{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,9]],"date-time":"2026-01-09T18:32:50Z","timestamp":1767983570965,"version":"3.49.0"},"reference-count":52,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2021,11,15]],"date-time":"2021-11-15T00:00:00Z","timestamp":1636934400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Symmetry"],"abstract":"<jats:p>Brain complexity can be revealed even through a comparison between two trivial conditions, such as eyes open and eyes closed (EO and EC respectively) during resting. Electroencephalogram (EEG) has been widely used to investigate brain networks, and several non-linear approaches have been applied to investigate EO and EC signals modulation, both symmetric and not. Entropy is one of the approaches used to evaluate the system disorder. This study explores the differences in the EO and EC awake brain dynamics by measuring entropy. In particular, an approximate entropy (ApEn) was measured, focusing on the specific cerebral areas (frontal, central, parietal, occipital, temporal) on EEG data of 37 adult healthy subjects while resting. Each participant was submitted to an EO and an EC resting EEG recording in two separate sessions. The results showed that in the EO condition the cerebral networks of the subjects are characterized by higher values of entropy than in the EC condition. All the cerebral regions are subjected to this chaotic behavior, symmetrically in both hemispheres, proving the complexity of networks dynamics dependence from the subject brain state. Remarkable dynamics regarding cerebral networks during simple resting and awake brain states are shown by entropy. The application of this parameter can be also extended to neurological conditions, to establish and monitor personalized rehabilitation treatments.<\/jats:p>","DOI":"10.3390\/sym13112178","type":"journal-article","created":{"date-parts":[[2021,11,15]],"date-time":"2021-11-15T20:46:47Z","timestamp":1637009207000},"page":"2178","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":31,"title":["Entropy as Measure of Brain Networks\u2019 Complexity in Eyes Open and Closed Conditions"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6004-9522","authenticated-orcid":false,"given":"Fabrizio","family":"Vecchio","sequence":"first","affiliation":[{"name":"Brain Connectivity Laboratory, Department of Neuroscience and Neurorehabilitation, IRCCS San Raffaele Roma, 00166 Rome, Italy"},{"name":"Department of Theoretical and Applied Sciences, eCampus University, 22060 Novedrate, Italy"}]},{"given":"Francesca","family":"Miraglia","sequence":"additional","affiliation":[{"name":"Brain Connectivity Laboratory, Department of Neuroscience and Neurorehabilitation, IRCCS San Raffaele Roma, 00166 Rome, Italy"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0020-6274","authenticated-orcid":false,"given":"Chiara","family":"Pappalettera","sequence":"additional","affiliation":[{"name":"Brain Connectivity Laboratory, Department of Neuroscience and Neurorehabilitation, IRCCS San Raffaele Roma, 00166 Rome, Italy"}]},{"given":"Alessandro","family":"Orticoni","sequence":"additional","affiliation":[{"name":"Brain Connectivity Laboratory, Department of Neuroscience and Neurorehabilitation, IRCCS San Raffaele Roma, 00166 Rome, Italy"}]},{"given":"Francesca","family":"Al\u00f9","sequence":"additional","affiliation":[{"name":"Brain Connectivity Laboratory, Department of Neuroscience and Neurorehabilitation, IRCCS San Raffaele Roma, 00166 Rome, Italy"}]},{"given":"Elda","family":"Judica","sequence":"additional","affiliation":[{"name":"Department of Neurorehabilitation Sciences, Casa Cura Policlinico, 20144 Milano, Italy"}]},{"given":"Maria","family":"Cotelli","sequence":"additional","affiliation":[{"name":"Neuropsychology Unit, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, 25125 Brescia, Italy"}]},{"given":"Paolo Maria","family":"Rossini","sequence":"additional","affiliation":[{"name":"Brain Connectivity Laboratory, Department of Neuroscience and Neurorehabilitation, IRCCS San Raffaele Roma, 00166 Rome, Italy"}]}],"member":"1968","published-online":{"date-parts":[[2021,11,15]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"177","DOI":"10.1007\/s00422-005-0547-1","article-title":"The physical basis of alpha waves in the electroencephalogram and the origin of the \u201cBerger effect\u201d","volume":"92","author":"Kirschfeld","year":"2005","journal-title":"Biol. 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