The structure of brains and the nature of intelligence may affect:
* How we think about the moral value of different animal species
* Our ability to create brain emulations of humans and other animals (which could lead to a lot of simulated suffering if we aren't careful)
* Our ability to create better drugs and other techniques to reduce suffering from issues like mental illness or cluster headaches
Posts with the intelligence and neuroscience tag might discuss these or many other issues.
See also Sentience & Consciousness.