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Melvyn A. Goodale - One of the best experts on this subject based on the ideXlab platform.
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grip Constancy but not perceptual Size Constancy survives lesions of early visual cortex
Current Biology, 2020Co-Authors: Robert L Whitwell, Philippe A Chouinard, Irene Sperandio, Gavin Buckingham, Melvyn A. GoodaleAbstract:Summary Object constancies are central constructs in theories of visual phenomenology. A powerful example is "Size Constancy," in which the perceived Size of an object remains stable despite changes in viewing distance [1–4]. Evidence from neuropsychology [5], neuroimaging [6–11], transcranial magnetic stimulation [12, 13], single-unit and lesion studies in monkey [14–20], and computational modeling [21] suggests that re-entrant processes involving reciprocal interactions between primary visual cortex (V1) and extrastriate visual areas [22–26] play an essential role in mediating Size Constancy. It is seldom appreciated, however, that object constancies must also operate for the visual guidance of goal-directed action. For example, when reaching out to pick up an object, the hand's in-flight aperture scales with Size of the goal object [27–30] and is refractory to the decrease in retinal-image Size with increased viewing distance [31–41] (Figure 1), a phenomenon we call "grip Constancy." Does grip Constancy, like perceptual Constancy, depend on V1 or can it be mediated by pathways that bypass it altogether? We tested these possibilities in an individual, M.C., who has bilateral lesions encompassing V1 and much of the ventral visual stream. We show that her perceptual estimates of object Size co-vary with retinal-image Size rather than real-world Size as viewing distance varies. In contrast, M.C. shows near-normal scaling of in-flight grasp aperture to object Size despite changes in viewing distance. Thus, although early visual cortex is necessary for perceptual object Constancy, it is unnecessary for grip Constancy, which is mediated instead by separate visual inputs to dorsal-stream visuomotor areas [42–48].
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changing the real viewing distance reveals the temporal evolution of Size Constancy in visual cortex
Current Biology, 2019Co-Authors: Irene Sperandio, Juan Chen, Molly J Henry, Melvyn A. GoodaleAbstract:Summary Our visual system provides a distance-invariant percept of object Size by integrating retinal image Size with viewing distance (Size Constancy). Single-unit studies with animals have shown that some distance cues, especially oculomotor cues such as vergence and accommodation, can modulate the signals in the thalamus or V1 at the initial processing stage [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. Accordingly, one might predict that Size Constancy emerges much earlier in time [ 8 , 9 , 10 ], even as visual signals are being processed in the thalamus. So far, the studies that have looked directly at Size coding have either used fMRI (poor temporal resolution [ 11 , 12 , 13 ]) or relied on inadequate stimuli (pictorial illusions presented on a monitor at a fixed distance [ 11 , 12 , 14 , 15 ]). Here, we physically moved the monitor to different distances, a more ecologically valid paradigm that emulates what happens in everyday life and is an example of the increasing trend of “bringing the real world into the lab.” Using this paradigm in combination with electroencephalography (EEG), we examined the computation of Size Constancy in real time with real-world viewing conditions. Our study provides strong evidence that, even though oculomotor distance cues have been shown to modulate the spiking rate of neurons in the thalamus and in V1, the integration of viewing distance cues and retinal image Size takes at least 150 ms to unfold, which suggests that the Size-Constancy-related activation patterns in V1 reported in previous fMRI studies (e.g., [ 12 , 13 ]) reflect the later processing within V1 and/or top-down input from other high-level visual areas.
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proprioceptive distance cues restore perfect Size Constancy in grasping but not perception when vision is limited
Current Biology, 2018Co-Authors: Juan Chen, Irene Sperandio, Melvyn A. GoodaleAbstract:Our brain integrates information from multiple modalities in the control of behavior. When information from one sensory source is compromised, information from another source can compensate for the loss. What is not clear is whether the nature of this multisensory integration and the re-weighting of different sources of sensory information are the same across different control systems. Here, we investigated whether proprioceptive distance information (position sense of body parts) can compensate for the loss of visual distance cues that support Size Constancy in perception (mediated by the ventral visual stream) [1, 2] versus Size Constancy in grasping (mediated by the dorsal visual stream) [3-6], in which the real-world Size of an object is computed despite changes in viewing distance. We found that there was perfect Size Constancy in both perception and grasping in a full-viewing condition (lights on, binocular viewing) and that Size Constancy in both tasks was dramatically disrupted in the restricted-viewing condition (lights off; monocular viewing of the same but luminescent object through a 1-mm pinhole). Importantly, in the restricted-viewing condition, proprioceptive cues about viewing distance originating from the non-grasping limb (experiment 1) or the inclination of the torso and/or the elbow angle of the grasping limb (experiment 2) compensated for the loss of visual distance cues to enable a complete restoration of Size Constancy in grasping but only a modest improvement of Size Constancy in perception. This suggests that the weighting of different sources of sensory information varies as a function of the control system being used.
