Fear-learning is altered in a mouse neuropathic pain model

Area of Science:

• Neuroscience
• Pain Research
• Behavioral Science

Background:

• Chronic neuropathic pain involves abnormal pain signaling and disabling comorbidities like anxiety and depression.
• These comorbidities may stem from maladaptive learning, associating pain with environmental cues.
• The influence of neuropathic pain models on fear learning, pain, and anxiety, especially early on, is not well understood.

Purpose of the Study:

• To investigate the impact of fear conditioning on fear, anxiety-like behaviors, and allodynia in an early-stage mouse model of neuropathic pain.
• To examine how fear conditioning interacts with pain and anxiety in the chronic constriction injury (CCI) model.

Main Methods:

• Utilized the mouse sciatic nerve chronic constriction injury (CCI) model.
• Assessed fear conditioning using an audio-tone/footshock paradigm.
• Evaluated anxiety-like behaviors using the light-dark box and open field tests.
• Measured cold and mechanical allodynia.

Main Results:

• Mice with CCI and sham-operated mice showed similar fear acquisition but CCI mice exhibited enhanced fear responses to context and tone.
• Fear conditioning increased anxiety-like behavior in CCI mice, but not sham mice.
• CCI induced cold and mechanical allodynia, which were not affected by fear conditioning.

Conclusions:

• Neuropathic pain models enhance learned fear behaviors and anxiety responses early after nerve injury.
• Fear conditioning can trigger exaggerated fear and anxiety even in the early stages of neuropathic pain.
• This suggests fear conditioning induces maladaptive fear learning that exacerbates pain-related emotional comorbidities.