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Shlomo Bentin - One of the best experts on this subject based on the ideXlab platform.
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training induced recovery of low level vision followed by mid level perceptual improvements in developmental Object and face Agnosia
Developmental Science, 2015Co-Authors: Maria Lev, Yoram Bonneh, Shlomo Bentin, Sharon Gilaiedotan, Dana Gotthilfnezri, Oren Yehezkel, Joseph L Brooks, Anat Perry, Uri PolatAbstract:Long-term deprivation of normal visual inputs can cause perceptual impairments at various levels of visual function, from basic visual acuity deficits, through mid-level deficits such as contour integration and motion coherence, to high-level face and Object Agnosia. Yet it is unclear whether training during adulthood, at a post-developmental stage of the adult visual system, can overcome such developmental impairments. Here, we visually trained LG, a developmental Object and face agnosic individual. Prior to training, at the age of 20, LG's basic and mid-level visual functions such as visual acuity, crowding effects, and contour integration were underdeveloped relative to normal adult vision, corresponding to or poorer than those of 5-6 year olds (Gilaie-Dotan, Perry, Bonneh, Malach & Bentin, 2009). Intensive visual training, based on lateral interactions, was applied for a period of 9 months. LG's directly trained but also untrained visual functions such as visual acuity, crowding, binocular stereopsis and also mid-level contour integration improved significantly and reached near-age-level performance, with long-term (over 4 years) persistence. Moreover, mid-level functions that were tested post-training were found to be normal in LG. Some possible subtle improvement was observed in LG's higher-order visual functions such as Object recognition and part integration, while LG's face perception skills have not improved thus far. These results suggest that corrective training at a post-developmental stage, even in the adult visual system, can prove effective, and its enduring effects are the basis for a revival of a developmental cascade that can lead to reduced perceptual impairments.
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implicit integration in a case of integrative visual Agnosia
Neuropsychologia, 2007Co-Authors: Hillel Aviezer, Ayelet N Landau, Mary A Peterson, Yaron Sacher, Yoram Bonneh, Nachum Soroker, Lynn C. Robertson, Shlomo BentinAbstract:We present a case (SE) with integrative visual Agnosia following ischemic stroke affecting the right dorsal and the left ventral pathways of the visual system. Despite his inability to identify global hierarchical letters [Navon, D. (1977). Forest before trees: The precedence of global features in visual perception. Cognitive Psychology, 9, 353–383], and his dense Object Agnosia, SE showed normal global-to-local interference when responding to local letters in Navon hierarchical stimuli and significant picture-word identity priming in a semantic decision task for words. Since priming was absent if these features were scrambled, it stands to reason that these effects were not due to priming by distinctive features. The contrast between priming effects induced by coherent and scrambled stimuli is consistent with implicit but not explicit integration of features int oa unified whole. We went on to show that possible/impossible Object decisions were facilitated by words in a word-picture priming task, suggesting that prompts could activate perceptually integrated images in a backward fashion. We conclude that the absence of SE’s ability to identify visual Objects except through tedious serial construction reflects a deficit in accessing an integrated visual representation through bottom-up visual processing alone. However, top-down generated images can help activate these visual representations through semantic links. © 2007 Elsevier Ltd. All rights reserved.
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implicit integration in a case of integrative visual Agnosia
Neuropsychologia, 2007Co-Authors: Hillel Aviezer, Ayelet N Landau, Mary A Peterson, Yaron Sacher, Yoram Bonneh, Nachum Soroker, Lynn C. Robertson, Shlomo BentinAbstract:We present a case (SE) with integrative visual Agnosia following ischemic stroke affecting the right dorsal and the left ventral pathways of the visual system. Despite his inability to identify global hierarchical letters [Navon, D. (1977). Forest before trees: The precedence of global features in visual perception. Cognitive Psychology, 9, 353-383], and his dense Object Agnosia, SE showed normal global-to-local interference when responding to local letters in Navon hierarchical stimuli and significant picture-word identity priming in a semantic decision task for words. Since priming was absent if these features were scrambled, it stands to reason that these effects were not due to priming by distinctive features. The contrast between priming effects induced by coherent and scrambled stimuli is consistent with implicit but not explicit integration of features into a unified whole. We went on to show that possible/impossible Object decisions were facilitated by words in a word-picture priming task, suggesting that prompts could activate perceptually integrated images in a backward fashion. We conclude that the absence of SE's ability to identify visual Objects except through tedious serial construction reflects a deficit in accessing an integrated visual representation through bottom-up visual processing alone. However, top-down generated images can help activate these visual representations through semantic links.
