{"id":240245,"date":"2026-07-03T19:08:35","date_gmt":"2026-07-04T00:08:35","guid":{"rendered":"https:\/\/lifeboat.com\/blog\/2026\/07\/sub-second-fluctuations-between-top-down-and-bottom-up-modes-distinguish-diverse-human-brain-states"},"modified":"2026-07-03T19:08:35","modified_gmt":"2026-07-04T00:08:35","slug":"sub-second-fluctuations-between-top-down-and-bottom-up-modes-distinguish-diverse-human-brain-states","status":"publish","type":"post","link":"https:\/\/lifeboat.com\/blog\/2026\/07\/sub-second-fluctuations-between-top-down-and-bottom-up-modes-distinguish-diverse-human-brain-states","title":{"rendered":"Sub-second fluctuations between top-down and bottom-up modes distinguish diverse human brain states"},"content":{"rendered":"<p><a class=\"aligncenter blog-photo\" href=\"https:\/\/lifeboat.com\/blog.images\/sub-second-fluctuations-between-top-down-and-bottom-up-modes-distinguish-diverse-human-brain-states.jpg\"><\/a><\/p>\n<p>Information continuously flows between regions of the human brain, forming patterns that shift across states of consciousness, cognitive modes, and neuropsychiatric conditions. While functional magnetic resonance imaging (fMRI) reveals large-scale activity changes over seconds, the electrophysiological dynamics governing sub-second reconfiguration remain poorly understood. Here, relative phase analysis (RPA), a method leveraging phase lead\/lag relationships, is introduced to capture whole-brain dynamics with millisecond precision in real time from electroencephalography (EEG). RPA reveals sub-second alternations, occurring approximately every 200 ms, between two dominant modes of information flow: a top-down mode, where anterior regions drive posterior activity, and a bottom-up mode, characterized by reverse directionality. These dynamics are most prominent during wakefulness, gradually diminish under anesthesia, and exhibit pathological imbalance in attention-deficit\/hyperactivity disorder (ADHD). Simultaneous EEG-fMRI recordings demonstrate that top-down dynamics coincide with increased activity of higher-order cognitive networks, whereas bottom-up dynamics correspond to heightened activity in sensory networks. A connectome-based coupled-oscillator model reproduces these transitions, indicating that sub-second fluctuations emerge naturally from inter-regional interactions shaped by underlying structural connectivity. This study establishes RPA as a framework for tracking whole-brain dynamics precisely in real time and identifies sub-second top-down\/bottom-up alternations as a fundamental organizing principle of human brain function and consciousness.<\/p>\n<p><strong class=\"\"> Keywords: <\/strong> ADHD; Kuramoto model; cortical traveling waves; coupled-oscillator model; general anesthesia; human brain dynamics; relative phase analysis; simultaneous EEG-fMRI; sub-second transitions; top-down versus bottom-up modes.<\/p>\n<p>Copyright \u00a9 2026 Elsevier Inc. All rights reserved.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Information continuously flows between regions of the human brain, forming patterns that shift across states of consciousness, cognitive modes, and neuropsychiatric conditions. While functional magnetic resonance imaging (fMRI) reveals large-scale activity changes over seconds, the electrophysiological dynamics governing sub-second reconfiguration remain poorly understood. Here, relative phase analysis (RPA), a method leveraging phase lead\/lag relationships, is [\u2026]<\/p>\n","protected":false},"author":556,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[47],"tags":[],"class_list":["post-240245","post","type-post","status-publish","format-standard","hentry","category-neuroscience"],"_links":{"self":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts\/240245","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/users\/556"}],"replies":[{"embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/comments?post=240245"}],"version-history":[{"count":0,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts\/240245\/revisions"}],"wp:attachment":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/media?parent=240245"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/categories?post=240245"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/tags?post=240245"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}