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The Removal of Binocular Cues Disrupts the Calibration of Grasping in Patients with Visual Form Agnosia
2018Co-Authors: Jonathan J Marotta, Marlene Behrmann, Melvyn A. GoodaleAbstract:The present study tested the idea that the visuomotor systems mediating prehension do not have independent access to pictorial cues processed by perceptual mechanisms. Individuals with visual form agnosia, whose perceptual systems are compromised but who have intact visuomotor control, were examined to determine whether they could use pictorial scene cues to calibrate manual prehension when binocular information was removed. The removal of binocular cues produced considerable disruptions in Size-Constancy of grip aperture, which, combined with earlier observations in normal subjects, suggests that binocular cues are of primary importance in calibration of grasping. In the absence of binocular vision, normal subjects can use pictorial information, information that is severely compromised in individuals with visual form agnosia, to compute the distance (and thus the Size) of the goal object. Thus, individuals with visual form agnosia must rely on a retinal image that remains uncalibrated, leading to inaccurate calibrations of grip aperture. The fact that these individuals scaled their grasp much less accurately under the monocular viewing condition, despite showing normal binocular grasping, suggests that pictorial cues to depth, which are presumably processed by mechanisms mediating our perception of objects and events in the world, can be accessed by visuomotor mechanisms only indirectly. These results, together with others, suggest that the visuomotor system ‘prefers’ to use binocular information and uses pictorial cues only as a last resort
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a blind human expert echolocator shows Size Constancy for objects perceived by echoes
Neurocase, 2015Co-Authors: Jennifer L Milne, Melvyn A. Goodale, Mimma Anello, Lore ThalerAbstract:Some blind humans make clicking noises with their mouth and use the reflected echoes to perceive objects and surfaces. This technique can operate as a crude substitute for vision, allowing human echolocators to perceive silent, distal objects. Here, we tested if echolocation would, like vision, show Size Constancy. To investigate this, we asked a blind expert echolocator (EE) to echolocate objects of different physical Sizes presented at different distances. The EE consistently identified the true physical Size of the objects independent of distance. In contrast, blind and blindfolded sighted controls did not show Size Constancy, even when encouraged to use mouth clicks, claps, or other signals. These findings suggest that Size Constancy is not a purely visual phenomenon, but that it can operate via an auditory-based substitute for vision, such as human echolocation.
Irene Sperandio - One of the best experts on this subject based on the ideXlab platform.
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developmental trajectories of Size Constancy as implicitly examined by simple reaction times
Vision (Basel Switzerland), 2021Co-Authors: Irene SperandioAbstract:It is still unclear whether Size Constancy is an innate ability or whether it develops with age. As many developmental studies are limited to the child’s comprehension of the task instructions, here, an implicit measure of perceived Size, namely, simple manual reaction time (RT), was opted for based on the assumption that perceptually bigger objects generate faster detection times. We examined Size Constancy in children (from 5 to 14 years of age) and adults using a simple RT approach. Participants were presented with pictures of tennis balls on a screen that was physically moved to two viewing distances. Visual stimuli were adjusted in physical Size in order to subtend the same visual angle across distances, determining two conditions: a small-near tennis ball vs. a big-far tennis ball. Thanks to Size Constancy, the two tennis balls were perceived as different even though they were of equal Size on the retina. Stimuli were also matched in terms of luminance. Participants were asked to react as fast as possible to the onset of the stimuli. The results show that the RTs reflected the perceived rather than the retinal Size of the stimuli across the different age groups, such that participants responded faster to stimuli that were perceived as bigger than those perceived as smaller. Hence, these findings are consistent with the idea that Size Constancy is already present in early childhood, at least from the age of five, and does not require extensive visual learning.
