Linking gray matter structure to trust in mild cognitive impairment: a voxel-based morphometry study

Area of Science:

• Neuroscience
• Psychology
• Gerontology

Background:

• Older adults with mild cognitive impairment (MCI) often display reduced trust propensity (TP).
• This decline in TP is linked to heightened emotional responses to betrayal.
• The interplay between cognitive changes, emotional sensitivity, and brain structure in MCI regarding trust is not fully understood.

Purpose of the Study:

• To investigate the mediating role of affect in the decline of TP in MCI.
• To examine how structural brain alterations influence TP through affect in MCI.
• To compare trust-related cognitive and affective mechanisms between MCI patients and healthy controls.

Main Methods:

• Multiple mediation analyses were used to compare TP between MCI and normal healthy controls (NHCs).
• Whole-brain mediation analyses identified neural correlates of reduced TP.
• Moderated mediation analyses explored the influence of structural brain changes on TP via affect.

Main Results:

• Affect demonstrated a significant mediating effect on the difference in TP between MCI and NHCs.
• Atrophy in the thalamus and anterior insula (AI) correlated with diminished TP in the MCI group.
• Structural changes in the thalamus and AI influenced TP through affect specifically in MCI patients.

Conclusions:

• Reduced TP in older adults with MCI is primarily driven by increased sensitivity to betrayal.
• This heightened sensitivity is associated with structural alterations in the salience network (thalamus and AI).
• Cognitive domains like motivation, executive function, and social cognition play a lesser role in this trust deficit.