Ump3 micro 4

For drug infusions, stainless-steel injectors (33 gauge; Plastics One) were inserted into the bilaterally implanted guide cannulas and extended 1 mm beyond the tip of the cannulas. Injectors were connected to 10 μl Hamilton syringes (Hamilton Company, Reno, NV) which were mounted on microinfusion pumps (UMP3/Micro 4, World Precision Instruments, Sarasota, FL). Inactivation of the OFC was achieved by infusing a combination of GABA_B and GABA_A agonists baclofen and muscimol (B+M; 1.0 and 0.1 mM, respectively; Tocris Bioscience, Bristol, UK) in artificial cerebrospinal fluid (aCSF). Vehicle infusion was performed using aCSF. Infusions were delivered at a volume of 0.6 μl (lOFC) or 0.3 μl (mOFC) per hemisphere over 2 min. After infusion, injectors were left in place for 1 min to allow diffusion. This rate, volume and concentration of drug infusion have been shown to influence behavior when infused into the medial or lateral OFC (Fuchs et al., 2004 (link)). Animals received both B+M and aCSF on separate days, separated by intervening non-treatment days.

Under isoflurane anesthesia (1.5%−2.5%), rats in Experiments 1a and 2 received 0.6 μL AAV8-hSyn-hM4D(Gi)-mCherry (Addgene: Watertown, MA) delivered bilaterally to lateral and, to a lesser extent, ventral OFC (A/P 3.6 – 4.6, M/L 2.6 to 3.0, D/V −5.0 to −5.2 mm from bregma) using silica tubing connected to 10μl Hamilton syringes (Hamilton Company, Reno, NV) mounted on microinfusion pumps (UMP3/Micro 4, World Precision Instruments, Sarasota, FL). Extent of expression across rats is shown in Fig. 1D. Rats in Experiment 1b received 0.6 μL AAV8-hSyn-EGFP, (Addgene). Rats received antibiotic (0.1 ml cefazolin, 330 mg/ml, i.m.) and analgesic (meloxicam, 1 mg/kg, s.c.).