Short- and long-range spatial interactions: A redefinition

First level short- and long-range spatial interactions are considered to be processed in the primary visual cortex. In psychophysics, they are measured with two kinds of stimuli, Gabor patches and lines/points. Each has its own short- and long-range definitions. We show that first, in terms of visual angle separation, the two definitions do not correspond to identical scales of interactions and second, that Gabor data can be matched to the lines/points definition by properly considering the observed effects. As a consequence, three regimes of spatial interaction are present: a case where overlapping of stimuli is present, and two others for spatially separated stimuli which we define as the short- and long-range regimes. Both types of stimuli show compatible lateral interactions and, we think, permit the measurement of the same underlying mechanisms. (c) 2005 Elsevier Ltd. All rights reserved.