Figure 8.

Fast-spiking interneurons that evoked IPSPs in HVC_X neurons are PV+. A, Top, A single optical section of a confocal image of an intracellularly stained interneuron (green) with immunohistochemical staining for PV (red). Action potentials in this interneuron evoked IPSPs in an HVC_X cell (data not shown). In the bottom panel, only the red wavelength is shown, showing that the soma of the interneuron was PV+. B, An HVC_X neuron (green) that received inhibitory input from a fast-spiking interneuron; a PV+ cell body was closely apposed to the HVC_X neuron soma.