Electronic Thesis and Dissertation Repository


Master of Science




Dr. Klaus-Peter Ossenkopp


The present study examined the effects of neonatal (postnatal days 3 and 5) acute immune system activation with lipopolysaccharide (LPS) on adolescent and adult anxiety behaviours. The major findings suggest that neonatal LPS does not have general long-lasting effects on adolescent anxiety and locomotor behaviours. Rather, early endotoxin treatment has highly specific effects on certain anxiety behaviours that vary depending on the development period. Moreover, neonatal LPS does not seem to influence adult voluntary and non-voluntary locomotor activity or anhedonia, independent of, or in response to, an adult immune challenge. Finally, sex differences were observed in various responses in adulthood, independent of neonatal drug treatment. The findings of this study provide a better understanding of adolescent and adult behavioural outcomes in response to endotoxin, and suggest that early exposure to pathogens may not be a significant risk factor in the general development of later anxiety disorders.