- Each nerve cell in the primary visual cortex responds to specific lines and edges of a specific orientation. - When one line orientation of line is in our view a particular set of nuerons get activated. --- David Hubel and Torsten Wiesel, working first at Johns Hopkins University and then at Harvard, discovered that each nerve cell in the primary visual cortex of the brain responds to simple lines and edges with a specific orientation, whether vertical, horizontal, or oblique (fig. 6.6). These lines are the building blocks of form and contour. Eventually, higher regions of the brain assemble these edges and angles into geometric shapes, which in turn become representations of images in the brain. - [[Reductionism]]