lateral Ventral Horns

12. Spinal cord n Dorsal horn l sensory input l via dorsal root ganglion n Lateral horn - autonomic N.S. n Ventral horn l motor output l via ventral root ~

13. n Clinically important anatomy l Descending & ascending tracts n Motor 1. corticospinal tract distal muscles l only descending tract with overt effects ~ Spinal Cord Tracts

14. n Sensory 2. Dorsal column-medial lemniscal tract l touch, vibration, & proprioception l axons ascend ipsilaterally l synapse then decussate at medulla 3. Spinothalamic tract (lateral) l pain & temperature l decussate at SC entry level l ascends contralaterally ~

15. Medulla Dorsal column-medial lemniscal path Spinothalamic path Corticospinal tract

16. Dorsal Ventral Dorsal columns Spinal Cord anterolateral columns Corticospinal tract Rubrospinal tract