Characteristics of the tonic activity in different groups of neurons of the superior cervical ganglion in the rabbit

The patterns of tonic activity were studied by intracellular recording from neurons of rabbit superior cervical ganglion at rest and with stimulation of chemoreceptors. According to reflex changes in the activity pattern all neurons studied were classified into three groups by the functional value. Action potentials of the first and second types may be observed in the tonic activity of all groups, that suggests the presence of dominant and accessory inputs for neurons innervating various target organs. The analysis of changes in action potentials and EPSP frequencies of tonic activity for neurons of different groups makes it possible to suggest that preganglionic fibres converging on the neurons of these groups possess a similar type of tonic activity.