A Gaze into the Eyebrow Standards of Asian Versus Caucasian Women.

BACKGROUND: Eyebrow position affects perceived facial expression and youthfulness, and its modification is a key component of facial rejuvenation. OBJECTIVE: This investigation aimed to assess the preferred vertical eyebrow position, apex location, and eyebrow shape in Caucasian and Asian individuals and to analyze gaze patterns during aesthetic judgment using eye-tracking technology. MATERIALS AND METHODS: The study included 76 Asian and Caucasian volunteers with no medical background. Eye movements were captured with a Tobii Pro Nano eye-tracker. Participants viewed AI-generated images of Caucasian and Asian females with varied eyebrow positions (ratios 1:1.3 to 1:2.5), shapes (angles 8° to 20°), and apex positions. Aesthetic preferences were rated on a 5-point Likert scale. Eye-tracking metrics and aesthetic ratings were statistically analyzed using ANOVA and bivariate correlations. RESULTS: Both genders across ethnicities preferred a moderate eyebrow position ratio of 1:1.6. For eyebrow shapes, a 12° angle received the highest ratings, while extremes were less favored, indicating a preference for moderately curved eyebrows. The most appealing apex position was above the lateral canthus for Asians, and halfway between the lateral limbus and lateral canthus for Caucasians. Eye-tracking revealed longer fixations on unattractive features, suggesting more complex cognitive processing, while attractive features were processed more efficiently. CONCLUSION: The study revealed that aesthetic preferences for eyebrow features are influenced by both ethnic background and gender, with a general preference toward moderately curved eyebrows and subtle variations in preferred positions. These findings suggest a need for culturally sensitive approaches in facial aesthetic procedures and highlight the potential of eye-tracking technology to enhance surgical planning. Surgeons are advised to adopt a conservative, patient-centered approach when modifying eyebrow features, considering individual and cultural aesthetics to maximize patient satisfaction. LEVEL OF EVIDENCE V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Seeing and extrapolating motion trajectories share common informative activation patterns in primary visual cortex.

The natural environment is dynamic and moving objects become constantly occluded, engaging the brain in a challenging completion process to estimate where and when the object might reappear. Although motion extrapolation is critical in daily life-imagine crossing the street while an approaching car is occluded by a larger standing vehicle-its neural underpinnings are still not well understood. While the engagement of low-level visual cortex during dynamic occlusion has been postulated, most of the previous group-level fMRI-studies failed to find evidence for an involvement of low-level visual areas during occlusion. In this fMRI-study, we therefore used individually defined retinotopic maps and multivariate pattern analysis to characterize the neural basis of visible and occluded changes in motion direction in humans. To this end, participants learned velocity-direction change pairings (slow motion-upwards; fast motion-downwards or vice versa) during a training phase without occlusion and judged the change in stimulus direction, based on its velocity, during a following test phase with occlusion. We find that occluded motion direction can be predicted from the activity patterns during visible motion within low-level visual areas, supporting the notion of a mental representation of motion trajectory in these regions during occlusion.

Electrophysiological hallmarks of location-based and object-based visual multiple objects tracking.

Converging evidence shows that our visual system can track multiple visual, independently moving items over time. This is accomplished location-based by maintaining the individual spatial information of each target item or object-based by constructing an abstract object-based representation out of the tracked items. Previous work showed specific behavioural, electrophysiological and haemodynamic markers for location-based or object-based representations of the relevant targets by probing the encoded information subsequently after tracking. However, domain-specific differences of representational correlates during visual tracking itself have not been reported yet. The current study aims to identify spectral properties of the electrophysiological signal during tracking that might indicate location-based versus object-based maintenance of visual information. Subjects had to covertly track four out of eight visually identical items for several seconds while electrophysiological signals were recorded. Subsequently, a probe consisting of four items appeared and the subjects had to indicate with a button press whether the probe matched all targets or not. Subjects employing an object-based strategy showed an enhanced gamma response during the presentation of the target items at the beginning of the trial. On the other hand, subjects using a location-based strategy showed enhanced gamma synchronization throughout the tracking itself. Both the object- and location-based gamma responses yielded identical spatial topographical field distributions. These results indicate that object-based tracking is supported by enhanced encoding during the initial presentation of the targets to be tracked. Location-based tracking is characterized by the sustained maintenance of the individual targets during the entire tracking period in that same processing network.

