During sleep, memories are consolidated via oscillatory events that occur in temporal and phasic synchrony. Several studies show that sleep spindles peaking close to the depolarized positive peaks of slow oscillations (SO) associate with better retention of memories. The exact timing of this synchrony presumably depends on the properties of the related neural network that, in turn, is affected by certain genetic variants associated with brain development and function. Brain-derived neurotrophic factor (BDNF) Val66Met and Catechol-O-methyltransferase (COMT) Val158Met are repeatedly reported to implicate the structure and function of prefrontal and hippocampal areas as well as molecular events promoting synaptic plasticity. In this study, we examined with a community-based sample of 153 adolescents (~17 years) whether these variants (1) affected the coupling properties between frontal SOs and spindles and (2) moderated the association between SO-spindle coupling and overnight recognition accuracy. We found SO-upstate-coupled fast (> 13 Hz) sleep spindles to associate with better recognition in the whole sample. Additionally, Val66Met moderated this association such that SO-spindle coupling was predictive of memory outcome only in those homozygous to ValBDNF alleles but not in MetBDNF carriers. Memory outcome was not associated with the SO-coupling properties of slow spindles nor affected by the interaction between Val158Met and coupling measures. Finally, in the whole sample we found that SO-upstate-coupled fast spindles were more strongly associated with the recognition of positive, relative to neutral, pictures. In conclusion, precise coupling of SOs and fast spindles associates with overnight recognition accuracy and this association is moderated by BDNF Val66Met.
Keywords: SO-spindle coupling; Sleep spindle; Slow oscillation; Val158Met; Val66Met; Visual recognition.
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