Neurons of the central and basal part of the amygdala complex were recorded in conscious, freely moving cats. These neurons have various cardiac rhythmic discharge patterns (CRDPs) which are estimated by post-event-time histograms (PETH). When the firing level of the neurons changed, the CRDPs were modulated. These modulations became obvious, when 'partial' PETHs of the neuronal activity were constructed according to the discharge level of the neurons. With changes of the neuronal discharge level different types of CRDPs were observed, interlaced in time during recordings of the same neuron. In 'total' PETHs, taken from the continuous periods of neuronal activity, cardiac rhythm was hidden or often was not so clearly visible as in 'partial' PETHs, taken at different discharge levels. As in case of neurons of the nucleus tractus solitarii (NTS) and for brainstem reticular neurons, amygdala neurons exhibited modulations of CRDPs as their activity level changed. The results indicate that the processing of activity patterns in these neurons depends on their activity level and functional organization, which is essentially dependent on afferent signals and influences from central structures reaching these neurons.