Breastfeeding linked to ‘drug’ rewards
When suckling their offspring, the brains of female rats are activated in the same reward areas as stimulated by cocaine, an American study has found.
Earlier work at the University of Toronto shows rat mothers prefer to press a lever to gain access to their suckling pups, than press an alternative lever to receive a dose of cocaine.
Stimulation of the reward areas of the brains is thought to be analogous to ‘pleasure’ in humans, encouraging a repeat of the behaviour activating that part of the brain.
This mechanism may encourage bonding between rat mothers and their pups, and may occur in other species, according to University of Massachusetts scientists.
Dr Craig Ferris and his colleagues used MRI scans to monitor the brains of rat mothers as they nursed their young pups. The rats were restrained in a specially built holder designed to keep the head still while ensuring comfort for the mother. The pups were suspended on a box beneath their mum’s abdomen and scans of her brain were taken as they supped.
They found that as the pups aged, less activation of the pleasure pathways occurred. Dr Ferris explains: ‘Cocaine is an effective activator of the reward systems, so it’s not surprising that in the lever pressing studies the pups compete with cocaine when young, but don’t when older.’
The scans showed several other brain areas are activated by suckling pups, and the team is planning to investigate further the development of brain activity as the pups grow.
The research was presented at the Society for Neuroscience Annual meeting in New Orleans this week.
