Scientific Reports 7, Article number: 12936 (2017)
DOI: 10.1038/s41598-017-13278-3
Ivaylo Borislavov Iotchev1, Anna Kis2, Róbert Bódizs3, Gilles van Luijtelaar4 & Enikő Kubinyi1
1Department of Ethology, Eötvös Loránd University, Budapest, Hungary
2Institute of Cognitive Neuroscience and Psychology, Hungarian Academy of Sciences, Budapest, Hungary
3Institute of Behavioural Sciences, Semmelweis University, Budapest, Hungary
4Donders Centre of Cognition, Radboud University, Nijmegen, The Netherlands
Abstract
Sleep spindles are phasic bursts of thalamo-cortical activity, visible in the cortex as transient oscillations in the sigma range (usually defined in humans as 12–14 or 9–16 Hz). They have been associated with sleep-dependent memory consolidation and sleep stability in humans and rodents. Occurrence, frequency, amplitude and duration of sleep spindles co-vary with age, sex and psychiatric conditions. Spindle analogue activity in dogs has been qualitatively described, but never quantified and related to function. In the present study we used an adjusted version of a detection method previously validated in children to test whether detections in the dogs show equivalent functional correlates as described in the human literature. We found that the density of EEG transients in the 9–16 Hz range during non-REM sleep relates to memory and is characterized by sexual dimorphism similarly as in humans. The number of transients/minute was larger in the learning condition and for female dogs, and correlated with the increase of performance during recall. It can be concluded that in dogs, automatic detections in the 9–16 Hz range, in particular the slow variant (<13 Hz), are functional analogues of human spindles.
Keywords: consolidation, prognostic markers