{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,22]],"date-time":"2026-10-22T12:03:48Z","timestamp":1792670628390,"version":"4.5.0"},"reference-count":35,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"6","content-domain":{"domain":["lww.com","ovid.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2013,6]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Introduction:<\/jats:title>\n                    <jats:p>Directional connectivity from anterior to posterior brain regions (or \u201cfeedback\u201d connectivity) has been shown to be inhibited by propofol and sevoflurane. In this study the authors tested the hypothesis that ketamine would also inhibit cortical feedback connectivity in frontoparietal networks.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods:<\/jats:title>\n                    <jats:p>Surgical patients (n = 30) were recruited for induction of anesthesia with intravenous ketamine (2 mg\/kg); electroencephalography of the frontal and parietal regions was acquired. The authors used normalized symbolic transfer entropy, a computational method based on information theory, to measure directional connectivity across frontal and parietal regions. Statistical analysis of transfer entropy measures was performed with the permutation test and the time-shift test to exclude false-positive connectivity. For comparison, the authors used normalized symbolic transfer entropy to reanalyze electroencephalographic data gathered from surgical patients receiving either propofol (n = 9) or sevoflurane (n = 9) for anesthetic induction.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results:<\/jats:title>\n                    <jats:p>\n                      Ketamine reduced alpha power and increased gamma power, in contrast to both propofol and sevoflurane. During administration of ketamine, feedback connectivity gradually diminished and was significantly inhibited after loss of consciousness (mean \u00b1 SD of baseline and anesthesia: 0.0074 \u00b1 0.003 and 0.0055 \u00b1 0.0027;\n                      <jats:italic toggle=\"yes\">F<\/jats:italic>\n                      (5, 179) = 7.785,\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      &lt; 0.0001). By contrast, feedforward connectivity was preserved during exposure to ketamine (mean \u00b1 SD of baseline and anesthesia: 0.0041 \u00b1 0.0015 and 0.0046 \u00b1 0.0018;\n                      <jats:italic toggle=\"yes\">F<\/jats:italic>\n                      (5, 179) = 2.07;\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      = 0.072). Like ketamine, propofol and sevoflurane selectively inhibited feedback connectivity after anesthetic induction.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions:<\/jats:title>\n                    <jats:p>Diverse anesthetics disrupt frontal\u2013parietal communication, despite molecular and neurophysiologic differences. Analysis of directional connectivity in frontal\u2013parietal networks could provide a common metric of general anesthesia and insight into the cognitive neuroscience of anesthetic-induced unconsciousness.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1097\/aln.0b013e31829103f5","type":"journal-article","created":{"date-parts":[[2013,5,22]],"date-time":"2013-05-22T08:36:38Z","timestamp":1369211798000},"page":"1264-1275","update-policy":"https:\/\/doi.org\/10.1097\/lww.0000000000001000","source":"Crossref","is-referenced-by-count":426,"title":["Disruption of Frontal\u2013Parietal Communication by Ketamine, Propofol, and Sevoflurane"],"prefix":"10.1097","volume":"118","author":[{"given":"UnCheol","family":"Lee","sequence":"first","affiliation":[{"name":"Research Investigator, Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, Michigan."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"SeungWoo","family":"Ku","sequence":"additional","affiliation":[{"name":"Associate Professor"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"GyuJeong","family":"Noh","sequence":"additional","affiliation":[{"name":"Professor, Department of Clinical Pharmacology and Therapeutics, Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"SeungHye","family":"Baek","sequence":"additional","affiliation":[{"name":"Assistant Professor, Department of Anesthesiology and Pain Medicine"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"ByungMoon","family":"Choi","sequence":"additional","affiliation":[{"name":"Assistant Professor, Department of Anesthesiology and Pain Medicine"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"George A.","family":"Mashour","sequence":"additional","affiliation":[{"name":"Assistant Professor and Associate Chair for Faculty Affairs, Department of Anesthesiology, and Faculty, Neuroscience Graduate Program, University of Michigan Medical School."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"276","reference":[{"key":"R1-20241219","doi-asserted-by":"crossref","first-page":"704","DOI":"10.1097\/00000542-199004000-00021","article-title":"Is the site of action of ketamine anesthesia the N-methyl-d-aspartate receptor?","volume":"72","year":"1990","journal-title":"Anesthesiology"},{"key":"R2-20241219","doi-asserted-by":"crossref","first-page":"460","DOI":"10.1038\/nm0498-460","article-title":"Nitrous oxide (laughing gas) is an NMDA antagonist, neuroprotectant and neurotoxin.","volume":"4","year":"1998","journal-title":"Nat Med"},{"key":"R3-20241219","doi-asserted-by":"crossref","first-page":"600","DOI":"10.1523\/JNEUROSCI.3481-08.2009","article-title":"HCN1 channel subunits 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