Face Configuration Research Articles

Identification and Function of a Cytoplasmic K+ Site of the Na+, K+-ATPase

A cytoplasmic nontransport K(+)/Rb(+) site in the P-domain of the Na(+), K(+)-ATPase has been identified by anomalous difference Fourier map analysis of crystals of the [Rb(2)].E(2).MgF(4)(2-) form of the enzyme. The functional roles of this third K(+)/Rb(+) binding site were studied by site-directed mutagenesis, replacing the side chain of Asp(742) donating oxygen ligand(s) to the site with alanine, glutamate, and lysine. Unlike the wild-type Na(+), K(+)-ATPase, the mutants display a biphasic K(+) concentration dependence of E(2)P dephosphorylation, indicating that the cytoplasmic K(+) site is involved in activation of dephosphorylation. The affinity of the site is lowered significantly (30-200-fold) by the mutations, the lysine mutation being most disruptive. Moreover, the mutations accelerate the E(2) to E(1) conformational transition, again with the lysine substitution resulting in the largest effect. Hence, occupation of the cytoplasmic K(+)/Rb(+) site not only enhances E(2)P dephosphorylation but also stabilizes the E(2) dephosphoenzyme. These characteristics of the previously unrecognized nontransport site make it possible to account for the hitherto poorly understood trans-effects of cytoplasmic K(+) by the consecutive transport model, without implicating a simultaneous exposure of the transport sites toward the cytoplasmic and extracellular sides of the membrane. The cytoplasmic K(+)/Rb(+) site appears to be conserved among Na(+), K(+)-ATPases and P-type ATPases in general, and its mode of operation may be associated with stabilizing the loop structure at the C-terminal end of the P6 helix of the P-domain, thereby affecting the function of highly conserved catalytic residues and promoting helix-helix interactions between the P- and A-domains in the E(2) state.

Brief Report: Face Configuration Accuracy and Processing Speed Among Adults with High-Functioning Autism Spectrum Disorders

The present study investigates the accuracy and speed of face processing employed by high-functioning adults with autism spectrum disorders (ASDs). Two behavioral experiments measured sensitivity to distances between features and face recognition when performance depended on holistic versus featural information. Results suggest adults with ASD were less accurate, but responded as quickly as controls for both tasks. In contrast to previous findings with children, adults with ASD demonstrated a holistic advantage only when the eye region was tested. Both groups recognized large manipulations to second-order relations more accurately than no change or small changes, but controls responded more quickly than participants with ASD when recognizing these large manipulations to configural information.

Prosopagnosia associated with a left occipitotemporal lesion

Acquired prosopagnosia is usually associated with bilateral or right-sided lesions of the occipital or temporal lobes. In rare cases of prosopagnosia after left-sided lesions in left-handed subjects, it is attributed to a reversed hemispheric specialization for face processing. This study examines the face-processing functions of a left-handed prosopagnosic patient with a left-sided lesion affecting the region of the occipital face area and possibly the fusiform face area, to contrast his deficits with those of prosopagnosic patients with right-hemispheric lesions. Similar to those patients, he has a moderately severe reduction in familiarity judgments, is impaired in processing face configuration, and shares with some of those patients a greater failure to process eye than mouth information, indicating an altered pattern of facial saliency. He has a mild reduction in the identification of exemplars of non-face objects. Unlike those patients, he has better residual familiarity on a two-alternative forced-choice task and can processing facial configuration if given more time, indicating a reduction in efficiency rather than a severe limitation. He has more difficulty accessing semantic–biographic information from names. He has trouble with facial feature imagery but not imagery for global face shape. Thus this subject's deficits represent a combination of impaired familiarity and configuration processing (normally right-sided functions in right-handed subjects), and impaired feature processing and access to semantic–biographic information (normally left-sided functions). His prosopagnosia likely reflects partially anomalous rather than reversed lateralization of hemispheric perceptual functions.

Inhibition of return for the discrimination of faces

When a target appears unpredictably in the same rather than a different location relative to a preceding onset cue, reaction times (RTs) of participants tasked with responding to the target are slowed. This pattern of results, referred to as inhibition of return (IOR), is believed to reflect the operation of a mechanism that prevents perseverative search of nontarget locations. On the grounds that an evolved mechanism might be sensitive to social stimuli, Taylor and Therrien (2005) examined IOR for localization responses under conditions in which cues and targets could be intact face configurations or nonface configurations; contrary to their predictions, there was no influence of cue or target configuration on the magnitude of IOR, indicating that the mere occurrence of task-irrelevant face and nonface stimuli does not alter IOR. In the present study, we further examined this issue in a task that required a face/nonface target discrimination. When target configuration was thereby made task relevant, we found that IOR differed for face and nonface targets in terms of magnitude (when a single cue-target stimulus onset asynchrony was employed) and time course. We suggest that the RT delay associated with IOR may enable additional processing time and/or response selection when a task-relevant face is presented at the cued location.

