Sleep and Cognition

Riemersma-van der Lek R, Swaab DF, Twisk J, Hol EM, Hoogendijk WJG and Van Someren EJW (2008) Effect of bright light and melatonin on cognitive and non-cognitive function in elderly residents of group care facilities: a randomized controlled trial. JAMA 299:2642-2655.

Raymann RJEM, Swaab DF and Van Someren EJW (2008) Skin deep: cutaneous temperature determines sleep depth. Brain 131:500-513.

Van Der Werf YD, Altena E, Schoonheim MM, Sanz-Arigita E, Vis JC, De Rijke W and Van Someren EJW (2009) Sleep benefits subsequent hippocampal functioning. Nat Neurosci 12:122-123.

The Sleep & Cognition group of Eus van Someren and Ysbrand van der Werf works at several locations, including their home base of Netherlands Institute for Neuroscience (KNAW), the VU University (FALW-Integrative Neurophysiology), the VUmc (Dept. Anatomy and Neurosciences) and the Leiden University Medical Center (Sleep Center Leiden). Against the background of their 24-hour rhythm, driven by the circadian clock of the brain, sleep and wakefulness show a mutual dependency.

The Sleep & Cognition group investigates how sleep affects brain function, cognition, mood and behavior during subsequent wakefulness, and how experiences and brain activity during wakefulness affect subsequent sleep. The group aims firstly to elucidate factors that promote and disturb sleep at the systems level and secondly to investigate the brain mechanisms involved in the favorable and disruptive effects of, respectively, sleep and sleep disturbances on cognition. The group aims to obtain fundamental insights and translate them into applications to improve sleep, vigilance and daytime function. Research tools and expertise include, in addition to the standard sleep-lab: ambulatory monitoring, brain imaging (high-density-EEG, MEG, MRI), transcranial magnetic stimulation (TMS), eye-tracking, computerized task presentation and performance assessment.

At present the Netherlands Sleep Registry is finalized. This is a web-based survey-, task assessment, database and individual user-portal that allows for repeated assessment in large populations through internet. One out of ten people suffer from insomnia. Some have trouble falling asleep, others wake up early. Some lie awake worrying, others merely complain of cold feet. This diversity makes it unlikely that ‘insomnia’ is a single entity with a single underlying risk factor. The National Sleep Registry first uses web-based survey methods to obtain a database of psychometric and sleep data. Latent classes of subtypes of insomniacs – and of very sound sleepers – will subsequently be selected to undergo extensive neuroimaging, using high-density EEG, fMRI and TMS. The aim is to elucidate brain processes involved in subtypes of insomnia, and to find endophenotypes necessary for the ultimate goal: genotyping and understanding the molecular mechanisms involved in good and poor sleep.

The group consists of group leader Prof. Dr. Eus Van Someren, senior scientist Dr. Ysbrand van der Werf, Postdocs Dr. Jeroen Benjamins, Dr. Jennifer Ramautar and Dr. Diederick Stoffers and Dr. Germán Gómez Herrero, PhD-candidates Drs. Cathalijn Leenaars, Drs. Els Møst, Drs. Giovanni Piantoni, Drs. Nico Romeijn, Drs. Rebecca Schutte and Drs. Ilse Verweij.