Changes in the eye contour signs due to age among Mexican women: Comparison with women of other ethnic origins.

OBJECTIVE: To evaluate the changes in certain ocular signs because of age, among Mexican women and to compare these with those previously obtained on women of other ethnicities. MATERIAL AND METHODS: Photographs were taken of the faces of 203 Mexican women of different ages, under standardized conditions. These photographs allowed us to focus and define nine ocular signs, which were then graded by 15 experts and dermatologists, using standardized scales provided by a reference Skin Aging Atlas. Hence, the same protocol, previously used on 3240 women of four other ethnic origins (Caucasian: 600; Chinese: 990; Japanese: 1010; Indian: 300; African: 340), allowed us to compare the results obtained on Mexican women. RESULTS: The severity of crow's feet wrinkles for Mexican women shows a more intense progression with age than those of women from other ancestries. The lower eyelid wrinkles of Mexican women, that show weak or erratic changes with time, were however found to have higher and significant severity at a young age. Pigmentation disorders of their ocular area were found less pronounced as compared to those of Asian or Indian women. Eye bags were observed with similar slight changes in all five ancestries. CONCLUSION: The present work confirms that the clinical signs of age for the female eye area develop differently depending on the ethnic origins of the volunteer.

OBJECTIF: D'évaluer les variations avec l'âge de signes cliniques de la zone des yeux pour des femmes mexicaines et de les comparer avec des données précédemment acquises pour des femmes d'autres origines ethniques. MATERIEL ET METHODES: 203 femmes mexicaines, d'âges différents, ont été photographiées sous des conditions standardisées pour analyser neuf signes cliniques relatifs à la zone des yeux. Ces derniers couvrent des clusters cliniques de Rides/Texture, de Désordres pigmentaires ou de Ptose/relâchement et ont été évalués dans leurs sévérités respectives suivant les échelles éditées dans les Atlas cliniques du Vieillissement de référence par un groupe de 15experts et dermatologues. Ce même protocole a été utilisé précédemment sur 3240 femmes de 4 origines différentes (caucasiennes :600 ; chinoises : 990 ; japonaises : 1010 ; indiennes : 300 ; africaines : 340) et nous permet de pouvoir comparer ces résultats aux données obtenues sur les femmes mexicaines. RESULTATS: La sévérité des rides de la patte d'oie pour les femmes mexicaines présente une progression plus rapide avec l'âge que celles observées dans les autres ethnicités. Les rides de la paupière inférieure des femmes mexicaines, présentant des variations faibles ou erratiques avec l'âge, ont cependant été scorées avec une sévérité significativement supérieure pour les âges les plus jeunes. Les désordres pigmentaires pour la zone des yeux ont été trouvés comme moins prononcés en comparaison des femmes d'origine asiatique ou indienne. Les poches sous les yeux ont été observées avec des évolutions similaires avec l'âge quelle que soit l'origine ethnique. CONCLUSION: Ces travaux confirment que les signes cliniques de la zone des yeux présentent différentes évolutions avec l'âge en fonction des origines ethniques.

Morphological criteria of feminine upper eyelashes, quantified by a new semi-automatized image analysis: Application to the objective assessment of mascaras.

BACKGROUND: The wide diversity of feminine eyelashes in shape, length, and curvature makes it a complex domain that remains to be quantified in vivo, together with their changes brought by application of mascaras that are visually assessed by women themselves or make-up experts. METHODS: A dedicated software was developed to semi-automatically extract and quantify, from digital images (frontal and lateral pictures), the major parameters of feminine eyelashes of Mexican and Caucasian women and to record the changes brought by the applications of various mascaras and their brushes, being self or professionally applied. RESULTS: The diversity of feminine eyelashes appears as a major influencing factor in the application of mascaras and their related results. Eight marketed mascaras and their respective brushes were tested and their quantitative profiles, in terms of coverage, morphology, or curvature were assessed. Standard applications by trained aestheticians led to higher and more homogeneous deposits of mascara, as compared to those resulting from self-applications. CONCLUSION: The developed software appears a precious tool for both quantifying the major characteristics of eyelashes and assessing the making-up results brought by mascaras and their associated brushes.

[How does the brain control eye movements? Motor and premotor neurons of the brainstem]. / Comment le cerveau contrôle-t-il les mouvements des yeux ? Les neurones moteurs et prémoteurs du tronc cérébral.

