The Experts below are selected from a list of 80421 Experts worldwide ranked by ideXlab platform
Nancy Kanwisher - One of the best experts on this subject based on the ideXlab platform.
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how Face Perception unfolds over time
Nature Communications, 2019Co-Authors: Katharina Dobs, Leyla Isik, Dimitrios Pantazis, Nancy KanwisherAbstract:Within a fraction of a second of viewing a Face, we have already determined its gender, age and identity. A full understanding of this remarkable feat will require a characterization of the computational steps it entails, along with the representations extracted at each. Here, we used magnetoencephalography (MEG) to measure the time course of neural responses to Faces, thereby addressing two fundamental questions about how Face processing unfolds over time. First, using representational similarity analysis, we found that facial gender and age information emerged before identity information, suggesting a coarse-to-fine processing of Face dimensions. Second, identity and gender representations of familiar Faces were enhanced very early on, suggesting that the behavioral benefit for familiar Faces results from tuning of early feed-forward processing mechanisms. These findings start to reveal the time course of Face processing in humans, and provide powerful new constraints on computational theories of Face Perception.
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How Face Perception unfolds over time
2018Co-Authors: Katharina Dobs, Leyla Isik, Dimitrios Pantazis, Nancy KanwisherAbstract:Abstract Within a fraction of a second of viewing a Face, we have already determined its gender, age and identity. A full understanding of this remarkable feat will require a characterization of the computational steps it entails, along with the representations extracted at each. To this end, we used magnetoencephalography to measure the time course of neural responses to Faces, thereby addressing two fundamental questions about how Face processing unfolds over time. First, using representational similarity analysis, we found that facial gender and age information emerged before identity information, suggesting a coarse-to-fine processing of Face dimensions. Second, identity and gender representations of familiar Faces were enhanced very early on, indicating that the previously-reported behavioral benefit for familiar Faces results from tuning of early feed-forward processing mechanisms. These findings start to reveal the time course of Face Perception in humans, and provide powerful new constraints on computational theories of Face Perception.
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Face Perception domain specific not process specific
Neuron, 2004Co-Authors: Galit Yovel, Nancy KanwisherAbstract:Evidence that Face Perception is mediated by special cognitive and neural mechanisms comes from fMRI studies of the fusiform Face area (FFA) and behavioral studies of the Face inversion effect. Here, we used these two methods to ask whether Face Perception mechanisms are stimulus specific, process specific, or both. Subjects discriminated pairs of upright or inverted Faces or house stimuli that differed in either the spatial distance among parts (configuration) or the shape of the parts. The FFA showed a much higher response to Faces than to houses, but no preference for the configuration task over the part task. Similarly, the behavioral inversion effect was as large in the part task as the configuration task for Faces, but absent in both part and configuration tasks for houses. These findings indicate that Face Perception mechanisms are not process specific for parts or configuration but are domain specific for Face stimuli per se.
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Face Perception: Domain Specific, Not Process Specific
Neuron, 2004Co-Authors: Galit Yovel, Nancy KanwisherAbstract:Evidence that Face Perception is mediated by special cognitive and neural mechanisms comes from fMRI studies of the fusiform Face area (FFA) and behavioral studies of the Face inversion effect. Here, we used these two methods to ask whether Face Perception mechanisms are stimulus specific, process specific, or both. Subjects discriminated pairs of upright or inverted Faces or house stimuli that differed in either the spatial distance among parts (configuration) or the shape of the parts. The FFA showed a much higher response to Faces than to houses, but no preference for the configuration task over the part task. Similarly, the behavioral inversion effect was as large in the part task as the configuration task for Faces, but absent in both part and configuration tasks for houses. These findings indicate that Face Perception mechanisms are not process specific for parts or configuration but are domain specific for Face stimuli per se.
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stages of processing in Face Perception an meg study
Nature Neuroscience, 2002Co-Authors: Jia Liu, Nancy Kanwisher, Alison HarrisAbstract:Here we used magnetoencephalography (MEG) to investigate stages of processing in Face Perception in humans. We found a Face-selective MEG response occurring only 100 ms after stimulus onset (the 'M100'), 70 ms earlier than previously reported. Further, the amplitude of this M100 response was correlated with successful categorization of stimuli as Faces, but not with successful recognition of individual Faces, whereas the previously-described Face-selective 'M170' response was correlated with both processes. These data suggest that Face processing proceeds through two stages: an initial stage of Face categorization, and a later stage at which the identity of the individual Face is extracted.
Bruno Rossion - One of the best experts on this subject based on the ideXlab platform.
