Sleep dysfunction mediates the relationship between hemodynamic response height of the secondary somatosensory cortex and fear-somatic symptom severity bidirectionally in young adults

Sleep dysfunction exerts profound effects on cognition and emotion. Among neurophysiological indices, the hemodynamic response height (HRH), as derived from functional magnetic resonance imaging (fMRI), represents a key marker of neural activities. Here, we addressed the interplay amongst sleep quality, HRH, and negative emotional states in young adults.

We curated fMRI and clinical data of 735 young adults (373 women) from the Human Connectome Project. All participants were assessed for sleep quality with the Pittsburgh Sleep Quality Index (PSQI) and subjective emotional state with the NIH Toolbox of Negative Affect. Imaging data were processed with published routines and evaluated with a corrected threshold. In whole-brain regression we identified regional HRH correlates of PSQI score and, in mediation analysis, assessed the interrelationship amongst the regional HRH, PSQI, and clinical measures.

With age and sex as covariates, lower HRH in the secondary somatosensory cortex (SII) was associated with higher PSQI score across all subjects. No clusters were identified for hemodynamic time to peak or full width at half maximum at the same threshold. Both SII HRH and PSQI score were significantly correlated with fear-somatic symptom severity. Moreover, mediation analyses showed that PSQI score mediated the relationship between SII HRH and fear-somatic score bidirectionally.

Reduced hemodynamic responsiveness in the SII is associated with poorer sleep quality and heightened somatic fear symptoms. These findings suggest that sleep dysfunction mediates a bidirectional link between somatosensory activities and emotional dysregulation, highlighting a potential mechanism of affective dysfunction in link with sleep deficiency.