Abstract of a paper studying the neuroanatomy of irreligion:
We hypothesized that irreligiosity, a set of traits variably expressed in the population, is modulated by neuroanatomical variability. We tested this idea by determining whether aspects of irreligiosity were predicted by variability in regional cortical volume. We performed structural magnetic resonance imaging of the brain in 100 healthy adult participants who reported different degrees and patterns of irreligiosity on a survey. We identified four principal components of irreligiosity by factor analysis of the survey items and associated them with regional cortical volumes measured by voxel-based morphometry. (1) Experiencing a profound disconnect with God and engaging in irreligious behavior was associated with decreased volume of R middle temporal cortex, BA 21. (2) Experiencing hatred of God was associated with increased volume of L precuneus and L orbitofrontal cortex BA 11. (3) A cluster of traits related with pragmatism and doubting God's existence was associated with increased volume of the R precuneus. (4) Variability in irreligiosity of upbringing was not associated with variability in cortical volume of any region. Therefore, key aspects of irreligiosity are associated with cortical volume differences. This conclusion complements our prior functional neuroimaging findings in elucidating the proximate causes of irreligion in the brain.