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the non linear development of the right hemispheric specialization for human Face Perception
Neuropsychologia, 2017Co-Authors: Aliette Lochy, Adelaide De Heering, Bruno RossionAbstract:Abstract The developmental origins of human adults’ right hemispheric specialization for Face Perception remain unclear. On the one hand, infant studies have shown a right hemispheric advantage for Face Perception. On the other hand, it has been proposed that the adult right hemispheric lateralization for Face Perception slowly emerges during childhood due to reading acquisition, which increases left lateralized posterior responses to competing written material (e.g., visual letters and words). Since methodological approaches used in infant and children typically differ when their Face capabilities are explored, resolving this issue has been difficult. Here we tested 5-year-old preschoolers varying in their level of visual letter knowledge with the same fast periodic visual stimulation (FPVS) paradigm leading to strongly right lateralized electrophysiological occipito-temporal Face-selective responses in 4- to 6-month-old infants (de Heering and Rossion, 2015). Children's Face-selective response was quantitatively larger and differed in scalp topography from infants’, but did not differ across hemispheres. There was a small positive correlation between preschoolers’ letter knowledge and a non-normalized index of right hemispheric specialization for Faces. These observations show that previous discrepant results in the literature reflect a genuine nonlinear development of the neural processes underlying Face Perception and are not merely due to methodological differences across age groups. We discuss several factors that could contribute to the adult right hemispheric lateralization for Faces, such as myelination of the corpus callosum and reading acquisition. Our findings point to the value of FPVS coupled with electroencephalography to assess specialized Face Perception processes throughout development with the same methodology.
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the non linear development of the right hemispheric specialization for human Face Perception
bioRxiv, 2017Co-Authors: Aliette Lochy, Adelaide De Heering, Bruno RossionAbstract:The developmental origins of human adults9 right hemispheric specialization for Face Perception remain unclear. On the one hand, infant studies have generally shown a right hemispheric advantage for Face Perception. On the other hand, the adult right hemispheric lateralization for Face Perception is thought to slowly emerge during childhood, due to reading acquisition, which increases left lateralized posterior responses to competing written material (i.e., visual letters and words). Since methodological approaches used in infant and children usually differ, resolving this issue has been difficult. Here we tested 5-year-old preschoolers varying in their level of visual letter knowledge with the same fast periodic visual stimulation (FPVS) paradigm leading to strongly right lateralized electrophysiological occipito-temporal Face-selective responses in 4- to 6-month-old infants (de Heering & Rossion, 2015). Children9s Face-selective response was much larger and more complex than in infants, but did not differ across hemispheres. However, there was a small positive correlation between preschoolers9 letter knowledge and their right hemispheric specialization for Faces. These observations suggest that several factors contribute to the adult right hemispheric lateralization for Faces, and point to the value of FPVS coupled with electroencephalography to assess specialized Face Perception processes throughout development with the same methodology.
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Understanding Face Perception by means of human electrophysiology
Trends in cognitive sciences, 2014Co-Authors: Bruno RossionAbstract:Electrophysiological recordings on the human scalp provide a wealth of information about the temporal dynamics and nature of Face Perception at a global level of brain organization. The time window between 100 and 200 ms witnesses the transition between low-level and high-level vision, an N170 component correlating with conscious interpretation of a visual stimulus as a Face. This Face representation is rapidly refined as information accumulates during this time window, allowing the individualization of Faces. To improve the sensitivity and objectivity of Face Perception measures, it is increasingly important to go beyond transient visual stimulation by recording electrophysiological responses at periodic frequency rates. This approach has recently provided Face Perception thresholds and the first objective signature of integration of facial parts in the human brain.
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the composite Face illusion a whole window into our understanding of holistic Face Perception
Visual Cognition, 2013Co-Authors: Bruno RossionAbstract:Two identical top halves of a Face are perceived as being different when their bottom halves belong to different Faces, showing that the parts of a Face cannot be perceived independently from the whole Face. When this visual illusion is inserted in a matching task, observers make more mistakes and/or are slower at matching identical top Face halves aligned with different bottom halves than when the bottom halves are spatially offset: The composite Face effect. This composite Face paradigm has been used in more than 60 studies that have provided information about the specificity and nature of perceptual integration between facial parts (“holistic Face Perception”), the impairment of this process in acquired prosopagnosia, its developmental course, temporal dynamics, and neural basis. Following a review of the main contributions made with the paradigm, I explain its rationale and strengths, and discuss its methodological parameters, making a number of proposals for its optimal use and refinement in order to improve our understanding of holistic Face Perception. Finally, I explain how this standard composite Face paradigm is fundamentally different than the application to facial parts of a congruency/interference paradigm that has a long tradition in experimental psychology since Stroop (1935), and which was originally developed to measure attentional and response interference between different representations rather than perceptual integration. Moreover, a version of this congruency/interference paradigm used extensively over the past years with composite Faces lacks a baseline measure and has decisional, attentional, and stimulus confounds, making the findings of these studies impossible to interpret in terms of holistic Perception. I conclude by encouraging researchers in this field to concentrate fully on the standard composite Face paradigm, gaze contingency, and other behavioural measures that can help us take one of the most important challenges of visual Perception research: Understanding the neural mechanisms of holistic Face Perception.
