Figure 4. Early-life bacterial infection leads to LPS-induced memory impairment in adult males but not females.
Male and female rat pups injected with PBS or E. coli on postnatal day 4 were tested for memory as adults using a contextual fear-conditioning paradigm. Half of the rats in each neonatal group were injected with LPS immediately after learning. (A) Freezing to the context 48 h later was significantly reduced in adult males injected with LPS after learning, but only if they had also received E. coli as neonates (from Bilbo et al., 2006; *p<0.05). (B) In contrast to males, LPS had no effect on memory in females from either neonatal treatment.