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grip Constancy but not perceptual Size Constancy survives lesions of early visual cortex
Current Biology, 2020Co-Authors: Robert L Whitwell, Philippe A Chouinard, Irene Sperandio, Gavin Buckingham, Melvyn A. GoodaleAbstract:Summary Object constancies are central constructs in theories of visual phenomenology. A powerful example is "Size Constancy," in which the perceived Size of an object remains stable despite changes in viewing distance [1–4]. Evidence from neuropsychology [5], neuroimaging [6–11], transcranial magnetic stimulation [12, 13], single-unit and lesion studies in monkey [14–20], and computational modeling [21] suggests that re-entrant processes involving reciprocal interactions between primary visual cortex (V1) and extrastriate visual areas [22–26] play an essential role in mediating Size Constancy. It is seldom appreciated, however, that object constancies must also operate for the visual guidance of goal-directed action. For example, when reaching out to pick up an object, the hand's in-flight aperture scales with Size of the goal object [27–30] and is refractory to the decrease in retinal-image Size with increased viewing distance [31–41] (Figure 1), a phenomenon we call "grip Constancy." Does grip Constancy, like perceptual Constancy, depend on V1 or can it be mediated by pathways that bypass it altogether? We tested these possibilities in an individual, M.C., who has bilateral lesions encompassing V1 and much of the ventral visual stream. We show that her perceptual estimates of object Size co-vary with retinal-image Size rather than real-world Size as viewing distance varies. In contrast, M.C. shows near-normal scaling of in-flight grasp aperture to object Size despite changes in viewing distance. Thus, although early visual cortex is necessary for perceptual object Constancy, it is unnecessary for grip Constancy, which is mediated instead by separate visual inputs to dorsal-stream visuomotor areas [42–48].
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changing the real viewing distance reveals the temporal evolution of Size Constancy in visual cortex
Current Biology, 2019Co-Authors: Irene Sperandio, Juan Chen, Molly J Henry, Melvyn A. GoodaleAbstract:Summary Our visual system provides a distance-invariant percept of object Size by integrating retinal image Size with viewing distance (Size Constancy). Single-unit studies with animals have shown that some distance cues, especially oculomotor cues such as vergence and accommodation, can modulate the signals in the thalamus or V1 at the initial processing stage [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. Accordingly, one might predict that Size Constancy emerges much earlier in time [ 8 , 9 , 10 ], even as visual signals are being processed in the thalamus. So far, the studies that have looked directly at Size coding have either used fMRI (poor temporal resolution [ 11 , 12 , 13 ]) or relied on inadequate stimuli (pictorial illusions presented on a monitor at a fixed distance [ 11 , 12 , 14 , 15 ]). Here, we physically moved the monitor to different distances, a more ecologically valid paradigm that emulates what happens in everyday life and is an example of the increasing trend of “bringing the real world into the lab.” Using this paradigm in combination with electroencephalography (EEG), we examined the computation of Size Constancy in real time with real-world viewing conditions. Our study provides strong evidence that, even though oculomotor distance cues have been shown to modulate the spiking rate of neurons in the thalamus and in V1, the integration of viewing distance cues and retinal image Size takes at least 150 ms to unfold, which suggests that the Size-Constancy-related activation patterns in V1 reported in previous fMRI studies (e.g., [ 12 , 13 ]) reflect the later processing within V1 and/or top-down input from other high-level visual areas.
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proprioceptive distance cues restore perfect Size Constancy in grasping but not perception when vision is limited
Current Biology, 2018Co-Authors: Juan Chen, Irene Sperandio, Melvyn A. GoodaleAbstract:Our brain integrates information from multiple modalities in the control of behavior. When information from one sensory source is compromised, information from another source can compensate for the loss. What is not clear is whether the nature of this multisensory integration and the re-weighting of different sources of sensory information are the same across different control systems. Here, we investigated whether proprioceptive distance information (position sense of body parts) can compensate for the loss of visual distance cues that support Size Constancy in perception (mediated by the ventral visual stream) [1, 2] versus Size Constancy in grasping (mediated by the dorsal visual stream) [3-6], in which the real-world Size of an object is computed despite changes in viewing distance. We found that there was perfect Size Constancy in both perception and grasping in a full-viewing condition (lights on, binocular viewing) and that Size Constancy in both tasks was dramatically disrupted in the restricted-viewing condition (lights off; monocular viewing of the same but luminescent object through a 1-mm pinhole). Importantly, in the restricted-viewing condition, proprioceptive cues about viewing distance originating from the non-grasping limb (experiment 1) or the inclination of the torso and/or the elbow angle of the grasping limb (experiment 2) compensated for the loss of visual distance cues to enable a complete restoration of Size Constancy in grasping but only a modest improvement of Size Constancy in perception. This suggests that the weighting of different sources of sensory information varies as a function of the control system being used.
