Distribution within Po of GABAergic axon terminals. a, b, Coronal sections of wild-type mice Po immunostained for GAD65/67. Dorsal is to the top and medial to the left. Note the uneven and relatively sparse neuropil labeling of Po, compared with that of the adjacent parafascicular (Pf) and VPM nuclei. c, d, Coronal sections of wild-type mice Po immunostained for vesicular GABA transporter (vGAT). High-magnification details (c1–c4) of the regions outlined by rectangles on the image in panel c are shown. Arrowheads indicate focal clusters of larger immunopositive puncta. PC: Paracentral nucleus; PF: Parafascicular nucleus. Bregma level in mm is indicated in the upper right corner. Scale bars: 250 µm (a–d) and 25 µm (c1–c4).