Higher sleep spindle activity is associated with fewer false memories in adolescent girls.

BACKGROUND: Sleep facilitates the extraction of semantic regularities amongst newly encoded memories, which may also lead to increased false memories. We investigated sleep stage proportions and sleep spindles in the recollection of adolescents' false memories, and their potential sex-specific differences.

METHODS: 196 adolescents (mean age 16.9 y; SD=0.1, 61 % girls) underwent the Deese, Roediger & McDermott (DRM) false memory procedure and overnight polysomnography, with free recall the following morning. Sleep was scored manually into stages 1, 2, 3 and REM. Stage 2 sleep spindle frequency, density, and peak amplitude were used as measures of spindle activity for slow (10-13 Hz) and fast (13-16 Hz) ranges.

RESULTS: In girls, a lower number of critical lures was associated with higher spindle frequency (p≤0.01), density (p≤0.01), and amplitude (p=0.03). Additionally, girls' longer sleep duration was associated with more intrusion words (p=0.03), but not with critical lures. These associations survived adjustment for age, pubertal status, and intelligence. No significant results emerged in boys.

CONCLUSIONS: In adolescent girls, higher spindle activity was associated with fewer critical lures being falsely recalled in the DRM paradigm. Unlike studies using adult participants, we did not observe any association between slow-wave sleep and false memory recollection.