The Representation of Brightness in Primary Visual Cortex

Rossi, Andrew F.; Rittenhouse, Cynthia D.; Paradiso, Michael A.

doi:10.1126/science.273.5278.1104

Cited by 255 publications

(173 citation statements)

References 16 publications

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“…The perceived brightness of a surface depends not only on surface luminance but also on the luminance distribution in the surrounding visual field (26, ʈ). It has already been demonstrated in cats and monkeys that single neurons in primary visual cortex exhibit a surround modulation that matches contextual effects in human brightness perception (6,9,27,28). By establishing the dynamics of surface-related responses in early visual cortex, our findings therefore provide the fundamental information necessary for the interpretation of future neuroimaging studies of contextual effects in human subjects.…”

Section: Discussionmentioning

confidence: 85%

“…Theoretical accounts of surface perception have therefore often postulated a processing of ''filling in'' that mediates creation of surface representations at some level in the visual system (4,5). However, more recent reports suggest that some cells in primary visual cortex do indeed respond to the luminance of uniform surfaces (6)(7)(8)(9)(10). Furthermore, in humans there is a close relationship between perceived brightness contrast and responses in primary visual cortex (11)(12)(13)(14)(15), suggesting that other sensations of brightness may also be encoded in primary visual cortex.…”

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confidence: 96%

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Responses of human visual cortex to uniform surfaces

Haynes

Lotto

Rees

2004

Proc. Natl. Acad. Sci. U.S.A.

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Surface perception is fundamental to human vision, yet most studies of visual cortex have focused on the processing of borders. We therefore investigated the responses of human visual cortex to parametric changes in the luminance of uniform surfaces by using functional MRI. Early visual areas V1 and V2͞V3 showed strong and reliable increases in signal for both increments and decrements in surface luminance. Responses were significantly larger for decrements than for increments, which was fully accounted for by differences in retinal illumination arising from asymmetric pupil dynamics. Responses to both sustained and transient changes of illumination were transient. Signals in early visual cortex scaled linearly with the magnitude of change in retinal illumination, as did subjects' subjective ratings of the perceived brightness of the stimuli. Our findings show that early visual cortex responds strongly to surfaces and that perception of surface brightness is compatible with brain responses at the earliest cortical stages of processing.T he perception of surfaces is fundamental to visual behavior, yet little is known about how they are processed in visual cortex. Early studies suggested that neurons in visual cortex respond strongly to edges but only weakly or not at all to uniform illumination (1). Subsequent work has therefore focused almost exclusively on neural mechanisms of contour processing. Indeed, in most contemporary computational models, visual cortical cells are characterized as filters that are unresponsive to uniform illumination (2, 3). The presence of strong edge responses and weak surface responses in early visual cortex is contrary to the intuition that perception of surface brightness should be mediated by neurons responding strongly to the entire spatial extent of a surface. Theoretical accounts of surface perception have therefore often postulated a processing of ''filling in'' that mediates creation of surface representations at some level in the visual system (4, 5). However, more recent reports suggest that some cells in primary visual cortex do indeed respond to the luminance of uniform surfaces (6-10). Furthermore, in humans there is a close relationship between perceived brightness contrast and responses in primary visual cortex (11)(12)(13)(14)(15), suggesting that other sensations of brightness may also be encoded in primary visual cortex. However, the cortical response function for surfaces of uniform luminance in early visual areas, and its relationship to perceived brightness, has remained uninvestigated.We therefore sought to address this question by using functional MRI (fMRI) to characterize the relationship between parametric variations in surface luminance, cortical responses, and perceived brightness. Understanding such a relationship is a prerequisite for a complete understanding of the general mechanisms and principles that underlie perception of brightness.When studying responses to uniform surfaces, it is critical to avoid contamination by contour-related processes. With ...

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Section: Discussionmentioning

confidence: 85%

mentioning

confidence: 96%

Responses of human visual cortex to uniform surfaces

Haynes

Lotto

Rees

2004

Proc. Natl. Acad. Sci. U.S.A.

