Four male Brown Norway-Fisher 344 hybrid rats (Harlan, IA, USA), aged 10–12 months at the start of behavioral training, were trained to run the Multiple-T task, as described previously (van der Meer and Redish, 2009). Rats were food deprived to no less than 85% of their free-feeding body weight during behavioral training; water was available ad libitum in the home cage at all times. Animals were housed individually and maintained on a 12-h light/dark cycle, with the lights on during the day, when training and recording sessions took place. All procedures were conducted in accordance with National Institutes of Health guidelines for animal care and approved by the Institutional Animal Care and Use Committee (IACUC) at the University of Minnesota. Care was taken to minimize the number of animals used in these experiments and to minimize suffering. The four animals included in this study were the same as those used in van der Meer and Redish (2009), except that one animal from that earlier study (R129) was excluded (before the start of analyses) owing to uncertain histological localization of recording sites; this can be more problematic for LFP recordings than for unit recording.
