The process of perceptual retouch: nonspecific afferent activation dynamics in explaining visual masking.

A model for visual masking based on the notion of interaction of the specific and nonspecific afferent visual systems is presented. Discussion is focused on nonmonotonic masking functions. In particular, it is proposed that in order for visual information Ipatterns, forms, etc.) to be consciously perceived, both specific retino-geniculo-striate impulses and nonspecific retino-reticulocortical impulses should converge in the same cortical space. Nonspecific activity is shown to be necessary for subjective awareness. This activity is shown to be of longer latency than specific activity. It is concluded that trailing conscious-experience-generating impulses are elicited by collateral activity from the specific information received from the first stimulus. These impulses reach the cortex at the same moment as the specific activity of the second Imasking~ stimulus as coded, which has a relatively higher signal-to-noise ratio in the given retinotopically specified cortical space. Consequently, subjects consciously perceive the second stimulus. This operation of awareness generation is termed perceptual retouch and is considered as a special psychological mechanism worthy of psychophysical study.