Dreaming remains one of the great mysteries of human cognition. It is still not fully known when dreams occur, and which mechanisms in the brain produce them. A major difficulty for studying dreams is that they leave only a fleeting memory upon awakening.
Perrine Ruby and colleagues from the Lyon Neuroscience Research Center chose a new approach to investigate dreaming. They recorded brain activity of two groups of participants: high dream recallers who recall dreams nearly every day and low dream recallers who recall a dream once or twice a month. Brain activity (electroencephalogram) was recorded while they were hearing first names before and during sleep.
From the analysis of oscillatory brain signals, high and low dream recallers were found to differentially process first names during wakefulness, suggesting different functional organization of the brain in the two groups. Moreover, high dream recallers showed more intra-sleep wakefulness than low dream recallers.
Together with previous findings, these results suggest a greater brain reactivity in high than in low dream recallers which would facilitate awakenings during sleep and therefore dream memorisation