Revolutionizing Sleep Science: A Narrative Review of the Historical Origins and Current Applications of Sleep Neuroimaging

Daniel B Kay,1 Kara McRae Duraccio,1 Lars Michels,2,3 Francesca Siclari,4,5 Helmet T Karim,6,7 Elijah B Davis,8 Isaac J Wilkins1 1Department of Psychology, Brigham Young University, Provo, UT, USA; 2Department of Neuroradiology, University Hospital Zürich, University of Zürich, Zürich, Switzerland; 3Center for MR Research, University Children’s Hospital Zürich, University of Zürich, Zürich, Switzerland; 4Département de Médecine, Lausanne University Hospital, Lausanne, Switzerland; 5Netherlands Institute for Neuroscience, Amsterdam, The Netherlands; 6Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA; 7Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; 8Department of Neuroscience, Stanford University, Stanford, CA, USACorrespondence: Daniel B Kay, Brigham Young University, 1090 KMBL, Provo, UT, 84602, USA, Tel +1 801-422-7949, Email [email protected]: Sleep neuroimaging is a subfield of sleep science that goes beyond polysomnography by combining neuroimaging techniques with validated sleep research methods to characterize sleep-wake states and investigate sleep-related processes across the 24-hour day. In this article, we review the historical advancements and applications that grew out of somnography leading to current sleep neuroimaging methods. We highlight the power of somnoimages to help visualize sleep research results and communicate complex information about sleep processes. We also suggest several ways in which applying neuroimaging during sleep has opened new avenues to more fully capture the nature of sleep, uncovered mechanisms of sleep-wake regulation, and increased understanding of sleep-related processes. Current applications and future directions of sleep neuroimaging are also discussed.Plain Language Summary: Sleep neuroimaging is an advanced area of research that combines brain imaging techniques with other validated sleep measures to better understand sleep. This article reviews how sleep research has evolved from basic monitoring techniques like polysomnography to modern multimodal sleep neuroimaging methods. It highlights how these new approaches provide clearer insights into sleep processes and have led to discoveries about sleep that were previously inaccessible. The article also discusses future directions for using neuroimaging to further explore sleep and its related neuronal, behavioral, and experiential processes.Keywords: sleep neuroimaging, sleep fMRI, EEG-fMRI, somnoimages, somnoimaging