Purpose: To validate recent reports of specific visual evoked potentials associated with preattentive texture segregation (tsVEPs) and to quantitatively compare perceptual segregation strength and tsVEP amplitudes across different local features.
Methods: Four local features were selected: crossed vs noncrossed, line segments differing in orientation by 90 degrees, U-shapes differing in orientation by 90 degrees, and U-shapes differing in orientation by 180 degrees. The two variants of each local feature were spatially arranged in a checkerboard pattern; for the first three features this led to pop-out of a "preattentive checkerboard." In seven subjects, perceptual segregation strength was assessed using ranking, and tsVEPs were recorded in these and three additional subjects.
Results: Statistically significant tsVEPs were obtained for the features crossed vs noncrossed and 90 degrees-line segments. Ranking results and tsVEP amplitudes were highly correlated (P < 0.001); the order of perceptual ranking and the order of tsVEP amplitudes were identical; 180 degrees-U-shapes had lowest ranking, mean tsVEP amplitude was 0.1 microV, close to noise. Line segments had maximal ranking, tsVEP amplitude was 1.5 microV.
Conclusions: The results suggest that tsVEPs quantitatively reflect the activity of cortical mechanisms involved in texture segregation across various features.