Human blindsight is mediated by an intact geniculo-extrastriate pathway

Human blindsight is mediated by an intact geniculo-extrastriate pathway

Blog Article

Although damage to the primary visual cortex (V1) causes hemianopia, many patients retain some residual vision; known as blindsight.We show that blindsight may be facilitated by an intact white-matter pathway between the lateral geniculate nucleus and motion area hMT+.Visual psychophysics, diffusion-weighted Foot Warmer magnetic resonance imaging and fibre tractography were applied in 17 patients with V1 damage acquired during adulthood and 9 age-matched controls.Individuals with V1 damage were subdivided into blindsight positive (preserved residual vision) and negative (no residual vision) according to psychophysical performance.

All blindsight positive individuals showed intact geniculo-hMT+ pathways, while this pathway was significantly impaired or not measurable in blindsight negative individuals.Two Pizza Crust white matter pathways previously implicated in blindsight: (i) superior colliculus to hMT+ and (ii) between hMT+ in each hemisphere were not consistently present in blindsight positive cases.Understanding the visual pathways crucial for residual vision may direct future rehabilitation strategies for hemianopia patients.