a, b, CX3CR1 deficiency leads to impairments in synaptic plasticity which are rescued through IL-1β antagonism. PTP was induced with HFS (1 s, 100 Hz bursts; arrow) after 1 min of baseline recording. LTP was induced with HFS (2 1 s, 100 Hz bursts separated by 20 s; arrow) after 20 min of baseline recording. Changes in fEPSP slope are expressed as a percentage of baseline. a, The IL-1β antagonist, IL-1ra (100 μg/ml), rescues the PTP deficit (red; n = 7) in hippocampi taken from CX3CR1−/− (black; n = 8) in area CA1 to levels seen in wild-type (white; n = 9). b, The LTP deficit seen in hippocampi taken from CX3CR1−/− (black; n = 10) mice is rescued with the IL-1β antagonist IL-1ra (100 μg/ml) (red; n = 11).