Todorović D. Polarity-dependent orientation illusions: Review, model, and simulations.
Vision Res 2021;
189:54-80. [PMID:
34628261 DOI:
10.1016/j.visres.2021.09.003]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 09/20/2021] [Accepted: 09/22/2021] [Indexed: 10/20/2022]
Abstract
Polarity-dependent orientation illusions are manifested in figures in which the impression of target orientation does not depend only on geometrical relations between the elements of the figure, but also on the relations between their luminances, that is, on luminance polarities. The best-known phenomenon belonging to this class of effects is the Münsterberg/Café Wall illusion. In this paper a considerable number of examples of this type of illusions are presented, many of which are novel variants. A two-level convolutional model of such illusions is introduced, in which the first level corresponds to the stimulus input and the second level contains units fashioned after simple cells in V1, whose spatial patterns of activity represent the model's reaction to the stimulus. The main finding of numerous simulations of the model is that the figures inducing illusory impressions of tilt share a common spatial pattern of neural activation, labeled 'oblique clusters', which is absent in related non-illusory figures. Furthermore, a similar pattern is also present in simulations of figures which induce veridical impressions of tilt. The simulations suggest that the neural basis of perception of a specific degree of tilt may not be the activity of neurons tuned narrowly to that particular degree of tilt, but rather the presence of certain signature spatial patterns of activity of populations of neurons.
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