Performance more than working memory disrupted by acute systemic inflammation in rats in appetitive tasks

Evidence from molecular biology, epidemiology, behavioral pharmacology, and clinical science support the conclusion that brain inflammation contribute s to the pathogenesis of cognitive symptoms in Alzheimer's disease (AD) and other neuropsychological disorders. Three different tests were conducted t o determine whether the acute inflammatory response induced by systemic lip opolysaccharide (LPS) treatment is accompanied by a selective disruption of working memory functioning in rats. Doses of LPS sufficient to induce a th ermoregulatory response were administered intraperitoneally and their effec ts on behavioral measures of symbolic working memory, spatial learning, and spatial memory consolidation, were assessed. LPS-induced immune activation was found not to significantly affect memory processes in any of the behav ioral tests used. However, LPS-induced immune activation caused performance deficits consistent with a disruptive effect of LPS on motivation and arou sal. These results suggest that sickness behavior induced by immune stimula tion is not necessarily accompanied by selective impairment in memory proce sses. The importance of distinguishing cognitive disruption from performanc e impairment in interpreting me behavioral effects oi inflammatory mediator s is discussed (C) 2001 Elsevier Science inc. All rights reserved.