The neural correlates of processing newborn and adult faces in 3-year-old children.

The current study examines the processing of upright and inverted faces in 3-year-old children (n = 35). Event-related potentials (ERPs) were recorded during a passive looking paradigm including adult and newborn face stimuli. We observed three face-sensitive components, the P1, the N170 and the P400. Inverted faces elicited shorter P1 latency and larger P400 amplitude. P1 and N170 amplitudes were larger for adult faces. To examine the role of experience in the development of face processing, the processing of adult and newborn faces was compared for children with a younger sibling (n = 23) and children without a younger sibling (n = 12). Age of sibling at test correlated negatively with P1 amplitude for adult and newborn faces. This may indicate more efficient processing of different face ages in children with a younger sibling and potentially reflects a more flexible face representation.

Urethral lift for benign prostatic hyperplasia: a comprehensive review of the literature.

Current treatments for benign prostatic hyperplasia (BPH) include watchful waiting, medical therapy, and interventional procedures. The post-surgical complication profile and the early discontinuation of medical therapy are significant drawbacks of the established approach and stimulate the search for less-invasive approaches. Our aim is to provide a comprehensive review all available literature on prostatic urethral lift (PUL), presenting an overview of safety, indications, surgical technique and results of the procedure, and to evaluate the potential role it could play in the treatment of BPH. A comprehensive search was conduct on PubMed and Scopus database to identify original articles in English dealing with PUL without any limit to publication date. Keywords used were prostatic urethral lift, urethral lifting, Urolift, benign prostatic hyperplasia and minimally invasive therapy. The PUL seems to offer a better IPSS improvement when compared to medical therapy, but the result is inferior when compared to surgical therapy. Published studies report an absence of degradation of erectile or ejaculatory function after treatment, which appears a noteworthy benefit of PUL. Additional advantages of the PUL are a better complication profile in comparison to other surgical therapies and the use of a local anesthesia, sometimes without postoperative catheterization. The PUL, a novel, minimally invasive treatment option for men affected by BPH, presents a promising potential although it is clear that PUL is not a substitute for traditional ablative surgical approach, as this procedure requires a scrupulous selection of the patient.

A steady-state visual evoked potential approach to individual face perception: effect of inversion, contrast-reversal and temporal dynamics.

Presentation of a face stimulus for several seconds at a periodic frequency rate leads to a right occipito-temporal evoked steady-state visual potential (SSVEP) confined to the stimulation frequency band. According to recent evidence (Rossion and Boremanse, 2011), this face-related SSVEP is largely reduced in amplitude when the exact same face is repeated at every stimulation cycle as compared to the presentation of different individual faces. Here this SSVEP individual face repetition effect was tested in 20 participants stimulated with faces at a 4 Hz rate for 84 s, in 4 conditions: faces upright or inverted, normal or contrast-reversed (2×2 design). To study the temporal dynamics of this effect, all stimulation sequences started with 15s of identical faces, after which, in half of the sequences, different faces were introduced. A larger response to different than identical faces at the fundamental (4 Hz) and second harmonic (8 Hz) components was observed for upright faces over the right occipito-temporal cortex. Weaker effects were found for inverted and contrast-reversed faces, two stimulus manipulations that are known to greatly affect the perception of facial identity. Addition of the two manipulations further decreased the effect. The phase of the fundamental frequency SSVEP response was delayed for inverted and contrast-reversed faces, to the same extent as the latency delay observed at the peak of the face-sensitive N170 component observed at stimulation sequence onset. Time-course analysis of the entire sequence of stimulation showed an immediate increase of 4Hz amplitude at the onset (16th second) of different face presentation, indicating a fast, large and frequency-specific release to individual face adaptation in the human brain. Altogether, these observations increase our understanding of the characteristics of the human steady-state face potential response and provide further support for the interest of this approach in the study of the neurofunctional mechanisms of face perception.

Extensive visual training in adulthood significantly reduces the face inversion effect.

The poorer recognition performance for inverted as compared to upright faces is one of the most well-known and robust behavioral effects observed in the field of face perception. Here we investigated whether extensive training at individualizing a large set of inverted faces in adulthood could significantly reduce this inversion effect for novel faces. This issue is important because inverted faces are as complex as upright faces but they are not visually experienced during development. Moreover, inverted faces violate the biological constraints, present at birth, for preferential looking (i.e., a larger number of elements in the top part than the bottom part of the stimulus). Eight adult observers were trained for 2 weeks (16 hr) to individualize 30 inverted face identities presented under different depth-rotated views. Following training, all participants showed a significant reduction of their inversion effect for novel face identities presented in a challenging four-alternatives delayed matching task. This reduction of the face inversion effect was observed in comparison to the magnitude of the same observers' effect before training, and to the magnitude of the face inversion effect of a group of untrained participants. These observations indicate that extensive training in adulthood can lead to a significant reduction of the inversion effect that generalizes to novel faces, suggesting a larger degree of flexibility of the adult face processing system than previously thought.

