Predictive coding for motion stimuli in human early visual cortex

Schellekens, Wouter; Wezel, Richard van; Petridou, Natalia; Ramsey, Nick F.; Raemaekers, Mathijs

doi:10.1007/s00429-014-0942-2

Cited by 38 publications

(41 citation statements)

References 42 publications

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“…An explanation can be provided by predictive coding theory, which assumes that responses in low-level visual areas signaling prediction error are suppressed when they are consistent with the higher-level prediction of motion by a single stimulus along the AM path. Such an explanation is in accordance with other studies reporting reduced V1 activation for local features that fit their surrounding context [17–19, 48, 49]. For instance, Alink et al [17] found that the predictability of stimuli in their surrounding AM context leads to reduced activation in V1.…”

Section: Discussionsupporting

confidence: 90%

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Apparent Motion Suppresses Responses in Early Visual Cortex: A Population Code Model

2016

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Two stimuli alternately presented at different locations can evoke a percept of a stimulus continuously moving between the two locations. The neural mechanism underlying this apparent motion (AM) is thought to be increased activation of primary visual cortex (V1) neurons tuned to locations along the AM path, although evidence remains inconclusive. AM masking, which refers to the reduced detectability of stimuli along the AM path, has been taken as evidence for AM-related V1 activation. AM-induced neural responses are thought to interfere with responses to physical stimuli along the path and as such impair the perception of these stimuli. However, AM masking can also be explained by predictive coding models, predicting that responses to stimuli presented on the AM path are suppressed when they match the spatio-temporal prediction of a stimulus moving along the path. In the present study, we find that AM has a distinct effect on the detection of target gratings, limiting the maximum performance at high contrast levels. This masking is strongest when the target orientation is identical to the orientation of the inducers. We developed a V1-like population code model of early visual processing, based on a standard contrast normalization model. We find that AM-related activation in early visual cortex is too small to either cause masking or to be perceived as motion. Our model instead predicts strong suppression of early sensory responses during AM, consistent with the theoretical framework of predictive coding.

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Section: Discussionsupporting

confidence: 90%

“…Presumably, early visual areas receive inhibitory feedback from the motion areas hMT/V5+ [4–6]. Several physiological studies have indeed demonstrated that sensory signals which can be predicted from their surrounding motion context evoke smaller responses in V1 [17–19]. …”

Section: Introductionmentioning

confidence: 99%

Apparent Motion Suppresses Responses in Early Visual Cortex: A Population Code Model

2016

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“…The reduction in neural response to expected inputs, hypothesized by predictive coding 6, 7 and known as expectation suppression, has been highlighted in the early visual cortex by several studies using cues to guide participants’ expectations 8, 26, 27, 32, 33 . Evidence for Expectation Suppression with more complex stimuli is sparser.…”

Section: Resultsmentioning

confidence: 99%

“…This is important, because although Expectation Suppression has been widely documented in the early visual cortex 8, 26, 27 , evidence for Expectation Suppression for more complex visual stimuli such as individual objects or faces remains limited. Two functional Magnetic Resonance Imaging (fMRI) studies report category-specific Expectation Suppression in the Fusiform Face Area (FFA), which responded less strongly to faces when participants were expecting faces rather than houses 9, 11 .…”

Section: Introductionmentioning

confidence: 99%

Unsuppressible Repetition Suppression and exemplar-specific Expectation Suppression in the Fusiform Face Area

Pajani

Kouider

Roux

et al. 2017

Sci Rep

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Recent work casts Repetition Suppression (RS), i.e. the reduced neural response to repeated stimuli, as the consequence of reduced surprise for repeated inputs. This research, along with other studies documenting Expectation Suppression, i.e. reduced responses to expected stimuli, emphasizes the role of expectations and predictive codes in perception. Here, we use fMRI to further characterize the nature of predictive signals in the human brain. Prior to scanning, participants were implicitly exposed to associations within face pairs. Critically, we found that this resulted in exemplar-specific Expectation Suppression in the fusiform face-sensitive area (FFA): individual faces that could be predicted from the associations elicited reduced FFA responses, as compared to unpredictable faces. Thus, predictive signals in the FFA are specific to face exemplars, and not only generic to the category of face stimuli. In addition, we show that under such circumstances, the occurrence of surprising repetitions did not trigger enhanced brain responses, as had been recently hypothesized, but still suppressed responses, suggesting that repetition suppression might be partly ‘unsuppressible’. Repetition effects cannot be fully modulated by expectations, which supports the recent view that expectation and repetition effects rest on partially independent mechanisms. Altogether, our study sheds light on the nature of expectation signals along the perceptual system.

