HRH3 and Cognitive impairment: Finally, H3R antagonists have also been found to attenuate amphetamine and N-methyl-D-aspartate receptor antagonist induced hyperlocomotion and stereotypy in several studies, suggesting potential for treating positive symptoms of the disorder as well as cognitive impairments (Clapham and Kilpatrick, 1994; Faucard et al., 2006; Morisset et al., 2002).