Electrophysiological correlates of the composite face illusion: disentangling perceptual and decisional components of holistic face processing in the human brain.

When the bottom halves of two faces differ, people's behavioral judgment of the identical top halves of those faces is impaired: they report that the top halves are different, and/or take more time than usual to provide a response. This behavioral measure is known as the composite face effect (CFE) and has traditionally been taken as evidence that faces are perceived holistically. Recently, however, it has been claimed that this effect is driven almost entirely by decisional, rather than perceptual, factors (Richler, Gauthier, Wenger, & Palmeri, 2008). To disentangle the contribution of perceptual and decisional brain processes, we aimed to obtain an event-related potential (ERP) measure of the CFE at a stage of face encoding (Jacques & Rossion, 2009) in the absence of a behavioral CFE effect. Sixteen participants performed a go/no-go task in an oddball paradigm, lifting a finger of their right or left hand when the top half of a face changed identity. This change of identity of the top of the face was associated with an increased ERP signal on occipito-temporal electrode sites at the N170 face-sensitive component (∼160 ms), the later decisional P3b component, and the lateralized readiness potential (LRP) starting at ∼350 ms. The N170 effect was observed equally early when only the unattended bottom part of the face changed, indicating that an identity change was perceived across the whole face in this condition. Importantly, there was no behavioral response bias for the bottom change trials, and no evidence of decisional biases from electrophysiological data (no P3b and LRP deflection in no-go trials). These data show that an early CFE can be measured in ERPs in the absence of any decisional response bias, indicating that the CFE reflects primarily the visual perception of the whole face.

Early experience predicts later plasticity for face processing: evidence for the reactivation of dormant effects.

Research has shown that experience acquired in infancy dramatically affects face-discrimination abilities. Yet much less is known about whether face processing retains any flexibility after the 1st year of life. Here, we show that early experience with an individual infant face can modulate the recognition performance of 3-year-old children and the perceptual processes they use to recognize infant faces (Experiment 1). Similar experience acquired in adulthood does not produce measurable effects (Experiment 2). We also show that the effects of early-acquired experience with an infant face become dormant during development in the absence of continued experience (Experiment 3) and can be reactivated in adulthood by reexposure to the original experience (Experiment 2). Overall, the results indicate that early experience can preserve the face-processing system from the loss of plasticity that would otherwise take place between childhood and adulthood.

Holistic processing for faces and cars in preschool-aged children and adults: evidence from the composite effect.

The current study compared the development of holistic processing for faces and non-face visual objects by testing for the composite effect for faces and frontal images of cars in 3- to 5-year-old children and adults in a series of four experiments using a two-alternative forced-choice recognition task. Results showed that a composite effect for faces was present as early as 3 1/2 years, and none of the age groups tested showed signs of a composite effect for cars. These findings provide the first demonstration that holistic processing is already selective for faces in early childhood, and confirm existing evidence that sensitivity to holistic information in faces does not increase from 4 years to adulthood.

Do all kids look alike? Evidence for an other-age effect in adults.

The current study provides evidence for the existence of an other-age effect (OAE), analogous to the well-documented other-race effect. Experiments 1 and 2 demonstrate that adults are better at recognizing adult faces compared with faces of newborns and children. Results from Experiment 3 indicate that the OAE obtained with child faces can be modulated by experience. Moreover, in each of the 3 experiments, differences in the magnitude of the observed face inversion effect for each age class of faces were taken to reflect a difference in the processing strategies used to recognize the faces of each age. Evidence from Experiment 3 indicates that these strategies can be tuned by experience. The data are discussed with reference to an experience-based framework for face recognition.

A behavioural and ERP investigation of 3-month-olds' face preferences.

Recent behavioural work suggests that newborns' face preferences are derived from a general, non-specific attentional bias toward patterns with more features in the upper versus lower half. In the current study, we predicted that selectivity for the specific geometry of the face may emerge during the first 3 months of life as a product of perceptual narrowing, leading to the construction of the first broadly defined face category segregating faces from other visual objects which may share with faces one or more visual properties. This was investigated behaviourally, using a standard preferential looking paradigm, and electrophysiologically, using high-density ERPs. Behavioural results indicated that, at 3 months, the top-heavy property is no longer a crucial factor in determining face preferences. ERP results showed evidence of differentiation between the two stimuli only for the N700. No differentiation was found for earlier components that are thought to reflect the adult-like structural encoding stage of face processing in infants (N290 and P400). Together, ERP and behavioural results suggest that, by 3 months, the perceptual narrowing process has led to a behavioural response specific to the geometry of the human face, but that this response is not purely perceptual in nature. Rather, it seems related to the acquired salience of this stimulus category, which may reflect the high degree of familiarity and/or the social value faces have gained over the infants' first 3 months of life.

