{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,2]],"date-time":"2026-10-02T05:55:43Z","timestamp":1790920543613,"version":"4.1.0"},"reference-count":31,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,10,2]],"date-time":"2026-10-02T00:00:00Z","timestamp":1790899200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Neurosci."],"abstract":"<jats:p>Antarctic polar night brings extreme light deprivation, prolonged isolation and severe circadian disruption, yet longitudinal resting-state electroencephalography (EEG) signatures reflecting neurophysiological alterations in this harsh environment remain poorly characterized. In this exploratory longitudinal research, resting-state EEG recordings with eyes open (EO) and eyes closed (EC) were acquired from 16 Antarctic expeditioners at four mission stages: pre-departure, pre-polar-night, early post-polar-night, and austral summer. Linear mixed-effects models with false discovery rate correction were applied to analyze delta eyes-closed\/open differentiation (the EC\u2013EO delta log-power difference), delta sub-bands, aperiodic spectral features, entropy, EEG microstates and delta-band functional connectivity. The delta EC\u2013EO difference exhibited consistent, progressively negative shifts in parietal, frontal, whole-brain and occipital regions across the expedition timeline, with the most pronounced shifts observed in recordings obtained during and after the polar-night period; this effect spanned all slow, mid and fast delta sub-bands. Secondary mild temporal variations were observed in aperiodic spectral metrics, occipital sample entropy and global delta connectivity, whereas EEG microstates displayed no significant longitudinal alterations. Collectively, the delta EC\u2013EO difference emerges as a candidate EEG index of resting-state condition differentiation in the low-frequency range, pending validation in larger studies with synchronized behavioral, physiological, and environmental measures.<\/jats:p>","DOI":"10.3389\/fnins.2026.1944325","type":"journal-article","created":{"date-parts":[[2026,10,2]],"date-time":"2026-10-02T05:37:57Z","timestamp":1790919477000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Longitudinal changes in resting-state EEG eyes-closed\/open delta differentiation during an Antarctic expedition"],"prefix":"10.3389","volume":"20","author":[{"given":"Weiting","family":"Yang","sequence":"first","affiliation":[{"name":"Department of Neurology, Shanghai East Hospital, School of Medicine, Tongji University","place":["Shanghai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Haoxin","family":"Tian","sequence":"additional","affiliation":[{"name":"Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine","place":["Shanghai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Guangming","family":"Xie","sequence":"additional","affiliation":[{"name":"Research Center for Translational Medicine, Shanghai East Hospital, School of Medicine, Tongji University","place":["Shanghai, China"]},{"name":"Institute of Basic Medicine, North Sichuan Medical College, Nanchong","place":["Sichuan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ying","family":"Xu","sequence":"additional","affiliation":[{"name":"Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine","place":["Shanghai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Qinwen","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine","place":["Shanghai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"You","family":"Yin","sequence":"additional","affiliation":[{"name":"Department of Neurology, Shanghai East Hospital, School of Medicine, Tongji University","place":["Shanghai, China"]},{"name":"Department of Neurology, Second Affiliated Hospital (Shanghai Changzheng Hospital) of Naval Medical University","place":["Shanghai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wuchao","family":"Liu","sequence":"additional","affiliation":[{"name":"Department of Neurology and Neurological Rehabilitation, Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), Tongji University School of Medicine","place":["Shanghai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yanyan","family":"Jiang","sequence":"additional","affiliation":[{"name":"Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine","place":["Shanghai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,10,2]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"174102","DOI":"10.1103\/PhysRevLett.88.174102","article-title":"Permutation entropy: a natural complexity measure for time series","volume":"88","author":"Bandt","year":"2002","journal-title":"Phys. Rev. Lett."