Which sequence correctly describes the pathway of visual information from the retina to the primary visual cortex?

Which sequence correctly describes the pathway of visual information from the retina to the primary visual cortex?

• A. Photoreceptor → bipolar cell → ganglion cell → optic nerve → optic chiasm → optic tract → lateral geniculate nucleus (LGN) → primary visual cortex (V1).
• B. Photoreceptor → ganglion cell → bipolar cell → optic nerve → chiasm → optic tract → LGN.
• C. Photoreceptor → bipolar cell → optic nerve → ganglion cell → LGN → V1.
• D. Photoreceptor → bipolar cell → ganglion cell → optic nerve → optic chiasm → LGN → V1.

Answer: (A)

Visual information flows through a precise chain of neurons starting in the retina and moving toward the cortex. Light is detected by photoreceptors and converted into signals that pass to bipolar cells, which then relay to retinal ganglion cells. The axons of these ganglion cells bundle together to form the optic nerve, carrying the signal toward the brain. At the optic chiasm, fibers from the nasal retina cross to the opposite side while temporal fibers stay on their original side, so information from each visual field is projected contralaterally. The signal then travels in the optic tract to the lateral geniculate nucleus of the thalamus. From the LGN, the information is sent to the primary visual cortex via the optic radiations. This sequence correctly reflects the order of synapses and major relay stations from retina to V1. Sequences that place the optic nerve before the ganglion cell output, or skip the optic tract, or omit the synaptic steps within the retina, don’t match the actual pathway.

Visual information flows through a precise chain of neurons starting in the retina and moving toward the cortex. Light is detected by photoreceptors and converted into signals that pass to bipolar cells, which then relay to retinal ganglion cells. The axons of these ganglion cells bundle together to form the optic nerve, carrying the signal toward the brain. At the optic chiasm, fibers from the nasal retina cross to the opposite side while temporal fibers stay on their original side, so information from each visual field is projected contralaterally. The signal then travels in the optic tract to the lateral geniculate nucleus of the thalamus. From the LGN, the information is sent to the primary visual cortex via the optic radiations. This sequence correctly reflects the order of synapses and major relay stations from retina to V1.

Sequences that place the optic nerve before the ganglion cell output, or skip the optic tract, or omit the synaptic steps within the retina, don’t match the actual pathway.