I will continue to validate the model by investigating the acoustic featuresmice use to discriminatephonemes, and compare these features to those used by humans
I think it's smart to keep your aims short and specific, and include any further experiments as brief 'future directions' at the bottom of the aim. Of course, the whole experiment includes these two 'future directions' but by doing this you can give your reviewer a sense of how you're thinking about the problem without spending the space actually describing all your experiments.