Illusory contours: a window onto the neurophysiology of constructing perception

Murray, Micah M.; Herrmann, Christoph S.

doi:10.1016/j.tics.2013.07.004

Cited by 73 publications

(95 citation statements)

References 116 publications

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“…for stimuli defined by luminance contrast and at 93ms for stimuli defined by chromatic contrast (Figure 2d). In general, the timing of the IC effects for both types of stimulus contrast are consistent with prior findings using high-contrast luminance stimuli (Knebel and Murray, 2012;Murray and Herrmann, 2013;Murray et al, 2002).…”

Section: Timing Of the Ic Effect As A Function Of Type Of Stimulus Cosupporting

confidence: 88%

“…during the P1/N1 components of the VEP) and is localised to the bilateral LOC . This IC effect has been observed across various manipulations of low-level stimulus features inducing ICs, including contrast polarity, eccentricity, types of inducers, and modal/amodal completion (Murray and Herrmann, 2013). However, a major shortcoming of all prior neurophysiologic studies of IC sensitivity in animals and humans is that the employed stimuli were invariably high in contrast (black and white, in fact).…”

Section: Introductionmentioning

confidence: 91%

“…The employed forms have been used in prior IC studies by our group and are known to result in similar IC sensitivity (Knebel and Murray, 2012;Knebel et al, 2011;Murray and Herrmann, 2013).…”

Section: Stimuli and Taskmentioning

confidence: 99%

“…These perceptions, including ICs, have been the subject of extensive theoretical debate and experimental research across species (Murray and Herrmann, 2013). A commonly-used stimulus was popularized by Kanizsa (1976) and includes an array of circular sectors (pacmen), whose mouths are oriented so to induce ICs or, alternatively, rotated as to prevent such perceptions (hereafter nocontour; NC) (Figure 1).…”

Section: Introductionmentioning

confidence: 99%

“…Several competing models have been proposed regarding how the brain produces ICs (Murray and Herrmann, 2013). Some propose that low-level areas V1/V2 mediate IC sensitivity in a feed-forward manner (Grosof et al, 1993;Nieder and Wagner, 1999;Redies et al, 1986;von der Heydt et al, 1984).…”

Section: Introductionmentioning

confidence: 99%

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Cue-dependent circuits for illusory contours in humans

et al. 2016

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Objects' borders are readily perceived despite absent contrast gradients, e.g. due to poor lighting or occlusion. In humans, a visual evoked potential (VEP) correlate of illusory contour (IC) sensitivity, the "IC effect", has been identified with an onset at ~90ms and generators within bilateral lateral occipital cortices (LOC). The IC effect is observed across a wide range of stimulus parameters, though until now it always involved high-contrast achromatic stimuli. Whether IC perception and its brain mechanisms differ as a function of the type of stimulus cue remains unknown. Resolving such will provide insights on whether there is a unique or multiple solutions to how the brain binds together spatially fractionated information into a cohesive perception. Here, participants discriminated IC from no-contour (NC) control stimuli that were either comprised of low-contrast achromatic stimuli or instead isoluminant chromatic contrast stimuli (presumably biasing processing to the magnocellular and parvocellular pathways, respectively) on separate blocks of trials. Behavioural analyses revealed that ICs were readily perceived independently of the stimulus cue -i.e. when defined by either chromatic or luminance contrast. VEPs were analysed within an electrical neuroimaging framework and revealed a generally similar timing of IC effects across both stimulus contrasts (i.e. at ~90ms). Additionally, an overall phase shift of the VEP on the order of ~30ms was consistently observed in response to chromatic vs. luminance contrast independently of the presence/absence of ICs. Critically, topographic differences in the IC effect were observed over the ~110-160ms period; different configurations of intracranial sources contributed to IC sensitivity as a function of stimulus contrast. Distributed source estimations localized these differences to LOC as well as V1/V2. The present data expand current models by demonstrating the existence of multiple, cue-dependent circuits in the brain for generating perceptions of illusory contours.

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Section: Timing Of the Ic Effect As A Function Of Type Of Stimulus Cosupporting

confidence: 88%

Section: Introductionmentioning

confidence: 91%

Section: Stimuli and Taskmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Cue-dependent circuits for illusory contours in humans

et al. 2016

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Representation of illusory and physical rotations in human MST: A cortical site for the pinna illusion

Pan

Wang

et al. 2016

Hum. Brain Mapp.

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Visual illusions have fascinated mankind since antiquity, as they provide a unique window to explore the constructive nature of human perception. The Pinna illusion is a striking example of rotation perception in the absence of real physical motion. Upon approaching or receding from the Pinna-Brelstaff figure, the observer experiences vivid illusory counter rotation of the two rings in the figure. Although this phenomenon is well known as an example of integration from local cues to a global percept, the visual areas mediating the illusory rotary perception in the human brain have not yet been identified. In the current study we investigated which cortical area in the human brain initially mediates the Pinna illusion, using psychophysical tests and functional magnetic resonance imaging (fMRI) of visual cortices V1, V2, V3, V3A, V4, and hMT+ of the dorsal and ventral visual pathways. We found that both the Pinna-Brelstaff figure (illusory rotation) and a matched physical rotation control stimulus predominantly activated subarea MST in hMT+ with a similar response intensity. Our results thus provide neural evidence showing that illusory rotation is initiated in human MST rather than MT as if it were physical rotary motion. The findings imply that illusory rotation in the Pinna illusion is mediated by rotation-sensitive neurons that normally encode physical rotation in human MST, both of which may rely on a cascade of similar integrative processes from earlier visual areas. Hum Brain Mapp 37:2097-2113, 2016. © 2016 Wiley Periodicals, Inc.

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Feedback from lateral occipital cortex to V1/V2 triggers object completion: Evidence from functional magnetic resonance imaging and dynamic causal modeling

Chen

Weidner

Zeng

et al. 2021

Human Brain Mapping

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Illusory figures demonstrate the visual system's ability to integrate disparate parts into coherent wholes. We probed this object integration process by either presenting an integrated diamond shape or a comparable ungrouped configuration that did not render a complete object. Two tasks were used that either required localization of a target dot (relative to the presented configuration) or discrimination of the dot's luminance. The results showed that only when the configuration was task relevant (in the localization task), performance benefited from the presentation of an integrated object. Concurrent functional magnetic resonance imaging was performed and analyzed using dynamic causal modeling to investigate the (causal) relationship between regions that are associated with illusory figure completion. We found object‐specific feedback connections between the lateral occipital cortex (LOC) and early visual cortex (V1/V2). These modulatory connections persisted across task demands and hemispheres. Our results thus provide direct evidence that interactions between mid‐level and early visual processing regions engage in illusory figure perception. These data suggest that LOC first integrates inputs from multiple neurons in lower‐level cortices, generating a global shape representation while more fine‐graded object details are then determined via feedback to early visual areas, independently of the current task demands.

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Illusory contours: a window onto the neurophysiology of constructing perception

Cited by 73 publications

References 116 publications

Cue-dependent circuits for illusory contours in humans

Cue-dependent circuits for illusory contours in humans

Representation of illusory and physical rotations in human MST: A cortical site for the pinna illusion

Feedback from lateral occipital cortex to V1/V2 triggers object completion: Evidence from functional magnetic resonance imaging and dynamic causal modeling

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