Novelty seeking and Intelligence as reflected in the individual differences in sleep spindling

• ¹ Károli Gáspár Reformed University, Hungary
• ² University of Surrey, United Kingdom
• ³ Semmelweis University, Institute of Behavioral Sciences, Hungary

The organization of sleep-dependent oscillations into synchronized systems is now widely known phenomenon of sleep physiology. Besides the general characteristics of these systems there is a growing interest in their individual aspects which are clearly recognizable and measurable and also highly stable in time. Sleep spindles are proved to be related to plastic processes of the nervous system, neural connectivity being essential in their emergence. In view of these aspects sleep spindles’ relations with several cognitive abilities have been examined. On the basis of all the results above we assume that sleep spindles could be related with other stable individual characteristics such as temperament. We studied 44 healthy subjects (21 with high [>130] and 23 with average [100±10] IQ, age average of 32,22 years, 29 [66%] male and 15 [34%] female) who slept two nights in the sleep laboratory monitored by polysomnography. To assess personality we used Cloninger’s Temperament and Character inventory (TCI) and intelligence was assessed by the advanced form of the Raven Progressive Matrices Test (RPMT). We measured sleep spindling in the first 4 cycles of sleep by the individual adjustment method. Our most outstanding result is the interaction between novelty seeking and intelligence, according to which novelty seeking positively predicts fast spindles’ duration in the average IQ group, but negatively in the high IQ group (F=11,952;p =0,00160). Among the subscales of novelty seeking extravagance (F=6,175;p =0,01837) and some items of exploratory excitement (F=7,745;p =0,00896) seem to be responsible for this result. Among these latter items the preference of new and modern methods over the old ones proved to be dominant. Results suggest a specific interrelationship between the sleep-dependent neurophysiologic markers of neural plasticity and their behavioral aspects, and also highlight an alternative approach of intelligence, which is empirically supported by our results.