Effect of SCI on Learning and Memory; Age, Gender and Species Differences?

Abstract

Spinal cord injury (SCI) results in damage to neurons that connect the brain to all areas of the body leading to disturbances in sensory and motor signals below the injury site. A few studies also show that neural changes occur above the site of injury and memory is affected. Preliminary data in our lab showed that the acquisition phase of learning was altered 2 weeks after injury in young male rats. This study hypothesized that older rats may not recover as quickly as young rats from SCI and therefore SCI may lead to more significant alterations in learning and memory. Older, female Sprague Dawley rats were anesthetized with ketamine and xylazine and a C2 hemisection (n=14) or a sham surgery (n=10) was performed. Rats were allowed to recover for 2 weeks before learning and memory was assessed with the Morris Water Maze. Rats completed 4 trials a day for 5 days followed by a probe trial. Results obtained were analyzed and compared to preliminary data that used young, male Long Evans rats. The results showed that SCI injured rats took longer to acquire new memories compared to sham controls, however this was only significant in young male Long Evans rats. The differences between the two groups of animals may be due to age, gender or species. Current studies are aimed at determining why SCI did not affect learning and memory in older, female Sprague Dawley rats.Support or Funding InformationThis work was funded by a Ferris Student Research Fellowship (RAK), the Dean's Student Research Grant (RAK), a Ferris Foundation Merit Award (MBZ) and a Ferris Faculty Grant (MBZ).