EMERGENCE OF MATURE CORTICAL ACTIVITY IN WAKEFULNESS AND SLEEP IN HEALTHY PRE-TERM AND FULL-TERM INFANTS

Oral Session 1
Saturday, April 28, 2018 | 2:15pm-3:45pm | Room 342B

3:15pm-3:30pm
EMERGENCE OF MATURE CORTICAL ACTIVITY IN WAKEFULNESS AND SLEEP IN HEALTHY PRE-TERM AND FULL-TERM INFANTS

Authors:
Kimberley Whitehead (United Kingdom)*
Pureza Laudiano-Dray (United Kingdom)
Judith Meek (United Kingdom)
Lorenzo Fabrizi (United Kingdom)

Introduction

Cortical activity patterns develop rapidly over the equivalent of the last trimester of gestation, in parallel with the establishment of sleep architecture. However, the emergence of mature cortical activity in wakefulness compared to sleep states in healthy pre-term infants, and the factors which influence this, is poorly understood.

Materials and methods

To investigate whether cortical activity has a different developmental profile in each vigilance state, we characterised the trajectory of delta, theta and alpha-beta oscillations in wakefulness, active sleep and non-REM sleep in 115 infants 34–43 weeks corrected age, with 0.5-17 days of postnatal age. Recording set-up included 10-channel electroencephalogram, electrooculogram, single lead electrocardiogram, and an abdominal transducer to monitor respiratory movement.

Results

Delta oscillations in wakefulness and active sleep decrease with corrected age, particularly in the temporal region, but not in non-REM sleep. Theta oscillations increase with corrected age in sleep, especially non-REM sleep, but not in wakefulness. On the other hand, alpha-beta oscillations decrease predominantly with postnatal age, independently of vigilance state, particularly in the occipital region.

Conclusions

The developmental trajectory of delta and theta rhythms is state-dependent, and results in changed cortical activity patterns across states with corrected age. The prominent changes in delta activity in wakefulness and active sleep, and in theta activity in non-REM sleep, may suggest that these frequency bands have particular functional roles in each state. Interestingly, postnatal age is associated with a decrease in alpha-beta oscillations overlying primary visual cortex in every vigilance state, suggesting that postnatal experience (including the first visual input through open eyes during periods of wakefulness) may especially modulate resting-state visual cortical activity.

Acknowledgements

We would like to thank the families who participated in our neonatal EEG research program. This work was supported by the Medical Research Council (MR/L019248/1).