What is the pathway order from the retina to the LGN?

What is the pathway order from the retina to the LGN?

• A. Retina → optic nerve → (optional) chiasm → optic tract → LGN.
• B. Retina → optic nerve → optic tract → chiasm → LGN.
• C. Retina → chiasm → optic nerve → LGN.
• D. Retina → optic nerve → chiasm → LGN.

Answer: (A)

Signals travel from the retina along the optic nerve as the axons of retinal ganglion cells bundle together. At the optic chiasm, fibers from the nasal retina cross to the opposite side while temporal fibers stay on the same side, allowing information from each visual field to be represented in the opposite hemisphere. After crossing, the fibers run as the optic tract to the dorsal lateral geniculate nucleus (LGN) in the thalamus, which then relays visual information toward the cortex. This order—retina, optic nerve, chiasm, optic tract, LGN—reflects the actual anatomical progression. The chiasm is the crossing point, and while some texts describe it as part of a continuous nerve–tract pathway, the functional sequence remains nerve → chiasm → tract → LGN.

Signals travel from the retina along the optic nerve as the axons of retinal ganglion cells bundle together. At the optic chiasm, fibers from the nasal retina cross to the opposite side while temporal fibers stay on the same side, allowing information from each visual field to be represented in the opposite hemisphere. After crossing, the fibers run as the optic tract to the dorsal lateral geniculate nucleus (LGN) in the thalamus, which then relays visual information toward the cortex. This order—retina, optic nerve, chiasm, optic tract, LGN—reflects the actual anatomical progression. The chiasm is the crossing point, and while some texts describe it as part of a continuous nerve–tract pathway, the functional sequence remains nerve → chiasm → tract → LGN.