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Chapter 2:

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  1. Chapter 2: Descriptions of the Thalamus in Representative Mammals

  2. Thalamic Division: • Precedent set by J.E. Rose (1942) • Epithalamus • Dorsal Thalamus • Known as “the thalamus” • Ventral Thalamus http://www.jamescarsondesign.com/images/portfolio/pirates2/flying_dutchman.jpg http://blog.sonicelectronix.com/wp-content/uploads/2012/04/sb_YouWish.jpg

  3. Cats:

  4. Evolved Visual System • Outgrowth of Lateral Nuclear Mass • Ventral Lateral Geniculate (LGv) • Lies within the Optic Tract http://images.luvimages.com/luvphotos/c/cat_with_sunglasses-4652.jpg

  5. Rodents • General Trends – Difficulty in distinguishing individual nuclei BUT… • Anterior intralaminar, ventral thalamus, three anterior nuclei are distinct populations • LGd not visually laminated as in the cat • Midline nuclei varies between rodents • Guinea Pig Rat Mouse http://www.arcadesplat.com/wallpaper/1080x762/mouse-wallpapers-cmice-bwallpaper-31569.html http://i.telegraph.co.uk/multimedia/archive/00786/GUINEA-PIG-WEIGHT-L_786613i.jpg http://www.grit.com/~/media/Images/GRT/Editorial/Blogs/Kahuna/Chickens%20and%20Rats%20or%20Just%20Rats/rat-ratatouille-remy.jpg • Great difficulty in labeling isolated cell clusters as independent nuclei • No Pulvinar Nucleus • No Centre Médian nucleus…possible off shoot of the Parafasicular (Pf) nucleus

  6. Rat Guinea Pig Mouse

  7. Mouse: Very distinct VPM/VPL in comparison to Rat Not Much Boundary borders along the midline nuclei Barreloids are much denser in the mouse than Rat Guinea Pig: Distinction in Myleoarchitecture Fiber tracts entering/leaving the Thalamus are clear Evidence of interneurons Rat: Better distinction along the midline than Mouse

  8. Macaque Monkey: • Chief Differences : SIZE!! • Greater Development of Ventral/Lateral Nuclei • More distinct subdivision than the cat • Massive Enlargement of the Pulvinar • 4 Major Nuclei Visible • Centre Médian is Particularly Large • Intralaminar Nuclei are Distinct http://www.redorbit.com/media/uploads/2004/10/42_191768e6c60ce0a3aa5dc3ccd4869451.jpg

  9. Humans http://0.tqn.com/d/psychology/1/0/Y/B/Thalamus.png • Comparison to the Monkey: • Super large Ventral Lateral Complex • Due to potential increase in relative size of somatosensory cortex/motor cortex • Visual Pulvinar much Larger • Other Distinguishing Features: • Merging of anteromedial and anteroventral nuclei • Fragmentation of Intralaminar Nuclei • Enlargement of Posterior Intralaminar Group

  10. Defining Features: External Medullary Laminae

  11. Defining Features: Internal Medullary Laminae

  12. Defining Features: Massa Intermedia

  13. Conclusions: • The Thalamus of most species is defined by its sensory relationship and interaction with its environment. • Examples: Echidna & Platypus “Flying Fox” http://scienceforkids.kidipede.com/biology/animals/chordates/mammals/pictures/platypus.jpg http://faunafemales.wikispaces.com/file/view/echidna.jpg/32869053/echidna.jpg http://www.bubblews.com/assets/images/news/1157361650_1378875206.jpg http://www.sydneybats.org.au/files/3913/0267/6109/X_Red_Faces3_2Jan06.jpg

  14. FIN