The role of featural and configural processing in own- and other-race face classification: Behavioral and ERP evidence

Event Abstract Back to Event The role of featural and configural processing in own- and other-race face classification: Behavioral and ERP evidence Z. Lun1, 2, 3 and Shlomo Bentin3* 1 Institute of Linguistics, Xuzhou Normal University, China 2 Key Laboratory of Language Sciences & Neuro-cognitive Engineering, China 3 Department Psychology, The Hebrew University of Jerusalem, Israel While individual own-race faces are identified easier than other-race faces ("the other race effect"; ORE), classification by race is faster for other-race than own-race faces (“the other-race advantage”; ORA). Putatively, both effects reflect acquired expertise within-race, which facilitates individual distinction of own-race faces (on the basis of the distinctive configuration of inner components) while renders other-race faces a more homogeneous group, easier to categorize on the basis of holistic structure or distinctive features. To this end we used ERP and RT measures to explore the consequences of holistic, configural and feature manipulations on the categorization of own and other races by race. Chinese participants in China and Israeli participants in Israel classified full faces, isolated eyes and faces with slight alterations of the spatial configuration of inner components as Chinese or Caucasian. Demonstrating the ORA, across all stimuli the other-race were classified faster than own-race by both Chinese and Israeli participants. For both groups isolating eyes or distorting the face configuration delayed classification of own-race stimuli. For Chinese participants the ORA was equal for full faces and isolated eyes and higher for distorted faces. Israeli participants classified full Chinese faces and isolated eyes at an equal speed (hence showing larger ORA for isolated eyes). Similarly, they classified regular and configural-distorted Chinese faces at equal speed, (hence showing larger ORA for configural faces). The N170 was relatively unaffected by race. In contrast N2 and P3 components elicited by other-race full faces and isolated eyes were bigger than by own-race ones for both groups. Other-race distorted faces also elicited larger N2 and P3 components than own-race faces for Israeli but not for Chinese participants. We conclude that the ORA is based primarily on post-perceptual mechanisms. However, some differences between perceptual strategies of Chinese and Israeliens were also observed: Configural and feature-focused face information is equally used by both groups to process own-race faces. In contrast, Chinese participants based the classification of Caucasian faces on configural/global face-information slightly more than on features, while Israelis focused slightly more on the characteristic features Chinese faces (eyes) than on their configural aspect. Conference: 10th International Conference on Cognitive Neuroscience, Bodrum, Turkey, 1 Sep - 5 Sep, 2008. Presentation Type: Oral Presentation Topic: Perceptual Processing and Recognition Citation: Lun Z and Bentin S (2008). The role of featural and configural processing in own- and other-race face classification: Behavioral and ERP evidence. Conference Abstract: 10th International Conference on Cognitive Neuroscience. doi: 10.3389/conf.neuro.09.2009.01.374 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 16 Dec 2008; Published Online: 16 Dec 2008. * Correspondence: Shlomo Bentin, Department Psychology, The Hebrew University of Jerusalem, Jerusalem, Israel, shlomo.bentin@huji.ac.il Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Z. Lun Shlomo Bentin Google Z. Lun Shlomo Bentin Google Scholar Z. Lun Shlomo Bentin PubMed Z. Lun Shlomo Bentin Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Using spatial frequency scales for processing face features and face configuration: An ERP analysis

In the present study we examined the influence of spatial filtering on the N170-effect, a relatively early face-selective ERP difference associated with face detection. We compared modulation of the N170-effect using spatially filtered stimuli that either facilitated feature analysis or impeded configural analysis. The salience of inner face components was enhanced by presenting them in isolation. Configural processing was manipulated by face inversion. The N170-effects elicited by upright faces and isolated inner components were similar across low- and high-spatial frequency scales. In contrast, the inversion effect (enhanced N170 amplitude for inverted compared with upright faces) was only observed with broadband and low-spatial frequency stimuli. These findings demonstrate that the N170-effect can be influenced by both low- and high-spatial frequency channels. Moreover, they indicate that different configural manipulations (isolated features vs. face inversion) affect face detection in distinct ways, consistent with separate processing mechanisms for different types of configural encoding.

