Mega brain networks are formed when babies interact

Researchers from the University of Cambridge have discovered that baby and caregiver brains can work together, forming what they term a ‘mega-network’ by synchronising brain waves as they interact. 

The level of connectivity of the brain waves varies according to the caregiver’s emotional state: when caregivers express more positive emotions their brain becomes much more strongly connected with the baby’s brain. This may help the baby to learn and its brain to develop, researchers said. 

Recently published in the journal NeuroImage, the researchers used dual electroencephalograhy (EEG) to look at brain signals in both mothers and babies while they were interacting with each other. They found that mothers and babies tend to synchronise their brain waves – an effect known as interpersonal neural connectivity – particularly in the frequency of 6-9 hertz, the infant alpha range. 

The researchers looked at both the qualities and structure of the connection using a mathematical network analysis, and this led them to be able to map how information flowed within each separate brain, and also how the two brains operated together as a network. 

When caregivers spent time together with babies in a positive emotional state, where interactions were pleasant, and there was lots of eye contact, there was an opportunity for this network to form and become stronger, promoting efficient sharing and flow of information between mother and infant. 

Previous work from one of the researchers, Dr Vicky Leong, had revealed that when the neural connection between mothers and babies is strong, babies are more receptive and ready to learn. 

“At this stage of life, the baby brain has the ability to change significantly, and these changes are driven by the baby’s experiences. By using a positive emotional tone during social interactions, parents can connect better with their infants, and stimulate development of their baby’s mental capacity,” Dr Leong said. 

The results also suggest that babies of depressed mothers may show less evidence of learning because of a weakened neural connection between mother and infant. Mothers who experience a persistently low or negative mental state due to clinical depression tend to have less interaction with their baby. Their speech is often flatter in tone, they make much less eye contact, and they are less likely to respond when their baby tries to get their attention. 

“Our emotions literally change the way that our brains share information with others – positive emotions help us to communicate in a much more efficient way,” said Dr Leong. “Depression can have a powerfully negative effect on a parent’s ability to establish connections with their baby. All the social cues that normally foster connection are less readily available to the child, so the child doesn’t receive the optimal emotional input it needs to thrive.” 

Emotional communication between caregivers and children is crucial during early life, yet little is known about its neural underpinnings. This is the first brain imaging study of two related individuals to investigate if and how babies’ interpersonal neural connectivity with their mothers is affected by the emotional quality of their social interaction.

As a social species, humans share emotional states with others. This work shows how emotions change the connection between two individuals at a neural level. The researchers say that their findings apply to many other types of affiliative bond, including between couples, close friends, and siblings, where each person is highly attuned to the other. The strength of the effect is likely to depend on how well the two people know each other and the level of trust between them.

For more information about the research, or to review it in full, please see here.