Retinotopic organization and functional subdivisions of the human lateral geniculate nucleus and superior colliculus

The lateral geniculate nucleus (LGN) of the thalamus and the superior colliculus (SC) have been well studied in other primates, but the study of their organization and function in humans has been largely limited to lesion and post-mortem analyses. Here we show that the retinotopic structure of the LGN, including its eccentricity and polar angle magnification factors, can be measured with a 3T MRI scanner and a high-resolution imaging sequence (1.5 × 1.5 × 2 mm voxel size). Sensitivity to stimulus contrast varied throughout the extent of the LGN, and based on this, we attempted to distinguish the magnocellular and parvocellular divisions. In the SC, contralateral activation was observed, but unlike in the LGN, contrast sensitivity was uniform throughout its extent. Overview