Abstract
The ability to recognize a shape is linked to figure-ground (FG) organization. Cell preferences appear to be correlated across contrast-polarity reversals and mirror reversals of polygon displays, but not so much across FG reversals. Here we present a network structure which explains both shape-coding by simulated IT cells and suppression of responses to FG reversed stimuli. In our model FG segregation is achieved before shape discrimination, which is itself evidenced by the difference in spiking onsets of a pair of output cells. The studied example also includes feature extraction and illustrates a classification of binary images depending on the dominance of vertical or horizontal borders.
Highlights
Neurons in the inferior temporal cortex (IT) have been linked to visual shape representation and object recognition (Rolls et al, 1977; Logothetis et al, 1995; DiCarlo and Maunsell, 2000; Riesenhuber and Poggio, 2000; Rollenhagen and Olson, 2000). Lesions in this area result in visual agnosia (Farah, 1990). fMRI studies in humans show how objects activate this part of the cortex and how restricted spots of it are driven by specific classes of stimuli (Desimone, 1991; Malach et al, 1995; Tanaka, 1996)
Feed-forward model of IT coding inhibition leading to rebound spiking on regions of smallest area, already introduced by Supèr et al (2010), and (2) An additional structure for extracting and processing features which, if applied to the considered image type, classifies shapes by vertical|horizontal edge dominance and reproduces the observed weakening in the response when the shape goes into the background
We have been able to design a network structure which models the suppression of responses to FG reversed stimuli, and shows the possibility of producing selective outputs that generalize across mirror reversed and contrast reversed stimuli
Summary
Neurons in the inferior temporal cortex (IT) have been linked to visual shape representation and object recognition (Rolls et al, 1977; Logothetis et al, 1995; DiCarlo and Maunsell, 2000; Riesenhuber and Poggio, 2000; Rollenhagen and Olson, 2000). A central mechanism is figure-ground (FG) segmentation, or the segregation of visual information into objects and their surrounding regions (Rubin, 1958) If this task were performed by the brain solely through the contours distinguishing the input displays, generalization under FG reversal would be expected as well. Feed-forward model of IT coding inhibition leading to rebound spiking on regions of smallest area, already introduced by Supèr et al (2010), and (2) An additional structure for extracting and processing features which, if applied to the considered image type, classifies shapes by vertical|horizontal edge dominance and reproduces the observed weakening in the response when the shape goes into the background
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