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Size Constancy is preserved but afterimages are prolonged in typical individuals with higher degrees of self reported autistic traits
Journal of Autism and Developmental Disorders, 2017Co-Authors: Irene Sperandio, Katy L Unwin, Oriane Landry, Philippe A ChouinardAbstract:Deficits in perceptual constancies from early infancy have been proposed to contribute to autism and exacerbate its symptoms (Hellendoorn et al., Frontiers in Psychology 6:1–16, 2015). Here, we examined Size Constancy in adults from the general population (N = 106) with different levels of self-reported autistic traits using an approach based on negative afterimages. The afterimage strength, as indexed by duration and vividness, was also quantified. In opposition to the Hellendoorn and colleagues’ model, we were unable to demonstrate any kind of relationship between abilities in Size Constancy and autistic traits. However, our results demonstrated that individuals with higher degrees of autistic traits experienced more persistent afterimages. We discuss possible retinal and post-retinal explanations for prolonged afterimages in people with higher levels of autistic traits.
Juan Chen - One of the best experts on this subject based on the ideXlab platform.
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changing the real viewing distance reveals the temporal evolution of Size Constancy in visual cortex
Current Biology, 2019Co-Authors: Irene Sperandio, Juan Chen, Molly J Henry, Melvyn A. GoodaleAbstract:Summary Our visual system provides a distance-invariant percept of object Size by integrating retinal image Size with viewing distance (Size Constancy). Single-unit studies with animals have shown that some distance cues, especially oculomotor cues such as vergence and accommodation, can modulate the signals in the thalamus or V1 at the initial processing stage [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. Accordingly, one might predict that Size Constancy emerges much earlier in time [ 8 , 9 , 10 ], even as visual signals are being processed in the thalamus. So far, the studies that have looked directly at Size coding have either used fMRI (poor temporal resolution [ 11 , 12 , 13 ]) or relied on inadequate stimuli (pictorial illusions presented on a monitor at a fixed distance [ 11 , 12 , 14 , 15 ]). Here, we physically moved the monitor to different distances, a more ecologically valid paradigm that emulates what happens in everyday life and is an example of the increasing trend of “bringing the real world into the lab.” Using this paradigm in combination with electroencephalography (EEG), we examined the computation of Size Constancy in real time with real-world viewing conditions. Our study provides strong evidence that, even though oculomotor distance cues have been shown to modulate the spiking rate of neurons in the thalamus and in V1, the integration of viewing distance cues and retinal image Size takes at least 150 ms to unfold, which suggests that the Size-Constancy-related activation patterns in V1 reported in previous fMRI studies (e.g., [ 12 , 13 ]) reflect the later processing within V1 and/or top-down input from other high-level visual areas.
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proprioceptive distance cues restore perfect Size Constancy in grasping but not perception when vision is limited
Current Biology, 2018Co-Authors: Juan Chen, Irene Sperandio, Melvyn A. GoodaleAbstract:Our brain integrates information from multiple modalities in the control of behavior. When information from one sensory source is compromised, information from another source can compensate for the loss. What is not clear is whether the nature of this multisensory integration and the re-weighting of different sources of sensory information are the same across different control systems. Here, we investigated whether proprioceptive distance information (position sense of body parts) can compensate for the loss of visual distance cues that support Size Constancy in perception (mediated by the ventral visual stream) [1, 2] versus Size Constancy in grasping (mediated by the dorsal visual stream) [3-6], in which the real-world Size of an object is computed despite changes in viewing distance. We found that there was perfect Size Constancy in both perception and grasping in a full-viewing condition (lights on, binocular viewing) and that Size Constancy in both tasks was dramatically disrupted in the restricted-viewing condition (lights off; monocular viewing of the same but luminescent object through a 1-mm pinhole). Importantly, in the restricted-viewing condition, proprioceptive cues about viewing distance originating from the non-grasping limb (experiment 1) or the inclination of the torso and/or the elbow angle of the grasping limb (experiment 2) compensated for the loss of visual distance cues to enable a complete restoration of Size Constancy in grasping but only a modest improvement of Size Constancy in perception. This suggests that the weighting of different sources of sensory information varies as a function of the control system being used.
Kazuo Fujita - One of the best experts on this subject based on the ideXlab platform.
