Editing Sleep (section)

===In studies on consciousness and philosophy===
As an [[altered state of consciousness]], dreamless deep sleep has been used as a way to investigate [[animal consciousness|animal]]/human [[consciousness]] and [[qualia]]. Insights about differences of the living sleeping brain to its wakeful state and the transition period may have implications for potential explanations of human subjective experience, the so-called [[hard problem of consciousness]], often delegated to the realm of [[philosophy]], including [[neurophilosophy]]<ref>{{cite book |last1=Churchland |first1=Patricia Smith |title=A neurophilosophical slant on consciousness research |series=Progress in Brain Research |date=1 January 2005 |volume=149 |pages=285–293 |publisher=Elsevier |language=en}}</ref><ref>{{cite journal |last1=Doerig |first1=Adrien |last2=Schurger |first2=Aaron |last3=Hess |first3=Kathryn |last4=Herzog |first4=Michael H. |title=The unfolding argument: Why IIT and other causal structure theories cannot explain consciousness |journal=Consciousness and Cognition |date=1 July 2019 |volume=72 |pages=49–59 |doi=10.1016/j.concog.2019.04.002 |pmid=31078047 |s2cid=147704603 |language=en |issn=1053-8100|doi-access=free }}</ref><ref>{{cite journal |last1=Tsytsarev |first1=Vassiliy |title=Methodological aspects of studying the mechanisms of consciousness |journal=Behavioural Brain Research |date=February 2022 |volume=419 |pages=113684 |doi=10.1016/j.bbr.2021.113684|pmid=34838578 |s2cid=244570791 }}</ref><ref>{{cite journal |last1=Kerskens |first1=Christian Matthias |last2=López Pérez |first2=David |title=Experimental indications of non-classical brain functions |journal=Journal of Physics Communications |date=1 October 2022 |volume=6 |issue=10 |pages=105001 |doi=10.1088/2399-6528/ac94be |bibcode=2022JPhCo...6j5001K |language=en |issn=2399-6528|doi-access=free|arxiv=1806.07998 }}</ref> (or in some cases to religion and similar approaches).