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“…Neurophysiological studies of monkey and cat visual cortex provide some support for the filling-in hypothesis. A small proportion of neurons, responding to the interiors of achromatic surfaces, exhibit properties consistent with aspects of human brightness constancy (MacEvoy and Paradiso, 2001), brightness induction (Rossi et al, 1996;Rossi and Paradiso, 1999;Kinoshita and Komatsu, 2001;Peng and Van Essen, 2005), the Craik-Cornsweet-O'Brian brightness illusion (Hung et al, 2001; Roe et al, 2005), and surface completion of the retinal blind spot (Komatsu et al, 2000(Komatsu et al, , 2002. No neurophysiological study, however, has yet revealed evidence of a topographic cortical representation corresponding to uniform surface regions von der Heydt et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

No Functional Magnetic Resonance Imaging Evidence for Brightness and Color Filling-In In Early Human Visual Cortex

Cornelissen¹,

Wade²,

Vladusich³

et al. 2006

J. Neurosci.

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The brightness and color of a surface depends on its contrast with nearby surfaces. For example, a gray surface can appear very light when surrounded by a black surface or dark when surrounded by a white surface. Some theories suggest that perceived surface brightness and color is represented explicitly by neural signals in cortical visual field maps; these neural signals are not initiated by the stimulus itself but rather by the contrast signals at the borders. Here, we use functional magnetic resonance imaging (fMRI) to search for such neural "filling-in" signals. Although we find the usual strong relationship between local contrast and fMRI response, when perceived brightness or color changes are induced by modulating a surrounding field, rather than the surface itself, we find there is no corresponding local modulation in primary visual cortex or other nearby retinotopic maps. Moreover, when we model the obtained fMRI responses, we find strong evidence for contributions of both local and long-range edge responses. We argue that such extended edge responses may be caused by neurons previously identified in neurophysiological studies as being brightness responsive, a characterization that may therefore need to be revised. We conclude that the visual field maps of human V1 and V2 do not contain filled-in, topographical representations of surface brightness and color.

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“…How the brain encodes such local and global brightness cues is unknown. Only a few studies have examined neuronal response to uniform surfaces (4)(5)(6)(7)(8)(9). These studies have shown that although cells modulated by luminance change are found as early as the retina and lateral geniculate nucleus (LGN), those modulated by perceived brightness change, which occur independent of actual luminance change over the receptive field (RF), can be found as early as the primary visual cortex (V1).…”

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confidence: 99%

Cortical processing of a brightness illusion

Roe

Hung

2005

Proc. Natl. Acad. Sci. U.S.A.

105

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Several brightness illusions indicate that borders can affect the perception of surfaces dramatically. In the Cornsweet illusion, two equiluminant surfaces appear to be different in brightness because of the contrast border between them. Here, we report the existence of cells in monkey visual cortex that respond to such an ''illusory'' brightness. We find that luminance responsive cells are located in color-activated regions (cytochrome oxidase blobs and bridges) of primary visual cortex (V1), whereas Cornsweet responsive cells are found preferentially in the color-activated regions (thin stripes) of second visual area (V2). This colocalization of brightness and color processing within V1 and V2 suggests a segregation of contour and surface processing in early visual pathways and a hierarchy of brightness information processing from V1 to V2 in monkeys.Cornsweet ͉ optical imaging ͉ thin stripes T he perception of surface brightness is influenced not only by local surface luminance but also by luminance and border contrast cues in the surrounding scene. Influence of nonlocal cues on brightness perception are illustrated by stimuli, such as simultaneous contrast stimuli (1), Mondrians (2), and scenes with 3D perceptual interpretations (3). How the brain encodes such local and global brightness cues is unknown. Only a few studies have examined neuronal response to uniform surfaces (4-9). These studies have shown that although cells modulated by luminance change are found as early as the retina and lateral geniculate nucleus (LGN), those modulated by perceived brightness change, which occur independent of actual luminance change over the receptive field (RF), can be found as early as the primary visual cortex (V1). Little is known regarding the functional organization of brightness processing in the visual system (cf. ref. 10, in cat visual cortex).Here, we examine the functional organization of brightness processing in the first two stages of Macaque monkey visual cortex, V1 and second visual area (V2). Monkeys have organization of the early visual pathways and perception of brightness similar to those of humans (11,12). Many single-unit recording (13-20), 2-deoxyglucose (21-23), and optical imaging studies (19, 20, 24-29, §) have demonstrated functional organization for the processing of contours and color. Such functional organization does not suggest strict segregation because each functional structure contains a mixture of neurons with varying selectivities. However, as demonstrated by optical imaging, there are clear differences in the overall population response within each structure. In V1, imaging for color, monocularity, or low spatial frequency response reveals patterns of activation that correlate well with cytochrome oxidase blobs (25, 26, 29-31, §). Domains of color activations in V1 tend to be larger than cytochrome oxidase blobs, and they occasionally span two neighboring blobs via cytochrome oxidase bridges (30). Thus, imaging for color is useful for revealing locations of cytochrome oxidase blob...

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The Representation of Brightness in Primary Visual Cortex

Cited by 255 publications

References 16 publications

Responses of human visual cortex to uniform surfaces

Responses of human visual cortex to uniform surfaces

No Functional Magnetic Resonance Imaging Evidence for Brightness and Color Filling-In In Early Human Visual Cortex

Cortical processing of a brightness illusion

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