Correlation between three-dimensional visual depth and N2 component: Evidence from event-related potential study

Abstract

In this paper, we investigated event-related potentials (ERPs) evoked by visual stimuli with different three-dimensional visual depths. Before the experiment, tests for binocular advantage and for sensitivity to three-dimensional depth were carried out, respectively. At the same time, it should be ensured that the distinguishing degree of different depths is big enough. After the qualified participants were selected, pictures with five different three-dimensional depths were presented to the participants who were asked to give a judgment of the depths. The behavioral results showed that under the five different depths, the participants had a very high accuracy of judgment. ERP results showed that in the time windows of 90–130ms and 150–200ms after the onset of visual target stimuli, P1 and N2 components appeared in the area from parietal to occipital regions. It was interesting that there existed a positive correlation between the amplitude of the N2 component and the absolute value of the depth. Meanwhile, time–frequency analysis results showed that, in the time window of 150–200ms after the onset of visual target stimuli, a similar positive correlation between the time–frequency distribution and the absolute value of the depth was also found. Additionally, in the time window of 200–600ms after the onset of visual target stimuli, the alpha waves evoked under the five different depths were almost the same, which reflected that the cognitive process of three-dimensional visual depth might be finished by 200ms after the onset of visual target stimuli, when the brain is in a state of relaxation.