Abstract
It has been well known that the right temporo-parietal junction (RTPJ), a part of the ventral attention network, plays a crucial role in reorienting attention. However, recently, several studies showed that the RTPJ was also involved in other cognitive processes than reorienting, such as an evaluative process, which refers to inferring or computing the behavioral significance/importance of the attended stimulus. Here, we investigated whether a region involved in reorienting of attention is also associated with evaluating the behavioral significance of attention-capturing stimuli. In an fMRI experiment, participants performed a modified Posner cueing task, in which four different arrow cues indicating four distinct locations were presented, followed by a target stimulus. Each cue predicted the target location to different extents; the cues predicted the target location with the probability of 80%, 20% (high-certainty cues), 60%, 40% (low-certainty cues). In each trial, participants made responses to a target, preceded by a cue stimulus. After four consecutive target responses, participants were required to infer how much each different cue predicts target location. We found that several fronto-parietal regions, frontal eye fields (FEF), intraparietal sulcus (IPS), and right temporo-parietal junction showed increased activity when the cued location and target location mismatched, evoking reorienting of attention. Notably, a dissociation was found from the cue inference activity; the RTPJ activity was greater for high-certainty cues, whereas the FEF and IPS showed similar activity for these cues or greater activity for low-certainty cues. We suggest that the RTPJ activation increased under the high-certainty cue presentation because this region is associated with acquiring sensory information to evaluate the behavioral significance of a stimulus; with the high-certainty cues, the amount of evidence for inferring the cue predictability should be abundant. By contrast, other fronto-parietal regions seem to be sensitive to increased task demand or effort.