Hierarchical and nonhierarchical features of the mouse visual cortical network

Mouse visual cortex is a dense, interconnected network of distinct areas. D'Souza et al. identify an anatomical index to quantify the hierarchical nature of pathways, and highlight the hierarchical and nonhierarchical features of the network. Neocortical computations underlying vision are performed by a distributed network of functionally specialized areas. Mouse visual cortex, a dense interareal network that exhibits hierarchical properties, comprises subnetworks interconnecting distinct processing streams. To determine the layout of the mouse visual hierarchy, we have evaluated the laminar patterns formed by interareal axonal projections originating in each of ten areas. Reciprocally connected pairs of areas exhibit feedforward/feedback relationships consistent with a hierarchical organization. Beta regression analyses, which estimate a continuous hierarchical distance measure, indicate that the network comprises multiple nonhierarchical circuits embedded in a hierarchical organization of overlapping levels. Single-unit recordings in anaesthetized mice show that receptive field sizes are generally consistent with the hierarchy, with the ventral stream exhibiting a stricter hierarchy than the dorsal stream. Together, the results provide an anatomical metric for hierarchical distance, and reveal both hierarchical and nonhierarchical motifs in mouse visual cortex.

Automated summary

The study identifies the hierarchical nature and nonhierarchical features of the mouse visual cortex network by evaluating the axonal projection patterns between different areas. Receptive field sizes in the cortex are generally consistent with the hierarchy. The results provide an anatomical metric for hierarchical distance and reveal both hierarchical and nonhierarchical motifs in the mouse visual cortex.