150 



DONALD M. MAYNARD 



Fig. 5. Intracellular recordings from anterior cardiac neurons {Paindints). 

 A. Follower discharge with spontaneity. Upper trace shows the simultaneously 

 recorded impulse discharge of the entire ganglion trunk. Calibrations for the 

 intracellular potential: 10 mV, time: 100 msec. (Courtesy, Hagiwara and 

 Bullock, J. Cell. Comp. Physiol. 50 : 28, 1957). b. Simple follower without 

 spontaneity, the upper and lower traces are from the same cell at different scales. 

 Calibration for upper trace: 10 mV, 500 msec. (Courtesy, Bullock and Terzuolo, /. 

 Physiol. {London) 138 : 341-364, 1957.) 



Table 1. Postsynaptic potentials in anterior cardiac ganglion neurons 



Presynaptic 



Postsynaptic potential 



Potentiates 

 spikes 



does not affect the spontaneous activity of the two smaller impulses. (3) If 

 a spontaneously active inhibitor is stimulated without cutting its central 

 connections, the higher stimulus frequency replaces the spontaneous fre- 

 quency of the inhibitor impulse in the ganglion and increased inhibition 

 occurs. When stimulation stops, a brief post-excitatory depression occurs 



