anne-Marie Schuller | Université du Luxembourg (original) (raw)

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Research paper thumbnail of Stepwise emergence of the face-sensitive N170 event-related potential component

Neuroreport, 2003

The present study used a parametric design to characterize early event-related potentials (ERP) t... more The present study used a parametric design to characterize early event-related potentials (ERP) to face stimuli embedded in gradually decreasing random noise levels. For both N170 and the vertex positive potential (VPP) there was a linear increase in amplitude and decrease in latency with decreasing levels of noise. In contrast, the earlier visual P1 component was stable across noise levels. The P1/N170 dissociation suggests not only a functional dissociation between low and high-level visual processing of faces but also that the N170 reflects the integration of sensorial information into a unitary representation. In addition, the N170/VPP association supports the view that they reflect the same processes operating when viewing faces.

Research paper thumbnail of Characterizing the Spatio-temporal Dynamics of the Neural Events Occurring prior to and up to Overt Recognition of Famous Faces

Journal of Cognitive Neuroscience, 2010

Although it is generally acknowledged that familiar face recognition is fast, mandatory, and proc... more Although it is generally acknowledged that familiar face recognition is fast, mandatory, and proceeds outside conscious control, it is still unclear whether processes leading to familiar face recognition occur in a linear (i.e., gradual) or a nonlinear (i.e., all-or-none) manner. To test these two alternative accounts, we recorded scalp ERPs while participants indicated whether they recognize as familiar the faces of famous and unfamiliar persons gradually revealed in a descending sequence of frames, from the noisier to the least noisy. This presentation procedure allowed us to characterize the changes in scalp ERP responses occurring prior to and up to overt recognition. Our main finding is that gradual and all-or-none processes are possibly involved during overt recognition of familiar faces. Although the N170 and the N250 face-sensitive responses displayed an abrupt activity change at the moment of overt recognition of famous faces, later ERPs encompassing the N400 and late positive component exhibited an incremental increase in amplitude as the point of recognition approached. In addition, famous faces that were not overtly recognized at one trial before recognition elicited larger ERP potentials than unfamiliar faces, probably reflecting a covert recognition process. Overall, these findings present evidence that recognition of familiar faces implicates spatio-temporally complex neural processes exhibiting differential pattern activity changes as a function of recognition state.

Research paper thumbnail of Characterizing the Spatio-temporal Dynamics of the Neural Events Occurring prior to and up to Overt Recognition of Famous Faces

Although it is generally acknowledged that familiar face recognition is fast, mandatory, and proc... more Although it is generally acknowledged that familiar face recognition is fast, mandatory, and proceeds outside conscious control, it is still unclear whether processes leading to familiar face recognition occur in a linear (i.e., gradual) or a nonlinear (i.e., all-or-none) manner. To test these two alternative accounts, we recorded scalp ERPs while participants indicated whether they recognize as familiar the faces of famous and unfamiliar persons gradually revealed in a descending sequence of frames, from the noisier to the least noisy. This presentation procedure allowed us to characterize the changes in scalp ERP responses occurring prior to and up to overt recognition. Our main finding is that gradual and all-or-none processes are possibly involved during overt recognition of familiar faces. Although the N170 and the N250 face-sensitive responses displayed an abrupt activity change at the moment of overt recognition of famous faces, later ERPs encompassing the N400 and late positive component exhibited an incremental increase in amplitude as the point of recognition approached. In addition, famous faces that were not overtly recognized at one trial before recognition elicited larger ERP potentials than unfamiliar faces, probably reflecting a covert recognition process. Overall, these findings present evidence that recognition of familiar faces implicates spatio-temporally complex neural processes exhibiting differential pattern activity changes as a function of recognition state.