Factors contributing to the adaptation aftereffects of facial expression

Previous studies have demonstrated the existence of adaptation aftereffects for facial expressions. Here we investigated which aspects of facial stimuli contribute to these aftereffects. In Experiment 1, we examined the role of local adaptation to image elements such as curvature, shape and orientation, independent of expression, by using hybrid faces constructed from either the same or opposing expressions. While hybrid faces made with consistent expressions generated aftereffects as large as those with normal faces, there were no aftereffects from hybrid faces made from different expressions, despite the fact that these contained the same local image elements. In Experiment 2, we examined the role of facial features independent of the normal face configuration by contrasting adaptation with whole faces to adaptation with scrambled faces. We found that scrambled faces also generated significant aftereffects, indicating that expressive features without a normal facial configuration could generate expression aftereffects. In Experiment 3, we examined the role of facial configuration by using schematic faces made from line elements that in isolation do not carry expression-related information (e.g. curved segments and straight lines) but that convey an expression when arranged in a normal facial configuration. We obtained a significant aftereffect for facial configurations but not scrambled configurations of these line elements. We conclude that facial expression aftereffects are not due to local adaptation to image elements but due to high-level adaptation of neural representations that involve both facial features and facial configuration.

Early Face Processing Specificity: It's in the Eyes!

Unlike most other objects that are processed analytically, faces are processed configurally. This configural processing is reflected early in visual processing following face inversion and contrast reversal, as an increase in the N170 amplitude, a scalp-recorded event-related potential. Here, we show that these face-specific effects are mediated by the eye region. That is, they occurred only when the eyes were present, but not when eyes were removed from the face. The N170 recorded to inverted and negative faces likely reflects the processing of the eyes. We propose a neural model of face processing in which face- and eye-selective neurons situated in the superior temporal sulcus region of the human brain respond differently to the face configuration and to the eyes depending on the face context. This dynamic response modulation accounts for the N170 variations reported in the literature. The eyes may be central to what makes faces so special.

Rapid Adaptation of the M170 Response: Importance of Face Parts

Face perception is often characterized as depending on configural, rather than part-based, processing. Here we examined the relative contributions of configuration and parts to early "face-selective" processing at the M170, a magnetoencephalographic response approximately 170 ms after stimulus onset, using adaptation. Previously (Harris and Nakayama 2007), we showed that rapid successive presentation of 2 stimuli (stimulus-onset asynchrony < 800 ms) attenuates the M170 response. Such adaptation is face-selective, with greater attenuation when faces are preceded by other faces than by houses. This technique therefore provides an independent method to assess the nature of this early neurophysiological marker. In these experiments, we measured the adapting power of face configurations versus parts using upright and inverted faces (Experiment 1), face-like configurations of black ovals versus scrambled nonface configurations of face parts (Experiment 2), and isolated face parts (Experiment 3). Although face configurations alone do not produce face-selective adaptation, scrambled and even isolated face parts adapt the M170 response to a similar extent as full faces. Thus, at least for the relatively early face-selective M170 response, face parts produce face-selective adaptation but face configurations do not. These results suggest that face parts are important at relatively early stages of face perception.

Dysfunction in configural face processing in patients with schizophrenia.

Background: Face recognition has important implications for patients with schizophrenia, who exhibit poor interpersonal and social skills. Previous reports have suggested that patients with schizophrenia have deficits in their ability to recognize faces, and because face recognition relies heavily on information about the configuration of faces, we hypothesized that patients with schizophrenia would have specific problems in processing configural information. Methods: We measured the performance of 20 patients with schizophrenia and 20 normal subjects in a face-discrimination task, using upright and inverted pairs of face photographs that differed in featural or configural information. Results: The patients with schizophrenia showed disproportionately poorer performance in discriminating configural compared with featural face sets. Conclusion: The result suggests that the face-recognition deficit in schizophrenic patients is due to specific impairments in configural processing of faces.

Adding magnetic flux to the baryon vertex

AbstractWe generalise the baryon vertex configuration of AdS/CFT by adding magnetic field on its worldvolume, dissolving D‐string charge. A careful analysis of the configuration shows that there is an upper bound on the number of dissolved strings. We provide a microscopical description of this configuration in terms of a dielectric effect for the dissolved strings.

