Distributed and Multifaceted Effects of Threat and Safety

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Psychology

Background:

• Anxious apprehension is a key feature of anxiety disorders.
• Brain regions like the anterior insula, amygdala, and bed nucleus of the stria terminalis are implicated in threat processing.
• Understanding the temporal dynamics of brain responses to threat is crucial.

Purpose of the Study:

• To investigate how the human brain processes anxious apprehension using fMRI.
• To test if the anterior insula shows sustained responses during threat periods.
• To compare transient and sustained threat responses in the amygdala and bed nucleus of the stria terminalis.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used in 109 participants.
• Participants underwent "threat" and "safe" trials with uncertain electrical stimulation.
• Bayesian multilevel analysis contrasted brain responses to threat versus safe trials in 85 regions.

Main Results:

• Anxious apprehension effects are distributed across numerous brain regions.
• Brain responses to threat exhibited varied temporal profiles, including sustained and transient patterns.
• Both signal increases and decreases were observed in response to threat cues.

Conclusions:

• Threat processing involves complex, distributed neural networks with dynamic temporal characteristics.
• The anterior insula, amygdala, and bed nucleus of the stria terminalis show diverse response patterns to threat.
• fMRI combined with Bayesian analysis provides insights into the neural basis of anxious apprehension.