Figure 1.

Experimental design of memory‐guided visual search task and signal processing. (a) An original and modified scene is presented in alternation, interleaved with a brief grey mask, requiring an effortful search to detect the changing target. A trial ends with a 0.8 s fixation on the target for which a fluid reward is delivered (HIT), or when the maximum trial time is reached (MISS). A “giveaway” then follows in which the two scenes are displayed without a mask, revealing the target location. A trial ends with a black screen inter‐trial‐interval (ITI) of 2–22 s before the next trial is presented. During daily recording sessions, scenes are presented in blocks of 30 and the task is bookended with two rest periods (quiescence; ≥10 min) where a black screen is presented and animals sleep. See Materials and Methods for more details. (b) The broadband LFP signal is bandpass filtered in the ripple band (100–250 Hz), z‐scored, rectified and then low pass filtered (1–40 Hz) to create the ripple envelope whose maximum value represents the ripple amplitude. The PRW envelope is a low pass filter (1–5 Hz) of the broadband signal and its peak represents the PRW amplitude