Deficiencies in traditional measures of in vitro hippocampal rhythms

An in vitro thick slice mouse hippocampus preparation exhibits spontaneous rhythmic local field potentials in the 3–4 Hz range due to synchronous discharges in the inhibitory interneuron population. Intracellular rhythms are recorded concurrently with field rhythms from this preparation in data sets of approximately 3 min durations. Cross-correlation, phase and frequency distribution are used to compare intracellular and field rhythms and generate groups of activity in the time–frequency domain. We find that patterns of activity present in time–frequency are obscured using other techniques and we characterize the activity that is omitted.