Categories rule: High-order brain centers pave the way for visual recognition
(Medical Xpress) -- The real world is, in a word, cluttered but thanks to evolution, we (and other mammals) have no trouble detecting objects in visually complex natural environments. Determining precisely how this occurs is a deceptively complex task, since the retinal and neural mechanisms responsible for simpler percepts lines, edges and the like do not account for this survival skill in fact, they actually interfere with it. Recently, however, scientists have used functional magnetic resonance imaging (fMRI) to elucidate the top-down processes by which high-level cortical areas that deal not with simple percepts, but rather abstract perceptual categories, actually prepare lower-level visual brain centers to perceive detail amidst disorder.