Research paper thumbnail of The perception of social interactions by subjects with social phobia: A study with virtual characters

Frontiers in Neuroengineering, 2009

Research paper thumbnail of A network of occipito-temporal face-sensitive areas besides the right middle fusiform gyrus is necessary for normal face processing

Brain, 2003

literature on the anatomical basis of prosopagnosia, it is suggested that the FFA and OFA in the ... more literature on the anatomical basis of prosopagnosia, it is suggested that the FFA and OFA in the right hemisphere and their re-entrant integration are necessary for normal face processing. Abbreviations: BORB = Birmingham Object Recognition Battery; FFA = fusiform face area; fMRI = functional MRI; OFA = occipital face area; rFFA = right fusiform face area; rOFA = right occipital face area Brain 126 ã Guarantors of Brain 2003; all rights reserved

Research paper thumbnail of Perception of static eye gaze direction facilitates subsequent early visual processing

Clinical Neurophysiology, 2004

Objective: Using event-related potentials (ERPs), it has been recently shown that a reflexive shi... more Objective: Using event-related potentials (ERPs), it has been recently shown that a reflexive shift of attention following the observation of a dynamic eye gaze cue enhances and speeds up early visual processing of a target presented at the gazed-at location. Here we investigate whether similar early sensory modulations are also elicited by static gaze cues, or if previously described attentional effects were caused mainly by visual motion cues and not by eye gaze direction per se. Furthermore, we explore if these possible attentional orienting effects reflect facilitation of the processing of cued stimuli, inhibition of the unattended stimuli, or both.Methods: Subjects were presented with a face looking to the right or left visual field (VF), or straight away, before the occurrence of a lateralized target to detect. There were 3 conditions in this nonpredictive cueing task: (1) target presented in the VF indicated by the eye gaze direction (congruent); (2) opposite to the eye gaze direction (incongruent); or (3) preceded by a straight gazing face (neutral).Results: Subjects were faster at detecting congruently than incongruently and neutrally cued targets. Facilitation effects were observed on early ERP components: the occipital P1 and occipito-temporal N1 components were speeded up as early as ∼100 ms following stimulus onset (P1), and enhanced (P1 and N1) in response to congruent trials, particularly in the right hemisphere.Conclusions: Spatial attention triggered by static eye gaze direction produces response facilitations – predominantly lateralized to the right hemisphere – from the early sensory stages of visual processing.Significance: This study provides the first evidence of a speeding up and amplification of early visual processing following attention triggered by static eye gaze perception.

Research paper thumbnail of Spatial attention triggered by eye gaze enhances and speeds up visual processing in upper and lower visual fields beyond early striate visual processing

Clinical Neurophysiology, 2005

Objective: The detection of a lateralized visual target is faster when preceded by a face gazing ... more Objective: The detection of a lateralized visual target is faster when preceded by a face gazing to the location of this stimulus. Here we aimed to clarify the time-course of the visual processing modulated by these reflexive shifts of attention. Methods: ERPs were measured on 16 subjects performing a speeded location task on a circular checkerboard. The checkerboard target appeared either on the left or right of the upper or lower visual field, and was preceded by a central face orienting its gaze obliquely to one of the four possible corner locations for the target to appear. Results: Congruently cued targets were located faster than incongruently cued targets and were associated with larger and earlier occipital P1 (w110 ms) and occipito-parieto-temporal N1 (w150 ms) components. However, no such attentional modulations were found on the earlier C1 visual component, best observed with a negative polarity for upper visual field stimulations, and thought to originate largely from primary visual cortex. Conclusions and significance: These results show that reflexive shifts of attention following oblique eye gaze to upper and lower visual fields increase and speed up the processing of visual information beyond the feedforward flow of information in primary visual cortex.

Research paper thumbnail of Spatial attention triggered by eye gaze increases and speeds up early visual activity

Neuroreport, 2001

What are the neuronal correlates of re¯exive shifts of attention triggered by eye gaze direction?... more What are the neuronal correlates of re¯exive shifts of attention triggered by eye gaze direction? Event related potentials (ERPs) were measured on 14 subjects performing a spatial attention task where eye gaze direction of a face cued the location of a forthcoming target. Subjects were faster in detecting a validly cued target, i.e. one appearing at the location the eye was gazing at, compared to invalidly cued targets, despite the non-predictive value of the eye cues. ERP results showed an enhanced and earlier occipito-parietal P1 and N1 for valid trials, demonstrating the early modulation of visual input by attentional allocation. These ®ndings provide the ®rst evidence that social attention can rapidly modify the processing of visual information in extrastriate cortex. NeuroReport