Early Visually Evoked Electrophysiological Responses Over the Human Brain (P1, N170) Show Stable Patterns of Face-Sensitivity from 4 years to Adulthood.

Whether the development of face recognition abilities truly reflects changes in how faces, specifically, are perceived, or rather can be attributed to more general perceptual or cognitive development, is debated. Event-related potential (ERP) recordings on the scalp offer promise for this issue because they allow brain responses to complex visual stimuli to be relatively well isolated from other sensory, cognitive and motor processes. ERP studies in 5- to 16-year-old children report large age-related changes in amplitude, latency (decreases) and topographical distribution of the early visual components, the P1 and the occipito-temporal N170. To test the face specificity of these effects, we recorded high-density ERPs to pictures of faces, cars, and their phase-scrambled versions from 72 children between the ages of 4 and 17, and a group of adults. We found that none of the previously reported age-dependent changes in amplitude, latency or topography of the P1 or N170 were specific to faces. Most importantly, when we controlled for age-related variations of the P1, the N170 appeared remarkably similar in amplitude and topography across development, with much smaller age-related decreases in latencies than previously reported. At all ages the N170 showed equivalent face-sensitivity: it had the same topography and right hemisphere dominance, it was absent for meaningless (scrambled) stimuli, and larger and earlier for faces than cars. The data also illustrate the large amount of inter-individual and inter-trial variance in young children's data, which causes the N170 to merge with a later component, the N250, in grand-averaged data. Based on our observations, we suggest that the previously reported "bi-fid" N170 of young children is in fact the N250. Overall, our data indicate that the electrophysiological markers of face-sensitive perceptual processes are present from 4 years of age and do not appear to change throughout development.

Personal familiarity influences the processing of upright and inverted faces in infants.

Infant face processing becomes more selective during the first year of life as a function of varying experience with distinct face categories defined by species, race, and age. Given that any individual face belongs to many such categories (e.g. A young Caucasian man's face) we asked how the neural selectivity for one aspect of facial appearance was affected by category membership along another dimension of variability. 6-month-old infants were shown upright and inverted pictures of either their own mother or a stranger while event-related potentials (ERPs) were recorded. We found that the amplitude of the P400 (a face-sensitive ERP component) was only sensitive to the orientation of the mother's face, suggesting that "tuning" of the neural response to faces is realized jointly across multiple dimensions of face appearance.

Why mix-ups don't happen in the nursery: evidence for an experience-based interpretation of the other-age effect.

Adults' face recognition abilities vary across face types, as evidenced by the other-race and other-species effects. Recent evidence shows that face age is another dimension affecting adults' performance in face recognition tasks, giving rise to an other-age effect (OAE). By comparing recognition performance for adult and newborn faces in a group of maternity-ward nurses and a control group of novice participants, the current study provides evidence for an experience-based interpretation of the OAE. Novice participants were better at recognizing adult than newborn faces and showed an inversion effect for adult faces. Nurses manifested an inversion cost of equal magnitude for both adult and newborn faces and a smaller OAE in comparison to the novices. The results indicate that experience acquired exclusively in adulthood is capable of modulating the OAE and suggest that the visual processes involved in face recognition are still plastic in adulthood, granted that extensive experience with multiple faces is acquired.

Modulation of face-sensitive event-related potentials by canonical and distorted human faces: the role of vertical symmetry and up-down featural arrangement.

This study examined the sensitivity of early face-sensitive event-related potential (ERP) components to the disruption of two structural properties embedded in faces, namely, "updown featural arrangement" and "vertical symmetry." Behavioral measures and ERPs were recorded as adults made an orientation judgment for canonical faces and distorted faces that had been manipulated for either or both of the mentioned properties. The P1, the N170, and the vertex positive potential (VPP) exhibited a similar gradient in sensitivity to the two investigated properties, in that they all showed a linear increase in amplitude or latency as the properties were selectively disrupted in the order of (1) up-down featural arrangement, (2) vertical symmetry, and (3) both up-down featural arrangement and vertical symmetry. Exceptions to this finding were seen for the amplitudes of the N170 and VPP, which were largest for the stimulus in which solely vertical symmetry was disrupted. Interestingly, the enhanced amplitudes of the N170 and VPP are consistent with a drop in behavioral performance on the orientation judgment for this stimulus.