Age-related decrease in cortical excitability circadian variations during sleep loss and its links with cognition

• DOI: 10.1016/j.neurobiolaging.2019.02.004
• Publication Date: 2019-02-13T03:55:18Z
• Authors: Giulia Gaggioni; Julien Q.M. Ly; Vincenzo Muto; Sarah L. Chellappa; Mathieu Jaspar; Christelle Meyer; Tillo Delfosse; Amaury Vanvincken...; Romain Dumont; Dorothée Coppiete...; Christian Berthomier; Justinas Narbutas; Maxime Van Egroo; Andé Luxen; Eric Salmon; Fabienne Collette; Christophe Phillips; Christina Schmidt; Gilles Vandewalle
• Keywords: Cerebral Cortex; Male; Aging; 610; Middle Aged; Circadian Rhythm; Healthy Aging; Young Adult; 03 medical and health sciences; Cognition; 0302 clinical medicine; Cognitive Aging; 616; Cortical Excitability; Homeostasis; Humans; Sleep Deprivation; Cognitive Dysfunction; Female; Wakefulness; Sleep; Aged

Cortical excitability depends on sleep-wake regulation, is central to cognition, and has been implicated in age-related cognitive decline. The dynamics of cortical excitability during prolonged wakefulness in aging are unknown, however. Here, we repeatedly probed cortical excitability of the frontal cortex using transcranial magnetic stimulation and electroencephalography in 13 young and 12 older healthy participants during sleep deprivation. Although overall cortical excitability did not differ between age groups, the magnitude of cortical excitability variations during prolonged wakefulness was dampened in older individuals. This age-related dampening was associated with mitigated neurobehavioral consequences of sleep loss on executive functions. Furthermore, higher cortical excitability was potentially associated with better and lower executive performance, respectively, in older and younger adults. The dampening of cortical excitability dynamics found in older participants likely arises from a reduced impact of sleep homeostasis and circadian processes. It may reflect reduced brain adaptability underlying reduced cognitive flexibility in aging. Future research should confirm preliminary associations between cortical excitability and behavior and address whether maintaining cortical excitability dynamics can counteract age-related cognitive decline.