The relationship between tryptophan and brain structure in school refusal with central fatigue

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K14255
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 10040:Experimental psychology-related
• Research Institution: University of Fukui (2022); Kyoto University (2020-2021)
• Principal Investigator: Yamashita Masatoshi 福井大学, 子どものこころの発達研究センター, 特命助教 (50828928)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 中枢性疲労 / トリプトファン / 脳機能

Outline of Final Research Achievements

Previous studies on central fatigue have demonstrated that patients with chronic fatigue syndrome have smaller volumes of the frontal and parietal lobe compared with healthy controls. Although this suggests that the role of tryptophan and its neuroactive metabolites is associated with central fatigue and brain dysfunctions, evidence in children with school refusal is scare. To address these gaps, we compared urinary tryptophan levels and regional brain grey matter volume (GMV) between children with school refusal and healthy controls. Biochemical analyses revealed an increase in tryptophan in the urine of children with school refusal. Whole-brain structural analysis revealed smaller GMVs in several brain regions, such as the precuneus, in children with school refusal. Our preliminary findings suggest that peripheral tryptophan is associated with severe central fatigue in children with school refusal and may have a negative impact on the GMV of the precuneus.

Free Research Field

実験心理学

Academic Significance and Societal Importance of the Research Achievements

本研究の学術的特徴は、生化学と認知神経科学の方法論を用いて、不登校の中枢性疲労に関する分子神経機序を明らかにすることを目指している点である。このような従来にない独創的なアプローチにより、非侵襲性に優れた尿指標のトリプトファンが不登校の中枢性疲労の引き金となる可能性を見出し、さらに脳イメージングを組み合わせることで不登校の脳構造の特徴をも明らかにした。このことにより、不登校の根本的理解と疲労し易い病態生理の解明に近づき、教育指導に繋げるための基礎的・科学的知見を提供できると考えられる。