Mesoscale developmental rivalry in human extrastriate visual cortex.

In humans and non-human primates, the extrastriate visual cortex contains fine-scale columns selectively responsive to motion, disparity, and color. However, the developmental interplay between these functional modules remains poorly understood. Using high-resolution fMRI, we compared the mesoscale organization of extrastriate cortex in 16 individuals with normal vision and 15 participants with amblyopia (PwA) caused by strabismus (n=8) or anisometropia (n=7). In controls, the cortical territory occupied by disparity-selective columns exhibited a competitive relationship with that of motion- and color-selective columns. Consistent with this pattern, PwA showed a reduction in disparity-selective responses accompanied by enhanced motion- and color-selective activity, as well as expansion of the cortical territory allocated to them. Our results show that the mesoscale modules of the human visual system are rivals in development allowing intact functions to usurp those that are compromised.