{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,16]],"date-time":"2026-05-16T00:51:18Z","timestamp":1778892678593,"version":"3.51.4"},"reference-count":45,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2023,12,6]],"date-time":"2023-12-06T00:00:00Z","timestamp":1701820800000},"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>Visual hallucinations are prevalent, potentially disabling symptoms of Parkinson\u2019s Disease. Multiple impairments in bottom-up sensory processing and top-down perceptual modulation are implicated in the pathophysiology of these phenomena. In healthy individuals, visual illusions are elicited by illusory figures through parametric manipulations of geometrical configurations, contrast, color, or spatial relationships between stimuli. These illusory percepts provide insight on the physiologic processes subserving conscious and unconscious perception. In this exploratory, cross-sectional, controlled study, perceptual performance on illusory figures was assessed on 11 PD patients with hallucinations, 10 non-hallucinating PD patients, and 10 age-matched healthy individuals. In order to characterize potential neural substrates of perceptual performances, patients\u2019 brain metabolic patterns on FDG PET were also analyzed. Illusions relying on attentional modulation and global perception were attenuated in PD patients without hallucinations. This pattern was no longer recognizable in hallucinating patients. Conversely, illusory effects normally counteracted by figure to background segregation and overlapping figures recognition were enhanced in PD patients with hallucinations. FDG PET findings further suggest that perceptual differences between PD patients might be linked to abnormal top-down perceptual modulation.<\/jats:p>","DOI":"10.3389\/fnins.2023.1256224","type":"journal-article","created":{"date-parts":[[2023,12,6]],"date-time":"2023-12-06T16:45:59Z","timestamp":1701881159000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":2,"title":["Using illusions to understand hallucinations: differences in perceptual performances on illusory figures may underscore specific visuoperceptual impairments in Parkinson\u2019s disease"],"prefix":"10.3389","volume":"17","author":[{"given":"Alberto","family":"Cucca","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Claudia Virginia","family":"Manara","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mauro","family":"Catalan","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Marco","family":"Liccari","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lucia","family":"Antonutti","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tiziana Maria Isabella","family":"Lombardo","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Valentina","family":"Cenacchi","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sophie","family":"Rangan","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Serena","family":"Mingolo","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Carmelo","family":"Crisafulli","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Franca","family":"Dore","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mauro","family":"Murgia","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tiziano","family":"Agostini","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Paolo","family":"Manganotti","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2023,12,6]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","first-page":"727","DOI":"10.1136\/jnnp.70.6.727","article-title":"Visual hallucinations in Parkinson\u2019s disease: a review and phenomenological survey","volume":"70","author":"Barnes","year":"2001","journal-title":"J. Neurol. Neurosurg. Psychiatry"},{"key":"ref2","doi-asserted-by":"publisher","first-page":"742","DOI":"10.1016\/j.parkreldis.2012.03.004","article-title":"Attention and visual dysfunction in Parkinson\u2019s disease","volume":"18","author":"Botha","year":"2012","journal-title":"Parkinsonism Relat. Disord."},{"key":"ref3","doi-asserted-by":"publisher","first-page":"S125","DOI":"10.1002\/ana.410320721","article-title":"Criteria for diagnosing Parkinson\u2019s disease","volume":"32","author":"Calne","year":"1992","journal-title":"Ann. Neurol."