A study published in Science suggests there is a small but critical window during early development when certain adverse life experiences can permanently alter a type of brain cell linked to behavior. Childhood neglect and deprivation have previously been linked to behavioral problems and changes to white matter in the forebrain, where nerve fibers are contained and protected by a layer of fat called a myelin sheath. This study offers possible clues to how adverse experiences in infants could lead to brain changes.

Researchers in Boston tested the effects of isolating groups of newly weaned mice by housing them in cages on their own. Other mice were housed in groups of four or groups of eight, with the latter given access to toys that were replaced every 48 hours. After four weeks, mice raised in isolation exhibited impaired social interaction and memory skills compared with the other groups. Tests showed that myelin-producing cells called oligodendrocytes were markedly shorter and simpler in isolated mice; these mice also had thinner myelin layers.

Experiments showed that the changes to behavior and oligodendrocyte development in mice only occurred when the isolation took place during a two-week period immediately after weaning, suggesting there is a critical period when the adverse experience influenced the myelin sheath, researchers said. Disabling an oligodendrocyte receptor called ErbB was also found to mimic the effects of social isolation in normal mice. The findings may offer a new approach to schizophrenia and other neuropsychiatric disorders associated with white matter and myelin changes, researchers said.

Caveat: The research hasn't been proven in human subjects.

Title: A Critical Period for Social Experience-Dependent Oligodendrocyte Maturation and Myelination

—Ann Lukits