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A functional cerebral response to frightening visual stimulation
G Wik1, M Fredrikson, K Ericson
1Department of Psychiatry and Psychology, Karolinska Institute and Hospital, Stockholm, Sweden.
Psychiatry Research
|April 1, 1993
Summary
The defense reaction involves anxiety and sympathetic nervous system activation. Brain imaging reveals altered regional cerebral blood flow (rCBF) in visual and emotional processing areas during threat perception in phobic individuals.
Area of Science:
- Neuroscience
- Psychology
- Medical Imaging
Background:
- The defense reaction is a primal survival mechanism involving anxiety and sympathetic nervous system arousal.
- Understanding the neural underpinnings of threat response is crucial for studying anxiety disorders.
Purpose of the Study:
- To investigate regional cerebral blood flow (rCBF) changes associated with the defense reaction.
- To examine the neural correlates of visually elicited threat perception in individuals with snake phobia.
Main Methods:
- Utilized positron emission tomography (PET) to measure rCBF in volunteers with snake phobia.
- Compared rCBF during phobogenic (snake images), aversive, and neutral visual stimulation.
Main Results:
- Increased rCBF was observed in the secondary visual cortex during phobic stimulation.
- Reduced rCBF was noted in the hippocampus, orbitofrontal, prefrontal, temporopolar, and posterior cingulate cortex.
- Aversive stimulation showed intermediate rCBF patterns compared to phobic and neutral stimuli.
Conclusions:
- The observed rCBF patterns provide a functional cerebral correlate for the visually elicited defense reaction.
- These findings highlight the role of specific brain regions in processing threat and associated emotions.