Cover picture: Wavelet spectrogram of hippocampal EEG during memory testing in a watermaze. A rat is searching for a hidden platform at a remembered location. Time is displayed on the horizontal axis (0-60 sec), frequency is displayed on the vertical axis (0-25 Hz), and wavelet power is indicated by color. Warm colors correspond to high power. The diagram shows that hippocampal EEG is strongly dominated by activity in the theta frequency band (6-10 Hz) throughout the session. For details, see the article by Hollup et al. in this issue (pages 1635-1644).