},{"key":"ref4","volume-title":"Seeing is deceiving: the psychology of visual illusions","author":"Coren","year":"1978"},{"key":"ref5","doi-asserted-by":"publisher","first-page":"129","DOI":"10.3758\/BF03199444","article-title":"An empirical taxonomy of visual illusions","volume":"20","author":"Coren","year":"1976","journal-title":"Percept. Psychophys."},{"key":"ref6","doi-asserted-by":"publisher","first-page":"148","DOI":"10.1016\/j.parkreldis.2021.01.013","article-title":"Art therapy for Parkinson\u2019s disease","volume":"84","author":"Cucca","year":"2021","journal-title":"Parkinsonism Relat. Disord."},{"key":"ref7","doi-asserted-by":"publisher","first-page":"331","DOI":"10.1038\/nrneurol.2009.62","article-title":"Hallucinations in Parkinson disease","volume":"5","author":"Diederich","year":"2009","journal-title":"Nat. Rev. Neurol."},{"key":"ref8","doi-asserted-by":"publisher","first-page":"3423","DOI":"10.1007\/s10072-021-05207-0","article-title":"ASL MRI and 18F-FDG-PET in autoimmune limbic encephalitis: clues from two paradigmatic cases","volume":"42","author":"Dinoto","year":"2021","journal-title":"Neurol. Sci."},{"key":"ref9","doi-asserted-by":"publisher","first-page":"24","DOI":"10.1016\/j.cortex.2016.05.005","article-title":"Learning to be inflexible: enhanced attentional biases in Parkinson\u2019s disease","volume":"82","author":"Fallon","year":"2016","journal-title":"Cortex"},{"key":"ref10","doi-asserted-by":"publisher","first-page":"733","DOI":"10.1093\/brain\/123.4.733","article-title":"Hallucinations in Parkinson\u2019s disease: prevalence, phenomenology and risk factors","volume":"123","author":"F\u00e9nelon","year":"2000","journal-title":"Brain"},{"key":"ref11","doi-asserted-by":"publisher","first-page":"605","DOI":"10.1016\/S0028-3932(98)00049-9","article-title":"Mechanisms underlying attentional set-shifting in Parkinsons disease","volume":"37","author":"Gauntlett-Gilbert","year":"1999","journal-title":"Neuropsychologia"},{"key":"ref12","doi-asserted-by":"publisher","first-page":"204166952093732","DOI":"10.1177\/2041669520937323","article-title":"Amodal completion revisited","volume":"11","author":"Gerbino","year":"2020","journal-title":"Iperception"},{"key":"ref13","doi-asserted-by":"publisher","first-page":"669","DOI":"10.1212\/WNL.45.4.669","article-title":"Mortality and hallucinations in nursing home patients with advanced Parkinson\u2019s disease","volume":"45","author":"Goetz","year":"1995","journal-title":"Neurology"},{"key":"ref14","doi-asserted-by":"publisher","first-page":"2129","DOI":"10.1002\/mds.22340","article-title":"Movement Disorder Society-sponsored revision of the unified Parkinson\u2019s disease rating scale (MDS-UPDRS): scale presentation and clinimetric testing results","volume":"23","author":"Goetz","year":"2008","journal-title":"Mov. Disord."},{"key":"ref15","doi-asserted-by":"publisher","first-page":"279","DOI":"10.1098\/rspb.1968.0071","article-title":"Perceptual illusions and brain models","volume":"171","author":"Gregory","year":"1968","journal-title":"Proc. R. Soc. Lond. B Biol. Sci."},{"key":"ref16","doi-asserted-by":"publisher","first-page":"837","DOI":"10.1002\/mds.23576","article-title":"Illusory misidentifications and cortical hypometabolism in Parkinson\u2019s disease","volume":"26","author":"Ishioka","year":"2011","journal-title":"Mov. Disord."},{"key":"ref17","first-page":"187","article-title":"Amodal completion and phenomenal shrinkage of surfaces in the visual field","volume":"2","author":"Kanizsa","year":"1975","journal-title":"Italian J. Psychol."},{"key":"ref18","doi-asserted-by":"publisher","first-page":"670","DOI":"10.1068\/p5747","article-title":"Area-specific attentional effect in the Delboeuf illusion","volume":"36","author":"Kawahara","year":"2007","journal-title":"Perception"},{"key":"ref19","doi-asserted-by":"publisher","first-page":"1053","DOI":"10.1080\/13803395.2012.716396","article-title":"Visuospatial transformation impairments in Parkinson\u2019s disease","volume":"34","author":"Kerai","year":"2012","journal-title":"J. Clin. Exp. Neuropsychol."