Background Object-based attention can group image elements of spatially extended objects into coherent representations, but its mechanisms have remained unclear. The mechanisms for object-based attention may include shape-selective neurons in higher visual cortical areas that feed back to lower areas to simultaneously enhance the representation of all image elements of a relevant shape. Another, nonexclusive mechanism is the spread of attention in early visual cortex according to Gestalt rules, which could successively add new elements to a growing object representation.
Pooresmaeili, A., & Roelfsema, P. R. (2014). A Growth-Cone Model for the Spread of Object-Based Attention during Contour Grouping. Current Biology, 24(24), 2869-2877. https://doi.org/10.1016/j.cub.2014.10.007