Research paper thumbnail of Perception of static eye gaze direction facilitates subsequent early visual processing

Objective: Using event-related potentials (ERPs), it has been recently shown that a reflexive shi... more Objective: Using event-related potentials (ERPs), it has been recently shown that a reflexive shift of attention following the observation of a dynamic eye gaze cue enhances and speeds up early visual processing of a target presented at the gazed-at location. Here we investigate whether similar early sensory modulations are also elicited by static gaze cues, or if previously described attentional effects were caused mainly by visual motion cues and not by eye gaze direction per se. Furthermore, we explore if these possible attentional orienting effects reflect facilitation of the processing of cued stimuli, inhibition of the unattended stimuli, or both.

Research paper thumbnail of Automatic visual attention triggered by eye gaze direction increases and speeds up early visual activity

Research paper thumbnail of Spatial attention triggered by eye gaze enhances and speeds up visual processing in upper and lower visual fields beyond early striate visual processing

Objective: The detection of a lateralized visual target is faster when preceded by a face gazing ... more Objective: The detection of a lateralized visual target is faster when preceded by a face gazing to the location of this stimulus. Here we aimed to clarify the time-course of the visual processing modulated by these reflexive shifts of attention. Methods: ERPs were measured on 16 subjects performing a speeded location task on a circular checkerboard. The checkerboard target appeared either on the left or right of the upper or lower visual field, and was preceded by a central face orienting its gaze obliquely to one of the four possible corner locations for the target to appear. Results: Congruently cued targets were located faster than incongruently cued targets and were associated with larger and earlier occipital P1 (w110 ms) and occipito-parieto-temporal N1 (w150 ms) components. However, no such attentional modulations were found on the earlier C1 visual component, best observed with a negative polarity for upper visual field stimulations, and thought to originate largely from primary visual cortex. Conclusions and significance: These results show that reflexive shifts of attention following oblique eye gaze to upper and lower visual fields increase and speed up the processing of visual information beyond the feedforward flow of information in primary visual cortex.

Research paper thumbnail of Stepwise emergence of the face-sensitive N170 event-related potential component

Neuroreport, 2003

The present study used a parametric design to characterize early event-related potentials (ERP) t... more The present study used a parametric design to characterize early event-related potentials (ERP) to face stimuli embedded in gradually decreasing random noise levels. For both N170 and the vertex positive potential (VPP) there was a linear increase in amplitude and decrease in latency with decreasing levels of noise. In contrast, the earlier visual P1 component was stable across noise levels. The P1/N170 dissociation suggests not only a functional dissociation between low and high-level visual processing of faces but also that the N170 reflects the integration of sensorial information into a unitary representation. In addition, the N170/VPP association supports the view that they reflect the same processes operating when viewing faces.

Research paper thumbnail of Characterizing the Spatio-temporal Dynamics of the Neural Events Occurring prior to and up to Overt Recognition of Famous Faces

Journal of Cognitive Neuroscience, 2010

Although it is generally acknowledged that familiar face recognition is fast, mandatory, and proc... more Although it is generally acknowledged that familiar face recognition is fast, mandatory, and proceeds outside conscious control, it is still unclear whether processes leading to familiar face recognition occur in a linear (i.e., gradual) or a nonlinear (i.e., all-or-none) manner. To test these two alternative accounts, we recorded scalp ERPs while participants indicated whether they recognize as familiar the faces of famous and unfamiliar persons gradually revealed in a descending sequence of frames, from the noisier to the least noisy. This presentation procedure allowed us to characterize the changes in scalp ERP responses occurring prior to and up to overt recognition. Our main finding is that gradual and all-or-none processes are possibly involved during overt recognition of familiar faces. Although the N170 and the N250 face-sensitive responses displayed an abrupt activity change at the moment of overt recognition of famous faces, later ERPs encompassing the N400 and late positive component exhibited an incremental increase in amplitude as the point of recognition approached. In addition, famous faces that were not overtly recognized at one trial before recognition elicited larger ERP potentials than unfamiliar faces, probably reflecting a covert recognition process. Overall, these findings present evidence that recognition of familiar faces implicates spatio-temporally complex neural processes exhibiting differential pattern activity changes as a function of recognition state.

