Omega-6 fatty acids are also needed in feline cognition diets. The important omega-6 fatty acid that plays a role in brain support and cognition is arachidonic acid.[43] Arachidonic acid or AA is found in animal sources such as meat and eggs.[43] AA is required in cat diets, as felines convert insignificant amounts of it from linoleic acid due to the limited delta-6 desaturase.[44] Like DHA, arachidonic acid is often found in the brain tissues of cats and seems to have a supporting role in brain function.[43] In a 2000 study completed by Contreras et al., it was found that DHA and AA made up 20% of the fatty acids in the mammalian brain.[45] Arachidonic acid makes up high amounts in the membrane of most cells and has many pro-inflammatory actions.[44]