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motion parallax via head movements modulates visuo motor control in pigeons
The Journal of Experimental Biology, 2021Co-Authors: Yuya Hataji, Hika Kuroshima, Kazuo FujitaAbstract:Although it has been proposed that birds acquire visual depth cues through dynamic head movements, behavioral evidence is lacking about how birds use motion parallax depth cues caused by self-motion. This study investigated whether self-generated motion parallax modulates pecking motor control and visual Size perception in pigeons (Columba livia). We trained pigeons to peck a target on a touch monitor and to classify it as small or large. To manipulate motion parallax of the target, we changed the target position on the monitor according to the bird9s head position in real time using a custom-built head tracker with two cameras. Pecking motor control was affected by the manipulation of motion parallax: when the motion-parallax signified the target position farther than the monitor surface, the head position just before pecking to target was near to the monitor surface, and vice versa. By contrast, motion parallax did not affect how the pigeons classified target Sizes, implying that motion parallax might not contribute to Size Constancy in pigeons. These results indicate that motion parallax via head movements modulates pecking motor control in pigeons, suggesting that head movements of pigeons have the visual function of accessing motion parallax depth cues.
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dynamic corridor illusion in pigeons humanlike pictorial cue precedence over motion parallax cue in Size perception
I-perception, 2020Co-Authors: Yuya Hataji, Hika Kuroshima, Kazuo FujitaAbstract:Depth information is necessary for perceiving the real Size of objects at varying visual distances. To investigate to what extent this Size Constancy present in another vertebrate class, we address...
Lutz Wiegrebe - One of the best experts on this subject based on the ideXlab platform.
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Size Constancy in bat biosonar perceptual interaction of object aperture and distance
PLOS ONE, 2013Co-Authors: Melina Heinrich, Lutz WiegrebeAbstract:Perception and encoding of object Size is an important feature of sensory systems. In the visual system object Size is encoded by the visual angle (visual aperture) on the retina, but the aperture depends on the distance of the object. As object distance is not unambiguously encoded in the visual system, higher computational mechanisms are needed. This phenomenon is termed “Size Constancy”. It is assumed to reflect an automatic re-scaling of visual aperture with perceived object distance. Recently, it was found that in echolocating bats, the ‘sonar aperture’, i.e., the range of angles from which sound is reflected from an object back to the bat, is unambiguously perceived and neurally encoded. Moreover, it is well known that object distance is accurately perceived and explicitly encoded in bat sonar. Here, we addressed Size Constancy in bat biosonar, recruiting virtual-object techniques. Bats of the species Phyllostomus discolor learned to discriminate two simple virtual objects that only differed in sonar aperture. Upon successful discrimination, test trials were randomly interspersed using virtual objects that differed in both aperture and distance. It was tested whether the bats spontaneously assigned absolute width information to these objects by combining distance and aperture. The results showed that while the isolated perceptual cues encoding object width, aperture, and distance were all perceptually well resolved by the bats, the animals did not assign absolute width information to the test objects. This lack of sonar Size Constancy may result from the bats relying on different modalities to extract Size information at different distances. Alternatively, it is conceivable that familiarity with a behaviorally relevant, conspicuous object is required for sonar Size Constancy, as it has been argued for visual Size Constancy. Based on the current data, it appears that Size Constancy is not necessarily an essential feature of sonar perception in bats.
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Size Constancy in bat biosonar
PLOS ONE, 2013Co-Authors: Melina Heinrich, Lutz WiegrebeAbstract:Perception and encoding of object Size is an important feature of sensory systems. In the visual system object Size is encoded by the visual angle (visual aperture) on the retina, but the aperture depends on the distance of the object. As object distance is not unambiguously encoded in the visual system, higher computational mechanisms are needed. This phenomenon is termed "Size Constancy". It is assumed to reflect an automatic re-scaling of visual aperture with perceived object distance. Recently, it was found that in echolocating bats, the 'sonar aperture', i.e., the range of angles from which sound is reflected from an object back to the bat, is unambiguously perceived and neurally encoded. Moreover, it is well known that object distance is accurately perceived and explicitly encoded in bat sonar. Here, we addressed Size Constancy in bat biosonar, recruiting virtual-object techniques. Bats of the species Phyllostomus discolor learned to discriminate two simple virtual objects that only differed in sonar aperture. Upon successful discrimination, test trials were randomly interspersed using virtual objects that differed in both aperture and distance. It was tested whether the bats spontaneously assigned absolute width information to these objects by combining distance and aperture. The results showed that while the isolated perceptual cues encoding object width, aperture, and distance were all perceptually well resolved by the bats, the animals did not assign absolute width information to the test objects. This lack of sonar Size Constancy may result from the bats relying on different modalities to extract Size information at different distances. Alternatively, it is conceivable that familiarity with a behaviorally relevant, conspicuous object is required for sonar Size Constancy, as it has been argued for visual Size Constancy. Based on the current data, it appears that Size Constancy is not necessarily an essential feature of sonar perception in bats.