},{"key":"B2","doi-asserted-by":"publisher","first-page":"2765","DOI":"10.1016\/j.clinph.2007.07.028","article-title":"EEG differences between eyes-closed and eyes-open resting conditions","volume":"118","author":"Barry","year":"2007","journal-title":"Clin. Neurophysiol."},{"key":"B3","doi-asserted-by":"publisher","first-page":"1162","DOI":"10.1016\/j.neuroimage.2010.02.052","article-title":"BOLD correlates of EEG topography reveal rapid resting-state network dynamics","volume":"52","author":"Britz","year":"2010","journal-title":"Neuroimage"},{"key":"B4","doi-asserted-by":"publisher","first-page":"12081","DOI":"10.1038\/s41598-023-39315-y","article-title":"Individual light history matters to deal with the Antarctic summer","volume":"13","author":"Castillo","year":"2023","journal-title":"Sci. Rep."},{"key":"B5","doi-asserted-by":"publisher","first-page":"1361","DOI":"10.1038\/s42003-022-04294-9","article-title":"One-year-later spontaneous EEG features predict visual exploratory human phenotypes","volume":"5","author":"Celli","year":"2022","journal-title":"Commun. Biol."},{"key":"B6","doi-asserted-by":"publisher","first-page":"1306","DOI":"10.3390\/jcm15031306","article-title":"Mapping executive function performance based on resting-state EEG in healthy individuals: a systematic and mechanistic review","volume":"15","author":"Chmiel","year":"2026","journal-title":"J. Clin. Med."},{"key":"B7","doi-asserted-by":"publisher","DOI":"10.4324\/9780203771587","author":"Cohen","year":"2013","journal-title":"Statistical Power Analysis for the Behavioral Sciences"},{"key":"B8","doi-asserted-by":"publisher","first-page":"1655","DOI":"10.1038\/s41593-020-00744-x","article-title":"Parameterizing neural power spectra into periodic and aperiodic components","volume":"23","author":"Donoghue","year":"2020","journal-title":"Nat. Neurosci."},{"key":"B9","doi-asserted-by":"publisher","first-page":"404","DOI":"10.1016\/j.brs.2021.02.007","article-title":"Spontaneous phase-coupling within cortico-cortical networks: how time counts for brain-state-dependent stimulation","volume":"14","author":"Ermolova","year":"2021","journal-title":"Brain Stimul."},{"key":"B10","doi-asserted-by":"publisher","first-page":"10875","DOI":"10.1038\/s41598-019-46900-7","article-title":"Sleep, napping and alertness during an overwintering mission at Belgrano II Argentine Antarctic station","volume":"9","author":"Folgueira","year":"2019","journal-title":"Sci. Rep."},{"key":"B11","doi-asserted-by":"publisher","first-page":"211","DOI":"10.1016\/j.clinph.2024.03.003","article-title":"EEG alpha reactivity on eyes opening discriminates patients with schizophrenia and schizoaffective disorder","volume":"161","author":"Garakh","year":"2024","journal-title":"Clin. Neurophysiol."},{"key":"B12","doi-asserted-by":"publisher","first-page":"2162","DOI":"10.1016\/j.clinph.2007.06.018","article-title":"Reliability of quantitative EEG features","volume":"118","author":"Gudmundsson","year":"2007","journal-title":"Clin. Neurophysiol."},{"key":"B13","doi-asserted-by":"publisher","first-page":"458","DOI":"10.1631\/jzus.B2200393","article-title":"Network controllability analysis of awake and asleep conditions in the brain","volume":"24","author":"He","year":"2023","journal-title":"J. Zhejiang Univ. Sci. B."},{"key":"B14","doi-asserted-by":"publisher","first-page":"16185","DOI":"10.1038\/s41598-018-33450-7","article-title":"Impact of long-term daylight deprivation on retinal light sensitivity, circadian rhythms and sleep during the Antarctic winter","volume":"8","author":"Kawasaki","year":"2018","journal-title":"Sci. Rep."},{"key":"B15","doi-asserted-by":"publisher","first-page":"e55092","DOI":"10.7554\/eLife.55092.sa2","article-title":"An electrophysiological marker of arousal level in humans","volume":"9","author":"Lendner","year":"2020","journal-title":"eLife"},{"key":"B16","doi-asserted-by":"publisher","first-page":"587","DOI":"10.1109\/TNSRE.2024.3355956","article-title":"Resting state EEG variability and implications for interpreting clinical effect sizes","volume":"32","author":"Liu","year":"2024","journal-title":"IEEE Trans. Neural Syst. Rehabil. Eng"},{"key":"B17","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1093\/sleep\/zsy206","article-title":"Preparing for mars: human sleep and performance during a 13 month stay in Antarctica","volume":"42","author":"Mairesse","year":"2019","journal-title":"Sleep"},{"key":"B18","doi-asserted-by":"publisher","first-page":"577","DOI":"10.1016\/j.neuroimage.2017.11.062","article-title":"EEG