The representation of the ipsilateral visual field in human cerebral cortex

Tootell, Roger B. H.; Mendola, Janine D.; Hadjikhani, Nouchine; Liu, Arthur K.; Dale, Anders M.

doi:10.1073/pnas.95.3.818

Cited by 229 publications

(182 citation statements)

References 43 publications

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“…Negative responses are found in the most foveal and peripheral parts of the response curves. This could indicate the presence of mechanisms generating a negative BOLD response (Tootell et al, 1998;Shmuel et al, 2002;Smith et al, 2004). In principle, this effect could mask small signals associated with the putative filling-in process.…”

Section: Resultsmentioning

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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Section: Resultsmentioning

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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“…There are also no callosal connections between the quadrants in V1 and V2 (26). Thus, the behavioral and neural integration we observed must reflect either feedback from higher cortical areas with bilateral receptive fields (35) or indirect subcortical connections (16). To test the latter hypothesis, we examined activity in the superior colliculus and the pulvinar, identified anatomically according to criteria described in ref.…”

Section: Resultsmentioning

confidence: 99%

Attentional integration between anatomically distinct stimulus representations in early visual cortex

Haynes

Tregellas

Rees

2005

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

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Vision often requires attending to, and integrating information from, distant parts of the visual field. However, the neural basis for such long-range integration is not clearly understood. Here, we demonstrate a specific neural signature of attentional integration between stimuli in different parts of the visual field. Using functional MRI, we found that a task requiring the integration of information between two attended but spatially separated stimuli actively modulated the degree of functional integration (in terms of effective connectivity) between their retinotopic representations in visual cortical areas V1, V2, and V4. Spatial attention enhanced long-distance coupling between distinct neuronal populations that represented the attended visual stimuli, even at the earliest stages of cortical processing. In contrast, unattended stimulus representations were decoupled both from attended representations and particularly strongly from each other. Furthermore, enhanced functional integration between cortical representations was associated with enhanced behavioral performance. Attention may thus serve to ''bind'' together cortical loci at multiple levels of the visual hierarchy that are commonly involved in processing attended stimuli, promoting integration between otherwise functionally isolated cortical loci.attention ͉ connectivity ͉ dynamic causal modeling ͉ functional MRI ͉ vision V ision often requires integration of information from distant locations within the visual field, but how this integration is achieved is currently not well understood. Receptive field properties of visually responsive cortical neurons suggest that, in early visual cortex, information is analyzed largely (although not entirely) locally, with further processing stages combining information from successively larger portions of the visual field (1-3). In such an anatomically convergent pathway, integration of information from distant positions within the visual field might occur entirely in higher visual areas, which have large receptive fields and corresponding possibilities for interactions between distant regions (1-3). However, response properties of cells in early visual areas are also modulated by remote stimuli presented far beyond their classical receptive fields (4-7). Thus, an alternate possibility is that a neural signature reflecting integration of distant information might already be identifiable in very early visual cortex. Possible anatomical substrates for such interactions include long-range horizontal projections within visual areas (8-10), the dense and reciprocal connections between visual areas (7,(11)(12)(13)(14)(15), and subcortical pathways via pulvinar and superior colliculus (16).Here, we used functional MRI (fMRI) in humans to test whether task-dependent interactions between stimulus representations in distant parts of the visual field could be seen in early retinotopic cortex. We placed stimuli in four well separated locations of the visual field and required participants to attend to and integrate informa...

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“…These results were replicated by DeYoe et al (1996) and Engel et al (1997), also utilizing a cortical surface-based analysis but manually distinguishing the borders based on polar-angle information. Further phase-encoded mapping studies with modifications of the stimulus revealed visual areas V3A (DeYoe et al, 1996;Tootell et al, 1997Tootell et al, , 1998c, V3B (Press et al, 2001;Smith et al, 1998), V7 (Mendola et al, 1999;Press et al, 2001;Tootell et al, 1998a,c;Tootell and Hadjikhani, 2001), V8 , a putative homologue of the lateral intraparietal area (LIP) (Sereno et al, 2001), and retinotopic organization in human MT/V5 (Huk et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Automatic volumetric segmentation of human visual retinotopic cortex

et al. 2003

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Previous identification of early visual cortical areas in humans with phase-encoded retinotopic mapping techniques have relied on an accurate cortical surface reconstruction. Here a 3D phase-encoded retinotopic mapping technique that does not require a reconstruction of the cortical surface is demonstrated. The visual field sign identification is completely automatic and the method directly supplies volumes for a region-of-interest analysis, facilitating the application of cortical mapping to a wider population. A validation of the method is provided by simulations and comparison to cortical surface-based methodology.

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The representation of the ipsilateral visual field in human cerebral cortex

Cited by 229 publications

References 43 publications

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

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

Attentional integration between anatomically distinct stimulus representations in early visual cortex

Automatic volumetric segmentation of human visual retinotopic cortex

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