The researchers wanted to see how propofol affects the memory of older rats with high cholesterol. They divided the rats into groups and gave them propofol or saline injections. After testing their memory, they found that propofol made it harder for the rats to learn and remember where things were. Rats with high cholesterol had even more trouble with memory when given propofol. This suggests that propofol can harm memory in older rats, especially if they have high cholesterol.