Figure 8.

Membrane properties of rhythmic neurons in the HF generator at E15. A, Left, Photograph of seven recorded neurons loaded with biocytin revealed with Extravidine-FITC (green) positioned in the region identified by its immunoreactivity for NK1R (red) and scheme of the recording montage. Right, Intracellular recording from a rhythmic neuron (top trace) recorded simultaneously with integrated population activity obtained with a suction electrode positioned at the surface in the ventrolateral region (bottom trace) at E15. The neuron discharged in phase with population activity but failed to generate a burst of action potentials during one population burst (^*), thus revealing underlying excitatory synaptic inputs. XII, Hypoglossal nucleus. B, The voltage-dependent bursting properties of a rhythmic neuron recorded simultaneously with the neighboring population activity was tested with current injection via the intracellular recording pipette. At -55 mV, the neuron fired in phase with the population activity, generated additional bursts of action potential (asterisks) at -48 mV in between population bursting activity, and discharged tonically at -42 mV. C₁, Graph representing the mean I-V curve obtained from 14 rhythmically active neurons recorded from 10 slices. C₂, Graph representing the mean I_h current amplitude versus voltage obtained from nine rhythmically active neurons from nine slices. Error bars represent SEM.