Marlene Behrmann - One of the best experts on this subject based on the ideXlab platform.
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congenital prosopAgnosia without Object Agnosia a literature review
Cognitive Neuropsychology, 2018Co-Authors: Jacob Geskin, Marlene BehrmannAbstract:A longstanding controversy concerns the functional organization of high-level vision, and the extent to which the recognition of different classes of visual stimuli engages a single system or multiple independent systems. We examine this in the context of congenital prosopAgnosia (CP), a neurodevelopmental disorder in which individuals, without a history of brain damage, are impaired at face recognition. This paper reviews all CP cases from 1976 to 2016, and explores the evidence for the association or dissociation of face and Object recognition. Of the 238 CP cases with data permitting a satisfactory evaluation, 80.3% evinced an association between impaired face and Object recognition whereas 19.7% evinced a dissociation. We evaluate the strength of the evidence and correlate the face and Object recognition behaviour. We consider the implications for theories of functional organization of the visual system, and offer suggestions for further adjudication of the relationship between face and Object recognition.
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Are Greebles like faces? Using the neuropsychological exception to test the rule.
2018Co-Authors: Isabel Gauthier, Marlene Behrmann, Michael J. TarrAbstract:Which image geometries count as face-like and which do not? Across multiple experiments, novel Objects called Greebles have been used to argue that face-specific effects can be obtained with non-face stimuli under certain situations, in particular with expert observers. However, this claim depends on the argument that these non-face stimuli are not a priori treated by the face processing system. To address this question, CK, a neuropsychological patient well-known for exhibiting severe visual Object Agnosia and dyslexia but intact face processing, was tested with Greebles. CK performed poorly on Greebles, indicating that his intact face-specific abilities do not extend to include Greebles. These results suggest that insofar as CK is relying on face-specific visual processes, these processes do not a priori treat Greebles as faces.
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Congenital ProsopAgnosia without Object Agnosia? A Literature Review
2017Co-Authors: Jacob Geskin, Marlene BehrmannAbstract:One of the longstanding controversies in the neuropsychology literature concerns the functional organization of high-level vision, and the extent to whichthe recognition of different classes of visual stimuli engage a single or multiple, independent underlying mechanisms. We explore this issue in the contextof congenital prosopAgnosia (CP), a neurodevelopmental disorder in which individuals, without a history of brain damage and with normal sensory andcognitive abilities, are impaired at face recognition. Whereas many researchers have asserted that individuals with CP have face-selective deficits, othershave claimed that the deficit extends to the recognition of stimuli from other visual classes as well. This paper reviews 119 published reports of CP (atotal of 716 cases) from 1976 to 2016, and examines the evidence for associations or dissociations of face and Object recognition behavior. The resultsrevealed that, of the 238 CP cases with data permitting a satisfactory evaluation of behavior, 80.3% had an associated face and Object recognition deficitwhereas 19.7% evinced a dissociation between face and Object recognition. We evaluate the strength of the evidence and correlate the face and Objectrecognition behavior where possible. We discuss the frequent pattern of an association between face and Object recognition deficits along with the lessfrequent case of dissociation, consider the implications for theories of functional organization of the visual system, and make suggestions for furtheradjudication of the relationship between face and Object recognition in prosopAgnosia and Object Agnosia.
