Figure 3

Neonatal immune activation directly affects neuronal function by reducing neurotransmitter function (including GABA in the hippocampus and glycine in the prefrontal cortex), decreasing the expression of presynaptic proteins in the hippocampus, inhibiting long-term potentiation, and producing a differential neuronal activation pattern during a learning task such as the novel object recognition task. Neonatal immune activation indirectly alters neuronal function by producing long-term changes in neuroimmune function that in turn negatively impact neuronal function. Decreased tonic inhibition of microglia via altered expression of neuronal inhibitory signals, including fractalkine (via its receptor CX3CR1) and CD200, also results in exaggerated cytokine responses, which impact neuronal function.