According to a new study, human brains are organised into networks that support mental functions such as vision and attention from birth.
Previous research has revealed that adults have seven such functional networks in their brain. The findings of this study, the first to take a fine-grained, whole-brain approach in newborns, show that five of those networks are active at birth.
Importantly, the study discovered individual variability in those networks in newborns, which may have implications for how genetics influences adult behaviour.
“For centuries, humans have wondered what makes them unique and the role of genetic programming versus our lifetime of experience,” said Zeynep Saygin, the study’s senior author and assistant professor of psychology at The Ohio State University.
“Our findings indicate that there is variability in the brain at birth, which may be related to some of the behavioural differences we see in adults.”
M. Fiona Molloy, an Ohio State psychology graduate student, led the study, which was recently published in the journal NeuroImage.
The researchers examined MRI scans of the brains of 267 newborns, the majority of whom were less than a week old and were participants in the Developing Human Connectome Project. While the infants were sleeping, they were all scanned for 15 minutes.
The researchers examined the smallest bits of brain possible with MRI, known as voxels or volumetric pixels, to see how the signals of each voxel were related to other voxels in the brain.
“Even when we sleep, the brain is active and different parts communicate with one another,” Saygin explained.
“We identify networks by determining which parts of the brain exhibit similar patterns of activity at the same time – for example, when one area activates, the other activates as well.” They are conversing with one another.”
The researchers discovered five networks in newborns that are similar to those found in adults: the visual, default, sensorimotor, ventral attention, and high-level vision networks.
Adults have two additional networks that newborns do not have: the control and limbic networks. Saygin explained that these are both involved with higher-level functions.
Adults can use the control network to make plans to achieve their objectives. Emotional regulation is aided by the limbic network.
“Babies have little cognitive control and emotional regulation, so it’s not surprising that these networks don’t develop,” Saygin explained.
“However, one possibility is that they are pre-programmed from birth and simply need to be honed.” But that’s not what we discovered. Those networks do not exist yet and must be developed through experience.”
Individual differences in the brain networks of the newborns studied were also investigated by the researchers. The ventral attention network showed the most variability in newborns, according to the findings. This is the network that directs attention to important stimuli encountered in the world, particularly those that are unexpected.
“Our findings indicate that the ventral attention network is a stable source of individual variability that exists at birth and may persist throughout one’s lifetime,” she said.
Individual variability in network organisation has been linked to behaviour and various disorders in adults.
“We see individual differences in network organisation as early as birth, and it could be interesting to see if these differences predict behaviour or risk of psychological disorders later in life,” said Molloy.
