Perceptual face processing in developmental prosopagnosia is not sensitive to the canonical location of face parts

Individuals with developmental prosopagnosia (DP) are strongly impaired in recognizing faces, but it is controversial whether this deficit is linked to atypical visual-perceptual face processing mechanisms. Previous behavioural studies have suggested that face perception in DP might be less sensitive to the canonical spatial configuration of face parts in upright faces. To test this prediction, we recorded event-related brain potentials (ERPs) to intact upright faces and to faces with spatially scrambled parts (eyes, nose, and mouth) in a group of ten participants with DP and a group of ten age-matched control participants with normal face recognition abilities. The face-sensitive N170 component and the vertex positive potential (VPP) were both enhanced and delayed for scrambled as compared to intact faces in the control group. In contrast, N170 and VPP amplitude enhancements to scrambled faces were absent in the DP group. For control participants, the N170 to scrambled faces was also sensitive to feature locations, with larger and delayed N170 components contralateral to the side where all features appeared in a non-canonical position. No such differences were present in the DP group. These findings suggest that spatial templates of the prototypical feature locations within an upright face are selectively impaired in DP

Brain activation during face perception: evidence of a developmental change.

Behavioral studies suggest that children under age 10 process faces using a piecemeal strategy based on individual distinctive facial features, whereas older children use a configural strategy based on the spatial relations among the face's features. The purpose of this study was to determine whether activation of the fusiform gyrus, which is involved in face processing in adults, is greater during face processing in older children (12-14 years) than in younger children (8-10 years). Functional MRI scans were obtained while children viewed faces and houses. A developmental change was observed: Older children, but not younger children, showed significantly more activation in bilateral fusiform gyri for faces than for houses. Activation in the fusiform gyrus correlated significantly with age and with a behavioral measure of configural face processing. Regions believed to be involved in processing basic facial features were activated in both younger and older children. Some evidence was also observed for greater activation for houses versus faces for the older children than for the younger children, suggesting that processing of these two stimulus types becomes more differentiated as children age. The current results provide biological insight into changes in visual processing of faces that occur with normal development

Developmental changes in the processing of faces as revealed by EEG decoding

Rapidly and accurately processing information from faces is a critical human function that is known to improve with developmental age. Understanding the underlying drivers of this improvement remains a contentious question, with debate continuing as to the presence of early vs. late maturation of face-processing mechanisms. Recent behavioural evidence suggests an important ‘hallmark’ of expert face processing – the face inversion effect – is present in very young children, yet neural support for this remains unclear. To address this, we conducted a detailed investigation of the neural dynamics of face processing in children spanning a range of ages (6 – 11 years) and adults. Uniquely, we applied multivariate pattern analysis (MVPA) to the electroencephalogram signal (EEG) to test for the presence of a distinct neural profile associated with canonical upright faces when compared both to other objects (houses) and to inverted faces. Results revealed robust discrimination profiles, at the individual level, of differentiated neural activity associated with broad face categorization and further with its expert processing, as indexed by the face inversion effect, from the youngest ages tested. This result is consistent with an early functional maturation of broad face processing mechanisms. Yet, clear quantitative differences between the response profile of children and adults is suggestive of age-related refinement of this system with developing face and general expertise. Standard ERP analysis also provides some support for qualitative differences in the neural response to inverted faces in children in contrast to adults. This neural profile is in line with recent behavioural studies that have reported impressively expert early face abilities during childhood, while also providing novel evidence of the ongoing neural specialisation between child and adulthood

DEVELOPMENTAL FMRI STUDY: FACE AND OBJECT RECOGNITION

Visual processing, though seemingly automatic, is complex. Typical humansprocess objects and faces routinely. Yet, when a disease or disorder disrupts face andobject recognition, the effects are profound. Because of its importance and complexity,visual processing has been the subject of many adult functional imaging studies.However, relatively little is known about the development of the neural organization andunderlying cognitive mechanisms of face and object recognition. The current projectused functional magnetic resonance imaging (fMRI) to identify maturational changes inthe neural substrates of face and object recognition in 5-8 year olds, 9-11 year olds, andadults. A passive face and object viewing task revealed cortical shifts in the faceresponsiveloci of the ventral processing stream (VPS), an inferior occipito-temporalregion known to function in higher visual processing. Older children and adults recruitedmore anterior regions of the ventral processing stream than younger children. Toinvestigate the potential cognitive basis for these developmental changes, researchersimplemented a shape-matching task with parametric variations of shape overlap,structural similarity (SS), in stimulus pairs. VPS regions sensitive to high SS emerged inolder children and adults. Younger children recruited no structurally-sensitive regions inthe VPS. Two right hemisphere VPS regions were sensitive to maturational changes inSS. A comparison of face-responsive regions from the passive viewing task and the VPSSS regions did not reveal overlap. Though SS drives organization of the VPS, it did notexplain the cortical shifts in the neural substrates for face processing. In addition to VPSregions, results indicated additional maturational SS changes in frontal, parietal, andcerebellar regions. Based on these findings, further analyses were conducted to quantifyand qualify maturational changes in face and object processing throughout the brain.Results indicated developmental changes in activation extent, signal magnitude, andlateralization of face and object recognition networks. Collectively, this project supportsa developmental change in visual processing between 5-8 years and 9-11 years of age.Chapters Four through Six provide an in-depth discussion of the implications of thesefindings

