Infant neglect surfaces in mid life

Evidence continues to mount that prenatal and early experience can have profound long-term effects on the developing central nervous system and its regulation of basic physiology, psychology, and immune function. Several reports demonstrate that this phenomenon is conserved across species--from the barn owl to rodents to humans--suggesting that these effects are mediated by fundamental mechanisms.

For instance, there are studies which demonstrate how maternal care can induce alterations in the gene methylation in offspring. Other research is uncovering how stresses during pregnancy and early life can affect learning and memory, as well as immune function, long after the stress has disappeared. Still others are unraveling the cellular basis for how early life stresses can lead to later cognitive impairment; the effects on adult emotional behavior from using selective serotonin reuptake inhibitors such as Prozac during early development; and how experience dramatically can increase adult animals' adaptability to new stimuli.

Stresses such as neglect and abuse during infancy may result in memory loss and impaired cognitive abilities that manifest later in life, a University of California, Irvine, study has found. The research of rats clearly shows a late onset of slow progression of deficits in communication among brain cells in the hippocampus, a brain region involved in learning, storage, and recall of memories.

Experiments found that limiting the nesting material in cages where neonatal rats lived with their mothers led to emotional stress of both the mothers and their pups. All evidence of this stress disappeared by the time the pups reached adulthood. However, starting in middle age, these so-called "graduates" of early life stress began to forget the location of objects they had seen before. They also got worse at recognizing objects they had encountered the previous day. These difficulties worsened as the rats grew older, much more rapidly than in rats that were raised for their first week of life under more nurturing conditions.

Communication among brain cells, considered to be the cellular basis for learning and memory, was faulty in the middle-aged rats. Recordings of the electrical activity of brain cells appeared normal in young adult rats exposed to early life stress, but became very disturbed as they reached middle age. "Now that concrete deficits in brain cell communication have been found in the early-life stressed, demented rats, it may be feasible to find the specific molecules involved and design medicines to prevent the deficits," concludes researcher Tallie Baram.

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