Fig. 4.

Episodic activity. A,B, Ten minute traces from two neurons demonstrating that spontaneous bursts can occur in episodes of activity that are separated by minutes of silence. The neuron in B was more active (see histogram in Fig. 5B). A represents the region indicated by the bar in the histogram in Figure 5A, and B represents the region in Figure 5B. Both neurons were hyperpolarized to −75 mV by current injection. Note the long periods of inactivity, the multiple bursts, and the oscillations in membrane potential in bothtraces. The data shown in A was obtained from a P17 mouse (same neuron as in Fig.3B,C), whereas the data shown in B was obtained from a P21 mouse.