Scan patterns during the processing of facial identity in prosopagnosia

The scan patterns of ocular fixations made by prosopagnosic patients while they attempt to identify faces may provide insights into how they process the information in faces. Contrasts between their scanning of upright versus inverted faces may index the presence of a hypothesized orientation-dependent expert mechanism for processing faces, while contrasts between their scanning of familiar versus novel faces may index the influence of residual facial memories on their search for meaningful facial information. We recorded the eye movements of two prosopagnosics while they viewed faces. One patient, with acquired prosopagnosia from a right occipitotemporal lesion, showed degraded orientation effects but still with a normal distribution of fixations to more salient facial features. However, the dynamics of his global scan patterns were more chaotic for novel faces, suggesting degradation of an internal facial schema, and consistent with other evidence of impaired face configuration perception in this patient. His global scan patterns for famous faces differed from novel faces, suggesting the influence of residual facial memories, as indexed previously by his relatively good imagery for famous faces. The other patient, with a developmental prosopagnosia, showed anomalous orientation effects, abnormal distribution of fixations to less salient regions, and chaotic global scan patterns, in keeping with a more severe loss of face-expert mechanisms. The effects of fame on her scanning were weaker than those in the first subject and non-existent in her global scan patterns. We conclude that scan patterns in prosopagnosia can both reflect the loss of orientation-dependent expert mechanisms and index the covert influence of residual facial memories. In these two subjects the scanning data were consistent with other results from tests of configuration perception, imagery, and covert recognition.

Self-diffraction of light waves by a local photorefractive grating in a crystal of the symmetry group bar 4̄3m in the transverse configuration

The exact solution of nonlinear equations describing the symmetric stationary interaction of two light waves of an arbitrary polarisation on a local photorefractive grating in a crystal of the symmetry group 4̄3m in the transverse configuration of crystal faces is obtained in the paraxial limit. The polarisation of light waves and efficiency of energy transfer between them are studied as functions of the reduced length of a sample and the intensity ratio of incident waves.

On the Accuracy of Precision Involute Hobs: An Analytical Approach

This paper investigates the impact of the major design parameters of an involute hob on deviations of the hob tooth profile. Desired and actual hob tooth profiles are considered. The desired hob tooth profile is given as the line of intersection of the generating surface of the involute hob by the rake face. The actual hob tooth profile is a certain linear approximation of the desired profile. To evaluate deviation of the actual hob tooth profile with respect to the desired profile, the maximal deviation of the profiles from each other is used. This deviation is measured along the pitch line of the involute hob. An analytical method for computation of the deviation is developed. Using the commercial software MathCAD/Scientific, numerous computer codes are developed. Analysis results reveal a significant impact of the major design parameters of involute hobs on hob accuracy. Optimal configuration of the hob rake face is determined in order to minimize the deviations of the actual hob tooth profile from the desired profile. Based on the research results, reliable ways are proposed for increasing the accuracy of involute hobs in actual practice.

Approximate limit load evaluation of structural frames using linear elastic analysis

This work investigates applications and limitations of iterative modulus variation procedures combined with linear elastic analysis to calculate lower bounds of collapse loads. These modulus variation procedures are currently used to account for inelastic behavior in pressure vessel and piping system design. Here, applications to framed structures are studied. Three different modulus variation procedures are implemented within a conventional linear elastic finite element code and compared. The procedure that reduces only elastic moduli at high stressed elements of a structural model is found to be the most convenient strategy to estimate collapse conditions. This procedure is then applied to two- and three-dimensional frames, with homogeneous and non-homogeneous cross-sections, and assuming both constant and proportional loading. Using this procedure, it is possible to predict satisfactory approximations of collapse loads and failure mechanisms. In earthquake engineering practice if the earthquake motions are simulated as equivalent static proportional loads, this simplified procedure may be a useful and economical tool in the implementation of performance based design procedures in preliminary engineering, in verification processes, in structural optimization, and when facing complex geometric configurations. This procedure can be used to estimate approximations of both load redistribution in collapse conditions and failure modes when assuming different lateral load patterns along with gravity loads. It can be useful to determine optimum failure modes in new structures or weak links in existing structures. The method requires only minimal conceptual bases for application and moderate computational effort.

The baryon vertex with magnetic flux

In this letter we generalise the baryon vertex configuration of AdS/CFT by adding a suitable instantonic magnetic field on its worldvolume, dissolving D-string charge. A careful analysis of the configuration shows that there is an upper bound on the number of dissolved strings. This should be a manifestation of the stringy exclusion principle. We provide a microscopical description of this configuration in terms of a dielectric effect for the dissolved strings.

