This last study performed histopathological analyses of CA3 pyramidal neurons observing neuronal loss, cellular disorganization, and shrinkage in nickel treated rats of both genders compared to their normal controls (Lamtai et al., 2020, El Brouzi et al., 2021) demonstrated that intracerebral injection of NiCl2 at the right hippocampus of the male Wistar rat causes anxiety and depression disorders and lead to cognitive impairment, and again the mechanism was the increase in LPO and NO levels accompanied by a significant decrease in SOD and CAT activities in the hippocampus. Here, CAT is linked to Cognitive impairment.