The visual pathway is the biological communication route between retina and visual experience.
retina
-> optic nerve
-> optic chiasm
-> optic tract
-> lateral geniculate nucleus
-> optic radiations
-> primary visual cortex
-> higher visual cortex
-> perception
| Stage | Role |
|---|---|
| Optic nerve | Carries ganglion-cell output from the eye. |
| Optic chiasm | Routes visual-field information from both eyes. |
| LGN | Thalamic relay that gates and organizes visual input. |
| V1 | Primary visual cortex; strongly retinotopic. |
| V2/V3/V4/MT and beyond | Processes form, color, motion, depth, and object features. |
| Association cortex | Links perception with attention, memory, action, and meaning. |
Retinotopy means neighboring visual-field locations map to neighboring regions in parts of the visual system. This is why cortex can be tempting to imagine as a display surface. The catch is that retinotopy is not a rectangular pixel grid. It is warped, layered, individual, and connected to feature processing.
| Target | Opportunity | Problem |
|---|---|---|
| Optic nerve | Bypasses damaged retina. | Fibers are mixed and difficult to address. |
| LGN | Bypasses eye and optic nerve damage. | Deep, complex, and not well suited to simple access. |
| V1 | Has spatial visual map. | Stimulation usually evokes phosphenes, not natural images. |
| Higher cortex | Encodes richer features. | Meaningful activity patterns are complex and distributed. |
Instead of forcing every target to act like a pixel display, a future interface could route different information to different representational systems:
This treats perception as a multi-stage system rather than a single screen.