Electrophysiology of "yellow cells," neurosecretory neurones in Lymnaea.

The thirty Yellow Cells of Lymnaea show single, double and other extra spike modes of firing. Yellow Cell bursts consist of various combinations of single, doublet and triplet spikes whose number per burst varies spontaneously. Single spike firing modes of activity can be converted into doublets or bursts (and vice versa) by applying steady currents of the appropriate polarity. Spike activity is basically endogenous although it is modulated by low frequency synaptic input originating from within the brain. Interburst interval is affected by the number of spikes occurring in the preceding burst. This varies spontaneously or can be induced by applying appropriately timed current pulses or occurs following synaptic input. Excitatory synaptic input often induces bursts which far exceed the duration of the input and which are followed by long periods of inhibition.