Dorsal raphe nucleus and harm avoidance: A resting-state investigation

Area of Science:

• Neuroscience
• Psychiatry
• Behavioral Science

Background:

• Harm avoidance, a personality trait characterized by anxious and cautious behavior, is highly comorbid with anxiety.
• The dorsal raphe nucleus is implicated in both harm avoidance and anxiety, suggesting shared neural underpinnings.
• Previous research has not clarified the influence of dorsal raphe network activity on harm avoidance.

Purpose of the Study:

• To investigate the relationship between ongoing activity within dorsal raphe networks and the personality dimension of harm avoidance.
• To identify specific brain regions within the dorsal raphe network that correlate with harm avoidance.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to collect brain activity data from 62 healthy subjects.
• Independent component analysis (ICA) was applied to define the dorsal raphe network and identify regions correlated with harm avoidance.
• Subjects completed the Temperament and Character Inventory-Revised (TCI-R) questionnaire to assess personality traits, including harm avoidance.

Main Results:

• ICA revealed dorsal raphe network interactions with the amygdala, hippocampus, nucleus accumbens, and prefrontal, insular, and cingulate cortices.
• Resting-state signal intensity fluctuations in the bilateral basal amygdala, ventral hippocampus, insula, nucleus accumbens, and medial prefrontal cortex were significantly coupled to harm avoidance.
• While direct serotonergic output was not measured, signal changes in the dorsal raphe likely reflect synaptic activity.

Conclusions:

• Resting-state activity within dorsal raphe networks is significantly related to the personality trait of harm avoidance.
• The identified neural circuitry may play a role in the development of anxiety disorders due to its connection with harm avoidance and anxiety-like behaviors.