Electrical signals from the brain may help identify potential issues in organ development, a new study reports. The researchers hope that their study will enable better tracking of infants’ neurodevelopment in the first months of life and reveal individual maps of brain maturation sooner.
Scientists from the University of Fribourg, Switzerland, and the University of Surrey, longitudinally examined electrical activity from the brains of sleeping infants at three and six months of age. They examined three electrical signals with different frequencies: slow wave activity (0.75–4.25 Hz), theta (4.5–7.5 Hz) power and sigma (9.75–14.75 Hz) power, which are key markers of sleep depth and brain development.
Dr. Salome Kurth, leader of the research group at the University of Friborg, said:
“At birth, the human brain has reached only 27 percent of its adult size. Growth is rapid in the first months of life, which is a critical period for brain maturation. Sleep plays a central role in neuronal development, although little is known about the electrical signals the brain generates during infant rest and their impact on their neurological maturation process.
“The use of EEG (electroencephalography) is non-invasive and can provide us with the opportunity to map brain activity, track how it matures, and assess its impact on later behavioral outcomes.”
To learn more, high-density EEG recordings (during which a mesh with 124 sensors was placed on the scalp) were taken of 11 healthy infants during regular sleep. Behavioral development was also assessed, focusing on infants’ gross motor skills and personal/social competence.
The research team found that between three and six months, the intensity of the electrical signal changed across all frequencies. This probably reflects an increase in the number of synaptic connections between neurons and an increase in wiring insulation through myelin, a fatty substance that wraps around nerve fibers and serves to increase the speed of electrical communication between neurons. These changes clarify how and where the infant brain reorganizes, with changing patterns of sleep-related brain activity reflecting the underlying maturation of neural networks.
Scientists say continuous monitoring of brain activity in sleep could uncover issues of neuronal network development with the potential for early diagnosis and intervention of many neuropsychiatric conditions such as ADHD.
The research team also found a connection between individual changes in electrical signals and behavioral development during this period. It was identified that at six months there is greater strength growth in frontal areas of the brain with more advanced skills in behavioral areas. Specifically, higher frontal theta power was associated with better gross motor skills whereas higher frontal sigma power was associated with better individual social skills.
Dr Valeria Jaramillo, Wellcome Early Career Fellow at the University of Surrey, said:
“Many neurodevelopmental disorders are not diagnosed until school-age age, highlighting the need to find a new way to identify such conditions before symptoms emerge. Tracking sleep brain activity using EEG is a promising technique when the brain has not matured as expected and can identify early indicators of developmental delays.”
The study was published in the journal NPJ Biological Timing and Sleep.
Source:
Journal Reference:
Beaugrand, M., Jaramillo, V., Muehlemetter, C., Schoch, SF, Reicher, V., Markovic, A., and Kurth, S. (2026). Longitudinally exploring infant sleep neurophysiology from 3 to 6 months: EEG gives insight into brain development. npj biological time and sleep, 3(1). https://doi.org/10.1038/s44323-026-00071-7. https://www.nature.com/articles/s44323-026-00071-7
