Hippocampal functional connectivity-based discrimination between bipolar and major depressive disorders

Area of Science:

• Neuroscience
• Psychiatry
• Medical Imaging

Background:

• Mood disorders like bipolar disorder (BD) and major depressive disorder (MDD) are frequently misdiagnosed.
• Abnormal hippocampal functional connectivity (FC) is implicated in both BD and MDD.
• Direct comparisons of hippocampal FC between BD and MDD are lacking.

Purpose of the Study:

• To investigate hippocampal resting-state FC (rsFC) to differentiate between BD and MDD.
• To identify distinct patterns of hippocampal rsFC in BD, MDD, and healthy controls (HCs).

Main Methods:

• Resting-state functional magnetic resonance imaging (fMRI) data acquired from 30 BD patients, 29 MDD patients, and 30 HCs.
• One-way ANOVA used to analyze differences in hippocampal FC across the three groups.
• Focus on resting-state functional connectivity (rsFC) of the hippocampus.

Main Results:

• Bipolar disorder patients showed increased FC between the hippocampus and the lingual gyrus and inferior frontal gyrus (IFG) compared to MDD patients.
• Both BD and MDD patients exhibited altered FC between the right anterior hippocampus and lingual gyrus, and the right posterior hippocampus and right IFG, compared to HCs.
• Distinct hippocampal FC patterns were observed in MDD patients compared to BD patients.

Conclusions:

• Hippocampal functional connectivity presents distinct patterns in bipolar disorder and major depressive disorder.
• These findings suggest that hippocampal rsFC can aid in distinguishing between BD and MDD.
• fMRI-based hippocampal connectivity analysis holds potential for improving differential diagnosis of mood disorders.