Surgical Window

After reaching the WLT training criterion, all rats underwent surgical implantation of electrode arrays. This was a 1-day surgery, involving stereotaxic craniotomies under isoflurane anesthesia, as previously described (Porter et al., 2019). Rats were given 10 days of post-operative recovery and then re-tested on the WLT using the last training parameter, i.e., 10 successful attempts each of 0 and 45 g in <5 min. Rats were now performing the WLT with a headplug connected to a headstage (Neuralynx HS-36-LED or HS-32-mux-LED), tethered to a commutator (3 m tether, Neuralynx Saturn-1). All rats achieved the WLT training criterion within 1–8 days of re-testing. All behavioral data reported here for the progressive weight (section “Progressive Weight Paradigm”) and fixed weight (section “Fixed Weight Paradigm”) paradigms were collected from tethered animals. Electrophysiological data are not analyzed in this manuscript; however, we mention this surgical window here to demonstrate that the WLT is conducive for use in surgically implanted, tethered animals. Example LFP traces from the anterior cingulate cortex (ACC) of a rat making 10 successful pulls on 135 g can be seen in Supplementary Figure 1.