PATTERN APPROACH OF EVENT-RELATED BRAIN DYNAMICS: A TWO-DIGIT NUMBER COMPARISON

The present study examined the possible influence of visual quality judgment on quantity judgments of numbers. To address this issue, volunteer adult subjects performed a mental number comparison task. Stimuli (Arabic number format), among the numbers between 31 and 99 were mentally compared to a memorized reference number, 65. The level of difficulty of the stimuli was controlled by two parameters: visual quality and semantic distance from the reference number. Two methods were chosen to specify the spatial brain patterns and temporal brain dynamics. The methods discussed are principal components analysis (PCA) and independent component analysis (ICA). We suggest that visual attributes of the stimulus facilitate/inhibit the number perception. In this unique approach, the mixed model of topographic map represents visual and number perception together.