Prenatal disturbance alters the size of the corpus callosum in young monkeys.

Many factors during fetal life and early infancy have been found to affect the development of the brain. The following study investigated whether maternal stress during pregnancy would influence the size and shape of one sensitive brain region, the corpus callosum, in infant monkeys. For 30% of the gestation period, from Days 90 to 140 postconception, gravid females were disturbed using an acoustical startle protocol for 10 min per day. Magnetic resonance imaging was then employed to obtain sagittal and coronal scans of their infants' brains. Morphometric measures of the corpus callosum were compared in 16 monkeys (5 controls and 11 from disturbed pregnancies). Prenatal conditions altered the corpus callosum, but in a differential manner for male and female monkeys. Based on the midsagittal and parasagittal scans, prenatally disturbed male offspring showed a decrease in overall size of the corpus callosum whereas the prenatal disturbance resulted in an increased area in females. An evaluation of callosal height from the coronal images suggested that the volumetric change was associated with a shift in anterior-to-posterior shape from the genu back toward the splenium. These findings concur with observations in other animals and humans, which have indicated that prenatal and postnatal factors can influence the development of the corpus callosum, possibly affecting communication between the hemispheres. Copyright 2002 Wiley Periodicals, Inc. Dev Psychobiol 41: 178-185, 2002. Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/dev.10063