Brain responses to self- and other- unfairness under resource distribution context: Meta-analysis of fMRI studies

•Brain activations, network analysis and functional decoding on unfairness evaluation and response processes regarding unfairness both to self and to others were analyzed.•Common activation of unfairness to self and to others was found in the dorsal anterior insula and anterior cingulate cortex, with stronger activation observed during unfairness to self.•In the evaluation process, unfairness to self activated reactive, automatic, and emotional brain areas implicated in affective and conflict processing, whereas unfairness to others activates theory of mind areas.•In the response process, unfairness to self-activated affective areas, whereas unfairness to others activated cognitive control areas.•Unfairness to self and unfairness to others rely on a combination of common and distinct affective-cognitive-motivational networks, with our findings providing neurobiological evidence for inequity aversion models. Under resource distribution context, individuals have a strong aversion to unfair treatment not only toward themselves but also toward others. However, there is no clear consensus regarding the commonality and distinction between these two types of unfairness. Moreover, many neuroimaging studies have investigated how people evaluate and respond to unfairness in the abovementioned two contexts, but the consistency of the results remains to be investigated. To resolve these two issues, we sought to summarize existing findings regarding unfairness to self and others and to further elucidate the neural underpinnings related to distinguishing evaluation and response processes through meta-analyses of previous neuroimaging studies. Our results indicated that both types of unfairness consistently activate the affective and conflict-related anterior insula (AI) and dorsal anterior cingulate cortex/supplementary motor area (dACC/SMA), but the activations related to unfairness to self appeared stronger than those related to others, suggesting that individuals had negative reactions to both unfairness and a greater aversive response toward unfairness to self. During the evaluation process, unfairness to self activated the bilateral AI, dACC, and right dorsolateral prefrontal cortex (DLPFC), regions associated with unfairness aversion, conflict, and cognitive control, indicating reactive, emotional and automatic responses. In contrast, unfairness to others activated areas associated with theory of mind, the inferior parietal lobule and temporoparietal junction (IPL