SIMILAR ELECTROPHYSIOLOGICAL CORRELATES OF TEXTURE SEGREGATION INDUCED BY LUMINANCE, ORIENTATION, MOTION AND STEREO

Certain local features induce preattentive texture segregation. Recent ly, components in the visual evoked potential (VEP) associated with pr eattentive texture segregation (tsVEPs) have been demonstrated. To ass ess the similarity and dissimilarity of visual processing across visua l dimensions, we compared VEPs and tsVEPs in texture segregation by lu minance, orientation, motion and stereo disparity. We found tsVEPs acr oss these four visual dimensions to be remarkably similar when compare d to the ''low-level'' VEPs, The tsVEPs were always negative; their im plicit time, peak latency and amplitude were (in msec/msec/mu V): 91/2 34/-5.7, luminance; 84/257/-3.9, orientation; 80/295/-8.3, motion; and 95/310/-5.0 for stereo. The cross-correlation function, as a quantita tive measure for similarity, on average was higher for the tsVEPs by a factor of 4.2 as compared to the low-level VEPs (P < 0.0001). The res ults suggest (1) that the tsVEPs represent activity of neural mechanis ms that have generalised to some degree across visual dimensions; and (2) that these hypothetical generalisation mechanisms might exist alre ady in the primary visual cortex. (C) 1997 Elsevier Science Ltd.