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Faces Are "Spatial"—Holistic Face Perception Is Supported by Low Spatial Frequencies
Journal of experimental psychology. Human perception and performance, 2006Co-Authors: Valerie Goffaux, Bruno RossionAbstract:Faces are perceived holistically, a phenomenon best illustrated when the processing of a Face feature is affected by the other features. Here, the authors tested the hypothesis that the holistic Perception of a Face mainly relies on its low spatial frequencies. Holistic Face Perception was tested in two classical paradigms: the whole-part advantage (Experiment 1) and the composite Face effect (Experiments 2-4). Holistic effects were equally large or larger for low-pass filtered Faces as compared to full-spectrum Faces and significantly larger than for high-pass filtered Faces. The disproportionate composite effect found for low-pass filtered Faces was not observed when holistic Perception was disrupted by inversion (Experiment 3). Experiment 4 showed that the composite Face effect was enhanced only for low spatial frequencies, but not for intermediate spatial frequencies known be critical for Face recognition. These findings indicate that holistic Face Perception is largely supported by low spatial frequencies. They also suggest that holistic processing precedes the analysis of local features during Face Perception.
Flavio Fröhlich - One of the best experts on this subject based on the ideXlab platform.
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Neurophysiological substrates of configural Face Perception in schizotypy.
Schizophrenia research, 2019Co-Authors: Sangtae Ahn, Caroline Lustenberger, L. Fredrik Jarskog, Flavio FröhlichAbstract:Abstract Face Perception is a highly developed function of the human visual system. Previous studies of event-related potentials (ERPs) have identified a Face-selective ERP component (negative peak at about 170 ms after stimulus onset, N170) in healthy participants. In contrast, patients with schizophrenia exhibit reduced amplitude of the N170, which may represent a pathological deficit in the neurophysiology of Face Perception. Interestingly, healthy humans with schizophrenia-like experiences (schizotypy) also exhibit abnormal processing of Face Perception. Yet, it has remained unknown how schizotypy in healthy humans is associated with the neurophysiological substrates of Face Perception. Here, we recruited 35 healthy participants and assessed their schizotypy by the magical ideation rating scale. We used high-density electroencephalography to obtain ERPs elicited by a set of Mooney Faces (Face and non-Face visual stimuli). We investigated median and mean reaction times and visual ERP components in response to the stimuli. We observed a significant difference in N170 amplitude between the two Face-stimulus conditions and found that the measured schizotypy scores were significantly correlated with both reaction times and N170 amplitude in response to the Face stimuli across all participants. Our results thus support the model of schizotypy as a manifestation of a continuum between healthy individuals and patients with schizophrenia, where the N170 impairment serves as a biomarker for the degree of pathology along this continuum.
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Neurophysiological Substrates of Configural Face Perception in Schizotypy
2019Co-Authors: Sangtae Ahn, Caroline Lustenberger, L. Fredrik Jarskog, Flavio FröhlichAbstract:Face Perception is a highly developed function of the human visual system. Previous studies of event-related potentials (ERPs) have identified a Face-selective ERP component (negative peak at about 170 milliseconds after stimulation onset, N170) in healthy participants. In contrast, patients with schizophrenia exhibit reduced amplitude of the N170, which may represent a pathological deficit in the neurophysiology of Face Perception. Interestingly, healthy humans with schizophrenia-like experiences (schizotypy) also exhibit abnormal processing of Face Perception. Yet, it has remained unknown how schizotypy in healthy humans is associated with the neurophysiological substrate of Face Perception. Here, we recruited 35 participants and assessed their schizotypy by the magical ideation rating scale. We used high-density electroencephalography to obtain ERPs elicited by a set of Mooney Faces (Face and non-Face conditions). We divided the participants into two groups (high and low schizotypy) by a median split of schizotypy scores. We investigated mean reaction times and the N170 component in response to the stimuli. We found significant slowed reaction times and reduced amplitude of the N170 component in response to the Face stimuli in the high-schizotypy group. In addition, across the full data set, we found that the schizotypy scores were significantly correlated with both the reaction times and the N170 amplitude. Our results thus support the model of schizotypy as a manifestation of a continuum between healthy individuals and patients with schizophrenia, where the N170 impairment serves as a biomarker for the degree of pathology along this continuum.
Galit Yovel - One of the best experts on this subject based on the ideXlab platform.
