NEW HAVEN — Newborns whose mothers were exposed during pregnancy to any one of a variety of environmental stressors — such as trauma, illness, and alcohol or drug abuse — become susceptible to various psychiatric disorders that frequently arise later in life. However, it has been unclear how these stressors affect the cells of the developing brain prenatally and give rise to conditions such as schizophrenia, post-traumatic stress disorder, and some forms of autism and bipolar disorders.  

Now, Yale University researchers have identified a single molecular mechanism in the developing brain that sheds light on how cells may go awry when exposed to a variety of different environmental insults. The findings, to be published in the May 7 issue of the journal Neuron, suggest that different types of stressors prenatally activate a single molecular trigger in brain cells that may make exposed individuals susceptible to late-onset neuropsychiatric disorders.

The researchers found that mouse embryos exposed to alcohol, methyl-mercury, or maternal seizures all activate in the developing brain cells a single gene — HSF1 or heat shock factor — which protects and enables some of the brain cells to survive prenatal insult. Mice lacking the HSF1 gene showed structural brain abnormalities and were prone to seizures after birth, even after exposure to very low levels of the toxins.