Sex Differences in Behavioral Sensitivities After Traumatic Brain Injury

Area of Science:

• Neuroscience
• Behavioral Science
• Sex Differences Research

Background:

• Traumatic brain injury (TBI) is linked to psychiatric and neurological issues, with females reporting worse outcomes.
• Sex differences in TBI comorbidities like anxiety and PTSD are not fully understood.
• TBI may heighten susceptibility to anxiety or PTSD after stressors, with sex-specific impacts unexplored.

Purpose of the Study:

• Investigate sex differences in TBI's impact on fear learning and sensory sensitivity.
• Determine if TBI enhances fear conditioning and defensive behaviors in female and male rats.
• Explore TBI-induced sensory hypersensitivity across different modalities in both sexes.

Main Methods:

• Adult male and female rats underwent lateral fluid percussion injury (FPI) or sham surgery.
• Behavioral tests included auditory fear conditioning to white noise and contextual fear conditioning.
• Sensory sensitivity was assessed using responses to white noise, footshocks, and a light gradient open field test.

Main Results:

• FPI significantly increased defensive behaviors to white noise, particularly in females, indicating enhanced auditory sensitivity.
• TBI led to faster contextual fear learning in both sexes.
• FPI females exhibited photophobia, suggesting TBI-induced sensory hypersensitivity across modalities.

Conclusions:

• TBI enhances fear acquisition and defensive phenotypes following stressors in both sexes.
• Females with TBI display heightened sensitivity to sensory stimuli across multiple modalities.
• These sex-specific TBI effects may contribute to the higher prevalence of comorbid PTSD and anxiety in women.