Lasting effects on mouse brain growth of 24 hr postpartum deprivation.

When inbred BALB/c mice were separated from their mother for 24 or 36 hr beginning shortly after birth, growth of the body, whole brain and corpus callosum was almost completely stopped. After being returned to their mother, mice deprived for 24 hr gained weight more slowly than non-deprived littermates over the next 6 days but later showed moderate catch-up growth after weaning at 4 weeks of age. After 55 days of recovery, mice deprived for only 24 hr showed significant reductions in brain weight and size of forebrain commissures compared to littermate controls. Approximately twice as many deprived mice had a corpus callosum that was abnormally small compared to controls. These results demonstrate that a rather brief but severe period of separation from the mother can have lasting effects on brain growth.