Event-related Potentials Affected by Spatial Frequencies of Background Visual Pattern During a Cognitive Task

摘要

Spatial variation in luminance, which is one of the most important attributes of a visual image, may cause characteristic reactions in higher order brain functions. We aim to characterize the event-related potentials (ERPs) associated with a cognitive task (simple addition) in terms of how they are influenced by the spatial frequencies of the background visual pattern. We use vertically striped visual stimuli with embedded numbers (0-9) and different spatial frequency characteristics (white noise, 1/f, 1/f~2, and 1/f~3). The subjects are instructed to perform two tasks: an addition task that involved adding numbers presented as visual stimuli, and a reference task wherein the numbers were not added. In ERPs averaged over four types of visual stimuli for the addition task, positive components peaking at latencies of 182 ms in the central and frontal areas and 360 ms in the parietal area are observed, and significant differences are found between ERPs for the addition and reference tasks. In the addition task, the 182-ms latency component shows a larger positive amplitude for 1/f~3 compared with other stimuli in the right parietal-occipital-temporal area (P_4, T_6, O_2), and the 360-ms latency component tends to show a larger positive amplitude for 1/f compared with other stimuli in the parietal-central area (C_3, P_3, P_z). We conclude that spatial frequency characteristics influence ERPs associated with the retrieval of arithmetic data and certain neural activities that accompany simple forms of addition.