A comprehensive score reflecting memory-related fMRI activations and deactivations as potential biomarker for neurocognitive aging.

Older adults and particularly those at risk for developing dementia typically show a decline in episodic memory performance, which has been associated with altered memory network activity detectable via functional magnetic resonance imaging (fMRI). To quantify the degree of these alterations, a score has been developed as a putative imaging biomarker for successful aging in memory for older adults (Functional Activity Deviations during Encoding, FADE; Düzel et al., Hippocampus, 2011; 21: 803-814). Here, we introduce and validate a more comprehensive version of the FADE score, termed FADE-SAME (Similarity of Activations during Memory Encoding), which differs from the original FADE score by considering not only activations but also deactivations in fMRI contrasts of stimulus novelty and successful encoding, and by taking into account the variance of young adults' activations. We computed both scores for novelty and subsequent memory contrasts in a cohort of 217 healthy adults, including 106 young and 111 older participants, as well as a replication cohort of 117 young subjects. We further tested the stability and generalizability of both scores by controlling for different MR scanners and gender, as well as by using different data sets of young adults as reference samples. Both scores showed robust age-group-related differences for the subsequent memory contrast, and the FADE-SAME score additionally exhibited age-group-related differences for the novelty contrast. Furthermore, both scores correlate with behavioral measures of cognitive aging, namely memory performance. Taken together, our results suggest that single-value scores of memory-related fMRI responses may constitute promising biomarkers for quantifying neurocognitive aging.

Modulating the global orientation bias of the visual system changes population receptive field elongations.

The topographical structure of the visual system in individual subjects can be visualized using fMRI. Recently, a radial bias for the long axis of population receptive fields (pRF) has been shown using fMRI. It has been theorized that the elongation of receptive fields pointing toward the fovea results from horizontal local connections bundling orientation selective units mostly parallel to their polar position within the visual field. In order to investigate whether there is a causal relationship between orientation selectivity and pRF elongation the current study employed a global orientation adapter to modulate the orientation bias for the visual system while measuring spatial pRF characteristics. The hypothesis was that the orientation tuning change of neural populations would alter pRF elongations toward the fovea particularly at axial positions parallel and orthogonal to the affected orientation. The results indeed show a different amount of elongation of pRF units and their orientation at parallel and orthogonal axial positions relative to the adapter orientation. Within the lower left hemifield, pRF radial bias and elongation showed an increase during adaptation to a 135° grating while both parameters decreased during the presentation of a 45° adapter stimulus. The lower right visual field showed the reverse pattern. No modulation of the pRF topographies were observed in the upper visual field probably due to a vertical visual field asymmetry of sensitivity toward the low contrast spatial frequency pattern of the adapter stimulus. These data suggest a direct relationship between orientation selectivity and elongation of population units within the visual cortex.

Attention to Color Sharpens Neural Population Tuning via Feedback Processing in the Human Visual Cortex Hierarchy.

Attention can facilitate the selection of elementary object features such as color, orientation, or motion. This is referred to as feature-based attention and it is commonly attributed to a modulation of the gain and tuning of feature-selective units in visual cortex. Although gain mechanisms are well characterized, little is known about the cortical processes underlying the sharpening of feature selectivity. Here, we show with high-resolution magnetoencephalography in human observers (men and women) that sharpened selectivity for a particular color arises from feedback processing in the human visual cortex hierarchy. To assess color selectivity, we analyze the response to a color probe that varies in color distance from an attended color target. We find that attention causes an initial gain enhancement in anterior ventral extrastriate cortex that is coarsely selective for the target color and transitions within ∼100 ms into a sharper tuned profile in more posterior ventral occipital cortex. We conclude that attention sharpens selectivity over time by attenuating the response at lower levels of the cortical hierarchy to color values neighboring the target in color space. These observations support computational models proposing that attention tunes feature selectivity in visual cortex through backward-propagating attenuation of units less tuned to the target.SIGNIFICANCE STATEMENT Whether searching for your car, a particular item of clothing, or just obeying traffic lights, in everyday life, we must select items based on color. But how does attention allow us to select a specific color? Here, we use high spatiotemporal resolution neuromagnetic recordings to examine how color selectivity emerges in the human brain. We find that color selectivity evolves as a coarse to fine process from higher to lower levels within the visual cortex hierarchy. Our observations support computational models proposing that feature selectivity increases over time by attenuating the responses of less-selective cells in lower-level brain areas. These data emphasize that color perception involves multiple areas across a hierarchy of regions, interacting with each other in a complex, recursive manner.

