Although many studies suggest that cytokines may influence synaptic plasticity and affect neurotransmitter metabolism in the CNS, especially serotonin levels and dopamine in the striatum (McAfoose & Baune, 2009; Miller, Maletic, & Raison, 2009), the mechanisms by which CD226 deficiency affects cognitive performance and anxiety are still unclear and need further investigation. This evidence concerns the gene CD226 and Anxiety.