{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,15]],"date-time":"2026-10-15T05:53:41Z","timestamp":1792043621034,"version":"4.4.0"},"reference-count":63,"publisher":"Public Library of Science (PLoS)","issue":"4","license":[{"start":{"date-parts":[[2023,4,11]],"date-time":"2023-04-11T00:00:00Z","timestamp":1681171200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Lumenate Growth Ltd"}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS ONE"],"abstract":"<jats:p>Flicker light stimulation (FLS) uses stroboscopic light on closed eyes to induce transient visual hallucinatory phenomena, such as the perception of geometric patterns, motion, and colours. It remains an open question where the neural correlates of these hallucinatory experiences emerge along the visual pathway. To allow future testing of suggested underlying mechanisms (e.g., changes in functional connectivity, neural entrainment), we sought to systematically characterise the effects of frequency (3 Hz, 8 Hz, 10 Hz and 18 Hz) and rhythmicity (rhythmic and arrhythmic conditions) on flicker-induced subjective experiences. Using a novel questionnaire, we found that flicker frequency and rhythmicity significantly influenced the degree to which participants experienced simple visual hallucinations, particularly the perception of Kl\u00fcver forms and dynamics (e.g., motion). Participants reported their experience of geometric patterns and dynamics was at highest intensity during 10 Hz rhythmic stimulation. Further, we found that frequency-matched arrhythmic FLS strongly reduced these subjective effects compared to equivalent rhythmic stimulation. Together, these results provide evidence that flicker rhythmicity critically contributes to the effects of FLS beyond the effects of frequency alone, indicating that neural entrainment may drive the induced phenomenal experience.<\/jats:p>","DOI":"10.1371\/journal.pone.0284271","type":"journal-article","created":{"date-parts":[[2023,4,11]],"date-time":"2023-04-11T13:25:07Z","timestamp":1681219507000},"page":"e0284271","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":21,"title":["Effect of frequency and rhythmicity on flicker light-induced hallucinatory phenomena"],"prefix":"10.1371","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7815-6270","authenticated-orcid":true,"given":"Ioanna Alicia","family":"Amaya","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nele","family":"Behrens","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3779-396X","authenticated-orcid":true,"given":"David John","family":"Schwartzman","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Trevor","family":"Hewitt","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1612-1301","authenticated-orcid":true,"given":"Timo Torsten","family":"Schmidt","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2023,4,11]]},"reference":[{"key":"pone.0284271.ref001","doi-asserted-by":"crossref","first-page":"1344","DOI":"10.1016\/j.concog.2010.10.026","article-title":"Flicker-light induced visual phenomena: Frequency dependence and specificity of whole percepts and percept features.","volume":"20","author":"C Allefeld","year":"2011","journal-title":"Conscious Cogn"},{"key":"pone.0284271.ref002","doi-asserted-by":"crossref","first-page":"e0253779","DOI":"10.1371\/journal.pone.0253779","article-title":"Altered states phenomena induced by visual flicker light stimulation.","volume":"16","author":"MT Bartossek","year":"2021","journal-title":"Plos One"},{"key":"pone.0284271.ref003","first-page":"511766","article-title":"Increased spontaneous EEG signal diversity during stroboscopically-induced altered states of consciousness.","author":"DJ Schwartzman","year":"2019","journal-title":"Biorxiv"},{"key":"pone.0284271.ref004","doi-asserted-by":"crossref","first-page":"1690","DOI":"10.1093\/brain\/awl348","article-title":"Exploring the visual hallucinations of migraine aura: the tacit contribution of illustration","volume":"130","author":"GD Schott","year":"2007","journal-title":"Brain"},{"key":"pone.0284271.ref005","first-page":"1","article-title":"Visual Hallucinations and Migraine Aura.","author":"JD Cowan","year":"2013","journal-title":"Encyclopedia of Computational Neuroscience"},{"key":"pone.0284271.ref006","doi-asserted-by":"crossref","first-page":"1371","DOI":"10.1136\/jnnp.57.11.1371","article-title":"Elementary visual hallucinations in migraine and epilepsy","volume":"57","author":"CP Panayiotopoulos","year":"1994","journal-title":"J Neurology Neurosurg Psychiatry"},{"key":"pone.0284271.ref007","first-page":"544","article-title":"Visual Hallucinations: Charles Bonnet Syndrome.","volume":"13","author":"T Jan","year":"2012","journal-title":"West J Emerg Medicine Integrating Emerg Care Popul Heal"},{"key":"pone.0284271.ref008","doi-asserted-by":"crossref","first-page":"1028","DOI":"10.3389\/fpsyg.2018.01028","article-title":"The Altered States Database: Psychometric Data of Altered States of Consciousness.","volume":"9","author":"TT Schmidt","year":"2018","journal-title":"Front Psychol."},{"key":"pone.0284271.ref009","doi-asserted-by":"crossref","first-page":"20200233","DOI":"10.1098\/rstb.2020.0233","article-title":"Hallucinations on demand: the utility of experimentally induced phenomena in hallucination research.","volume":"376","author":"S Rogers","year":"2021","journal-title":"Philosophical Transactions Royal Soc B"},{"key":"pone.0284271.ref010","volume-title":"Beitr\u00e4ge zur Kenntniss des Sehens in subjectiver Hinsicht","author":"J. 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