The balance between brain health and disease is often unpredictable and likely dependent on poorly understood vulnerability factors acquired particularly during early life 
. Changes in lifestyles and living conditions associated with globalization impose unprecedented new challenges for the etiology of neurological disorders. Dietary factors are surfacing as strong modulators of brain plasticity 
with the capacity to alter the course of brain disorders. We have embarked in studies to understand how dietary omega-3 fatty acid during brain maturation influences the capacity of the brain to cope with later challenges. Among the challenges, adoption of unhealthy dietary habits is becoming increasingly common in the modern society, and this transition may act as a vulnerability factor for neurological disorders.
In particular, post-traumatic stress disorder (PTSD) has emerged as a mysterious condition in which individuals exposed to trauma develop high levels of anxiety and inability to cope with routine living conditions 
. Among of the few clues, now we know that a large number of victims exposed to episodes of brain trauma develop PTSD, likely influenced by some pre-existing conditions. In the current study, we present evidence that switching from omega-3 fatty acids deficiency during brain formation to a diet high in calories in adult life weaken the substrates for brain plasticity and predispose the brain to elevated anxiety-like behavior.
The omega-3 fatty acid docosohexaenoic acid (DHA) is structured in neuronal plasma membranes and crucial for neuronal signaling. Diet is the only source of DHA for the brain and subnormal content of DHA has been associated with mood disorders in humans 
, i.e., increased risk of suicide in a population exposed to trauma 
. Dietary DHA has been shown to protect against cognitive impairment following brain trauma in rodents 
. Consumption of DHA is below recommended levels while the consumption of high fat and high sugar is on the raise in the western society 
, and this hardship has been attributed to increased incidence of psychiatric disorders 
. Therefore we embarked in studies to investigate how dietary DHA during brain formation could help resist the challenge imposed by transitioning to a western diet (WD) during adulthood and the outcome of brain trauma.
Given that TBI is a risk factor for PTSD, we sought to explore the effects of dietary switching on crucial mechanisms underlying the development of anxiety-like disorders in animals exposed to concussive injury. It has been previously shown that this type of concussive injury predispose to anxiety and fear with some similarities to a PTSD-like condition 
. Individuals affected with PTSD exhibit altered expression of molecules involved in immune activation 
while brain trauma alters release of cytokines such as interleukin-1β (IL-1β) and IL-10 
. Given that n-3 fatty acids have immunomodulatory capacity 
, we studied their effects on crucial parameters of peripheral and central immune function in our paradigm. We also assessed brain-derived neurotrophic factor (BDNF) based on its recognized role on anxiety and depression 
and the fact that it is reduced in the plasma of PTSD victims