Indeterminate Organization of the Visual System

The classic view of how the brain areas that control vision are connected is a complicated wiring diagram devised by manual sorting on the basis of existing anatomical data D. J. Felleman and D. C. Van Essen, Cereb. Cortex 1 , 1 (1991). Now, in this issue's Enhanced Perspective, Hilgetag and co-workers have used a computer algorithm to test whether there is a better way to organize the connections. They find that the brain is surprisingly indeterminate, and that no single hierarchy can satisfactorily represent the order implied by the anatomical data. A more detailed explanation of their analysis and a list of predictions derived from their hierarchies that will be particularly informative to test experimentally can be found on the home page of the authors.