Detailed analysis of orientation preference map in visual cortex

Mammalian primary visual cortex (V1) contains a functional map of orientation preference. Within the orientation preference map, neurons aggregate in two different local patterns. Neurons with similar orientation preferences gather within orientation domains, whereas neurons with all different orientation preferences converge at the center of pinwheel-like arrangements of orientation domains. The differences in local organization of domains and pinwheels have been the subject of considerable controversy. Here, we focus on the differences in global organizations of domains and pinwheels. We analyzed the spatial distribution of orientation preferences in wide regions around domains and pinwheels in monkey V1. A particular distribution pattern of orientation preferences was found more clearly in the regions around domains than in the regions around pinwheels. This suggests that neuronal responses to large stimuli outside of a neuron's receptive field can vary between domains and pinwheels.