Microglial activation has been used as a marker for neuroinflammation in multiple irradiation scenarios [29], and has been shown to be associated with space radiation-induced cognitive impairments [14] CD68 expression, a marker of microglial activation, was increased in the DG region of the HPC of the neutron-irradiated brain (Figure 2A). This evidence concerns the gene CD68 and Cognitive impairment.