A bilateral SPCN is elicited by to-be-memorized visual stimuli displayed along the vertical midline

Attentional suppression of weight-related distractors among females with weight dissatisfaction

Although many studies have investigated attentional biases toward weight-related information among individuals with weight dissatisfaction, the mechanisms underlying the processing of task-irrelevant and spatial-irrelevant weight-related information as distractors remain unclear. Participants were assigned to groups according to their levels of weight dissatisfaction to address this question. Participants with high weight dissatisfaction (HWD) were assigned to the experimental group; those with low weight dissatisfaction (LWD) were assigned to a control group. By recording event-related potentials during a visual search task along the median vertical line, fatness-related/thinness-related/neutral words and scrambled strokes were presented horizontally in pairs as task-irrelevant distractors. The results showed that intact words facilitated fast attentional orienting compared to scrambled strokes, as revealed by the significant N2pc for all types of intact words for both the HWD and LWD groups. More importantly, only fatness- and thinness-related words elicited the evident PD in the HWD group, and the PD amplitudes were larger in the HWD group compared to the LWD group. These findings suggest that weight-related distractors were actively suppressed after initial attentional orienting among females with HWD. This reveals the mechanisms of attentional biases toward weight-related information among females with HWD and contributes to the model of the cognitive-behavioral theory of body image disturbance. These results may help enhance prevention and interventions for reducing weight dissatisfaction.

Different prioritization states of working memory representations affect visual searches: Evidence from an event-related potential study

Previous evidence has shown that the contents of working memory (WM) can bias visual selection. However, not much is known about how WM effects change when the WM representation is held in different prioritization states. Here, we investigated this problem using event-related potentials. Subjects maintained two colors in WM while performing a search task. One of the colors was retro-cued, indicating that it was 80 % likely to be the target of the memory test. During the search display, one of the distractors was a salient color singleton, and this singleton distractor could carry the same color as the cued WM representation, the uncued WM representation, or be irrelevant to the memory content. Behaviorally, the memory test performance was found to be better for the cued color than for the uncued color, and we observed lower search accuracy (ACC) and longer search reaction time (RT) when the singleton distractor matched the cued WM representation than when it matched an uncued or an irrelevant WM representation. Event-related potential (ERP) data showed that the P3 amplitude of cue-color distractor conditions was smaller than that of uncued-color distractor conditions and irrelevant-color distractor conditions. These findings clearly indicate that prioritizing an item for enhanced representational quality enables the item to bias attention to a greater extent.

On target selection as reflected by posterior ERP components in feature-guided visual search

The N2pc event-related potential is a widely studied ERP component that reflects the covert deployment of visuo-spatial attention to target stimuli displayed laterally relative to fixation. Recently, an analogous ERP component, named N2pcb, has been proposed as a marker of the deployment of visuo-spatial attention to targets displayed on the vertical midline. Two studies that investigated the N2pcb component found analogous results, using however two different algorithms to compute the amplitude of N2pcb. One study subtracted the ipsilateral activity elicited by a lateral target from the bilateral activity elicited by a target displayed on the vertical midline, whereas the other study subtracted the bilateral activity elicited by target-absent displays from the bilateral activity elicited by a target displayed on the vertical midline. Here we show both algorithms estimate properly the N2pc as well as the N2pcb components. In addition, we explored whether the singleton detection positivity (SDP) component, a posterior bilateral positivity temporally concomitant to N2pc recently reported in studies using singleton search, could be observed in the present study in which a target was defined by a combination of features. Given that such component was indeed found using feature search, we named this component posterior processing positivity (PPP), and showed that bilateral activity elicited by target-absent displays is an adequate baseline for its correct isolation.