AbstractThe present study was designed to investigate the features of rhythmic slow‐wave potentials in the superior colliculi of rats and to study the relationship between these potentials and the activity of single collicular neurons. In contrast to studies in other portions of the visual system, rhythmic slow‐wave potentials in the colliculi fell within a single limited range of frequencies from 9 to 26 cycle/sec. Single‐cell recordings revealed that numerous collicular neurons were also responding rhythmically, with discharge frequencies generally coinciding with those established for collicular slow‐wave potentials. In some animals slow‐wave and single‐cell potentials were recorded simultaneously through adjacent electrodes, and in all instances the frequency of discharge of single neurons coincided with the frequency of oscillation of the slow‐wave potentials. These data suggest the rhythmic postsynaptic potentials in individual collicular neurons may be the mechanism by which rhythmic slow‐wave potentials are generated.