Habenula as a neural mediator of inattentive traits and sustained attention variability: A 7-Tesla magnetic resonance imaging study.
Authors
Affiliations (4)
Affiliations (4)
- Department of Psychiatry, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
- Human Brain Research Center, Kyoto University Graduate School of Medicine, Kyoto, Japan. Electronic address: [email protected].
- School of Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan; Organization for Promotion of Neurodevelopmental Disorder Research, Kyoto, Japan; Department of Developmental Disorders, National Institute of Mental Health, National Center of Neurology and Psychiatry, Tokyo, Japan.
- Department of Psychiatry, Graduate School of Medicine, Kyoto University, Kyoto, Japan; RIKEN Center for Advanced Intelligence Project Decentralized Big Data Team, Tokyo, Japan; The General Research Division, Osaka University Research Center on Ethical, Legal and Social Issues, Osaka, Japan. Electronic address: [email protected].
Abstract
Sustained attention requires continuous engagement and is sensitive to individual differences in motivational processes. Variability in sustained attention is commonly observed across individuals and can manifest as fluctuations in attentional stability during prolonged tasks. Such variability may reflect inattentive traits associated with attention-deficit/hyperactivity disorder (ADHD), which are continuously distributed across the general population. The habenula is a subcortical structure involved in motivation- and reward-related regulation, yet its contribution to individual differences in sustained attention remains unclear. This study examined whether habenular morphology is associated with dimensional ADHD-related inattentive traits and reaction-time variability during sustained attention. In 151 healthy adults (excluding high ADHD symptoms), we assessed self-reported ADHD symptoms and autistic traits, and measured sustained attention using a computerized visual processing task. Habenula volumes were quantified using 7-Tesla MRI with a deep-learning-based segmentation pipeline. Mediation analyses tested whether self-reported inattention and RVP SD latency were statistically linked via TIV-normalized relative habenula volume, controlling for age, sex, education, and autistic traits. Inattention scores were positively associated with relative habenula volume, whereas hyperactivity-impulsivity showed no such relationship. Larger relative habenula volume was associated with greater reaction-time variability (standard deviation [SD] latency). AQ total score was not significantly associated with relative total habenula volume or RVP SD latency. Mediation analysis identified a significant indirect statistical association linking inattention and SD latency via relative total habenula volume (ACME = 0.044, p = 0.032), independent of autistic traits, even in the absence of a significant total effect. Larger relative total habenula volume was associated with an indirect statistical link between self-reported inattention and reaction-time variability during sustained attention.