Figure 9.

The slow oscillation is a prominent feature of entorhinal activity during urethane anesthesia. A, Simultaneously recorded hippocampal (top), neocortical, and superficial entorhinal (supEC) field activity show that the SO is prominent in all three structures. Rectified sup EC multiunit activity (supEC MU; bottom) was rhythmic (A) and was modulated by the ongoing SO (95% confidence interval represented by gray lines) (C). Phase histogram (B) was constructed using rectified supEC MU trigger (threshold represented by gray line) against supEC field and demonstrates that EC units tend to discharge just before the negative phase of the hippocampal field oscillation rhythmically at ∼1 Hz (C). fiss, Fissure.