Figure 3.

Small volume muscimol microinjections (10–20 nL) locate the hotspot for anesthetic induction within the MPTA area. Symbols mark centers of the microinjections listed in Table 1, with the volume microinjected indicated for each symbol. Filled symbols indicate trials that yielded a significant bonus time; open symbols indicate bonus times that were not significant. Numbers above the coronal sections indicate the section's location caudal to bregma (in millimeters; outlines from Paxinos and Watson, 1998). Microinjections that fell on planes −7.0 to −8.0 are gathered on the most rostral section outline (−7.8 mm), those on planes −8.0 to −9.16 are gathered on the middle section (−8.8 mm), and those that fell on planes −9.3 to −10.8 are gathered on the caudal section (−9.8 mm). Many effective microinjections overlap, especially in the dark (red) clusters.