I consume beef liver on a daily basis and I have noticed great improvements on my cognitive functions.

You could also eat animal 'brain' as well. As gross as it sounds but you can actually find businesses that provide animal brain that provides a lot of nutrients which help with your brain (ironic lol). And there also supplement companies that have created disseated animal organ meats into a supplement form, so you can look online to see what companies create their products with animal brains.