Stimulation of the Visual System Using a Cognitive Task in a Virtual Environment in Patients with Schizophrenia and Depression

摘要

This paper describes research data that evaluated the effect of a course of visual stimulation with a cognitive task in an interactive virtual environment on the functioning of the magno- and parvo-systems in patients with schizophrenia and depression. To demonstrate the images, a large-angular-size monitor was used, which provided a more complete immersion of the subjects into a virtual environment. To assess the effectiveness of the technique, we used the analysis of the amplitude of the components of cognitive visual evoked potentials in the demonstration of images that differ in physical features (spatial-frequency spectrum) for selective activation of low-frequency (magno) and high-frequency (parvo) channels and semantic features (objects of living and inanimate nature). It was shown that in patients of both groups a decrease in the amplitude of the components of evoked potentials to stimuli, filtered mainly by high spatial frequencies (parvo-system), is observed. There was evidence that patients with schizophrenia experienced disturbances of the processing of visual information, both in the early and late stages. In depressed patients, only the early stages of processing are affected. After a course of exposure to interactive virtual environments with a cognitive task, patients with schizophrenia experience improvement in the processing of visual information, both at the early and late stages. In depressed patients, improvement occurred at the early stages of treatment. In patients of both groups, a significant increase in the amplitude of the components of cognitive visual potentials at high spatial frequencies (parvo-system) is observed. Thus, the result of the course of exposure is a pronounced activation of the parvo-system, namely, the system that is more affected in these patients.