Echoing another commenter, mouse studies don't necessarily replicate in humans. In fact, it turns out that the mouse => human replication rate is rather poor in many domains. (Turns out we are rather different in many ways!)

Additionally, most cognitive traits come with tradeoffs, so increasing ability in one area may decrease it in another. For instance, some nootropics (modafinil) temporarily improve cognitive performance on complex tasks, at the expense of speed. I don't remember the specifics, but I've also read about similar tradeoffs regarding memory, where boosts in short-term memory may reduce the ability to form new long-term memories. The brain is pretty well-optimized on average, when you consider the unique properties and limitations of its constituent parts/materials.