Purchase this article with an account.
Myriam Vandenbroucke, H. Steven Scholte, Herman van Engeland, Chantal Kemner, Victor Lamme; A deficit in horizontal interactions causes an imbalance between feedforward and recurrent visual processing, resulting in texture segregation deficits. Journal of Vision 2007;7(9):906. doi: 10.1167/7.9.906.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Although there is considerable evidence for the role of feedforward, horizontal, and recurrent interactions in figure-ground segregation, little is known about how this process would be affected by a selective deficit in one of these interactions. We conjectured that an early deficit in horizontal interactions would disturb the balance between feedforward and recurrent activity. Such an imbalance was expected in Autism Spectrum Disorder (ASD), considering their aberrancies in visual perception. Accordingly, while recording EEG we tested healthy subjects and subjects with ASD on a new texture discrimination task, where surface segregation was varied independently from orientation boundaries. The data confirmed the already established role of recurrent processing in figure-ground segregation, as the feedback related activity decreased with decreasing perceptibility of the surface layout. Second, we found that subjects with ASD had lower performance scores compared to healthy controls on stimuli for which the detection of texture discontinuities was important. However, performance was similar for stimuli in which an extra surface layout was present. The EEG data confirmed this as the ERP associated with the detection of orientation boundaries was absent in the patient group. Interestingly, consecutive feedforward activity to extrastriate cortex was enhanced compared to controls and, finally, feedback activity was normal (although slightly delayed). Apparently, an initial deficit in boundary detection results in a subsequent imbalance between feedforward and recurrent activity. By this imbalance the visual system is able to compensate for deficits in early visual processing, resulting in the proper interpretation of a surface layout.
This PDF is available to Subscribers Only