Qualitative analysis of intracellular characteristics of spontaneous neurons in the nucleus reticularis gigantocellularis of the cat

The intracellular characteristics of spontaneous neurons reticularis gigantocellularis (NRGC) of cats were evaluated. Apart from an irregular pattern of spontaneous discharge, we demonstrated that out of 895 successfully impaled NRGC neurons, 744 had a relatively low transmembrane potential of - 12 to - 40 mV. Many reticular neurons manifested spontaneous pre-potentials and post-spike depolarizations, from which action potentials were observed to arise. It is discussed that the spontaneous nature of NRGC neuronal discharge may be the result of continuous presynpatic bombardments because of the special anatomic and physiologic features of the reticular formation. Alternatively, the NRGC neurons may possess pacemaker-like membrane properties.