ABSTRACT
PURPOSE: The goals of the study were to further assess contrast sensitivity to (1) investigate the existence of monocular vs. binocular differences; (2) observe possible differences between sample sizes; (3) investigate the effects of test-retest repeatability. METHODS: Contrast sensitivity measurements were obtained by presenting eight horizontal sine-wave gratings (ranging from 0.2 to 20 cycles per degree). A three-up-one-down method was used to obtain thresholds with a criterion of 79.4% correct responses for each spatial frequency. The mean of 12 reversals was used for obtaining thresholds, and the two-alternative forced-choice method was used. Data were recorded in 55 naive observers from 20 to 45 years. All participants were free from identifiable ocular disease and had normal visual acuity. RESULTS: We observed the absence of differences on CSF for both monocular and binocular observers, as well as the absence of differences between large sample sizes. The latter investigation revealed a high degree of repeatability across time (baseline to 6 months later) with the higher test-retest for low and high spatial frequencies. CONCLUSIONS: Our results indicated that spatial contrast sensitivity measurements were little influenced by variables, such as binocular summation, eye dominance, sample size and time using the Metropsis test. The results obtained here have significance for basic and clinical vision science.
Subject(s)
Contrast Sensitivity/physiology , Software , Spatial Processing/physiology , Vision Tests/instrumentation , Adult , Female , Humans , Male , Mental Status and Dementia Tests , Middle Aged , Reproducibility of Results , Vision, Binocular/physiology , Visual Acuity/physiology , Young AdultABSTRACT
El procesamiento visoespacial es una función adaptativa del organismo que permite su interacción con los elementos que se encuentran en su medio ambiente. Se considera una función superior, ya que involucra sistemas de reconocimiento y de memoria, entre otros. Hasta el momento se ha descrito la participación de diversas estructuras cerebrales en el procesamiento de información visoespacial, por ejemplo, tradicionalmente se considera una especialización funcional por parte del hemisferio derecho; sin embargo aún existen muchas controversias con respecto a la participación de diversas áreas cerebrales tanto ipsilaterales como contralaterales en estás funciones visoespaciales. En el presente trabajo se discute el papel de la comunicación interhemisferica, y específicamente del papel que juega el cuerpo calloso en el procesamiento visoespacial. Se inicia con una descripción de las vías de procesamiento visoespacial desde el ojo hasta la corteza V1 y las conexiones anatómicas funcionales que se establecen a partir de ésta. Posteriormente se resume la estructura-función del cuerpo calloso y se revisan los trabajos que han reportado relaciones entre éste y la función visoespacial. Por último, se revisan algunas de las patologías neurológicas que cursan con afectación del cuerpo calloso y que se ha reportado en la literatura que afectan a la función visoespacial...
The visuospatial processing is an adaptive function of the organism that allows it to interact with the elements that are in their environment. It is considered a high-order function as it involves recognition systems, memory, among others. So far described the participation of various brain structures in processing visuospatial information, for example, is traditionally considered a functional specialization by the right hemisphere, but there are still many controversies regarding the participation of various brain areas, both ipsilateral and contralateral in the visuospatial functions. In this paper we discuss the role of interhemispheric communication, and specifically the role of the corpus callosum in visuospatial processing. It begins with a description of visuospatial processing pathways from the eye to the cortex V1 and the anatomical-functional connections are established from this. Later summarizes the structure-function of the corpus callosum and reviews the studies that have reported relationships between this and visuospatial function. Finally we review some of the neurological disorders that present with involvement of the corpus callosum and it has been reported in the literature that affect visuospatial function...