Figure 1.
Up states are network-driven events. A, B, Dual current clamp recordings from LIII medial entorhinal cortex cells (<200 μm apart; A) show simultaneous Up and Down state transitions reflected in a bimodal distribution of the membrane potential (time shown on logarithmic scale; B). Spikes are truncated at 0 mV. C, The Vm cross-correlation shows an average lag of 0.19 ± 0.07 s for five dual recordings. Average in black, colored traces from individual recordings. D, E, Pooled data from four dual recordings show that mean Up state transition delays (0.29 ± 0.09 s, D) are not significantly different from mean Down state transition delays (0.48 ± 0.16 s, E). However, comparison of the collated delay histograms shows a significantly tighter distribution of Up delays than Down delays (K–S test, p < 0.001). Top panel shows individual delays. Vertical bars indicate mean ± SEM. F, The return plot does not show any dependency between the durations of 30 consecutive Up and Down states. “S” and “E” indicate start and end of the recordings; LI, layer I; LIII, layer III.