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“…[13] demonstrated that the trailing edge of a motion stimulus evokes larger responses than the leading edge, at least in early visual cortex (V1-V3) but not in V5/hMT+. Furthermore, several studies showed that responses decrease gradually with distance from the trailing edge [13,14,15].Although the effects initially reported by [11] are now better understood, it still remains elusive which neuronal mechanisms underlie perceptual position shifts in humans. When monkeys and cats were presented with motion stimuli that lead to perceptual shifts for human observers, electro-physiological recordings revealed that the receptive field (RF) of V1 [10] and V4 [16] neurons were shifted against the direction of motion.…”

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confidence: 99%

Motion Displaces Population Receptive Fields in the Direction Opposite to Motion

Schneider

Marquardt

Sengupta

et al. 2019

Preprint

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Motion signals can bias the perceived position of visual stimuli. While the apparent position of a stimulus is biased in the direction of motion, electro-physiological studies have shown that the receptive field (RF) of neurons is shifted in the direction opposite to motion, at least in cats and macaque monkeys. In humans, it remains unclear how motion signals affect population RF (pRF) estimates. We addressed this question using psychophysical measurements and functional magnetic resonance imaging (fMRI) at 7 Tesla. We systematically varied two factors: the motion direction of the carrier pattern (inward, outward and flicker motion) and the contrast of the mapping stimulus (low and high stimulus contrast). We observed that while physical positions were identical across all conditions, presence of low-contrast motion, but not high-contrast motion, shifted perceived stimulus position in the direction of motion. Correspondingly, we found that pRF estimates in early visual cortex were shifted against the direction of motion for low-contrast stimuli but not for high stimulus contrast. We offer an explanation in form of a model for why apertures are perceptually shifted in the direction of motion even though pRFs shift in the opposite direction.Keywords visual neuroscience · position perception · population receptive fields · visual field projections 1 IntroductionAn important task of the visual system is to infer the location of objects in our environment. A wide range of psychophysical studies shows that motion signals lead to systematic localisation biases [1,2,3,4,5,6,7,8,9]. In illusions called motion-induced position shifts (MIPS), a coherent motion signal shifts the apparent location of a stimulus [1]. For example, when drifting Gabor patches are presented within a stationary aperture, the stimulus appears shifted in the direction of motion [2,6,7]. Such illusions raise the question how our visual system encodes location and how, in the case of MIPS, the apparent position shift can be explained. Furthermore, they offer a dissociation between the physical and the perceived position of a stimulus that can clarify which neuronal processes correspond to the apparent position of the stimulus. MOTION DISPLACES POPULATION RECEPTIVE FIELDSThe magnitude of MIPS is known to depend on spatial and temporal properties of the stimulus. MIPS are larger when the stimulus is shown for longer duration (tested up to 453 ms; [6]), presented at higher speed [6,9] or at higher eccentricities [10,6,9]. The magnitude of MIPS furthermore depends on spatial blurring of the presented stimulus. Blurred stimulus edges lead to larger perceptual displacements than sharp edges [4,9] and increasing the size of the Gaussian envelope of a Gabor stimulus yields larger MIPS [4]. Arnold et al. [7] have suggested that MIPS are driven by modulation of apparent contrast of the stimulus. Supporting this suggestion, they reported perceived position shifts when observers were asked to match the extremities of two contrast envelopes (low-contrast region),...

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Predictive coding for motion stimuli in human early visual cortex

Cited by 38 publications

References 42 publications

Apparent Motion Suppresses Responses in Early Visual Cortex: A Population Code Model

Apparent Motion Suppresses Responses in Early Visual Cortex: A Population Code Model

Unsuppressible Repetition Suppression and exemplar-specific Expectation Suppression in the Fusiform Face Area

Motion Displaces Population Receptive Fields in the Direction Opposite to Motion

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