Figure 5.

Glutamate-evoked responses in human SP neurons. A, SP neuron fires a burst of action potentials upon a single glutamatergic pulse (duration 5 ms, intensity = 4 μA) delivered 150 μm away from the cell body. Glut. indicates the timing of the glutamate pulse. Two experimental trials (identical stimulation) are superimposed. B, Subthreshold membrane potential transients in human SP neuron (21 gw) induced by three successive glutamate pulses (frequency = 1 Hz; glutamate pulse duration = 5 ms; intensity = 1.1 μA), repeated five times. All five recordings are superimposed. Inset, In the same cell, a somatic current injection reveals repetitive AP firing—a hallmark of the human SP neuron physiology. C, A single glutamatergic pulse (duration 5 ms, intensity = 3 μA) triggers a sustained depolarization of the SP neuron. Two experimental trials, same stimulation, are shown. Inset, Repetitive AP firing in the same cell.