Knowledge of cognitive and neural architecture and processes that control eye movements has advanced enough to allow precise and quantitative analysis of hitherto unsolved phenomena. In this review, we revisit from a neuropsychological viewpoint Hering vs. Helmholtz' hypotheses on binocular coordination. Specifically, we reexamine the behavior and the neural bases of saccade-vergence movement, to move the gaze in both direction and depth under natural conditions. From the psychophysical viewpoint, neo-Heringian and neo-Helmholtzian authors have accumulated arguments favoring distinct conjugate (for saccades) and disconjugate (for vergence) systems, as well as advocating for monocularly programmed eye movements. From the neurophysiological viewpoint, which reports brain cell recordings during the execution of a given task, neo-Heringian and neo-Helmholtzian physiologists have also provided arguments in favor of both hypotheses at the level of the brainstem premotor circuitry. Bridging the two, we propose that Hering and Helmholtz were both right. The emphasis placed by the latter on adaptive processes throughout life cycle is compatible with the importance of neurobiological constraints pointed out by the former. In the meanwhile, the study of saccade-vergence eye movements recalls how much the psychophysical definition of the task determines the interpretation that is made from neurophysiological data.

[Transcranial magnetic stimulation (TMS) in basic and clinical neuroscience research]. / La stimulation magnétique transcrânienne (SMT) dans la recherche fondamentale et clinique en neuroscience.

INTRODUCTION: Non-invasive brain stimulation methods such as transcranial magnetic stimulation (TMS) are starting to be widely used to make causality-based inferences about brain-behavior interactions. Moreover, TMS-based clinical applications are under development to treat specific neurological or psychiatric conditions, such as depression, dystonia, pain, tinnitus and the sequels of stroke, among others. BACKGROUND: TMS works by inducing non-invasively electric currents in localized cortical regions thus modulating their activity levels according to settings, such as frequency, number of pulses, train and regime duration and intertrain intervals. For instance, it is known for the motor cortex that low frequency or continuous patterns of TMS pulses tend to depress local activity whereas high frequency and discontinuous TMS patterns tend to enhance it. Additionally, local cortical effects of TMS can result in dramatic patterns in distant brain regions. These distant effects are mediated via anatomical connectivity in a magnitude that depends on the efficiency and sign of such connections. PERSPECTIVES: An efficient use of TMS in both fields requires however, a deep understanding of its operational principles, its risks, its potential and limitations. In this article, we will briefly present the principles through which non-invasive brain stimulation methods, and in particular TMS, operate. CONCLUSION: Readers will be provided with fundamental information needed to critically discuss TMS studies and design hypothesis-driven TMS applications for cognitive and clinical neuroscience research.

[Presentation of an assessment battery for visual mental imagery and visual perception]. / Normalisation d'une batterie d'évaluation de l'imagerie mentale visuelle et de la perception visuelle.

INTRODUCTION: The relationship between visual perception and visual mental imagery are at the center of a lively theoretical debate between those postulating common neurocognitive processes between perception and imagery and those who emphasize the differences between these two entities. Neuropsychology can make an important contribution to this debate, by assessing associations and dissociations between perceptual and imaginal deficits in patients with brain damage. However, currently there is no standardized test battery available for such assessments. MATERIAL AND METHODS: Here we present a battery of paper-and-pencil tests assessing different domains of visual mental imagery and visual perception abilities: object form and color, animals, orthographic material, numbers, faces, and space. We also explored the effects of age, educational level and gender on performance on a group of 103 participants free of neurological damage. RESULTS: The battery includes two parts: one composed of 14 tests assessing mental imagery and the second part composed of eight tests assessing the abilities of visual perception. We calculated the correlations between the tests, and found that, with the exception of orthographic material, there were generally poor correlations between imagery and perceptual tests. CONCLUSION: This result seems inconsistent with hypotheses postulating a strict correspondence between perceptual and imagery abilities.

Prolongation of latency of horizontal saccades in elderly is distance and task specific.

The present study examined horizontal saccades in healthy subjects: 9 adults (20-32 years) and 10 aged subjects (63-83 years), under gap (fixation target extinguishes prior to target onset) and overlap (fixation stays on after target onset). The gap paradigm is known to promote fast initiation of saccades while the overlap paradigm promotes voluntary saccades with longer latency. In real life we perform saccades at various distances. In this study each paradigm was run at three viewing distances-20, 40 and 150 cm, corresponding to a convergence angle of 17.1 degrees, 8.6 degrees and 2.3 degrees, respectively. Eye movements were recorded with the Chronos video eye tracker or with the photoelectric IRIS. The main findings are: (i) increase in latency of saccades with age, with distance and with the overlap condition; (ii) evidence for interaction between these factors, indicating the following anomaly: in the gap condition and at near, aged subjects show short latencies similar to those of young adults; (iii) express type of latencies (between 80 and 120 ms) occur most frequently at near in the gap condition and at similar rates in young (25%) and aged subjects (20%). The specificity of close distance combined with the gap for triggering short latency saccades could be related to both attention and oculomotor fixation disengagement. The strength of coupling between fixation-eye movement control and visual attention control varies for different locations in space, and its decline with aging can be also different.