Surface-Related Features Figure 12. Recurrent processing of illusory contours formed by line ends. An alternative version of the Kanizsa figure is used where line ends lead to the impression of an illusory white square. Model responses are visualized according to Figure 8. Note, that illusory contours signalled by V2 bipole responses develop over time. Note also, that over time this leads to the development of T-junction signals (red) which suggest for the presence of an occluding surface. doi:10.1371/journal.pone.0005909.g012 PLoS ONE | www.plosone.org 14 June 2009 | Volume 4 | Issue 6 | e5909