From upright to upside-down presentation: A spatio-temporal ERP study of the parametric effect of rotation on face and house processing

<p>Abstract</p> <p>Background</p> <p>While there is a general agreement that picture-plane inversion is more detrimental to face processing than to other seemingly complex visual objects, the origin of this effect is still largely debatable. Here, we address the question of whether face inversion reflects a quantitative or a qualitative change in processing mode by investigating the pattern of event-related potential (ERP) response changes with picture plane rotation of face and house pictures. Thorough analyses of topographical (Scalp Current Density maps, SCD) and dipole source modeling were also conducted.</p> <p>Results</p> <p>We find that whilst stimulus orientation affected in a similar fashion participants' response latencies to make face and house decisions, only the ERPs in the N170 latency range were modulated by picture plane rotation of faces. The pattern of N170 amplitude and latency enhancement to misrotated faces displayed a curvilinear shape with an almost linear increase for rotations from 0° to 90° and a dip at 112.5° up to 180° rotations. A similar discontinuity function was also described for SCD occipito-temporal and temporal current foci with no topographic distribution changes, suggesting that upright and misrotated faces activated similar brain sources. This was confirmed by dipole source analyses showing the involvement of bilateral sources in the fusiform and middle occipital gyri, the activity of which was differentially affected by face rotation.</p> <p>Conclusion</p> <p>Our N170 findings provide support for both the quantitative and qualitative accounts for face rotation effects. Although the qualitative explanation predicted the curvilinear shape of N170 modulations by face misrotations, topographical and source modeling findings suggest that the same brain regions, and thus the same mechanisms, are probably at work when processing upright and rotated faces. Taken collectively, our results indicate that the same processing mechanisms may be involved across the whole range of face orientations, but would operate in a non-linear fashion. Finally, the response tuning of the N170 to rotated faces extends previous reports and further demonstrates that face inversion affects perceptual analyses of faces, which is reflected within the time range of the N170 component.</p

Cross-orientation transfer of adaptation for facial identity is asymmetric: A study using contrast-based recognition thresholds

AbstractRecent studies suggest that adaptation effects for face shape and gender transfer from upright to inverted faces more than the reverse. We investigated whether a similar asymmetry occurred for face identity, using a recently developed adaptation method based on contrast-recognition thresholds. When adapting and test stimuli shared the same orientation, aftereffects were similar for upright and inverted faces. When orientation differed, there was significant transfer of aftereffects from upright adapting to inverted test faces, but none from inverted to upright faces. We show that asymmetric cross-orientation transfer of face aftereffects generalize across two distinct face adaptation paradigms: the previously used perceptual-bias methodology and the recently introduced contrast-threshold based adaptation paradigm. These results also represent a generalization from aftereffects for face shape and gender to aftereffects for face identity. While these results are consistent with the dual-mode hypothesis, they can also be accounted for by a single population of units of varying orientation selectivity

Are advanced methods necessary to improve infant fNIRS data analysis? An assessment of baseline-corrected averaging, general linear model (GLM) and multivariate pattern analysis (MVPA) based approaches

In the last decade, fNIRS has provided a non-invasive method to investigate neural activation in developmental populations. Despite its increasing use in developmental cognitive neuroscience, there is little consistency or consensus on how to pre-process and analyse infant fNIRS data. With this registered report, we investigated the feasibility of applying more advanced statistical analyses to infant fNIRS data and compared the most commonly used baseline-corrected averaging, General Linear Model (GLM)-based univariate, and Multivariate Pattern Analysis (MVPA) approaches, to show how the conclusions one would draw based on these different analysis approaches converge or differ. The different analysis methods were tested using a face inversion paradigm where changes in brain activation in response to upright and inverted face stimuli were measured in thirty 4-to-6-month-old infants. By including more standard approaches together with recent machine learning techniques, we aim to inform the fNIRS community on alternative ways to analyse infant fNIRS datasets

Qualitative differences in the spatiotemporal brain states supporting configural face processing emerge in adolescence in autism

BACKGROUND Studying the neural processing of faces can illuminate the mechanisms of compromised social expertise in autism. To resolve a longstanding debate, we examined whether differences in configural face processing in autism are underpinned by quantitative differences in the activation of typical face processing pathways, or the recruitment of non-typical neural systems. METHODS We investigated spatial and temporal characteristics of event-related EEG responses to upright and inverted faces in a large sample of children, adolescents, and adults with and without autism. We examined topographic analyses of variance and global field power to identify group differences in the spatial and temporal response to face inversion. We then examined how quasi-stable spatiotemporal profiles - microstates - are modulated by face orientation and diagnostic group. RESULTS Upright and inverted faces produced distinct profiles of topography and strength in the topographical analyses. These topographical profiles differed between diagnostic groups in adolescents, but not in children or adults. In the microstate analysis, the autistic group showed differences in the activation strength of normative microstates during early-stage processing at all ages, suggesting consistent quantitative differences in the operation of typical processing pathways; qualitative differences in microstate topographies during late-stage processing became prominent in adults, suggesting the increasing involvement of non-typical neural systems with processing time and over development. CONCLUSIONS These findings suggest that early difficulties with configural face processing may trigger later compensatory processes in autism that emerge in later development

