Theories of attention commonly refer to the "attentional template" as the collection of features in working memory that represent the target of visual search. Many models of attention assume that the template contains a veridical representation of target features, but recent studies have shown that the target representation is "shifted" away from distractor features in order to optimize their distinctiveness and facilitate visual search. Here, we manipulated the probability of target-similar distractors during a visual search task in 2 groups, and separately measured the contents of the attentional template. We hypothesized that having a high probability of target-similar distractors would increase pressure to shift and/or sharpen the target representation in order to increase the distinctiveness of targets from distractors. We found that the high-similarity group experienced less distractor interference during visual search, but only for highly target-similar distractors. Additionally, while both groups shifted the target representation away from the actual target color, the high-similarity group also had a sharper representation of the target color. We conclude that the contents of the attentional template in working memory can be flexibly adjusted with multiple mechanisms to increase target-to-distractor distinctiveness and optimize attentional selection. (PsycINFO Database Record

Contextual cues are predictive and provide behaviorally relevant information; they are not the main objective of the current task but can make behavior more efficient. Using fMRI, we investigated the brain networks involved in representing contextual information and translating it into an attentional control signal. Human subjects performed a visual search task for a low-contrast target accompanied by a single non-target that was either perceptually similar or more salient (i.e., higher contrast). Shorter reaction times (RTs) and higher accuracy were found on salient trials, suggesting that the salient item was rapidly identified as a non-target and immediately acts as a spatial "anti-cue" to reorient attention to the target. The relative saliency of the non-target determined BOLD responses in the left temporoparietal junction (TPJ) and inferior frontal gyrus (IFG). IFG correlated with RT specifically on salient non-target trials. In contrast, bilateral dorsal frontoparietal regions [including the frontal eye fields (FEFs)] were correlated with RT in all conditions. Effective connectivity analyses using dynamic causal modeling found an excitatory pathway from TPJ to IFG to FEF, suggesting that this was the pathway by which the contextual cue was translated into an attentional control signal that facilitated behavior. Additionally, the connection from FEF to TPJ was negatively modulated during target-similar trials, consistent with the inhibition of TPJ by dorsal attentional control regions during top-down serial visual search. We conclude that left TPJ and IFG form a sensory-driven network that integrates contextual knowledge with ongoing sensory information to provide an attentional control signal to FEF.

Perceptually salient distractors typically interfere with target processing in visual search situations. Here we demonstrate that a perceptually salient distractor that captures attention can nevertheless facilitate task performance if the observer knows that it cannot be the target. Eye-position data indicate that facilitation is achieved by two strategies: inhibition when the first saccade was directed to the target, and rapid rejection when the first saccade was captured by the salient distractor. Both mechanisms relied on the distractor being perceptually salient and not just perceptually different. The results demonstrate how bottom-up attentional capture can play a critical role in constraining top-down attentional selection at multiple stages of processing throughout a single trial.

Our ability to process visual information is fundamentally limited. This leads to competition between sensory information that is relevant for top-down goals and sensory information that is perceptually salient, but task-irrelevant. The aim of the present study was to identify, from EEG recordings, pre-stimulus and pre-saccadic neural activity that could predict whether top-down or bottom-up processes would win the competition for attention on a trial-by-trial basis. We employed a visual search paradigm in which a lateralized low contrast target appeared alone, or with a low (i.e., non-salient) or high contrast (i.e., salient) distractor. Trials with a salient distractor were of primary interest due to the strong competition between top-down knowledge and bottom-up attentional capture. Our results demonstrated that 1) in the 1-sec pre-stimulus interval, frontal alpha (8–12 Hz) activity was higher on trials where the salient distractor captured attention and the first saccade (bottom-up win); and 2) there was a transient pre-saccadic increase in posterior-parietal alpha (7–8 Hz) activity on trials where the first saccade went to the target (top-down win). We propose that the high frontal alpha reflects a disengagement of attentional control whereas the transient posterior alpha time-locked to the saccade indicates sensory inhibition of the salient distractor and suppression of bottom-up oculomotor capture.

The most prevalent neurobiological theory of attentional control posits 2 distinct brain networks: The dorsal and ventral attention networks. The role of the dorsal attentional network in top-down attentional control is well established, but there is less evidence for the putative role of the ventral attentional network in initiating stimulus-driven reorienting. Here, we used functional magnetic resonance imaging and dynamic causal modeling (DCM) to test the role of the ventral and dorsal networks in attentional reorienting during instances of attentional capture by a target-colored distracter. In the region of interest analyses, we found that frontal eye field (FEF) was selectively activated by conditions where attention was reoriented (i.e. to spatial cues and target-colored distracters). In contrast, temporoparietal junction (TPJ) responded positively to all stimulus conditions. The DCM results indicated that FEF received sensory inputs earlier than TPJ, and that only the connection from FEF to TPJ was modulated by the appearance of the target-colored distracter. The results provide novel empirical evidence against the idea that TPJ generates stimulus-driven reorientations of attention. We conclude that our results are incompatible with existing theories of TPJ involvement in the stimulus-driven reorientation of attention and discuss alternative explanations such as contextual updating.