Sex Differences in Memory Performance after Traumatic Brain Injury in Rats

Area of Science:

• Neuroscience
• Neurotrauma
• Cognitive Science

Background:

• Traumatic brain injury (TBI) frequently causes persistent cognitive deficits.
• Clinical data suggest biological sex influences TBI outcomes.
• Preclinical TBI research predominantly uses male subjects, limiting understanding of sex-specific effects.

Purpose of the Study:

• To investigate sex-specific long-term memory outcomes following TBI in rats.
• To examine the influence of the estrous cycle on female TBI outcomes.
• To compare cognitive performance deficits between male and female rats post-TBI.

Main Methods:

• Moderate-to-severe fluid percussion injury was induced in male and female rats.
• Behavioral assessments included open field test, novel object location (NOL), novel object recognition (NOR), and Barnes maze (BM).
• Female estrous cycle phase was monitored during testing.

Main Results:

• Females exhibited higher locomotor activity than males, irrespective of injury.
• TBI impaired NOL and NOR performance, with females showing greater deficits in object recognition than males.
• Barnes maze revealed TBI-induced shifts to nonspatial strategies in both sexes, with males showing greater spatial navigation disruption.

Conclusions:

• Sex differences in cognitive outcomes after TBI are domain-specific.
• Female rats exhibit heightened vulnerability in novelty-driven memory tasks post-TBI.
• Incorporating sex as a biological variable in preclinical TBI models is crucial for understanding outcome variability.