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the functional neuroanatomy of Object Agnosia a case study
Neuron, 2011Co-Authors: Christina S Konen, Marlene Behrmann, Mayu Nishimura, Sabine KastnerAbstract:SUMMARY Cortical reorganization ofvisual and Object representations following neural injury was examined using fMRI and behavioral investigations. We probed the visual responsivity of the ventral visual cortex of an agnosic patient who was impaired at Object recognition following a lesion to the right lateral fusiform gyrus. In both hemispheres, retinotopic mapping revealed typical topographic organization and visual activation of early visual cortex. However, visual responses, Object-related, and -selective responses were reduced in regions immediately surrounding the lesion in the right hemisphere, and also, surprisingly, in corresponding locations in the structurally intact left hemisphere. In contrast, hV4 of the right hemisphere showed expanded response properties. These findings indicate that the right lateral fusiform gyrus is critically involved in Object recognition and that an impairment to this region has widespread consequences for remote parts of cortex. Finally, functional neural plasticity is possible even when a cortical lesion is sustained in adulthood.
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what is special about face recognition nineteen experiments on a person with visual Object Agnosia and dyslexia but normal face recognition
Journal of Cognitive Neuroscience, 1997Co-Authors: Morris Moscovitch, Gordon Winocur, Marlene BehrmannAbstract:In order to study face recognition in relative isolation from visual processes that may also contribute to Object recognition and reading, we investigated CK, a man with normal face recognition but with Object Agnosia and dyslexia caused by a closed-head injury. We administered recognition tests of up right faces, of family resemblance, of age-transformed faces, of caricatures, of cartoons, of inverted faces, and of face features, of disguised faces, of perceptually degraded faces, of fractured faces, of faces parts, and of faces whose parts were made of Objects. We compared CK's performance with that of at least 12 control participants. We found that CK performed as well as controls as long as the face was upright and retained the configurational integrity among the internal facial features, the eyes, nose, and mouth. This held regardless of whether the face was disguised or degraded and whether the face was represented as a photo, a caricature, a cartoon, or a face composed of Objects. In the last case, CK perceived the face but, unlike controls, was rarely aware that it was composed of Objects. When the face, or just the internal features, were inverted or when the configurational gestalt was broken by fracturing the face or misaligning the top and bottom halves, CK's performance suffered far more than that of controls. We conclude that face recognition normally depends on two systems: (1) a holistic, face-specific system that is dependent on orientationspecific coding of second-order relational features (internal), which is intact in CK and (2) a part-based Object-recognition system, which is damaged in CK and which contributes to face recognition when the face stimulus does not satisfy the domain-specific conditions needed to activate the face system.
Yoram Bonneh - One of the best experts on this subject based on the ideXlab platform.
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training induced recovery of low level vision followed by mid level perceptual improvements in developmental Object and face Agnosia
Developmental Science, 2015Co-Authors: Maria Lev, Yoram Bonneh, Shlomo Bentin, Sharon Gilaiedotan, Dana Gotthilfnezri, Oren Yehezkel, Joseph L Brooks, Anat Perry, Uri PolatAbstract:Long-term deprivation of normal visual inputs can cause perceptual impairments at various levels of visual function, from basic visual acuity deficits, through mid-level deficits such as contour integration and motion coherence, to high-level face and Object Agnosia. Yet it is unclear whether training during adulthood, at a post-developmental stage of the adult visual system, can overcome such developmental impairments. Here, we visually trained LG, a developmental Object and face agnosic individual. Prior to training, at the age of 20, LG's basic and mid-level visual functions such as visual acuity, crowding effects, and contour integration were underdeveloped relative to normal adult vision, corresponding to or poorer than those of 5-6 year olds (Gilaie-Dotan, Perry, Bonneh, Malach & Bentin, 2009). Intensive visual training, based on lateral interactions, was applied for a period of 9 months. LG's directly trained but also untrained visual functions such as visual acuity, crowding, binocular stereopsis and also mid-level contour integration improved significantly and reached near-age-level performance, with long-term (over 4 years) persistence. Moreover, mid-level functions that were tested post-training were found to be normal in LG. Some possible subtle improvement was observed in LG's higher-order visual functions such as Object recognition and part integration, while LG's face perception skills have not improved thus far. These results suggest that corrective training at a post-developmental stage, even in the adult visual system, can prove effective, and its enduring effects are the basis for a revival of a developmental cascade that can lead to reduced perceptual impairments.