Research paper thumbnail of Characterizing the Spatio-temporal Dynamics of the Neural Events Occurring prior to and up to Overt Recognition of Famous Faces

Although it is generally acknowledged that familiar face recognition is fast, mandatory, and proc... more Although it is generally acknowledged that familiar face recognition is fast, mandatory, and proceeds outside conscious control, it is still unclear whether processes leading to familiar face recognition occur in a linear (i.e., gradual) or a nonlinear (i.e., all-or-none) manner. To test these two alternative accounts, we recorded scalp ERPs while participants indicated whether they recognize as familiar the faces of famous and unfamiliar persons gradually revealed in a descending sequence of frames, from the noisier to the least noisy. This presentation procedure allowed us to characterize the changes in scalp ERP responses occurring prior to and up to overt recognition. Our main finding is that gradual and all-or-none processes are possibly involved during overt recognition of familiar faces. Although the N170 and the N250 face-sensitive responses displayed an abrupt activity change at the moment of overt recognition of famous faces, later ERPs encompassing the N400 and late positive component exhibited an incremental increase in amplitude as the point of recognition approached. In addition, famous faces that were not overtly recognized at one trial before recognition elicited larger ERP potentials than unfamiliar faces, probably reflecting a covert recognition process. Overall, these findings present evidence that recognition of familiar faces implicates spatio-temporally complex neural processes exhibiting differential pattern activity changes as a function of recognition state.

Research paper thumbnail of The perception of social interactions by subjects with social phobia: A study with virtual characters

Frontiers in Neuroengineering, 2009

Research paper thumbnail of A network of occipito-temporal face-sensitive areas besides the right middle fusiform gyrus is necessary for normal face processing

Brain, 2003

literature on the anatomical basis of prosopagnosia, it is suggested that the FFA and OFA in the ... more literature on the anatomical basis of prosopagnosia, it is suggested that the FFA and OFA in the right hemisphere and their re-entrant integration are necessary for normal face processing. Abbreviations: BORB = Birmingham Object Recognition Battery; FFA = fusiform face area; fMRI = functional MRI; OFA = occipital face area; rFFA = right fusiform face area; rOFA = right occipital face area Brain 126 ã Guarantors of Brain 2003; all rights reserved

Research paper thumbnail of Perception of static eye gaze direction facilitates subsequent early visual processing

Clinical Neurophysiology, 2004

Objective: Using event-related potentials (ERPs), it has been recently shown that a reflexive shi... more Objective: Using event-related potentials (ERPs), it has been recently shown that a reflexive shift of attention following the observation of a dynamic eye gaze cue enhances and speeds up early visual processing of a target presented at the gazed-at location. Here we investigate whether similar early sensory modulations are also elicited by static gaze cues, or if previously described attentional effects were caused mainly by visual motion cues and not by eye gaze direction per se. Furthermore, we explore if these possible attentional orienting effects reflect facilitation of the processing of cued stimuli, inhibition of the unattended stimuli, or both.Methods: Subjects were presented with a face looking to the right or left visual field (VF), or straight away, before the occurrence of a lateralized target to detect. There were 3 conditions in this nonpredictive cueing task: (1) target presented in the VF indicated by the eye gaze direction (congruent); (2) opposite to the eye gaze direction (incongruent); or (3) preceded by a straight gazing face (neutral).Results: Subjects were faster at detecting congruently than incongruently and neutrally cued targets. Facilitation effects were observed on early ERP components: the occipital P1 and occipito-temporal N1 components were speeded up as early as ∼100 ms following stimulus onset (P1), and enhanced (P1 and N1) in response to congruent trials, particularly in the right hemisphere.Conclusions: Spatial attention triggered by static eye gaze direction produces response facilitations – predominantly lateralized to the right hemisphere – from the early sensory stages of visual processing.Significance: This study provides the first evidence of a speeding up and amplification of early visual processing following attention triggered by static eye gaze perception.

