Sixteen healthy participants across a range of ages were recruited to take part in an experiment. Participants carried out two tasks – the masked prime task and a control task where participants simply responded when they saw a red or blue square on a screen. Participants practiced the tasks and then either stayed awake or took a 90-minute nap before doing the tasks again.
Using an EEG, which records the electrical activity naturally produced in the brain, researchers measured the change in brain activity and response pre-and-post nap.
Sleep (but not wake) improved processing speed in the masked prime task – but not in the control task – suggesting sleep-specific improvements in processing of subconsciously presented primes.
The findings suggest that even a short bout of sleep may help improve our responses and process information. Therefore, the results here suggest a potentially sleep-dependent, task-specific enhancement of brain processing that could optimise human goal-directed behaviour.
Importantly, while it is already known that the process of acquiring knowledge and information recall, memory, is strengthened during sleep. This study suggests that information acquired during wakefulness may potentially be processed in some deeper, qualitative way during sleep
Dr Liz Coulthard, Consultant Senior Lecturer in Dementia Neurology at the University of Bristol Medical School: Translational Health Sciences, said: “The findings are remarkable in that they can occur in the absence of initial intentional, conscious awareness, by processing of implicitly presented cues beneath participants’ conscious awareness.
“Further research in a larger sample size is needed to compare if and how the findings differ between ages, and investigation of underlying neural mechanisms.”