Object perception recruits overlapping networks across two visual pathways
Two peer-reviewed brain-imaging experiments found extensive overlap between networks associated with visual pathways traditionally linked to recognizing objects and acting on them. The pattern persisted for tools and other objects, and after accounting for activity shared between the pathways. The measurements describe relationships among brain signals during picture viewing, while preserving evidence of pathway-specific connections and functions.
Science··Morning
Two visual pathways connect to shared brain regions
Networks linked to recognizing objects and acting on them overlap extensively across the brain, according to a single peer-reviewed study. Two experiments used functional magnetic resonance imaging while participants viewed pictures of objects. The researchers mapped connections from an upper, dorsal visual region and a lower, ventral region to the rest of the brain. The traditional distinction associates the dorsal pathway with spatial and action processing and the ventral pathway with object recognition.[1]
Overlap persists beyond pictures of tools
Both maps extended across occipital, temporal and parietal cortex. Within a person, the two maps resembled one another more than either map resembled its counterpart in other people. Comparing objects with scrambled images retained substantial overlap, addressing the possibility of a general response to visual input. Separately examining tools and other objects gave similar overlapping networks; the result extended beyond familiar implements with obvious uses.[1]
Shared signals leave pathway-specific connections
Statistically controlling activity shared between the two starting regions left both overlapping and distinct connections. The dorsal network reached frontal areas as well as ventral regions, while the ventral network also included dorsal areas. Functional connectivity measures relationships among blood-oxygenation signals; indirect connections and common inputs can contribute. The measurements cannot identify direct anatomical wiring or determine how information moves causally between regions. The experiments concern object pictures, with the pathways retaining distinct functions.[1]
