Maps of Visual Space in Human Occipital Cortex Are Retinotopic, Not Spatiotopic

Gardner, Justin L.; Merriam, Elisha P.; Movshon, J. Anthony; Heeger, David J.

doi:10.1523/jneurosci.5476-07.2008

Cited by 189 publications

(205 citation statements)

References 80 publications

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“…Neurons with spatiotopic receptive fields were found in the parietal lobe (Galletti et al, 1995;Duhamel et al, 1997;Mullette-Gillman et al, 2005, which is part of the dorsal stream known to be involved in visuomotor processing. Enhanced spatiotopic representation for action rather than for pure visual perception can explain why our delayed saccade task showed spatiotopic effects, whereas other imaging studies using perceptual recognition tasks and strict control on spatial attention did not (Gardner et al, 2008). Concurrent with this notion, behavioral studies that used perceptual tasks, such as visual discrimination (Golomb et al, 2008) or visual matching (McKyton et al, 2009), report retinotopic effects.…”

Section: The Putative Role Of Spatiotopic Representation Of Saccadicmentioning

confidence: 50%

Multiple Reference Frames for Saccadic Planning in the Human Parietal Cortex

Pertzov¹,

Avidan²,

Zohary³

2011

J. Neurosci.

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We apply functional magnetic resonance imaging and multivariate analysis methods to study the coordinate frame in which saccades are represented in the human cortex. Subjects performed a memory-guided saccade task in which equal-amplitude eye movements were executed from several starting points to various directions. Response patterns during the memory period for same-vector saccades were correlated in the frontal eye fields and the intraparietal sulcus (IPS), indicating a retinotopic representation. Interestingly, response patterns in the middle aspect of the IPS were also correlated for saccades made to the same destination point, even when their movement vector was different. Thus, this region also contains information about saccade destination in (at least) a head-centered coordinate frame. This finding may explain behavioral and neuropsychological studies demonstrating that eye movements are also anchored to an egocentric or an allocentric representation of space rather than strictly to the retinal visual input and that parietal cortex is involved in maintaining these representations of space.

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Section: The Putative Role Of Spatiotopic Representation Of Saccadicmentioning

confidence: 50%

Multiple Reference Frames for Saccadic Planning in the Human Parietal Cortex

Pertzov¹,

Avidan²,

Zohary³

2011

J. Neurosci.

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“…Representing visual information in body-centered reference frames provides robustness against the accumulation of error over multiple saccades (Karn et al 1997), and it can be utilized for motor planning and sensor fusion (Andersen et al 1997). The retinocentric representation enables direct attentional modulation within the predominantly retinocentric visual processing stream (Gardner et al 2008). Retinocentric information also is relevant as input for the planning of saccadic eye movements.…”

Section: Discussionmentioning

confidence: 99%

A neural mechanism for coordinate transformation predicts pre-saccadic remapping

Schneegans

Schöner

2012

Biol Cybern

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Whenever we shift our gaze, any location information encoded in the retinocentric reference frame that is predominant in the visual system is obliterated. How is spatial memory retained across gaze changes? Two different explanations have been proposed: Retinocentric information may be transformed into a gaze-invariant representation through a mechanism consistent with gain fields observed in parietal cortex, or retinocentric information may be updated in anticipation of the shift expected with every gaze change, a proposal consistent with neural observations in LIP. The explanations were considered incompatible with each other, because retinocentric update is observed before the gaze shift has terminated. Here, we show that a neural dynamic mechanism for coordinate transformation can also account for retinocentric updating. Our model postulates an extended mechanism of reference frame transformation that is based on bidirectional mapping between a retinocentric and a bodycentered representation and that enables transforming multiple object locations in parallel. The dynamic coupling between the two reference frames generates a shift of the retinocentric representation for every gaze change. We account for the predictive nature of the observed remapping activity by using the same kind of neural mechanism to generate an internal representation of gaze direction that is predictively updated based on corollary discharge signals. We provide evidence for the model by accounting for a series of behavioral and neural experimental observations.

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“…The ability to classify trials with different contrast levels is in itself unsurprising because there is a well known shift in mean response level with increasing contrast, which has previously been well characterized in early visual cortex (Albrecht and Hamilton, 1982;Ohzawa et al, 1985;Boynton et al, 1999;Reich et al, 2001;Gardner et al, 2005). Most neurons in early visual cortex exhibit a monotonic increase in response as a function of contrast, but some cells show very different patterns of response saturation (and even supersaturation) with contrast (Ledgeway et al, 2005;Peirce, 2007;Hu and Wang, 2011).…”

Section: Spatial Pattern Of Responses Underlying Contrast Decodingmentioning

confidence: 99%

Decoding Working Memory of Stimulus Contrast in Early Visual Cortex

Xing

Ledgeway

McGraw

et al. 2013

Journal of Neuroscience

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Most studies of the early stages of visual analysis (V1-V3) have focused on the properties of neurons that support processing of elemental features of a visual stimulus or scene, such as local contrast, orientation, or direction of motion. Recent evidence from electrophysiology and neuroimaging studies, however, suggests that early visual cortex may also play a role in retaining stimulus representations in memory for short periods. For example, fMRI responses obtained during the delay period between two presentations of an oriented visual stimulus can be used to decode the remembered stimulus orientation with multivariate pattern analysis. Here, we investigated whether orientation is a special case or if this phenomenon generalizes to working memory traces of other visual features. We found that multivariate classification of fMRI signals from human visual cortex could be used to decode the contrast of a perceived stimulus even when the mean response changes were accounted for, suggesting some consistent spatial signal for contrast in these areas. Strikingly, we found that fMRI responses also supported decoding of contrast when the stimulus had to be remembered. Furthermore, classification generalized from perceived to remembered stimuli and vice versa, implying that the corresponding pattern of responses in early visual cortex were highly consistent. In additional analyses, we show that stimulus decoding here is driven by biases depending on stimulus eccentricity. This places important constraints on the interpretation for decoding stimulus properties for which cortical processing is known to vary with eccentricity, such as contrast, color, spatial frequency, and temporal frequency.

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Maps of Visual Space in Human Occipital Cortex Are Retinotopic, Not Spatiotopic

Cited by 189 publications

References 80 publications

Multiple Reference Frames for Saccadic Planning in the Human Parietal Cortex

Multiple Reference Frames for Saccadic Planning in the Human Parietal Cortex

A neural mechanism for coordinate transformation predicts pre-saccadic remapping

Decoding Working Memory of Stimulus Contrast in Early Visual Cortex

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