The Visual N1 Is Sensitive to Deviations from Natural Texture Appearance

Abstract

Disruptions of natural texture appearance are known to negatively impact performance in texture discrimination tasks, for example, such that contrast-negated textures, synthetic textures, and textures depicting abstract art are processed less efficiently than natural textures. Presently, we examined how visual ERP responses (the P1 and the N1 in particular) were affected by violations of natural texture appearance. We presented participants with images depicting either natural textures or synthetic textures made from the original stimuli. Both stimulus types were additionally rendered either in positive or negative contrast. These appearance manipulations (negation and texture synthesis) preserve a range of low-level features, but also disrupt higher-order aspects of texture appearance. We recorded continuous EEG while participants completed a same/different image discrimination task using these images and measured both the P1 and N1 components over occipital recording sites. While the P1 exhibited no sensitivity to either contrast polarity or real/synthetic appearance, the N1 was sensitive to both deviations from natural appearance. Polarity reversal and synthetic appearance affected the N1 latency differently, however, suggesting a differential impact on processing. Our results suggest that stages of visual processing indexed by the P1 and N1 are sensitive to high-order statistical regularities in natural textures and also suggest that distinct violations of natural appearance impact neural responses differently.

Neural Sensitivity to Natural Image Statistics Changes during Middle Childhood

“…Our results demonstrate an intriguing developmental trajectory that suggests differential change during middle childhood with regard to the visual system's sensitivity to natural image statistics. First, with regard to our adult participants, the data largely replicate previous results we reported using a similar ERP task designed to measure the P1 and N1's responses to deviations from natural image structure (Balas & Conlin, 2015b).…”

Children's use of visual summary statistics for material categorization

“…Thus, despite important advances in characterizing visual crowding (Balas et al, 2009 ) and visual search (Rosenholtz et al, 2012 ) in terms of summary-statistic representations, these results provide additional evidence that the particular texture code used by the P–S algorithm also has important shortcomings in settings where it may seem to offer good expressive power. By itself, this is not particularly surprising to see given that material images in both tasks were presented at the fovea in this task (not in peripheral vision like many of the studies described already), and so we would expect observers to be capable of measuring features beyond those available in P–S summary statistics, as is evident in foveal tasks requiring invariant texture recognition (Balas & Conlin, 2015b ) and ERP results demonstrating sensitivity to higher-order structure at early visual components (Balas & Conlin, 2015a ) Nonetheless it is an important demonstration that material images contain diagnostic information in higher-order visual features and that observers use this information for categorization. In particular, contextualizing our results this way is useful because whereas studies examining the limits of true metamerism for the P–S representation of textures (or other representations such as those obtained from deep neural nets) usually emphasize discrimination at the level of an image, the representational vocabulary of such a feature set can also be evaluated at the level of a category even if the image level representation is not high-fidelity.…”

Electrophysiological Correlates of Emotional Content and Volume Level in Spoken Word Processing

“…Independent of emotional aspects, N1 and P1 amplitudes are comparably modulated by both objects in near space (Kasai et al, 2003 ; Valdés-Conroy et al, 2014 ) and by bigger images (Nakayama and Fujimoto, 2015 ; Pfabigan et al, 2015 ), indicating a close link between image size and proximity. Similarly, these early stages of perceptual processing were shown to be impacted by other stimulus features as brightness, contrast, and texture appearance (Johannes et al, 1995 ; Balas and Conlin, 2015 ; Schettino et al, 2016 ).…”