Figure 1.

Induction of Arc expression in hippocampal neurons by pharmacological network activation. Hippocampal neurons (DIV19-21) were treated with 4BF, which pharmacologically stimulates network activity and induces LTP of excitatory synapses. After 4 h of enhanced network activity, neurons were fixed and stained for Arc (red) and the neuronal marker Map2 (green). Under vehicle (DMSO) treatment, very little Arc staining could be detected (left panel, vehicle), whereas the increase in network activity induced strong nuclear Arc expression in approximately half of the neurons: 49 ± 8% (n = 3) (right panel, 4BF) White scale bar is 20 µm.