Rescaling Retinal Size into Perceived Size: Evidence for an Occipital and Parietal Bottleneck

Abstract

The spatial and temporal context of an object influence its perceived size. Two visual illusions illustrate this nicely: the size adaptation effect and the Ebbinghaus illusion. Whereas size adaptation affects size rescaling of a target circle via a previously presented, differently sized adaptor circle, the Ebbinghaus illusion alters perceived size by virtue of surrounding circles. In the classical Ebbinghaus setting, the surrounding circles are shown simultaneously with the target. However, size underestimation persists when the surrounding circles precede the target. Such a temporal separation of inducer and target circles in both illusions permits the comparison of BOLD signals elicited by two displays that, although objectively identical, elicit different percepts. The current study combined both illusions in a factorial design to identify a presumed common central mechanism involved in rescaling retinal into perceived size. At the behavioral level, combining both illusions did not affect perceived size further. At the neural level, however, this combination induced functional activation beyond that induced by either illusion separately: An underadditive activation pattern was found within left lingual gyrus, right supramarginal gyrus, and right superior parietal cortex. These findings provide direct behavioral and functional evidence for the presence of a neural bottleneck in rescaling retinal into perceived size, a process vital for visual perception.

Distinct Contributions of Genes and Environment to Visual Size Illusion and the Underlying Neural Mechanism

“…This pattern of results suggests that the underestimation and the overestimation portions might be supported by different neural mechanisms. Considering that brain responses only in the visual cortex and parts of the parietal and the temporal regions were recorded (a limited number of channels were available for simultaneous recording), it is possible that the underestimation portion of the Ebbinghaus illusion engages critical neural processing in other brain regions (e.g., the frontal cortex; Kreutzer et al. 2015 ) than the recorded sites, which might account for the heritability observed with the behavioral underestimation effect.…”

“…2013 ), the extrastriate cortex ( Frassinetti et al. 1999 ; Kreutzer et al. 2015 ), the lateral occipital complex ( Weidner and Fink 2007 ; Mancini et al.…”

Size aftereffect is non-local

“…Pooresmaeili, Arrighi, Biagi, & Morrone, 2013;Kreutzer, Fink, & Weidner, 2015;Laycock, Sherman, Sperandio, & Chouinard, 2017;Zeng, Kreutzer, Fink, & Weidner, 2017) have mainly addressed where in the visual pathway the size aftereffect emerges. But relatively few studies investigated the spatial aspects of the size adaptation (Kreutzer, Ralph, & Fink, 2015). Most critically, previous studies on size adaptation tested the perceptual effect always at the same visuospatial location as the adapter.…”

The spatial properties of adaptation-induced distance compression

“…Functional magnetic resonance brain imaging studies have reported that the size of the activated area of V1 is related to the perceived rather than retinal size of a stimulus ( Murray, Boyaci, & Kersten, 2006 ; Pooresmaeili, Arrighi, Biagi, & Morrone, 2013 ; Sperandio, Chouinard, & Goodale, 2012 ). The lateral occipital cortex and the superior parietal cortex have also been implicated in illusory size perception ( Kreutzer, Weidner, & Fink, 2015 ; Plewan, Weidner, Eickhoff, & Fink, 2015 ; Shen, Zhang, & Chen, 2016 ; Zeng, Fink, & Weidner, 2020 ), with feedback projections to the early visual areas having been proposed to mediate the changes seen in early visual cortex ( Chen et al, 2019 ; Koivisto, Railo, Revonsuo, Vanni, & Salminen-Vaparanta, 2011 ; Zeng et al, 2020 ). Furthermore, there is some evidence that size aftereffects can transfer across space ( Altan & Boyaci, 2020 ; Corbett & Melcher, 2013 ), suggesting that additional mechanisms beyond primary visual cortex contribute to size perception.…”