Figure 3.

Illusory contour perception in Kanizsa shapes (Kanizsa, 1979). (A) Traditional and more complex Kanizsa shapes that evoke strong illusory contour percepts. Complex shapes courtesy of Steven Lehar (http://cns-alumni.bu.edu/~slehar/Lehar.html). (B) Perception of illusory contours has been suggested to arise by virtue of recurrent feedback from extrastriate areas to V1. Specifically, feedback from an extrastriate neuron drives neurons that code similarly oriented contours that fall within its receptive field, spreading activation across the gap in the Kanizsa shape. Adapted from Lee (2003).