Decreased functional connectivity between the dorsal anterior cingulate cortex and lingual gyrus in Alzheimer's disease patients with depression.

BACKGROUND: Depression is one of the most common psychiatric symptoms in Alzheimer's disease (AD), occurring in up to 40% of AD patients. It influences the cognitive function of patients and increases the burden on their caregivers. Currently, there are few effective medical treatments for reducing the symptoms of depression in AD patients. Understanding the underlying neurobiological mechanisms in AD patients with depression (D-AD) is crucial for developing effective interventions. The anterior cingulate cortex (ACC) is an important brain region involved in emotional and cognitive processing. Several functional magnetic resonance imaging studies have shown that patients with major depressive disorder have structural, functional, and metabolic abnormalities in the ACC.

METHODS: We investigated the resting-state functional connectivity (FC) of ACC subregions in 15 D-AD patients and 17 non-depressed AD (nD-AD) patients, by parcellating the ACC into the rostral and dorsal ACC (dACC).

RESULTS: Our results revealed that D-AD patients have decreased FC between the dACC and the right occipital lobe and right lingual gyrus, compared with nD-AD patients.

CONCLUSIONS: Decreased FC between the dACC and the right occipital lobe and right lingual gyrus may play an important role in the neuropathophysiology of depression in AD.