Experience-dependent reshaping of body processing: from perception to clinical implications

Starting from the moment we come into the world, we are compelled to pay large attention to the body and its representation, which can be considered as a set of cognitive structures that have the function of tracing and coding our state (de Vignemont, 2010). However, we cannot consider body aside from its image, which can determine the way we emotionally perceive ourselves and other people as well as the way we experience the world. With a brief look to the body, we can identify a persons’ identity, thus catching distinctive elements such as her age or gender; further, by means of body posture and movements we can understand the affective state of others and appropriately shape our social interaction and communication. Several socially significant cues can be detected and provided through the body, but this thesis principally aims to increase the knowledge about how we perceive gender from bodily features and shape. Specifically, I report on a series of behavioral studies designed to investigate the influence of the visual experience on the detection of gender dimension, considering the contribution of brain networks which may also have a role in the development of mental disorders related to body misperception (i.e. Eating Disorders; ED). In the first chapter, I provide evidence for the interdependence of morphologic and dynamic cues in shaping gender judgment. By manipulating various characteristics of virtual-human body stimuli, the experiment I carried out demonstrates the association between stillness and femininity rating, addressing the evolutionary meaning of sexual selection and the influence of cultural norms (D’Argenio et al., 2020). In the second chapter, I present a study that seeks to define the relative role of parvo- and magnocellular visual streams in the identification of both morphologic and dynamic cues of the body. For these experiments, I used the differential tuning of the two streams to low- (LSF) and high-spatial frequencies (HSF) and I tested how the processing of body gender and postures is affected by filtering images to keep only the LSF or HSF (D’Argenio et al., submitted). The third chapter is dedicated to a series of experiments aimed at understanding how gender perception can be biased by the previous exposure to specific body models. I utilized a visual adaptation paradigm to investigate the mechanisms that drives the observers’ perception to a masculinity or femininity judgement (D’Argenio et al., 2021) and manipulates the spatial frequency content of the bodies in order to account for the contribution of parvo- and magnocellular system in in this process. In conclusion, in the last two chapters, I briefly report the preliminary results emerging from two visual adaptation studies. The first one, which is described in the fourth chapter, explored the role of cortical connections in body gender adaptation by means of Transcranial Magnetic Stimulation (TMS), with the aim to investigate neural correlates of dysfunctional body perception. The second represents the intent to explain, at least partially, body misperception disorders by applying adaptation paradigms to ED clinical population. Results were discussed in the fifth chapter.Starting from the moment we come into the world, we are compelled to pay large attention to the body and its representation, which can be considered as a set of cognitive structures that have the function of tracing and coding our state (de Vignemont, 2010). However, we cannot consider body aside from its image, which can determine the way we emotionally perceive ourselves and other people as well as the way we experience the world. With a brief look to the body, we can identify a persons’ identity, thus catching distinctive elements such as her age or gender; further, by means of body posture and movements we can understand the affective state of others and appropriately shape our social interaction and communication. Several socially significant cues can be detected and provided through the body, but this thesis principally aims to increase the knowledge about how we perceive gender from bodily features and shape. Specifically, I report on a series of behavioral studies designed to investigate the influence of the visual experience on the detection of gender dimension, considering the contribution of brain networks which may also have a role in the development of mental disorders related to body misperception (i.e. Eating Disorders; ED). In the first chapter, I provide evidence for the interdependence of morphologic and dynamic cues in shaping gender judgment. By manipulating various characteristics of virtual-human body stimuli, the experiment I carried out demonstrates the association between stillness and femininity rating, addressing the evolutionary meaning of sexual selection and the influence of cultural norms (D’Argenio et al., 2020). In the second chapter, I present a study that seeks to define the relative role of parvo- and magnocellular visual streams in the identification of both morphologic and dynamic cues of the body. For these experiments, I used the differential tuning of the two streams to low- (LSF) and high-spatial frequencies (HSF) and I tested how the processing of body gender and postures is affected by filtering images to keep only the LSF or HSF (D’Argenio et al., submitted). The third chapter is dedicated to a series of experiments aimed at understanding how gender perception can be biased by the previous exposure to specific body models. I utilized a visual adaptation paradigm to investigate the mechanisms that drives the observers’ perception to a masculinity or femininity judgement (D’Argenio et al., 2021) and manipulates the spatial frequency content of the bodies in order to account for the contribution of parvo- and magnocellular system in in this process. In conclusion, in the last two chapters, I briefly report the preliminary results emerging from two visual adaptation studies. The first one, which is described in the fourth chapter, explored the role of cortical connections in body gender adaptation by means of Transcranial Magnetic Stimulation (TMS), with the aim to investigate neural correlates of dysfunctional body perception. The second represents the intent to explain, at least partially, body misperception disorders by applying adaptation paradigms to ED clinical population. Results were discussed in the fifth chapter