During in vitro ripples, intracellular spikelets correspond to extracellular population spikes, hence presumably correspond to coupling potentials; Draguhn et al. 1998, Nature.

CA1 pyramidal cells are dye-coupled through their axons by light microscopic criteria. Schmitz et al. 2001, Neuron.

Farid Hamzei-Sichani, 2006, unpublished data

Model: full network generates brief bursts of >100 Hz activity, every 30 ms (i.e. gamma period) Isolated axonal plexus generates continuous 100 Hz. Traub et al. 2003, PNAS.

Experiment (isolated CA1): full network generates bursts of >100 Hz activity at gamma frequency. Isolated stratum oriens (containing pyramidal axonal plexus) generates near-continuous ~150 Hz activity. Traub et al. 2003, PNAS