IL17A and Anxiety: For example, cytokines have a central physiological role in brain development, cognitive functions and behavioral regulation such as interleukin-1 beta in synapses formation and contextual learning, interleukin 4 in promoting neurogenesis and spatial learning or interleukin 17a (IL-17a) for synaptic plasticity and the regulation of anxiety (for a complete review see [14, 15]).