Spatial elongation of population receptive field profiles revealed by model-free fMRI back-projection.

Estimates of visual field topographies in human visual cortex obtained through fMRI traveling wave techniques usually provide the parameters of population receptive field (pRF) location (polar angle, eccentricity) and receptive field size. These parameters are obtained by fitting the recorded data to a standard model population receptive field. In this work, pRF profiles are measured directly by back-projecting preprocessed fMRI time-series to sweeps of a bar across the visual field in different angles. The current data suggest that the model-free pRF profiles contain information not only about receptive field location and size but also about the pRF shape characteristics. The elongation (ellipticity) of pRFs decreases along the early visual hierarchy to a different degree for the ventral and the dorsal stream. Furthermore, ellipticity changes as a function of eccentricity. pRF orientation shows a high degree of collinearity with its angular position within the visual field. Using model-free pRF measurements, the traveling wave technique provides additional characteristics of pRF topographies that are not restricted to size and provide robust measures within the single subject.

Spatio-temporal dynamics of attentional selection stages during multiple object tracking.

Subjects can visually track several moving items simultaneously, a fact that is difficult to explain by classical attention models. Previous work revealed that building a global shape based on the spatial position of the tracked items improves performance. Here we investigated the involved neural processes and the role of attention. A task-irrelevant probe stimulus was presented during multiple objects tracking at a fixed spatial location. Depending on the tracked item's trajectories the probe appeared either outside, inside, or on the edge of aforementioned global shape. Event-related potentials to the probe stimulus revealed two subsequent stages of attentional selection during multiple object tracking. After 100ms attention was deployed on the edge/boundary of the figure formed by the tracked items. In the following 80ms, attention spread from the outline to the full figure. These findings clarify the eminent contribution of attentional mechanisms in multiple objects tracking.

Vaccination using melanoma cells treated with p19arf and interferon beta gene transfer in a mouse model: a novel combination for cancer immunotherapy.

Previously, we combined p19(Arf) (Cdkn2a, tumor suppressor protein) and interferon beta (IFN-ß, immunomodulatory cytokine) gene transfer in order to enhance cell death in a murine model of melanoma. Here, we present evidence of the immune response induced when B16 cells succumbing to death due to treatment with p19(Arf) and IFN-ß are applied in vaccine models. Use of dying cells for prophylactic vaccination was investigated, identifying conditions for tumor-free survival. After combined p19(Arf) and IFN-ß treatment, we observed immune rejection at the vaccine site in immune competent and nude mice with normal NK activity, but not in NOD-SCID and dexamethasone immunosuppressed mice (NK deficient). Combined treatment induced IL-15, ULBP1, FAS/APO1 and KILLER/DR5 expression, providing a mechanism for NK activation. Prophylactic vaccination protected against tumor challenge, where markedly delayed progression and leukocyte infiltration were observed. Analysis of primed lymphocytes revealed secretion of TH1-related cytokines and depletion protocols showed that both CD4(+) and CD8(+) T lymphocytes are necessary for immune protection. However, application of this prophylactic vaccine where cells were treated either with IFN-ß alone or combined with p19(Arf) conferred similar immune protection and cytokine activation, yet only the combination was associated with increased overall survival. In a therapeutic vaccine protocol, only the combination was associated with reduced tumor progression. Our results indicate that by harnessing cell death in an immunogenic context, our p19(Arf) and IFN-ß combination offers a clear advantage when both genes are included in the vaccine and warrants further development as a novel immunotherapy for melanoma.

Determinants of Global Color-Based Selection in Human Visual Cortex.

