Spikelets, small spike-like membrane potential deflections, are prominent in the activity of hippocampal pyramidal neurons in vivo . The origin of spikelets is still a source of much controversy. Somatically recorded spikelets were postulated to originate from: dendritic spikes, ectopic spikes or spikes in an electrically coupled neuron . In order to differentiate between the different proposed mechanisms we used a dual recording approach where we simultaneously recorded the intracellular activity of one CA1 pyramidal neuron and the extracellular activity in its vicinity, thus monitoring extracellularly both the activity of the intracellularly recorded cell as well as other units in its surrounding. We reasoned that observing a second extracellular unit whose firing correlates with spikelet occurrences would support the coupling mechanism over the other two mechanisms. This was indeed the case in 8 out of 9 recordings from cells that exhibited spikelet activity. The extracellular spikes of these secondary units preceded spikelets onsets. While the intracellular spikelet amplitude was voltage dependent, the simultaneously recorded extracellular unit remained unchanged. Spikelets often triggered action potentials in neurons resulting with a characteristic 1–2 ms delay between spikelet onset and firing. Here we show that this relationship is bi-directional, with spikes being triggered by and also triggering spikelets. Secondary units, coupled to pyramidal neurons, showed similar discharge patterns as the recorded pyramidal neuron. These findings suggest that spikelets reflect spikes in an electrically coupled neighboring neuron, most likely of pyramidal cell type. Such coupling might contribute to the synchronization of pyramidal neurons with millisecond precision.