This study aimed to explore attention alteration in mild cognitive impairment (MCI) patients and their association with abnormalities of autonomic brain activity within the attention network to reveal the neuroimaging basis behind these changes.

A total of 25 MCI patients and 31 normal controls (NCs) were recruited for the study. The Test of Attention Performance (TAP) version 2.3 was used to evaluate alertness, selective attention, and divided attention in MCI patients and NCs. Subsequently, participants underwent resting-state magnetic resonance imaging (MRI) scans to compare whole-brain autonomic activity characteristics between groups using the amplitude of low-frequency fluctuation (ALFF). Data preprocessing and analysis were conducted using Data Processing & Analysis of Brain Imaging in MATLAB R2018b.

There were significant differences in omissions of intrinsic alertness, total omissions of divided attention, omissions and correct of visual divided attention between the two groups. Meanwhile, independent sample t-tests indicated that the MCI group exhibited higher z-scored ALFF (zALFF) in the left middle occipital gyrus, left superior frontal gyrus (orbital part), and right inferior frontal gyrus (orbital part) when compared with the NC group. The MCI group exhibited reduced zALFF in the left median cingulate and paracingulate gyrus, left precuneus, and right rolandic operculum. Notably, the decreased zALFF in the left precuneus showed a significant negative correlation with divided attention.

Our findings suggest that patients with MCI exhibit relatively normal performance in selective attention and phase alertness tasks, while they demonstrate a decline in capacity for divided attention and intrinsic alertness tasks. Divided attention in MCI patients may be associated with abnormalities in spontaneous neural activity in the left precuneus. This study provides new and complementary insights into the neural basis of divided attention in patients with MCI.