Theta motion: a paradoxical stimulus to explore higher order motion extraction

Zanker, Johannes M.

doi:10.1016/0042-6989(93)90258-x

Cited by 78 publications

(59 citation statements)

References 44 publications

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“…The mechanism for eliciting OFRs is exclusively driven by the luminance-based motion energy of the stimuli (Hayashi et al 2008;Masson et al 2002;Miura et al 2006;Sheliga et al 2005). On the other hand, motion perception is also mediated by complex processes known as a second-order or non-Fourier motion system, the processing of which cannot be understood directly in terms of the motion energy of visual inputs (Cavanagh and Mather 1989;Chubb and Sperling 1988;Fleet and Langley 1994;Lu and Sperling 2001;Nishida and Sato 1992;Zanker 1993). The measurement of the OFRs therefore allows us to specifically investigate the inter-frequency integration of the motion energy signals.…”

Section: Introductionmentioning

confidence: 99%

How Motion Signals Are Integrated Across Frequencies: Study on Motion Perception and Ocular Following Responses Using Multiple-Slit Stimuli

Hayashi

Sugita

Nishida

et al. 2010

Journal of Neurophysiology

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Hayashi R, Sugita Y, Nishida S, Kawano K. How motion signals are integrated across frequencies: study on motion perception and ocular following responses using multiple-slit stimuli. J Neurophysiol 103: 230 -243, 2010. First published November 11, 2009 doi:10.1152/jn.00064.2009. Visual motion signals, which are initially extracted in parallel at multiple spatial frequencies, are subsequently integrated into a unified motion percept. Cross-frequency integration plays a crucial role when directional information conflicts across frequencies due to such factors as occlusion. We investigated the human observers' open-loop oculomotor tracking responses (ocular following responses, or OFRs) and the perceived motion direction in an idealized situation of occlusion-multiple-slits viewing (MSV)-in which a moving pattern is visible only through an array of slits. We also tested a more challenging viewing condition, contrast-alternating MSV (CA-MSV), in which the contrast polarity of the moving pattern alternates when it passes the slits. We found that changes in the distribution of the spectral content of the slit stimuli, introduced by variations of both the interval between the slits and the frame rate of the image stream, modulated the OFR and the reported motion direction in a rather complex manner. We show that those complex modulations could be explained by the weighted sum of the motion signal (motion contrast) of each spatiotemporal frequency. The estimated distribution of frequency weights (tuning maps) indicate that the cross-frequency integration of supra-threshold motion signals gives strong weight to low spatial frequency components (Ͻ0.25 cpd) for both OFR and motion perception. However, the tuning map estimated with the MSV stimuli were significantly different from those estimated with the CA-MSV (and from those measured in a more direct manner using grating stimuli), suggesting that interfrequency interactions (e.g., interaction producing speed-dependent tuning) was involved.

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Section: Introductionmentioning

confidence: 99%

How Motion Signals Are Integrated Across Frequencies: Study on Motion Perception and Ocular Following Responses Using Multiple-Slit Stimuli

Hayashi

Sugita

Nishida

et al. 2010

Journal of Neurophysiology

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“…The oriented structure of distortion is indistinct. However, the disturbance of distortion in low frequency regions (see Sections 15,17, and 19) is apparent.…”

Section: Discussionmentioning

confidence: 99%

“…x Þ). In addition, the shape of the characteristic function ðxÞ is not explicitly described in [17], [9] (cf. (12) in [9]), while Beauchemin and Barron modified this function into a step function (cf.…”

Section: D Occlusion Spectrummentioning

confidence: 99%

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Oriented structure of the occlusion distortion: is it reliable?

Sommer²,

Beauchemin

et al. 2002

IEEE Trans. Pattern Anal. Machine Intell.

