Elucidation of neural mechanism for visual hallucinations of dementia with Lewy bodies with mathematical modelling

2016 Fiscal Year Final Research Report

• Project/Area Number: 26280093
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Soft computing
• Research Institution: Hokkaido University
• Principal Investigator: Tsuda Ichiro 北海道大学, 理学(系)研究科(研究院), 教授 (10207384)
• Co-Investigator(Kenkyū-buntansha): 合原 一幸 東京大学, 生産技術研究所, 教授 (40167218) ; 奈良 重俊 岡山大学, 自然科学研究科, 特命教授 (60231495)
• Research Collaborator: FUJII Hiroshi ; KATORI Yuichi ; COLLERTON Daniel
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 視覚性幻覚 / アセチルコリン / レビー小体型認知症 / 注意機構 / カオス的遍歴

Outline of Final Research Achievements

Elucidation of the neural mechanism for dementia with Lewy body (DLB) is an urgent issue in our society since the number of such patients is rapidly increasing. A typical characteristic of DLB is the appearance of complex visual hallucinations (CVH): Patients can see what are not there, and those hallucinations appear at only a partial location of a whole visual scene. In the present study, we investigated a neural mechanism of CVH that DLB patients can see, making a mathematical model of neural networks for CVH. Our neural network model yielded a hallucinatory behavior. Indeed, when we reduced drastically the number of local nicotinic receptors after a correct learning of each pair of index and object patterns, incorrect object patterns were locally produced for inputs of index patterns indicating correct contextual information. This computer experiment suggests that nicotinic receptors provide one of the neural mechanisms of CVH that DLB patients experience.

Free Research Field

複雑系科学、応用数学、脳神経科学