Rough 68% of Americans are deficient in omega-3 fatty acids, despite it having an enormous amount of benefits.  In order to do omega-3 fatty acids justice, we have dubbed it the CEO of brain-supporting nutrients. It has such versatility and functionality within the human brain. For starters, omega-3s are a primary structural component of the organ itself, representing 8% of its total weight, and the majority of the weight of substructures like neuronal plasma membranes. Additionally, greater consumption of these acids has been found to correlate with higher gray matter volume in critical components of the brain - especially in its memory center, the hippocampus.   The core diver of this correlation is omega-3’s apparent capacity to induce the creation of brain-derived neurotrophic factor (BDNF), a protein that supports new neuron formation
One of the most beneficial aspects of omega-3 fatty acids that have been realized through studies is their ability to counteract inflammation and free radicals that contribute to a whole host of maladies from brain fog to literal damage. The aspect of omega-3s that gives it the ability to do this is its signaling capabilities to the body to mass-produce the antioxidant protein Nrf2 and “mediator” molecules that prevent, halt, and resolve inflammation.     The impact of these biological mechanisms has been shown to be substantial across structural and emotional cognitive outcomes. For instance, studies have found that consumers of omega-3s are less likely to be anxious or depressed.  Additionally, a 2007 study tracked over 8,000 healthy older adults and found that those who regularly ingested omega-3-rich oils were 60% less likely to develop dementia than others. 
Furthermore, the consumption of omega-3 fatty acids has a strong correlation with neuronal plasticity, memory retention, and capacity to learn. Studies that took a look at 4-10 year-olds, found that omega-3 intake was associated with improved reading ability, listening comprehension and vocabulary acquisition, and activation of the prefrontal cortex.    Moreover, Two 2012 studies found that the working memories of both younger (aged 18-25) and older (aged 51-72) adults improved when omega-3 pills were taken for extended periods of time.   Lastly, across animal studies where brain injury occurred, omega-3’s corresponded with greater plasticity through reductions in oxidative damage, learning impairment, and cellular homeostasis disruptions.   
In essence, omega-3 fatty acids can do a good bit of everything.