Discrimination of the local orientation structure of spiral Glass patterns early in human visual cortex

Mannion, Damien J.; McDonald, J. Scott; Clifford, Colin W. G.

doi:10.1016/j.neuroimage.2009.01.052

Cited by 60 publications

(72 citation statements)

References 21 publications

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“…More recently, a human brain imaging study by Apthorp et al (2013) showed that motion streaks are likely to be extracted at early stages of visual analysis, implying that motion and form, while seemingly separate, are processed and combined as early as the primary visual cortex. In addition, there is brain imaging and psychophysical evidence that early visual areas can encode and pool the sparse local orientation cues in translational GPs (Ohla et al, 2005;Ostwald et al, 2008;Mannion et al, 2009Mannion et al, , 2010Pavan et al, 2016).…”

Section: Discussionmentioning

confidence: 99%

The interaction between orientation and motion signals in moving oriented Glass patterns

et al. 2017

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Previous psychophysical evidence suggests that motion and orientation processing systems interact asymmetrically in the human visual system, with orientation information having a stronger influence on the perceived motion direction than vice-versa. To investigate the mechanisms underlying this motion-form interaction we used moving and oriented Glass patterns (GPs), which consist of randomly distributed dot pairs (dipoles) that induce the percept of an oriented texture. In Experiment 1 we varied the angle between dipole orientation and motion direction (conflict angle). In separate sessions participants either judged the orientation or motion direction of the GP. In addition, the spatiotemporal characteristics of dipole motion were manipulated as a way to limit (Experiment 1) or favour (Experiment 2) the availability of orientation signals from motion (motion streaks). The results of Experiment 1 showed that apparent GP motion direction is attracted towards dipole orientation, and apparent GP orientation is repulsed from GP motion. The results of Experiment 2 showed stronger repulsion effects when judging the GP orientation, but stronger motion streaks from the GP motion can dominate over the signals provided by conflicting dipole orientation. These results are consistent with the proposal that two separate mechanisms contribute to our perception of stimuli which contain conflicting orientation and motion information: (i) perceived GP motion is mediated by spatial motion-direction sensors, in which signals from motion sensors are combined with excitatory input from orientationtuned sensors tuned to orientations parallel to the axis of GP motion, (ii) perceived GP orientation is mediated by orientation-tuned sensors which mutually inhibit each other. The two mechanisms are revealed by the different effects of conflict angle and dipole lifetime on perceived orientation and motion direction.

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Section: Discussionmentioning

confidence: 99%

The interaction between orientation and motion signals in moving oriented Glass patterns

et al. 2017

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“…Such variation in sensory encoding could arise, for example, due to feedback from downstream areas selective for global shape (Pasupathy and Connor, 2002;Ostwald et al, 2008;Williams et al, 2008;Mannion et al, 2010b;Mannion and Clifford, 2011) or from differences in attention to the different kinds of stimuli (Wannig et al, 2011). However, we were able to predict responses to one type of large pattern (spirals) by measuring responses to another type of large pattern (grating), implying that the orientation preference of a voxel generalizes between stimuli and is robust to differences in global context.…”

Section: Discussionmentioning

confidence: 99%

“…Random irregularities in this organization for orientation may yield small but reliable biases in voxel responses (Boynton, 2005;Kamitani and Tong, 2005). An alternative interpretation is that orientation decoding exploits a coarse-scale organization, including biases for radial and cardinal orientations (Furmanski and Engel, 2000;Sasaki et al, 2006;Mannion et al, 2010a;Freeman et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Coarse-Scale Biases for Spirals and Orientation in Human Visual Cortex

2013

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Multivariate decoding analyses are widely applied to functional magnetic resonance imaging (fMRI) data, but there is controversy over their interpretation. Orientation decoding in primary visual cortex (V1) reflects coarse-scale biases, including an over-representation of radial orientations. But fMRI responses to clockwise and counter-clockwise spirals can also be decoded. Because these stimuli are matched for radial orientation, while differing in local orientation, it has been argued that fine-scale columnar selectivity for orientation contributes to orientation decoding. We measured fMRI responses in human V1 to both oriented gratings and spirals. Responses to oriented gratings exhibited a complex topography, including a radial bias that was most pronounced in the peripheral representation, and a near-vertical bias that was most pronounced near the foveal representation. Responses to clockwise and counter-clockwise spirals also exhibited coarse-scale organization, at the scale of entire visual quadrants. The preference of each voxel for clockwise or counterclockwise spirals was predicted from the preferences of that voxel for orientation and spatial position (i.e., within the retinotopic map). Our results demonstrate a bias for local stimulus orientation that has a coarse spatial scale, is robust across stimulus classes (spirals and gratings), and suffices to explain decoding from fMRI responses in V1.

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“…Most such studies have conducted separate MVPA analyses in two or more different brain regions and have confined analysis and conclusions to statements of whether performance is or is not significantly above chance in each area, with no explicit comparison across areas (Brouwer and Ee, 2007;Etzel et al, 2008;Fu et al, 2008;Haynes et al, 2007;Li et al, 2007;Mannion et al, 2009;Preston et al, 2008;Serences and Boynton, 2007;Sterzer et al, 2008). In such cases, any indication that one brain area has greater specificity for the experimental variable than another is implicit, or at least not endorsed by statistical comparisons.…”

Section: Introductionmentioning

confidence: 99%