Fronto-cingulate effective connectivity in major depression: a study with fMRI and dynamic causal modeling

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Psychology

Background:

• Functional imaging studies suggest impaired error monitoring and executive control in the fronto-cingulate network in major depression.
• Univariate statistical analyses have limitations in assessing directed neuronal interactions within brain networks.

Purpose of the Study:

• To re-analyze fMRI data using dynamic causal modeling (DCM) to investigate directed neuronal interactions in the fronto-cingulate network.
• To compare functional connectivity differences in this network between drug-free patients with major depression and healthy controls during a cognitive task.

Main Methods:

• Utilized dynamic causal modeling (DCM) to analyze fMRI data from a Stroop Color-Word Test.
• Studied 16 drug-free patients with major depression and 16 healthy controls.
• Focused on the fronto-cingulate network, including the prefrontal cortex (PFC) and anterior cingulate cortex (ACC).

Main Results:

• A significant reciprocal interregional connectivity was found in the cognitive control network (PFC and ACC) in both groups.
• Patients with major depression exhibited significantly higher intrinsic connectivity from the dorsal to rostral ACC compared to controls.
• A task by group interaction indicated enhanced task-related input from the dorsal to rostral ACC in patients with depression.

Conclusions:

• The findings suggest altered intrinsic connectivity within the fronto-cingulate network in major depression, specifically increased dorsal to rostral ACC connectivity.
• Enhanced task-related input from dorsal to rostral ACC in depressed patients may relate to difficulties in down-regulating activation.
• The relationship between dorsal ACC control over DLPFC and interference scores is preserved in both depressed patients and controls.