},{"key":"ref20","doi-asserted-by":"publisher","first-page":"270","DOI":"10.1016\/j.parkreldis.2010.01.003","article-title":"Attentional and perceptual impairments in Parkinson\u2019s disease with visual hallucinations","volume":"16","author":"Koerts","year":"2010","journal-title":"Parkinsonism Relat. Disord."},{"key":"ref21","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1155\/2021\/2704755","article-title":"Pareidolia in Parkinson\u2019s disease and multiple system atrophy","volume":"2021","author":"Kurumada","year":"2021","journal-title":"Parkinsons Dis."},{"key":"ref22","doi-asserted-by":"publisher","first-page":"145","DOI":"10.1016\/j.bandc.2007.06.007","article-title":"Top-down predictions in the cognitive brain","volume":"65","author":"Kveraga","year":"2007","journal-title":"Brain Cogn."},{"key":"ref23","doi-asserted-by":"publisher","first-page":"36284","DOI":"10.1038\/srep36284","article-title":"Hallucinations and conscious access to visual inputs in Parkinson\u2019s disease","volume":"6","author":"Lefebvre","year":"2016","journal-title":"Sci. Rep."},{"key":"ref24","doi-asserted-by":"publisher","first-page":"683","DOI":"10.1016\/j.parkreldis.2015.04.005","article-title":"Structural and functional neuroimaging in patients with Parkinson\u2019s disease and visual hallucinations: a critical review","volume":"21","author":"Lenka","year":"2015","journal-title":"Parkinsonism Relat. Disord."},{"key":"ref25","doi-asserted-by":"publisher","first-page":"259","DOI":"10.1212\/WNL.0000000000007913","article-title":"Minor hallucinations in Parkinson disease: a subtle symptom with major clinical implications","volume":"93","author":"Lenka","year":"2019","journal-title":"Neurology"},{"key":"ref26","doi-asserted-by":"publisher","first-page":"397","DOI":"10.3233\/JPD-212838","article-title":"Structural and functional correlates of hallucinations and illusions in Parkinson\u2019s disease","volume":"12","author":"Marques","year":"2022","journal-title":"J. Parkinsons Dis."},{"key":"ref27","doi-asserted-by":"publisher","first-page":"e250","DOI":"10.1093\/brain\/awt124","article-title":"Ocular paradoxical movement and severity of Parkinson\u2019s disease","volume":"136","author":"Matsumoto","year":"2013","journal-title":"Brain J. Neurol."},{"key":"ref28","doi-asserted-by":"publisher","first-page":"58","DOI":"10.12688\/f1000research.2-58.v2","article-title":"The binding ring illusion: assimilation affects the perceived size of a circular array","volume":"2","author":"McCarthy","year":"2013","journal-title":"F1000Res"},{"key":"ref29","doi-asserted-by":"publisher","first-page":"161","DOI":"10.1016\/j.cortex.2021.11.001","article-title":"Cognitive and visual processing performance in Parkinson\u2019s disease patients with vs without visual hallucinations: a meta-analysis","volume":"146","author":"Montagnese","year":"2022","journal-title":"Cortex"},{"key":"ref30","doi-asserted-by":"publisher","first-page":"2091","DOI":"10.1212\/01.WNL.0000145764.70698.4E","article-title":"Visual perception in Parkinson disease dementia and dementia with Lewy bodies","volume":"63","author":"Mosimann","year":"2004","journal-title":"Neurology"},{"key":"ref31","doi-asserted-by":"publisher","first-page":"6898","DOI":"10.1523\/JNEUROSCI.1996-04.2004","article-title":"Setting boundaries: brain dynamics of modal and amodal illusory shape completion in humans","volume":"24","author":"Murray","year":"2004","journal-title":"J. Neurosci."},{"key":"ref32","doi-asserted-by":"publisher","first-page":"801","DOI":"10.1002\/mds.20129","article-title":"Visual hallucination in Parkinson\u2019s disease with FDG PET","volume":"19","author":"Nagano-Saito","year":"2004","journal-title":"Mov. Disord."},{"key":"ref33","doi-asserted-by":"publisher","first-page":"111","DOI":"10.1016\/j.parkreldis.2018.05.023","article-title":"Defining visual illusions in Parkinson\u2019s disease: kinetopsia and object misidentification illusions","volume":"55","author":"Nishio","year":"2018","journal-title":"Parkinsonism Relat. Disord."},{"key":"ref34","doi-asserted-by":"publisher","first-page":"21","DOI":"10.1186\/1471-2377-8-21","article-title":"A questionnaire-based (UM-PDHQ) study of hallucinations in Parkinson\u2019s disease","volume":"8","author":"Papapetropoulos","year":"2008","journal-title":"BMC Neurol."