Feature attention operates in a spatially global way, with attended feature values being prioritized for selection outside the focus of attention. Accounts of global feature attention have emphasized feature competition as a determining factor. Here, we use magnetoencephalographic recordings in humans to test whether competition is critical for global feature selection to arise. Subjects performed a color/shape discrimination task in one visual field (VF), while irrelevant color probes were presented in the other unattended VF. Global effects of color attention were assessed by analyzing the response to the probe as a function of whether or not the probe's color was a target-defining color. We find that global color selection involves a sequence of modulations in extrastriate cortex, with an initial phase in higher tier areas (lateral occipital complex) followed by a later phase in lower tier retinotopic areas (V3/V4). Importantly, these modulations appeared with and without color competition in the focus of attention. Moreover, early parts of the modulation emerged for a task-relevant color not even present in the focus of attention. All modulations, however, were eliminated during simple onset-detection of the colored target. These results indicate that global color-based attention depends on target discrimination independent of feature competition in the focus of attention.

Neural correlates of visual motion processing without awareness in patients with striate cortex and pulvinar lesions.

Patients with striate cortex lesions experience visual perception loss in the contralateral visual field. In few patients, however, stimuli within the blind field can lead to unconscious (blindsight) or even conscious perception when the stimuli are moving (Riddoch syndrome). Using functional magnetic resonance imaging (fMRI), we investigated the neural responses elicited by motion stimulation in the sighted and blind visual fields of eight patients with lesions of the striate cortex. Importantly, repeated testing ensured that none of the patients exhibited blindsight or a Riddoch syndrome. Three patients had additional lesions in the ipsilesional pulvinar. For blind visual field stimulation, great care was given that the moving stimulus was precisely presented within the borders of the scotoma. In six of eight patients, the stimulation within the scotoma elicited hemodynamic activity in area human middle temporal (hMT) while no activity was observed within the ipsilateral lesioned area of the striate cortex. One of the two patients in whom no ipsilesional activity was observed had an extensive lesion including massive subcortical damage. The other patient had an additional focal lesion within the lateral inferior pulvinar. Fiber-tracking based on anatomical and functional markers (hMT and Pulvinar) on individual diffusion tensor imaging (DTI) data from each patient revealed the structural integrity of subcortical pathways in all but the patient with the extensive subcortical lesion. These results provide clear evidence for the robustness of direct subcortical pathways from the pulvinar to area hMT in patients with striate cortex lesions and demonstrate that ipsilesional activity in area hMT is completely independent of conscious perception.

Spatio-temporal patterns of brain activity distinguish strategies of multiple-object tracking.

Human observers can readily track up to four independently moving items simultaneously, even in the presence of moving distractors. Here we combined EEG and magnetoencephalography recordings to investigate the neural processes underlying this remarkable capability. Participants were instructed to track four of eight independently moving items for 3 sec. When the movement ceased a probe stimulus consisting of four items with a higher luminance was presented. The location of the probe items could correspond fully, partly, or not at all with the tracked items. Participants reported whether the probe items fully matched the tracked items or not. About half of the participants showed slower RTs and higher error rates with increasing correspondence between tracked items and the probe. The other half, however, showed faster RTs and lower error rates when the probe fully matched the tracked items. This latter behavioral pattern was associated with enhanced probe-evoked neural activity that was localized to the lateral occipital cortex in the time range 170-210 msec. This enhanced response in the object-selective lateral occipital cortex suggested that these participants performed the tracking task by visualizing the overall shape configuration defined by the vertices of the tracked items, thereby producing a behavioral advantage on full-match trials. In a later time range (270-310 msec) probe-evoked neural activity increased monotonically as a function of decreasing target-probe correspondence in all participants. This later modulation, localized to superior parietal cortex, was proposed to reflect the degree of mismatch between the probe and the automatically formed visual STM representation of the tracked items.

Location- and Object-Based Representational Mechanisms Account for Bilateral Field Advantage in Multiple-Object Tracking.

