the workings of the system depend on its anatomical connections. therefore, passingham’s work is firmly based on these connections. he demonstrated that each cortical area has a unique set of inputs and outputs, and has argued that it is these that mainly determine the functions of the area. however, his work also shows that there are ‘families’ of areas that show similarities in their inputs and outputs, and these form systems. the anatomical connections that he charted in the macaque brain formed the basis for the anatomical models that he has tested in imaging studies of the human brain, devoted to understanding how one area influences another, for example using structural equation modelling.