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In the energy spectrum of an occlusion sequence, the distortion term has the same orientation as the velocity of the occluding signal. Recent works claimed that this oriented structure can be used to distinguish the occluding velocity from the occluded one. Here, we argue that the orientation structure of the distortion cannot always work as a reliable feature due to the rapidly decreasing energy contribution. This already weak orientation structure is further blurred by a superposition of distinct distortion components. We also indicate that the superposition principle of Shizawa and Mase for multiple motion estimation needs to be adjusted. KeywordsOptical flow, occlusion, motion discontinuities, spectral analysis This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of the University of Pennsylvania's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to pubs-permissions@ieee.org. By choosing to view this document, you agree to all provisions of the copyright laws protecting it. Abstract-In the energy spectrum of an occlusion sequence, the distortion term has the same orientation as the velocity of the occluding signal. Recent works claimed that this oriented structure can be used to distinguish the occluding velocity from the occluded one. Here, we argue that the orientation structure of the distortion cannot always work as a reliable feature due to the rapidly decreasing energy contribution. This already weak orientation structure is further blurred by a superposition of distinct distortion components. We also indicate that the superposition principle of Shizawa and Mase for multiple motion estimation needs to be adjusted.

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“…The term "higher-order motion" refers to movement of visual objects that have no net motion energy (3) or that contain paradoxical motion cues (4). A "drift-balanced" stimulus can be described as a moving object that contains an internal pattern that varies from and replaces the background as the object itself moves, but which itself is nonmoving.…”

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confidence: 99%

Higher-order motion sensitivity in fly visual circuits

Lee

Nordström

2012

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

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In higher-order motion stimuli, the direction of object motion does not follow the direction of luminance change. Such stimuli could be generated by the wing movements of a flying butterfly and further complicated by its motion in and out of shadows. Human subjects readily perceive the direction of higher-order motion, although this stands in stark contrast to prevailing motion vision models. Flies and humans compute motion in similar ways, and because flies behaviorally track bars containing higher-order motion cues, they become an attractive model system for investigating the neurophysiology underlying higher-order motion sensitivity. We here use intracellular electrophysiology of motionvision-sensitive neurons in the hoverfly lobula plate to quantify responses to stimuli containing higher-order motion. We show that motion sensitivity can be broken down into two separate streams, directionally coding for elementary motion and figure motion, respectively, and that responses to Fourier and theta motion can be predicted from these. The sensitivity is affected both by the stimulus' time course and by the neuron's underlying receptive field. Responses to preferred-direction theta motion are sexually dimorphic and particularly robust along the visual midline.T here is broad evidence that essentially all animals with imageforming eyes compute visual motion by correlating the luminance from two neighboring photo-inputs, after delaying the signal from one of these inputs (1). The detection of such firstorder motion, or Fourier motion, therefore depends on the coherent correlation of luminance across space and time and forms the theoretical basis for the elementary motion detector (EMD) (2). However, motion signals in nature may not form exact spacetime correlations, but may also be composed of higher-order signals related to changes in contrast or texture.The term "higher-order motion" refers to movement of visual objects that have no net motion energy (3) or that contain paradoxical motion cues (4). A "drift-balanced" stimulus can be described as a moving object that contains an internal pattern that varies from and replaces the background as the object itself moves, but which itself is nonmoving. Drift-balanced bars generate no response from standard EMDs, but sensitivity can be generated by adding front-end nonlinearities to the inputs (5). "Theta motion stimuli" (4) consist of a moving object that contains an internal pattern that moves coherently in the direction opposite to the object itself. In this case, an EMD would encode the motion of the internal pattern (i.e., the elementary motion, or EM) instead of the motion of the object itself (i.e., the figure motion, or FM). Sensitivity to theta motion can be generated by, for example, layering two EMD networks (6) or by recurrent motion processing (7).Vertebrates, including human observers, readily perceive higher-order motion, including drift-balanced and theta motion, even though these contain no net EM cues in the direction of FM (for recent review, see ref. 8)....

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Theta motion: a paradoxical stimulus to explore higher order motion extraction

Cited by 78 publications

References 44 publications

How Motion Signals Are Integrated Across Frequencies: Study on Motion Perception and Ocular Following Responses Using Multiple-Slit Stimuli

How Motion Signals Are Integrated Across Frequencies: Study on Motion Perception and Ocular Following Responses Using Multiple-Slit Stimuli

Oriented structure of the occlusion distortion: is it reliable?

Higher-order motion sensitivity in fly visual circuits

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