Introduction: Neural correlates of sleep deprivation are not fully understood and the difference between young and older adults in this regard has received little attention. We aimed to investigate the effect of partial sleep deprivation on resting state connectivity.

Methods: 30 younger (20–30 years) and 23 older (65–75 years) healthy participants underwent MR imaging after normal sleep and partial sleep deprivation (3 h sleep). We acquired two runs of eyes-open resting state functional magnetic resonance images. Participants were monitored with eye-tracking to ensure their eyes remained open during scanning.

Results: Global signal variability, defined as log-transformed standard deviation of average gray matter signal, was increased following partial sleep deprivation (0.16 [0.07, 0.24], p = 0.0004). In contrast to previous studies, we did not find that partial sleep deprivation inhibited connectivity in the default mode network, nor in other major networks investigated.

Conclusion: Sleep deprivation caused increased global signal variability. This novel finding should be confirmed using independent data. Our finding of no difference in default mode connectivity in the sleep deprived state, could possibly be due to stricter monitoring of participants’ wakefulness compared to some earlier studies.