Journal: eneuro

Article Title: A Selective Projection from the Subthalamic Nucleus to Parvalbumin-Expressing Interneurons of the Striatum

doi: 10.1523/eneuro.0417-21.2023

Figure Lengend Snippet: Figure 1. Subthalamic nucleus neurons can send axons to dorsal striatum. A, Strategy for selective anterograde tracing of glutama- tergic subthalamic nucleus (STN) neurons with green fluorescent protein (GFP). Inset, a viral vector expressing GFP in a Cre recom- binase-dependent manner (AAV2-CAG-FLEX-GFP) was unilaterally injected into the STN of adult VGluT2-Cre mice. Transduced anterogradely-labeled neurons were revealed with immunoreactivity for GFP (green). Main image, Coronal tissue section (D, dorsal; L, lateral) from a VGluT2-Cre mouse, showing a circumscribed group of transduced neurons in STN (boundaries marked by dashed lines). Immunoreactivity for the transcription factor FoxP2 (magenta) was used to facilitate delineation of STN and other brain re- gions. cp, cerebral peduncle; Ctx, cortex; fr, fascicularis retroflexus; Hc; hippocampus; Pf, parafascicular nucleus of the thalamus; Po, posterior thalamus; Str, striatum; VPL, ventral posterolateral nucleus; VPM, ventral posteromedial nucleus; ZI, zona incerta. B– D, Immunofluorescence signals for anterogradely-labeled neurons (AAV-GFP) and FoxP2 in coronal sections from the same mouse as shown in A. Note that AAV-GFP1 somata and dendrites were located in “rostral” (B), “central” (C), and “caudal” (D) parts of STN. A standard stereotaxic reference (approximate distance relative to Bregma) is given for each rostrocaudal level. E–H, Immunofluorescence signals for AAV-GFP1 axons in the dorsal striatum (boundaries marked by dashed lines) and other forebrain regions of the same mouse as that shown in A–D. Sections are ordered from most rostral (E) to most caudal (H). Note the relatively dense plexus of AAV-GFP1 axons within the external globus pallidus (GPe), which is well known to be a major target of STN neu- rons (H). ac, anterior commissure; NAc, nucleus accumbens. I, J, AAV-GFP1 axons exhibit boutons, both “en passant” and “aux terminaux,” in dorsal striatum. Immunoreactivity for NeuN (orange) was used to reveal the somata of striatal neurons. K, L, Higher- magnification confocal micrographs of boxed zones in J (with NeuN channel omitted). AAV-GFP1 axonal boutons (arrowheads) ex- pressed immunoreactivity for the vesicular glutamate transporter VGluT2 (cyan). Scale bars: A, 750 mm; B–D, 200 mm; E–H, 750 mm; I, 100 mm; J, 5 mm; K, L, 1 mm.

Article Snippet: To target glutamatergic neurons of the STN for anterograde labeling, we used a VGluT2-Cre mouse line (B6J.129S6 (FVB)-Slc17a6tm2(cre)Lowl/MwarJ; The Jackson Laboratory; RRID:IMSR_JAX:028863).

Techniques: Anterograde Tracing, Plasmid Preparation, Expressing, Injection, Labeling, Immunofluorescence