Self-esteem modulates dorsal medial prefrontal cortical response to self-positivity bias in implicit self-relevant processing

Abstract

Processing self-related material recruits similar neural networks regardless of whether the self-relevance is made explicit or not. However, when considering the neural mechanisms that distinctly underlie cognitive and affective components of self-reflection, it is still unclear whether the same mechanisms are involved when self-reflection is explicit or implicit, and how these mechanisms may be modulated by individual personality traits, such as self-esteem. In the present functional MRI study, 25 participants were exposed to positive and negative words that varied with respect to the degree of self-relevance for each participant; however, the participants were asked to make a judgment about the color of the words. Regions-of-interest analysis showed that medial prefrontal cortex (mPFC) and posterior cingulate cortex were associated with gauging the self-relevance of information. However, no main effect of valence or an interaction effect between self-relevance and valence was observed. Further, positive correlations were observed between levels of self-esteem and response within dorsal mPFC (dmPFC) both in the contrast positive-high in self-relevance trials vs positive-low in self-relevance trials and in the contrast negative-low in self-relevance trials vs positive-low in self-relevance trials. These results suggested that the activation of dmPFC may be particularly associated with the processes of self-positivity bias.

Keywords: dorsal medial prefrontal cortex (dMPFC); implicit self-relevant processing; self-esteem; self-positivity bias.

Fig. 1

Reaction time (A) and adjectives endorsed (%) (B) for positive and negative words that were high self-relevant and low self-relevant for each participant. The error bars indicate the standard deviation of the mean.

Fig. 2

Axial sections display mPFC (left top), dmPFC (left middle), vmPFC (left bottom), dACC (right top), vACC (right middle) and PCC (right bottom) spherical ROIs superimposed on a normalized anatomic image. Graphs to the right of each image display signal change (parameter estimates) across each condition. Error bars indicate standard error of the mean.

Fig. 3

(A) The curve estimation between beta value of dmPFC in the contrast of PH > PL and the self-esteem score in 25 participants. (B) The curve estimation between beta value of dmPFC in the contrast of NL > PL and the self-esteem score in 25 participants. (C) The curve estimation between beta value of dmPFC in the contrast of [PH + NL] > [NH + PL] and the self-esteem score in 25 participants.