Figure 1.

The dendrites of GnRH neurons propagate fast spikes. A, Image of three GFP-GnRH neurons. Simultaneous loose-seal, on-cell recordings were performed from the soma and dendrite of the middle neuron as indicated. Blue, Somatic recording; red, dendritic recording. B, The top panel shows a burst of five spikes recorded simultaneously at the somatic and dendritic on-cell recording sites from the neuron shown in A. The bottom panel in B shows the first spike of the burst at a much higher time resolution. All spikes recorded in this neuron were seen at the somatic recording electrode before the dendritic recording electrode. C, Dual on-cell recordings from a different GnRH neuron. This cell showed a spontaneous bursting pattern of action potential firing. In addition, all spikes were observed at the dendritic recording electrode before the somatic electrode. D, The latency between spikes recorded at the somatic and dendritic locations is plotted against the site of the dendritic recording electrode for all spontaneously active neurons (n = 39 cells). Negative latencies indicate that spikes were recorded at the dendritic electrode before the somatic electrode.