TDDFT Studies of Absorption and SERS Spectra of Pyridine Interacting with Au20

We present time dependent density functional theory (TDDFT) calculations for a tetrahedral Au20 complex interacting with pyridine for the purpose of modeling absorption and surface enhanced Raman scattering, with emphasis on chemical and electrodynamic enhancement effects. These calculations are done using the ADF code with the BP86 functional, the zeroth-order regular approximation and with the resonant electronic response modeled using a short time approximation expression for the perturbed density matrix, with a damping factor that is empirically chosen. The absorption spectrum of bare Au20 shows strong intraband (sp-sp) and interband (sp-d) coupling with a low-energy peak at 2.89 eV that is mostly intraband and other peaks at 3.94 and 4.70 eV that have mixed intra- and interband character. SERS spectra are calculated for pyridine/Au20 for both vertex (V) and surface (S) configurations at their respective lowest energy absorption maxima (near 2.89 eV), and we find that the V configuration has higher intensities that correspond to SERS enhancements of 10(3)-10(4), whereas S has an enhancement of 10(2)-10(3). These enhancement values are significantly lower than the analogous results for pyridine/Ag20 primarily because of reduced oscillator strength associated with the intraband transition in Au20. Decomposition of the pyridine/Au20 enhancement factor into chemical and electromagnetic contributions (through an analysis of the static SERS intensities) shows enhanced chemical enhancements compared to Ag20 but reduced electromagnetic enhancements.

Spatial summation of face information

Do all parts of the face contribute equally to face detection or are some parts more detectable than others? To evaluate this issue, we studied detection of the presence of normalized frontal-face images within aperture windows of varying extent. We performed a face summation study using two-alternative forced-choice psychophysics. The face stimuli were scaled to equal eye-to-chin distance, centered on the bridge of the nose, and windowed by fourth-power Gaussian envelopes of various sizes. The faces were intermixed with control stimuli consisting inverted faces to test for configuration effects, split-half inverted faces to perturb the symmetry, and phase-scrambled versions of the faces with equal Fourier energy. Face detectability improved rapidly at first, then at a progressively shallower rate for larger window sizes, in a similar fashion for the three face-based stimulus types. The spectrally equated noise stimuli were less detectable than the face stimuli for all except the smallest apertures. The results were fit with a model incorporating global face-specific and local nonspecific spatial integration mechanisms. Detection of the noise images was consistent with local detection mechanisms accessed through a wide-field attention mechanism. The data for face detection implied detection mechanisms that integrated linearly up to some small size, integrated more slowly up to an intermediate size, and failed to gain any improvement for information beyond some larger size. This performance supports the concept of a specialized face configuration mechanism operating at detection threshold, similar in extent among the observers.

Face Configuration Processing in the Human Brain: The Role of Symmetry

Symmetry is an important cue in face perception. We manipulated symmetry and other configurational variables to study their role in face processing in the human brain. We employed 2 types of symmetry: image symmetry (where one part of the image is defined as the mirrored transform of the other part about an axis) and object symmetry (where the spatial relationships among the image components are interpreted as parts of a symmetric 3-dimensional object). We compared blood oxygenation level dependent responses in healthy human observers for upright front-view faces with responses to different symmetry-controlled images. The cortical areas activated by the face images, relative to Fourier-matched scrambled images, were the fusiform (FFA) and occipital (OFA) face areas, the middle occipital gyri (MOG), and areas around the superior temporal and intraoccipital sulci (IOS). Contrasting faces and their image-symmetric scrambled versions showed a similar activation pattern except in the right OFA, suggesting an involvement in facial symmetry processing. The upright versus inverted faces (with the same image symmetry but unfamiliar object identity) showed robust differential activation in the FFA, OFA, MOG, IOS, and precuneus. The response to frontal-view versus 3/4-view faces (having the same object symmetry but disrupted image symmetry) showed little differential activation in the FFA or the OFA but strong responses in the MOG and IOS, suggesting that face processing in the FFA and the OFA is holistic and viewpoint invariant.

Processing the Trees and the Forest during Initial Stages of Face Perception: Electrophysiological Evidence

Although configural processing is considered a hallmark of normal face perception in humans, there is ample evidence that processing face components also contributes to face recognition and identification. Indeed, most contemporary models posit a dual-code view in which face identification relies on the analysis of individual face components as well as the spatial relations between them. We explored the interplay between processing face configurations and inner face components by recording the N170, an event-related potential component that manifests early detection of faces. In contrast to a robust N170 effect elicited by line-drawn schematic faces compared to line-drawn schematic objects, no N170 effect was found if a pair of small objects substituted for the eyes in schematic faces. However, if a pair of two miniaturized faces substituted for the eyes, the N170 effect was restored. Additional experiments ruled out an explanation on the basis of miniaturized faces attracting attention independent of their location in a face-like configuration and show that global and local face characteristics compete for processing resources when in conflict. The results are discussed as they relate to normal and abnormal face processing.