Decreased sleep in adolescents is linked to lasting changes in how the brain communicates

A recent study published in Developmental Cognitive Neuroscience suggests that getting less sleep is associated with specific, lasting changes in how different areas of the brain communicate with one another. By tracking adolescents over two years and observing adults who underwent a night of sleep deprivation, scientists found evidence that sleep loss tends to alter the brain’s internal network organization.

Sleep is necessary for physical and mental health, yet many young people regularly fail to get enough rest. Inadequate sleep has been linked to worse academic performance, social difficulties, and various emotional challenges. During adolescence, the brain undergoes major developmental changes that are highly sensitive to environmental factors and daily routines.

The human brain is organized into complex networks of interconnected regions, and the coordinated activity across these networks supports cognition and emotional regulation. When people rest without performing a specific task, neuroscientists can measure spontaneous brain activity, known as resting-state functional connectivity, to understand how well these networks communicate. Previous research has indicated a link between sleep duration and resting-state functional connectivity, but past studies often yielded inconsistent results and primarily looked at data from a single point in time.

It has remained largely unknown whether structural changes in brain connectivity lead to poor sleep, or if poor sleep causes these brain changes. A team of researchers led by M. Fiona Molloy and Chandra Sripada from the University of Michigan set out to clarify the relationship between sleep and the developing adolescent brain. They designed a study to examine how sleep habits track with brain connectivity changes over time. They also wanted to test the directional nature of this relationship to see if sleep deprivation directly triggers specific brain connectivity patterns.

The researchers first analyzed data from the Adolescent Brain Cognitive Development Study, a large observational project tracking youth in the United States. They focused on a sample of 2,991 children, aged 11 to 12 years old. To measure sleep duration, the authors combined parent reports, self-reports from the children, and objective data collected via activity trackers. They also examined the participants’ resting-state functional magnetic resonance imaging brain scans, which track blood flow to measure neural activity.

Using advanced statistical modeling, the scientists identified a specific pattern of brain connectivity that strongly correlated with shorter sleep duration. They found that less sleep was associated with increased communication within the somatomotor network, a brain system traditionally linked to movement and sensory processing but increasingly recognized for its role in goal-directed behavior. The visual network, on the other hand, showed reduced internal communication in youth who slept less.

Next, the authors looked at a separate group of 1,574 participants from the same large dataset to observe changes over time. They compared sleep duration and brain scans taken when the children were 9 to 10 years old with data collected two years later. The statistical models accounted for variables like biological sex, age, and head motion during the brain scans to ensure these factors did not artificially inflate the results.

The analysis indicated that changes in a child’s sleep duration over the two-year period corresponded with changes in their brain networks. Specifically, youth who experienced a decrease in their sleep duration across the two years showed a corresponding increase in the expression of the reduced-sleep brain pattern, yielding a standardized beta effect size of 0.10. This provides evidence that as sleep habits shift, the brain’s internal communication architecture shifts in a predictable manner.

To test whether a lack of sleep directionally leads to this brain pattern, the researchers examined a completely different dataset called the Stockholm Sleepy Brain Study. This experimental sample included 76 adults who underwent brain scans on two separate occasions. One scan took place after a typical night of sleep, and the other occurred after a night of sleep deprivation where participants were restricted to three hours of sleep or less.

The authors took the specific reduced-sleep brain pattern they had identified in the youths and mathematically projected it onto the brain scans of the adult participants. They controlled for factors like sex, age group, and head movement during the scanning process. This allowed them to measure how strongly the youth-derived brain pattern appeared in the adults under different sleep conditions.

The expression of the reduced-sleep brain pattern increased in the adult participants after they were sleep-deprived. Following a normal night of sleep, the adults had a mean expression score of 2.03 for this brain pattern. After the sleep deprivation manipulation, the mean expression score rose to 3.39, indicating that a lack of rest reliably amplified this specific brain configuration.

The scientists also generated a new, independent brain pattern map based entirely on the adult sleep deprivation data. When they compared the sleep-deprivation map from the adults to the reduced-sleep map from the youth, the two patterns showed a spatial correlation of 0.38, indicating a high degree of overlap. Both maps prominently featured increased communication within the somatomotor network.

The observed relationship between sleep and brain connectivity could be bidirectional. Just as sleep loss alters brain networks, pre-existing brain connectivity patterns might also make it harder for a person to fall or stay asleep. Establishing a definitive, one-way biological cause would require artificially manipulating human brain connectivity in an experiment, which is not ethically or scientifically possible.

The methods used to track sleep habits also present some limitations. The observational data relied heavily on sleep measurements taken at yearly intervals, which may miss the constant daily or weekly fluctuations in how much rest a child actually gets. Retrospective reports from parents and children can also introduce memory biases compared to continuous objective tracking.

Future research could benefit from using more frequent, detailed sleep tracking methods over longer periods. Measuring sleep and brain activity simultaneously over a span of weeks could provide a sharper picture of how quickly the brain adapts to changes in rest. Tracking the current adolescent participants into their later teenage years will also help scientists understand how these brain connectivity patterns evolve as youth mature.

The study, “Decreased Sleep Is Linked Longitudinally and Directionally to Alterations in the Brain’s Intrinsic Functional Architecture,” was authored by M. Fiona Molloy, Aman Taxali, Mike Angstadt, Katherine Toda-Thorne, Katherine L. McCurry, Alexander Weigard, Omid Kardan, Camille Lehrmann, Joshua Vens, Cleanthis Michael, Mary M. Heitzeg, and Chandra Sripada.