The definition mask in image processing refers to a nondestructive way to edit an image or layer by hiding parts of it without erasing them ( Adobe-2025 ). In neurophysiological models it refers to an inhibitory feedback signal that blocks the tansmission of more than a few excitatory signals (action potentials) from a previous signal processing level to subsequent processing levels. The block allows accurate detection of the stimulus by the level in question but makes further transmission of the signal unreliable and, thus, useless to and ignorable by the organism. In psychophysiological models, masking the surround of an object allows the organism to focus attention on the stimulus and to evaluate its significance to the organism. See, for example, how the opponent functions of tufted cells and mitral cells in the main olfactory bulb (MOB) define and intensify the boundary between the class of oderants of a single molecular structure and oderants of all other classes of molecular structure. In symbolic processing models, it enables humans to conceptualize (imagine) and evaluate different combinations and permutations of objects and surrounds in spatial location and temporal sequence so as to make rational decisions whether to approach or avoid a stimulus ( NeuroNames ).