Keeping track of multiple visually identical and independently moving objects is a remarkable feature of the human visual system. Theoretical accounts for this ability focus on resource-based models that describe parametric decreases of performance with increasing demands during the task (i.e., more relevant items, closer distances, higher speed). Additionally, the presence of two central tracking resources, one within each hemisphere, has been proposed, allowing for an independent maintenance of moving targets within each visual hemifield. Behavioral evidence in favor of such a model shows that human subjects are able to track almost twice as many targets across both hemifields compared with within one hemifield. A number of recent publications argue for two separate and parallel tracking mechanisms during standard object tracking tasks that allow for the maintenance of the relevant information in a location-based and object-based manner. Unique electrophysiological correlates for each of those processes have been identified. The current study shows that these electrophysiological components are differentially present during tracking within either the left or right hemifield. The present results suggest that targets are mostly maintained as an object-based representation during left hemifield tracking, while location-based resources are preferentially engaged during right hemifield tracking. Interestingly, the manner of representation does not seem to have an impact on behavioral performance within the subjects, while the electrophysiological component indicating object-based tracking does correlate with performance between subjects. We propose that hemifield independence during multiple-object tracking may be an indication of the underlying hemispheric bias for parallel location-based and object-based tracking mechanisms.

Parallel gain modulation mechanisms set the resolution of color selectivity in human visual cortex.

Color discrimination is fundamental to human behavior. We find bananas by coarsely searching for yellow but then differentiate nuances of yellow to pick the best exemplars. How does the brain adjust the resolution of color selectivity to our changing needs? Here, we analyze the brain magnetic response in the human visual cortex to show that color selectivity is adaptively set by coarse- and fine-resolving processes running in parallel at different hierarchical levels. Those include a gain enhancement in the higher-lever cortex of color units tuned away from the target to resolve very similar colors and a coarsely resolving gain enhancement in the mid-level cortex of units tuned to the target. Our findings suggest that attention operates on a form of multiresolution representation of color at different levels in the visual hierarchy, which keeps selectivity adaptive to a changing resolution context.

A cortical zoom-in operation underlies covert shifts of visual spatial attention.

Shifting the focus of attention without moving the eyes poses challenges for signal coding in visual cortex in terms of spatial resolution, signal routing, and cross-talk. Little is known how these problems are solved during focus shifts. Here, we analyze the spatiotemporal dynamic of neuromagnetic activity in human visual cortex as a function of the size and number of focus shifts in visual search. We find that large shifts elicit activity modulations progressing from highest (IT) through mid-level (V4) to lowest hierarchical levels (V1). Smaller shifts cause those modulations to start at lower levels in the hierarchy. Successive shifts involve repeated backward progressions through the hierarchy. We conclude that covert focus shifts arise from a cortical coarse-to-fine process progressing from retinotopic areas with larger toward areas with smaller receptive fields. This process localizes the target and increases the spatial resolution of selection, which resolves the above issues of cortical coding.

Serial attentional resource allocation during parallel feature value tracking.

The visual system has evolved the ability to track features like color and orientation in parallel. This property aligns with the specialization of processing these feature dimensions in the visual cortex. But what if we ask to track changing feature-values within the same feature dimension? Parallel tracking would then have to share the same cortical representation, which would set strong limitations on tracking performance. We address this question by measuring the precision of color representations when human observers track the color of two superimposed dot clouds that simultaneously change color along independent trajectories in color-space. We find that tracking precision is highly imbalanced between streams and that tracking precision changes over time by alternating between streams at a rate of ~1 Hz. These observations suggest that, while parallel color tracking is possible, it is highly limited, essentially allowing for only one color-stream to be tracked with precision at a given time.

Impairment of adenosine signaling disrupts early embryo development: unveiling the underlying mechanisms.

