Foreground-background segmentation revealed during natural image viewing

Papale, Paolo; Leo, Andrea; Cecchetti, Luca; Handjaras, Giacomo; Kay, Kendrick; Pietrini, Pietro; Ricciardi, Emiliano

doi:10.1101/109496

Cited by 4 publications

(1 citation statement)

References 60 publications

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“…Temporal dynamics analysis has shown that low-level properties like contrast and spatial frequencies, medial-axis like shape and category have an independent process at the early time window (100-150 ms) (Papale et al, 2019). Hence, the object shape is encoded along different dimensions and each representing orthogonal features (Papale et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

An fMRI study of visual geometric shapes processing

Wei

Huang

et al. 2023

Front. Neurosci.

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Cross-modal correspondence has been consistently evidenced between shapes and other sensory attributes. Especially, the curvature of shapes may arouse the affective account, which may contribute to understanding the mechanism of cross-modal integration. Hence, the current study used the functional magnetic resonance imaging (fMRI) technique to examine brain activity’s specificity when people view circular and angular shapes. The circular shapes consisted of a circle and an ellipse, while the angular shapes consisted of a triangle and a star. Results show that the brain areas activated by circular shapes mainly involved the sub-occipital lobe, fusiform gyrus, sub and middle occipital gyrus, and cerebellar VI. The brain areas activated by angular shapes mainly involve the cuneus, middle occipital gyrus, lingual gyrus, and calcarine gyrus. The brain activation patterns of circular shapes did not differ significantly from those of angular shapes. Such a null finding was unexpected when previous cross-modal correspondence of shape curvature was considered. The different brain regions detected by circular and angular shapes and the potential explanations were discussed in the paper.

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Section: Introductionmentioning

confidence: 99%

An fMRI study of visual geometric shapes processing

Wei

Huang

et al. 2023

Front. Neurosci.

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The influence of objecthood on the representation of natural images in the visual cortex

Papale

Zuiderbaan

Teeuwen

et al. 2021

Preprint

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Neurons in early visual cortex are not only sensitive to the image elements in their receptive field but also to the context determining whether the elements are part of an object or background. We here assessed the effect of objecthood in natural images on neuronal activity in early visual cortex, with fMRI in humans and electrophysiology in monkeys. We report that boundaries and interiors of objects elicit more activity than the background. Boundary effects occur remarkably early, implying that visual cortical neurons are tuned to features characterizing object boundaries in natural images. When a new image is presented the influence of the object interiors on neuronal activity occurs during a late phase of neuronal response and earlier when eye movements shift the image representation, implying that object representations are remapped across eye-movements. Our results reveal how object perception shapes the representation of natural images in early visual cortex.

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Feedback brings scene information to the representation of occluded image regions in area V1 of monkeys and humans

Papale

Wang

Morgan

et al. 2022

Preprint

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Neuronal activity in the primary visual cortex (V1) is driven by feedforward input from within the neurons’ receptive fields (RFs) and modulated by contextual information in regions surrounding the RF. The effect of contextual information on spiking activity occurs rapidly, and is therefore challenging to dissociate from feedforward input. To address this challenge, we recorded the spiking activity of V1 neurons in monkeys viewing either natural scenes or scenes where the information in the RF was occluded, effectively removing the feedforward input. We found that V1 neurons responded rapidly and selectively to occluded scenes. V1 responses elicited by occluded stimuli could be used to decode scene identity and could be predicted from those elicited by non-occluded images, indicating that there is overlap between visually-driven and contextual responses. We used representational similarity analysis to show that the structure of V1 representations of occluded scenes measured with electrophysiology in monkeys correlates strongly with the representations of the same scenes in humans measured with fMRI. Our results reveal that contextual influences alter the spiking activity of V1 in monkeys across large distances on a rapid time scale, carry information about scene identity and resemble those in human V1.

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Foreground-background segmentation revealed during natural image viewing

Abstract: One of the major challenges in visual neuroscience is represented by foregroundbackground segmentation. Data from nonhuman primates show that segmentation leads to two

Cited by 4 publications

References 60 publications

An fMRI study of visual geometric shapes processing

An fMRI study of visual geometric shapes processing

The influence of objecthood on the representation of natural images in the visual cortex

Feedback brings scene information to the representation of occluded image regions in area V1 of monkeys and humans

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