The study indicates that the infant children of mothers who had experienced childhood emotional neglect displayed altered brain circuitry involved in fear responses and anxiety.

"These results show that our brain development is not only shaped by what happens in our own life, but is also impacted by things that happened to our parents before we were even conceived," said lead author of the study, Cassandra Hendrix at New York University Langone Health in the US.

For the study, published in the journal Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, the team studied 48 mother-infant pairs starting in the first trimester of pregnancy.

Mothers were given a questionnaire to assess childhood trauma (experiences of early abuse or neglect). The mothers were also evaluated for current, prenatal stress levels, and for anxiety and depression.

One month after birth, infants underwent a brain scan using resting-state functional magnetic resonance imaging, a non-invasive technology that could be used while the babies slept naturally.

The researchers focused on brain connections between the amygdala, which is central to processing fearful emotions, and two other brain regions: the prefrontal cortex and the anterior cingulate cortex.

Both areas play a key role in regulating emotions. Babies whose mothers experienced childhood emotional neglect had stronger functional connections between the amygdala and the cortical regions.

After controlling for mothers' current stress levels, the researchers found that the more emotional neglect a mother had experienced during her own childhood, the more strongly her baby's amygdala was connected to the frontal cortical regions.