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Face Perception domain specific not process specific
Neuron, 2004Co-Authors: Galit Yovel, Nancy KanwisherAbstract:Evidence that Face Perception is mediated by special cognitive and neural mechanisms comes from fMRI studies of the fusiform Face area (FFA) and behavioral studies of the Face inversion effect. Here, we used these two methods to ask whether Face Perception mechanisms are stimulus specific, process specific, or both. Subjects discriminated pairs of upright or inverted Faces or house stimuli that differed in either the spatial distance among parts (configuration) or the shape of the parts. The FFA showed a much higher response to Faces than to houses, but no preference for the configuration task over the part task. Similarly, the behavioral inversion effect was as large in the part task as the configuration task for Faces, but absent in both part and configuration tasks for houses. These findings indicate that Face Perception mechanisms are not process specific for parts or configuration but are domain specific for Face stimuli per se.
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Face Perception: Domain Specific, Not Process Specific
Neuron, 2004Co-Authors: Galit Yovel, Nancy KanwisherAbstract:Evidence that Face Perception is mediated by special cognitive and neural mechanisms comes from fMRI studies of the fusiform Face area (FFA) and behavioral studies of the Face inversion effect. Here, we used these two methods to ask whether Face Perception mechanisms are stimulus specific, process specific, or both. Subjects discriminated pairs of upright or inverted Faces or house stimuli that differed in either the spatial distance among parts (configuration) or the shape of the parts. The FFA showed a much higher response to Faces than to houses, but no preference for the configuration task over the part task. Similarly, the behavioral inversion effect was as large in the part task as the configuration task for Faces, but absent in both part and configuration tasks for houses. These findings indicate that Face Perception mechanisms are not process specific for parts or configuration but are domain specific for Face stimuli per se.
Sangtae Ahn - One of the best experts on this subject based on the ideXlab platform.
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Neurophysiological substrates of configural Face Perception in schizotypy.
Schizophrenia research, 2019Co-Authors: Sangtae Ahn, Caroline Lustenberger, L. Fredrik Jarskog, Flavio FröhlichAbstract:Abstract Face Perception is a highly developed function of the human visual system. Previous studies of event-related potentials (ERPs) have identified a Face-selective ERP component (negative peak at about 170 ms after stimulus onset, N170) in healthy participants. In contrast, patients with schizophrenia exhibit reduced amplitude of the N170, which may represent a pathological deficit in the neurophysiology of Face Perception. Interestingly, healthy humans with schizophrenia-like experiences (schizotypy) also exhibit abnormal processing of Face Perception. Yet, it has remained unknown how schizotypy in healthy humans is associated with the neurophysiological substrates of Face Perception. Here, we recruited 35 healthy participants and assessed their schizotypy by the magical ideation rating scale. We used high-density electroencephalography to obtain ERPs elicited by a set of Mooney Faces (Face and non-Face visual stimuli). We investigated median and mean reaction times and visual ERP components in response to the stimuli. We observed a significant difference in N170 amplitude between the two Face-stimulus conditions and found that the measured schizotypy scores were significantly correlated with both reaction times and N170 amplitude in response to the Face stimuli across all participants. Our results thus support the model of schizotypy as a manifestation of a continuum between healthy individuals and patients with schizophrenia, where the N170 impairment serves as a biomarker for the degree of pathology along this continuum.
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Neurophysiological Substrates of Configural Face Perception in Schizotypy
2019Co-Authors: Sangtae Ahn, Caroline Lustenberger, L. Fredrik Jarskog, Flavio FröhlichAbstract:Face Perception is a highly developed function of the human visual system. Previous studies of event-related potentials (ERPs) have identified a Face-selective ERP component (negative peak at about 170 milliseconds after stimulation onset, N170) in healthy participants. In contrast, patients with schizophrenia exhibit reduced amplitude of the N170, which may represent a pathological deficit in the neurophysiology of Face Perception. Interestingly, healthy humans with schizophrenia-like experiences (schizotypy) also exhibit abnormal processing of Face Perception. Yet, it has remained unknown how schizotypy in healthy humans is associated with the neurophysiological substrate of Face Perception. Here, we recruited 35 participants and assessed their schizotypy by the magical ideation rating scale. We used high-density electroencephalography to obtain ERPs elicited by a set of Mooney Faces (Face and non-Face conditions). We divided the participants into two groups (high and low schizotypy) by a median split of schizotypy scores. We investigated mean reaction times and the N170 component in response to the stimuli. We found significant slowed reaction times and reduced amplitude of the N170 component in response to the Face stimuli in the high-schizotypy group. In addition, across the full data set, we found that the schizotypy scores were significantly correlated with both the reaction times and the N170 amplitude. Our results thus support the model of schizotypy as a manifestation of a continuum between healthy individuals and patients with schizophrenia, where the N170 impairment serves as a biomarker for the degree of pathology along this continuum.