Purinergic signaling has been implicated in many biological functions, including development. In this study, we investigate the functions of extracellular adenosine and adenosine receptors using a mouse embryonic stem cell (ESC) line and morula stages isolated from mouse embryos. Feeder-free mouse ESC was investigated in the absence and presence of the leukemia inhibitory factor (LIF), configuring undifferentiated cells and cells undergoing spontaneous differentiation. High alkaline phosphatase (ALPL) and low CD73 levels resulting in low adenosine (eADO) levels were characteristic for pluripotent cells in the presence of the LIF, while LIF deprivation resulted in augmented adenosine levels and reduced pluripotency marker expression, which indicated differentiation. Tracing ESC proliferation by BrdU labeling revealed that the inhibition of ALPL by levamisole resulted in a decrease in proliferation due to less eADO accumulation. Furthermore, caffeine and levamisole treatment, inhibiting adenosine receptor and eADO accumulation, respectively, reduced ESC migration, similar to that observed in the absence of the LIF. Pharmacological approaches of selective adenosine receptor subtype inhibition triggered specific adenosine receptor activities, thus triggering calcium or MAP kinase pathways leading to differentiation. In line with the in vitro data, mouse embryos at the morula stage were sensitive to treatments with A1 and A3 receptor antagonists, leading to the conclusion that A1 receptor and A3 receptor inhibition impairs proliferation and self-renewal and triggers inappropriate differentiation, respectively. The findings herein define the functions of eADO signaling in early development with implications for developmental disorders, in which adenosine receptors or ectonucleotidase dysfunctions are involved, and which could lead to malformations and miscarriages, due to exposure to caffeine.

Clinical overview of cutaneous features in hypereosinophilic syndrome.

The hypereosinophilic syndromes (HES) are a heterogeneous group of disorders defined as persistent and marked blood eosinophilia of unknown origin with systemic organ involvement. HES is a potentially severe multisystem disease associated with considerable morbidity. Skin involvement and cutaneous findings frequently can be seen in those patients. Skin symptoms consist of angioedema; unusual urticarial lesions; and eczematous, therapy-resistant, pruriginous papules and nodules. They may be the only obvious clinical symptoms. Cutaneous features can give an important hint to the diagnosis of this rare and often severe illness. Based on advances in molecular and genetic diagnostic techniques and on increasing experience with characteristic clinical features and prognostic markers, therapy has changed radically. Current therapies include corticosteroids, hydroxyurea, interferon-α, the tyrosine kinase inhibitor imatinib mesylate, and (in progress) the monoclonal anti-interleukin-5 antibodies. This article provides an overview of current concepts of disease classification, different skin findings, and therapy for HES.

Increased Amygdala Activity Associated With Cognitive Reappraisal Strategy in Functional Neurologic Disorder.

Cognitive reappraisal is an emotion regulation strategy to reduce the impact of affective stimuli. This regulation could be incomplete in patients with functional neurologic disorder (FND) resulting in an overflowing emotional stimulation perpetuating symptoms in FND patients. Here we employed functional MRI to study cognitive reappraisal in FND. A total of 24 FND patients and 24 healthy controls employed cognitive reappraisal while seeing emotional visual stimuli in the scanner. The Symptom Checklist-90-R (SCL-90-R) was used to evaluate concomitant psychopathologies of the patients. During cognitive reappraisal of negative IAPS images FND patients show an increased activation of the right amygdala compared to normal controls. We found no evidence of downregulation in the amygdala during reappraisal neither in the patients nor in the control group. The valence and arousal ratings of the IAPS images were similar across groups. However, a subgroup of patients showed a significant higher account of extreme low ratings for arousal for negative images. These low ratings correlated inversely with the item "anxiety" of the SCL-90-R. The increased activation of the amygdala during cognitive reappraisal suggests altered processing of emotional stimuli in this region in FND patients.

Attention expedites target selection by prioritizing the neural processing of distractor features.

Whether doing the shopping, or driving the car - to navigate daily life, our brain has to rapidly identify relevant color signals among distracting ones. Despite a wealth of research, how color attention is dynamically adjusted is little understood. Previous studies suggest that the speed of feature attention depends on the time it takes to enhance the neural gain of cortical units tuned to the attended feature. To test this idea, we had human participants switch their attention on the fly between unpredicted target color alternatives, while recording the electromagnetic brain response to probes matching the target, a non-target, or a distracting alternative target color. Paradoxically, we observed a temporally prioritized processing of distractor colors. A larger neural modulation for the distractor followed by its stronger attenuation expedited target identification. Our results suggest that dynamic adjustments of feature attention involve the temporally prioritized processing and elimination of distracting feature representations.