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implicit integration in a case of integrative visual Agnosia
Neuropsychologia, 2007Co-Authors: Hillel Aviezer, Ayelet N Landau, Mary A Peterson, Yaron Sacher, Yoram Bonneh, Nachum Soroker, Lynn C. Robertson, Shlomo BentinAbstract:We present a case (SE) with integrative visual Agnosia following ischemic stroke affecting the right dorsal and the left ventral pathways of the visual system. Despite his inability to identify global hierarchical letters [Navon, D. (1977). Forest before trees: The precedence of global features in visual perception. Cognitive Psychology, 9, 353–383], and his dense Object Agnosia, SE showed normal global-to-local interference when responding to local letters in Navon hierarchical stimuli and significant picture-word identity priming in a semantic decision task for words. Since priming was absent if these features were scrambled, it stands to reason that these effects were not due to priming by distinctive features. The contrast between priming effects induced by coherent and scrambled stimuli is consistent with implicit but not explicit integration of features int oa unified whole. We went on to show that possible/impossible Object decisions were facilitated by words in a word-picture priming task, suggesting that prompts could activate perceptually integrated images in a backward fashion. We conclude that the absence of SE’s ability to identify visual Objects except through tedious serial construction reflects a deficit in accessing an integrated visual representation through bottom-up visual processing alone. However, top-down generated images can help activate these visual representations through semantic links. © 2007 Elsevier Ltd. All rights reserved.
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implicit integration in a case of integrative visual Agnosia
Neuropsychologia, 2007Co-Authors: Hillel Aviezer, Ayelet N Landau, Mary A Peterson, Yaron Sacher, Yoram Bonneh, Nachum Soroker, Lynn C. Robertson, Shlomo BentinAbstract:We present a case (SE) with integrative visual Agnosia following ischemic stroke affecting the right dorsal and the left ventral pathways of the visual system. Despite his inability to identify global hierarchical letters [Navon, D. (1977). Forest before trees: The precedence of global features in visual perception. Cognitive Psychology, 9, 353-383], and his dense Object Agnosia, SE showed normal global-to-local interference when responding to local letters in Navon hierarchical stimuli and significant picture-word identity priming in a semantic decision task for words. Since priming was absent if these features were scrambled, it stands to reason that these effects were not due to priming by distinctive features. The contrast between priming effects induced by coherent and scrambled stimuli is consistent with implicit but not explicit integration of features into a unified whole. We went on to show that possible/impossible Object decisions were facilitated by words in a word-picture priming task, suggesting that prompts could activate perceptually integrated images in a backward fashion. We conclude that the absence of SE's ability to identify visual Objects except through tedious serial construction reflects a deficit in accessing an integrated visual representation through bottom-up visual processing alone. However, top-down generated images can help activate these visual representations through semantic links.
Christian Gerloff - One of the best experts on this subject based on the ideXlab platform.
