Evidence for reciprocal antagonism between motion sensors tuned to coarse and fine features

Early visual processing analyses fine and coarse image features separately. Here we show that motion signals derived from fine and coarse analyses are combined in rather a surprising way: Coarse and fine motion sensors representing the same direction of motion inhibit one another and an imbalance can reverse the motion perceived. Observers judged the direction of motion of patches of filtered two-dimensional noise, centered on 1 and 3 cycles/deg. When both sets of noise were present and only the 3 cycles/deg noise moved, judgments were reversed at short durations. When both sets of noise moved, judgments were correct but sensitivity was impaired. Reversals and impairments occurred both with isotropic noise and with orientation-filtered noise. The reversals and impairments could be simulated in a model of motion sensing by adding a stage in which the outputs of motion sensors tuned to 1 and 3 cycles/deg and the same direction of motion were subtracted from one another. The subtraction model predicted and we confirmed in experiments with orientation-filtered noise that if the 1 cycle/deg noise flickered and the 3 cycles/deg noise moved, the 1 cycle/deg noise appeared to move in the opposite direction to the 3 cycles/deg noise even at long durations.

Personalidad, género y vulnerabilidad a la depresión :(Women and vulnerability to depression : some personality and clinical factors)

En este trabajo se exploraron relaciones existentes entre las características de personalidad, género y la presencia de depresión, siguiendo la linea de investigación de Carrillo, Rojo y Staats (2004). Se intentó encontrar perfiles de personalidad caracterizados por determinados rasgos que fueran significativamente distintos entre hombres y mujeres y que a su vez se asociaran a una mayor presencia de síntomas depresivos. Esto se llevó a cabo en dos muestras de distintos países y culturas por separado: Chile (N= 448, 257 varones (57.37%) y 190 mujeres (42.41%), y un rango etario de 17-65) y España (N = 578, 196 varones (33.9%) y 381 mujeres (65,9%), y un rango etario de 17-67 ), con el propósito de aportar evidencia respecto de cómo afecta la cultura, como factor ambiental, en la conformación de la personalidad a partir de repertorios de aprendizajes. Orientado a eso en el presente trabajo se intentó buscar asociaciones significativas entre las dimensiones de Personalidad propuestas por Eysenk (1975), en el EPQ y EPQ-R, por los factores de Personalidad de los Cinco grandes a partir del NEO PI y del NEO PI-R (Costa y McCrae, 1985, citado en Carrillo et al. 2004) y otras variables clínicas, como rasgos de personalidad esquizotipicos, frecuencia e intensidad de emociones, habilidades sociales y sintomatología clínica. Las características de personalidad se compararon en función del género y finalmente se analizó si las diferencias de personalidad pudieron predecir depresión a partir del Beck Depression Inventory, (Beck, Rush, Shaw y Emery, 1979)...

Agreement and clinical comparison between a new swept-source optical coherence tomography-based optical biometer and an optical low-coherence reflectometry biometer

Purpose To compare measurements taken using a swept-source optical coherence tomography-based optical biometer (IOLmaster 700) and an optical low-coherence reflectometry biometer (Lenstar 900), and to determine the clinical impacts of differences in their measurements on intraocular lens (IOL) power predictions. Methods Eighty eyes of 80 patients scheduled to undergo cataract surgery were examined with both biometers. The measurements made using each device were axial length (AL), central corneal thickness (CCT), aqueous depth (AQD), lens thickness (LT), mean keratometry (MK), white-to-white distance (WTW), and pupil diameter (PD). Holladay 2 and SRK/T formulas were used to calculate IOL power. Differences in measurement between the two biometers were determined using the paired t-test. Agreement was assessed through intraclass correlation coefficients (ICC) and Bland–Altman plots. Results Mean patient age was 76.3±6.8 years (range 59–89). Using the Lenstar, AL and PD could not be measured in 12.5 and 5.25% of eyes, respectively, while IOLMaster 700 took all measurements in all eyes. The variables CCT, AQD, LT, and MK varied significantly between the two biometers. According to ICCs, correlation between measurements made with both devices was excellent except for WTW and PD. Using the SRK/T formula, IOL power prediction based on the data from the two devices were statistically different, but differences were not clinically significant. Conclusions No clinically relevant differences were detected between the biometers in terms of their measurements and IOL power predictions. Using the IOLMaster 700, it was easier to obtain biometric measurements in eyes with less transparent ocular media or longer AL.