microstates as a tool for studying the temporal dynamics of whole-brain neuronal networks: a review","volume":"180","author":"Michel","year":"2018","journal-title":"Neuroimage"},{"key":"B19","doi-asserted-by":"publisher","first-page":"371","DOI":"10.1016\/j.neuroimage.2011.12.039","article-title":"Towards the utilization of EEG as a brain imaging tool","volume":"61","author":"Michel","year":"2012","journal-title":"Neuroimage"},{"key":"B20","doi-asserted-by":"publisher","first-page":"15959","DOI":"10.1038\/s41598-023-42910-8","article-title":"Sleep impairment and altered pattern of circadian biomarkers during a long-term antarctic summer camp","volume":"13","author":"Moraes","year":"2023","journal-title":"Sci. Rep."},{"key":"B21","doi-asserted-by":"publisher","first-page":"658","DOI":"10.1109\/10.391164","article-title":"Segmentation of brain electrical activity into microstates: model estimation and validation","volume":"42","author":"Pascual-Marqui","year":"1995","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"B22","doi-asserted-by":"publisher","first-page":"159","DOI":"10.1016\/j.smrv.2017.03.001","article-title":"From the midnight sun to the longest night: sleep in Antarctica","volume":"37","author":"Pattyn","year":"2018","journal-title":"Sleep Med. Rev."},{"key":"B23","doi-asserted-by":"publisher","first-page":"567","DOI":"10.1111\/php.12418","article-title":"Light treatment improves sleep quality and negative affectiveness in high arctic residents during winter","volume":"91","author":"Paul","year":"2015","journal-title":"Photochem. Photobiol."},{"key":"B24","doi-asserted-by":"publisher","first-page":"2039","DOI":"10.1152\/ajpheart.2000.278.6.H2039","article-title":"Physiological time-series analysis using approximate entropy and sample entropy","volume":"278","author":"Richman","year":"2000","journal-title":"Am. J. Physiol. Heart Circ. Physiol."},{"key":"B25","doi-asserted-by":"publisher","first-page":"39","DOI":"10.1038\/s41526-025-00497-6","volume":"11","author":"Roalf","year":"2025"},{"key":"B26","doi-asserted-by":"publisher","first-page":"352","DOI":"10.3390\/clockssleep1030029","article-title":"Chronotype-dependent changes in sleep habits associated with dim light melatonin onset in the Antarctic summer","volume":"1","author":"Silva","year":"2019","journal-title":"Clocks & Sleep"},{"key":"B27","doi-asserted-by":"publisher","first-page":"782474","DOI":"10.3389\/fnins.2022.782474","article-title":"State changes during resting-state (magneto)encephalographic studies: the effect of drowsiness on spectral, connectivity, and network analyses","volume":"16","author":"Strijbis","year":"2022","journal-title":"Front. Neurosci."},{"key":"B28","doi-asserted-by":"publisher","first-page":"375","DOI":"10.1038\/s41746-024-01384-2","article-title":"Adaptive spatiotemporal encoding network for cognitive assessment using resting state EEG","volume":"7","author":"Sun","year":"2024","journal-title":"NPJ Digit. Med"},{"key":"B29","doi-asserted-by":"publisher","first-page":"20","DOI":"10.1016\/j.slsci.2016.01.002","article-title":"Extreme late chronotypes and social jetlag challenged by Antarctic conditions in a population of university students from Uruguay","volume":"9","author":"Tassino","year":"2016","journal-title":"Sleep Sci."},{"key":"B30","doi-asserted-by":"publisher","first-page":"15957","DOI":"10.1038\/s41598-023-43102-0","article-title":"Chronotype delay and sleep disturbances shaped by the Antarctic polar night","volume":"13","author":"Tortello","year":"2023","journal-title":"Sci. Rep."},{"key":"B31","doi-asserted-by":"publisher","DOI":"10.1162\/imag_a_00350","article-title":"Arbitrary methodological decisions skew inter-brain synchronization estimates in hyperscanning-EEG studies","author":"Zimmermann","year":"2024","journal-title":"Imaging Neurosci. 2"}],"container-title":["Frontiers in Neuroscience"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fnins.2026.1944325\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,10,2]],"date-time":"2026-10-02T05:37:58Z","timestamp":1790919478000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fnins.2026.1944325\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,10,2]]},"references-count":31,"alternative-id":["10.3389\/fnins.2026.1944325"],"URL":"https:\/\/doi.org\/10.3389\/fnins.2026.1944325","relation":{},"ISSN":["1662-453X"],"issn-type":[{"value":"1662-453X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,10,2]]},"article-number":"1944325"}}