Research paper thumbnail of Spatial attention triggered by eye gaze enhances and speeds up visual processing in upper and lower visual fields beyond early striate visual processing

Clinical Neurophysiology, 2005

Objective: The detection of a lateralized visual target is faster when preceded by a face gazing ... more Objective: The detection of a lateralized visual target is faster when preceded by a face gazing to the location of this stimulus. Here we aimed to clarify the time-course of the visual processing modulated by these reflexive shifts of attention. Methods: ERPs were measured on 16 subjects performing a speeded location task on a circular checkerboard. The checkerboard target appeared either on the left or right of the upper or lower visual field, and was preceded by a central face orienting its gaze obliquely to one of the four possible corner locations for the target to appear. Results: Congruently cued targets were located faster than incongruently cued targets and were associated with larger and earlier occipital P1 (w110 ms) and occipito-parieto-temporal N1 (w150 ms) components. However, no such attentional modulations were found on the earlier C1 visual component, best observed with a negative polarity for upper visual field stimulations, and thought to originate largely from primary visual cortex. Conclusions and significance: These results show that reflexive shifts of attention following oblique eye gaze to upper and lower visual fields increase and speed up the processing of visual information beyond the feedforward flow of information in primary visual cortex.

Research paper thumbnail of Spatial attention triggered by eye gaze increases and speeds up early visual activity

Neuroreport, 2001

What are the neuronal correlates of re¯exive shifts of attention triggered by eye gaze direction?... more What are the neuronal correlates of re¯exive shifts of attention triggered by eye gaze direction? Event related potentials (ERPs) were measured on 14 subjects performing a spatial attention task where eye gaze direction of a face cued the location of a forthcoming target. Subjects were faster in detecting a validly cued target, i.e. one appearing at the location the eye was gazing at, compared to invalidly cued targets, despite the non-predictive value of the eye cues. ERP results showed an enhanced and earlier occipito-parietal P1 and N1 for valid trials, demonstrating the early modulation of visual input by attentional allocation. These ®ndings provide the ®rst evidence that social attention can rapidly modify the processing of visual information in extrastriate cortex. NeuroReport

Research paper thumbnail of Perception of static eye gaze direction facilitates subsequent early visual processing

Objective: Using event-related potentials (ERPs), it has been recently shown that a reflexive shi... more Objective: Using event-related potentials (ERPs), it has been recently shown that a reflexive shift of attention following the observation of a dynamic eye gaze cue enhances and speeds up early visual processing of a target presented at the gazed-at location. Here we investigate whether similar early sensory modulations are also elicited by static gaze cues, or if previously described attentional effects were caused mainly by visual motion cues and not by eye gaze direction per se. Furthermore, we explore if these possible attentional orienting effects reflect facilitation of the processing of cued stimuli, inhibition of the unattended stimuli, or both.

Research paper thumbnail of Automatic visual attention triggered by eye gaze direction increases and speeds up early visual activity

Research paper thumbnail of Spatial attention triggered by eye gaze enhances and speeds up visual processing in upper and lower visual fields beyond early striate visual processing

Objective: The detection of a lateralized visual target is faster when preceded by a face gazing ... more Objective: The detection of a lateralized visual target is faster when preceded by a face gazing to the location of this stimulus. Here we aimed to clarify the time-course of the visual processing modulated by these reflexive shifts of attention. Methods: ERPs were measured on 16 subjects performing a speeded location task on a circular checkerboard. The checkerboard target appeared either on the left or right of the upper or lower visual field, and was preceded by a central face orienting its gaze obliquely to one of the four possible corner locations for the target to appear. Results: Congruently cued targets were located faster than incongruently cued targets and were associated with larger and earlier occipital P1 (w110 ms) and occipito-parieto-temporal N1 (w150 ms) components. However, no such attentional modulations were found on the earlier C1 visual component, best observed with a negative polarity for upper visual field stimulations, and thought to originate largely from primary visual cortex. Conclusions and significance: These results show that reflexive shifts of attention following oblique eye gaze to upper and lower visual fields increase and speed up the processing of visual information beyond the feedforward flow of information in primary visual cortex.