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C (2005): Larger interregional synchrony is associated with greater behavioral success in a complex sensory integration task in humans. Cereb Cortex 15:670–678
2015Co-Authors: Friedhelm Hummel, Christian GerloffAbstract:Successful behavior depends on effective communication between distant brain regions. Moreover, disturbance of effective commu-nication can cause neurological symptoms like apraxia, dyslexia or Object Agnosia. Interregional communication can be assessed by coherence analysis of synchronized neuronal oscillations, and has been referred to as synchrony or ‘binding’. The concept of synchrony as a means of information coding is attractive, but its functional relevance has been challenged. We hypothesized that if synchrony is functionally relevant in humans, then more synchrony should determine better behavioral performance. Here, we show in a visuotactile integration task that the amount of low-frequency (7--13Hz), long-range electroencephalographic coherence between visual and sensorimotor cortex is significantly correlated with the level of performance. Trials with highest coherences were the most successful ones and vice versa in the absence of differences in regional activation measured as task-related spectral power. In summary, quantitatively linking the amount of long-range synchrony with the degree of behavioral success in humans, the present data suggest that the ability to generate topographically specific syn-chrony of high amplitude is functionally relevant for behavioral success. They also raise the possibility that the magnitude of regional activation is less representative of the efficacy of brain functioning than interregional synchrony
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larger interregional synchrony is associated with greater behavioral success in a complex sensory integration task in humans
Cerebral Cortex, 2005Co-Authors: Friedhelm C Hummel, Christian GerloffAbstract:Successful behavior depends on effective communication between distant brain regions. Moreover, disturbance of effective communication can cause neurological symptoms like apraxia, dyslexia or Object Agnosia. Interregional communication can be assessed by coherence analysis of synchronized neuronal oscillations, and has been referred to as synchrony or "binding". The concept of synchrony as a means of information coding is attractive, but its functional relevance has been challenged. We hypothesized that if synchrony is functionally relevant in humans, then more synchrony should determine better behavioral performance. Here, we show in a visuotactile integration task that the amount of low-frequency (7-13Hz), long-range electroencephalographic coherence between visual and sensorimotor cortex is significantly correlated with the level of performance. Trials with highest coherences were the most successful ones and vice versa in the absence of differences in regional activation measured as task-related spectral power. In summary, quantitatively linking the amount of long-range synchrony with the degree of behavioral success in humans, the present data suggest that the ability to generate topographically specific synchrony of high amplitude is functionally relevant for behavioral success. They also raise the possibility that the magnitude of regional activation is less representative of the efficacy of brain functioning than interregional synchrony.
Uri Polat - One of the best experts on this subject based on the ideXlab platform.
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training induced recovery of low level vision followed by mid level perceptual improvements in developmental Object and face Agnosia
Developmental Science, 2015Co-Authors: Maria Lev, Yoram Bonneh, Shlomo Bentin, Sharon Gilaiedotan, Dana Gotthilfnezri, Oren Yehezkel, Joseph L Brooks, Anat Perry, Uri PolatAbstract:Long-term deprivation of normal visual inputs can cause perceptual impairments at various levels of visual function, from basic visual acuity deficits, through mid-level deficits such as contour integration and motion coherence, to high-level face and Object Agnosia. Yet it is unclear whether training during adulthood, at a post-developmental stage of the adult visual system, can overcome such developmental impairments. Here, we visually trained LG, a developmental Object and face agnosic individual. Prior to training, at the age of 20, LG's basic and mid-level visual functions such as visual acuity, crowding effects, and contour integration were underdeveloped relative to normal adult vision, corresponding to or poorer than those of 5-6 year olds (Gilaie-Dotan, Perry, Bonneh, Malach & Bentin, 2009). Intensive visual training, based on lateral interactions, was applied for a period of 9 months. LG's directly trained but also untrained visual functions such as visual acuity, crowding, binocular stereopsis and also mid-level contour integration improved significantly and reached near-age-level performance, with long-term (over 4 years) persistence. Moreover, mid-level functions that were tested post-training were found to be normal in LG. Some possible subtle improvement was observed in LG's higher-order visual functions such as Object recognition and part integration, while LG's face perception skills have not improved thus far. These results suggest that corrective training at a post-developmental stage, even in the adult visual system, can prove effective, and its enduring effects are the basis for a revival of a developmental cascade that can lead to reduced perceptual impairments.