Figure 2—Idealized postsynaptic potentials
In addition to synaptically induced potentials, low-frequency, spontaneous potential fluctuations have been observed in many neurons [(2)], [(7)], [(9)], [(10)], [(11)]. These fluctuations, generally referred to as pacemaker potentials, are usually rhythmic and may be undulatory or more nearly saw-toothed in form. The depolarizing phase may be accompanied by a spike, a volley of spikes, or no spikes at all. Pacemaker frequencies have been noted from ten or more cycles per second down to one cycle every ten seconds or more. Some idealized pacemaker wave forms are shown in [Figure 3].
