By carefully watching nearly a hundred hours of video showing mother rats protecting, warming, and feeding their young pups, and then matching up what they saw to real-time electrical readings from the pups’ brains, researchers have found that the mother’s presence and social interactions -— her nurturing role -— directly molds the early neural activity and growth of her offsprings’ brain.
For the study, a half-dozen rat mothers and their litters, of usually a dozen pups, were watched and videotaped from infancy for preset times during the day as they naturally developed. One pup from each litter was outfitted with a miniature wireless transmitter, invisibly placed under the skin and next to the brain to record its electrical patterns.
Specifically, study results showed that when rat mothers left their pups alone in the nest, infant cortical brain electrical activity, measured as local field potentials, jumped 50 percent to 100 percent, and brain wave patterns became more erratic, or desynchronous. Researchers point out that such periodic desynchronization is key to healthy brain growth and communication across different brain regions.
During nursing, infant rat pups calmed down after attaching themselves to their mother’s nipple. Brain activity also slowed and became more synchronous, with clearly identifiable electrical patterns.
However, these brain surges progressively declined during weaning, as infant pups gained independence from their mothers, leaving the nest and seeking food on their own as they grew past two weeks of age.
Additional experiments with a neural-signaling blocking agent, propranolol, confirmed that maternal effects were controlled in part by secretion of norepinephrine, a key neurotransmitter and hormone involved in most basic brain and body functions, including regulation of heart rate and cognition. Noradrenergic blocking in infant rats mostly dampened all previously observed effects induced by their mothers.
More work coming out of the lab :) Click on the title for link to ScienceDaily write-up.