Infant’s biological clock may be seasonal

The season in which a baby is born may have a lasting effect on his or her biological clock and susceptibility to neurological disorders, U.S. researchers say.

Researchers at Vanderbilt University in Nashville say mice studies show an infant’s biological clock may be seasonally imprinted. This may help explain why people born in winter months have a higher risk of a number of neurological disorders — including seasonal affective disorder, bipolar depression and schizophrenia.

The study, published in Nature Neuroscience, found the gene clocks in winter-born mice slowing compared to those born on a summer light cycle. This may affect the reaction of the biological clock to changes in season later in life.

“What is particularly striking about our results is the fact that the imprinting affects both the animal’s behavior and the cycling of the neurons in the master biological clock in their brains,” Chris Ciarleglio said in a statement.

The biological clocks and behavior of summer-born mice remained stable and aligned with dusk while that of the winter-born mice varied widely when placed in a summer light cycle.

“The mice raised in the winter cycle show an exaggerated response to a change in season that is strikingly similar to that of human patients suffering from seasonal affective disorder,” study leader Douglas McMahon said.