},{"key":"ref35","doi-asserted-by":"publisher","first-page":"395","DOI":"10.1037\/xan0000078","article-title":"Do you see what I see? A comparative investigation of the Delboeuf illusion in humans (Homo sapiens), rhesus monkeys (Macaca mulatta), and capuchin monkeys (Cebus apella)","volume":"41","author":"Parrish","year":"2015","journal-title":"J. Exp. Psychol. Anim. Learn. Cogn."},{"key":"ref36","doi-asserted-by":"publisher","first-page":"241","DOI":"10.1007\/BF02260863","article-title":"The development and validation of a short measure of functioning and well being for individuals with Parkinson\u2019s disease","volume":"4","author":"Peto","year":"1995","journal-title":"Qual. Life Res."},{"key":"ref37","doi-asserted-by":"publisher","first-page":"e110547","DOI":"10.1371\/journal.pone.0110547","article-title":"Neural substrates of cognitive subtypes in Parkinson\u2019s disease: a 3-year longitudinal study","volume":"9","author":"Shoji","year":"2014","journal-title":"PLoS One"},{"key":"ref38","doi-asserted-by":"publisher","first-page":"e23288391","DOI":"10.1101\/2023.04.11.23288391","article-title":"Abnormal higher-order network interactions in Parkinson\u2019s disease visual hallucinations","volume":"15","author":"Tan","year":"2023","journal-title":"PLoS One"},{"key":"ref39","doi-asserted-by":"publisher","first-page":"329","DOI":"10.1093\/braincomms\/fcac329","article-title":"Changes in both top-down and bottom-up effective connectivity drive visual hallucinations in Parkinson\u2019s disease","volume":"5","author":"Thomas","year":"2022","journal-title":"Brain Commun."},{"key":"ref40","doi-asserted-by":"publisher","first-page":"2649","DOI":"10.1002\/mds.23429","article-title":"Systematic review of levodopa dose equivalency reporting in Parkinson\u2019s disease","volume":"25","author":"Tomlinson","year":"2010","journal-title":"Mov. Disord."},{"key":"ref41","doi-asserted-by":"publisher","first-page":"269","DOI":"10.1002\/mdc3.13599","article-title":"Utility of the 20-item noise Pareidolia task (NPT-20) for assessing visuoperceptual disturbances associated with complex visual hallucinations in Parkinson\u2019s disease","volume":"10","author":"Turner","year":"2023","journal-title":"Mov. Disord. Clin. Pract."},{"key":"ref42","doi-asserted-by":"publisher","first-page":"273","DOI":"10.1006\/nimg.2001.0978","article-title":"Automated anatomical labeling of activations in SPM using a macroscopic anatomical parcellation of the MNI MRI single-subject brain","volume":"15","author":"Tzourio-Mazoyer","year":"2002","journal-title":"NeuroImage"},{"key":"ref43","doi-asserted-by":"publisher","first-page":"603","DOI":"10.1016\/j.parkreldis.2015.03.020","article-title":"Pareidolia in Parkinson\u2019s disease without dementia: a positron emission tomography study","volume":"21","author":"Uchiyama","year":"2015","journal-title":"Parkinsonism Relat. Disord."},{"key":"ref44","doi-asserted-by":"publisher","first-page":"20","DOI":"10.47795\/ONNS5189","article-title":"Hallucinations in Parkinson\u2019s disease: new insights into mechanisms and treatments","volume":"19","author":"Weil","year":"2020","journal-title":"Adv. Clin. Neurosci. Rehabil."},{"key":"ref45","doi-asserted-by":"publisher","first-page":"2827","DOI":"10.1093\/brain\/aww175","article-title":"Visual dysfunction in Parkinson\u2019s disease","volume":"139","author":"Weil","year":"2016","journal-title":"Brain"}],"container-title":["Frontiers in Neuroscience"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fnins.2023.1256224\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,12,6]],"date-time":"2023-12-06T16:46:02Z","timestamp":1701881162000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fnins.2023.1256224\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,12,6]]},"references-count":45,"alternative-id":["10.3389\/fnins.2023.1256224"],"URL":"https:\/\/doi.org\/10.3389\/fnins.2023.1256224","relation":{},"ISSN":["1662-453X"],"issn-type":[{"value":"1662-453X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,12,6]]},"article-number":"1256224"}}