In 4 rats, a guided cannula was implanted in the nRE along with pairs of recording electrodes in the PFC (one in each side), and the right dorsal (dHC) and ventral hippocampus (vHC) and stimulating electrodes in the RPO. After control recording, lidocaine (0.2 mg/microliter, volume of 1 microliter) was microinfused using a syringe pump at a rate of 347 nanoliters/min. Theta was elicited through RPO stimulation and electrophysiological recordings were performed as described.
