LTP is normal in the presence of Arc antisense ODNs. A, The magnitude of LTP was not significantly different between slices incubated in aCSF containing an ODN against Arc (purple circles), a scrambled ODN (black circles), or normal aCSF (gray triangles) over the first 5 min poststimulation or the last 5 min poststimulation when LTP was induced using a theta-burst stimulation protocol (4 trains at 10 s intertrain intervals; each train consisted of 10 bursts at 5 Hz, with each burst containing 4 stimuli at 100 Hz). Data are represented as mean ± SEM. Scale bars: 5 mV (horizontal) and 5 ms (vertical). After a 10 min baseline recording, normal aCSF was switched to aCSF containing ODN for the duration of the recording, as indicated by the black bar above the graph. B, Arc protein expression increased after TBS in the slices that were incubated with the scrambled ODN (black circles) but not in those that were incubated with the Arc ODN (purple circles).