The depth and volume of the primary olfactory sulcus and secondary orbital sulci in a sample of 22 adolescents with history of very-preterm birth (VPTB), compared to control subjects born at term, were measured, using MRI Anatomist/Brain VISA 3.0.1 package, and possible reductions in gray and white matter analyzed, using voxel-based morphometry (VBM), in a study at University of Barcelona, Spain. Significant reduction was observed in the depth of the secondary orbitoffontal sulci (which begin to develop at 28 weeks'gestation) but not in the primary olfactory sulci (developed at 16 weeks' gestation) of prematurely born compared to term born subjects at adolescence. Orbital sulcal depth reductions were accompanied by reduced gray-matter volume, using VBM analysis. 
COMMENT. The impaired development of the secondary orbital sulci is consistent with the premature birth before 32 weeks, and before these sulci have formed. In contrast, the primary sulci appear at 16 weeks' gestation and are well formed at 25 weeks. The sulcal abnormality appears to correlate with gray-matter volume reduction. The authors conclude that the orbitofrontal sulcal abnormality is a sequel of premature birth or neonatal complications. Special MR techniques are proving useful in detecting subtle structural cerebral defects that might explain cognitive and behavioral developmental deficits.