Ignoring the elephant in the room: A neural circuit to downregulate salience (2010)

Imagine searching for a dim target in a room where bright lights fl ash on and off. How do we ignore looking at the salient, bright lights and guide our attention to the low-saliency target? How do we accomplish this perceptual variant of ignoring the elephant in the room? Selection of the target under these circumstances depends on top-down guidance of attention away from high saliency distractors favored by bottom-up processes. Previous studies have shown that attentional guidance can modulate perceptual processing of visual information in the brain of both monkeys (Moran and Desimone, 1985; Chelazzi et al., 1998, 2001) and humans (Kastner et al., 1998; Kastner and Ungerleider, 2001; Beck and Kastner, 2005; Sylvester et al., 2008). Attention to a particular location in the visual fi eld activates retinotopic visual cortex (Kastner et al., 1999), whereas signals representing other locations are suppressed (Smith et al., 2000; Sylvester et al., 2008). Similarly, when a target is specifi ed by a nonspatial attribute, such as object category (e.g., a face), activity in specialized extrastriate areas (e.g., the fusiform face area) is boosted (O’Craven et al., 1999; Serences et al., 2004; Gazzaley et al., 2005). Attention-based responses are also found in other more anterior brain regions, which are thought to provide control signals to regulate perceptual processing (Desimone and Duncan, 1995). In particular, many studies have linked both parietal [e.g., the intraparietal sulcus (IPS)] and frontal [such as the frontal eye fi elds (FEFs)] brain regions to top-down attentional control.