Socioeconomic status in children is associated with spontaneous activity in right superior temporal gyrus.

Socioeconomic status (SES) during childhood is a well-documented life-course health determinant. Despite recent advances on characterizing brain structural variance associated with SES during development, how it influences brain's functional organization remains elusive. Associations between SES, an fMRI feature of regional spontaneous activity (fractional amplitude of low frequencies fluctuation, fALFF), and behavioral/emotional problems were investigated in a school-based sample of 655 Brazilian children. A voxel-by-voxel approach was applied in order to map brain regions where fALFF was correlated with SES. Based on compelling previous evidence, we hypothesized that fALFF should be associated with SES in areas involved in language processing or cognitive control. Further, we tested if the spontaneous activity in these mapped areas would also correlated with general, internalizing and externalizing problems. SES of children was found to be positively correlated with spontaneous activity in right superior temporal gyrus. In the exploratory analysis, the fALFF of this area was negatively correlated with the expression of internalizing problems. Extending previous behavioral and structural neuroimaging findings, we report an association between SES and the spontaneous activity of a brain area enrolled in the extended language network. This finding is consistent with the hypothesis that the variability on linguistic environment according to SES lead to different developmental trajectories of functional networks instantiating language.