MODULE 11
The LATERAL GENICULATE NUCLEUS
- - - As you recall, all sensory pathways (except olfaction) pass through a thalamic relay nucleus on the way to the cerebral cortex. The lateral geniculate nucleus is the thalamic relay nucleus for the visual system. It is shown, but not labeled, in Figure 2-16, where it appears to rest on the dorsolateral edge of the cerebral peduncle. You first saw it weeks ago when we overwhelmed you with a dorsal view of the brainstem in which EVERYTHING was labeled - Figure 2-5. See Blumenfeld's Pages 432-3 and Figure 11.7 for more detail about the significance of the layering of neurons in the lateral geniculate nucleus. Our goal is simply to show you that the retinotopic organization of the pathway is retained as it passes through the nucleus. As before, call up the slides using Figure 11-3.
- - - Slides 25, 24a and 22 all pass through the lateral geniculate nucleus. Slide 24b (the same slide 24 with a different overlay) outlines the pathway involved in the pupillary light reflex. Read about this on Blumenfeld's Page 59.
- - - Some optic tract fibers bypass the lateral geniculate nucleus and run through the brachium of the superior colliculus to terminate in the superior colliculus. This is shown in slides 22 and 20 and in Blumenfeld's Figure 11.6.
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