Behavioral and neural correlates of memory suppression in subthreshold depression

Area of Science:

• Neuroscience
• Cognitive Psychology
• Psychiatry

Background:

• Healthy individuals can intentionally control memory, but mechanisms in subthreshold depression (SD) are unclear.
• Subthreshold depression is prevalent and linked to significant functional impairments.
• Understanding memory control deficits in SD is crucial for addressing its societal burden.

Purpose of the Study:

• To investigate the behavioral and neural mechanisms of memory suppression in individuals with subthreshold depression (SD).
• To compare memory control abilities and associated brain activity between SD participants and healthy controls (HC).

Main Methods:

• Utilized functional magnetic resonance imaging (fMRI) and generalized psychophysiological interaction (gPPI) analysis.
• Employed the think/no-think task to assess memory suppression.
• Compared brain activation and functional connectivity in SD and HC groups.

Main Results:

• SD participants demonstrated an inability to suppress negative memories.
• The SD group exhibited greater prefrontal gyrus activation during memory processing compared to HC.
• SD participants showed reduced functional coupling between the right hippocampus and dorsolateral prefrontal cortex during negative memory suppression.

Conclusions:

• Subthreshold depression is associated with impaired memory suppression, particularly for negative stimuli.
• Executive and prefrontal inhibitory dysfunction in SD leads to increased reliance on frontal control resources.
• Abnormal prefrontal-hippocampal inhibitory pathways contribute to the failure of negative memory control in SD.