The role of right temporo-parietal junction in stimulus evaluation.

A predominant model of the temporo-parietal junction (TPJ) claims that this region is critical for attentional orienting/reorienting toward an unexpected, but behaviorally significant stimulus. However, recent studies have suggested that the TPJ is also involved in the process of evaluating stimulus, especially matching between external sensory inputs and internal representations. While some studies provide evidence for the involvement of the TPJ in stimulus evaluation, the nature of the evaluative process mediated by the TPJ remains unclear. To address this issue, we tested whether the TPJ activation amplitude and its peak latency is proportional to the demand of the evaluative process. We found that when the amount of sensory evidence for the matching process was abundant, the TPJ was transiently activated. Importantly, the TPJ activation showed a greater and more sustained pattern while the sensory evidence was accumulating for a longer period of time. These findings suggest that the TPJ function is associated with the evaluative process of matching sensory inputs with internal representations, as well as attentional reorienting.