Twelve Long-Evans rats (male, 250–400 g, 3–5 months

old) were housed individually in transparent Plexiglass cages. Details of surgery and recovery procedures have been described earlier (Csicsvari et al., 1998). After postsurgical recovery, recording wires were lowered over the course of several days in steps of 50 μm until large units and ripple activity were isolated at appropriate depths. The goal was to record, simultaneously, from at least three sites in the dorsal/intermediate CA1 pyramidal layer selleck compound along the long axis, and from at least 1 site in the CA1 pyramidal layer in the ventral pole (except 2 rats, in which recordings were obtained only along the transverse axis). All experiments were carried out in accordance with protocols approved by the Institutional Animal Care and Use Committee, Rutgers University. For details, see Experimental Procedures. The animals

were handled and trained in two mazes (an open field and a zigzag maze) for at least 2 weeks before surgery (Royer et al., 2010). The animals were water-restricted for 24 hr before the tasks. The same behavioral procedures were used for training and testing. For details, see Experimental Procedures. Since the main goal of the present experiments was to establish theta phase relationships among signals recorded along the LA of the hippocampus, the physical distances between the recording sites rather than the stereotaxic coordinates of the electrodes were measured by taking into account the curvature of the hippocampus. In all figures, the distances of the electrodes are given from the Bortezomib chemical structure septal end of the hippocampus (e.g., Figure 2). For details, see Experimental

Procedures. Neurophysiological signals were amplified (1,000×), band pass filtered (1–9 kHz), acquired continuously at 32 kHz on a 128-channel DigiLynx System (24-bit resolution; NeuraLynx, MT) and stored for offline analysis. Raw data were preprocessed using custom-developed suite of programs Digestive enzyme (Csicsvari et al., 1998). Spectral analysis was performed on detected theta periods. Theta amplitude and phase differences were measured taking the most ventral channel as reference. All numbers in the format X ± Y stand for mean ± standard deviation, unless otherwise mentioned. For statistics, two-way ANOVA was used unless otherwise mentioned. For details, see Experimental Procedures. This work was supported by National Institute of Health Grants NS34994 and MH54671, James S. McDonnell Foundation, the Global Institute for Scientific Thinking (G.B.), Marie Curie Fellowship, and the Rosztoczy Foundation (A.B.). We thank J. Csicsvari and S. Montgomery for providing valuable data and M. Bellucio, K. Mizuseki, E. Pastalkova, A. Amir, and D. Sullivan for providing critical comments and insightful suggestions. “
“An overarching view of adaptive behavior is that humans and animals act to maximize reward and minimize punishment as a consequence of their choices.