REAGENT or RESOURCE	SOURCE	IDENTIFIER
Bacterial and virus strains
AAV9-Ef1a-DIO-hChR2(E123T/T159C)-EYFP (stored at −80°C)	Addgene	Cat# 35509, RRID: Addgene_35509
Chemicals, peptides, and recombinant proteins
Isoflurane (stored at 20°C–25°C)	Baxter	Cat# HDG9623
Omnifill C dental cement	Omnident	Cat# 85182
Phosphate-buffered saline (PBS; stored at 20°C–25°C)	Gibco	Cat# 20012027
Isotonic sodium chloride (0.9%; stored at 20°C–25°C)	B. Braun	Cat# 3570310
Mixture of 0.25% bupivacaine & 1% lidocaine (stored at 20°C–25°C)	University Medical Center Hamburg-Eppendorf	N/A
Hydrogen peroxide (3%; stored at 20°C–25°C)	Carl Roth	Cat# 1A8Y.1
Ethanol (stored at 20°C–25°C)	Carl Roth	Cat# K928.3
Paraformaldehyde (PFA, 4%; stored at 20°C–25°C)	Carl Roth	Cat# P087.1
DiI (1,1′-Dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate; stored at 4°C)	Molecular Probes	Cat# D282
Ketamine (stored at 20°C–25°C)	Richter Pharma AG	Ketamidor
Xylazine (stored at 20°C–25°C)	Bayer	Rompun
MetriZyme detergent (stored at 20°C–25°C)	Metrex	Cat# SKU 10-4000
Experimental models: Organisms/strains
Mouse: Tbet-cre (B6; CBA-Tg(Tbx21-cre) 1Dlc/J; male/female, postnatal day (P) 8–11)	Jackson Laboratory	RRID: IMSR_JAX: 024507
Mouse: Tbet-cre (B6; CBA-Tg(Tbx21-cre) 1Dlc/J; male, ≥2 months)	Jackson Laboratory	RRID: IMSR_JAX: 024507
Mouse: C57BL/6J (female, ≥2 months)	Jackson Laboratory	RRID: IMSR_JAX: 000664
Software and algorithms
Cheetah 6	NeuraLynx	http://neuralynx.com/
OMICRON Control Center	Omicron-Laserage	v3.6.10
Other
Sterican single-use hypodermic needle (27G)	B. Braun	N/A
Microdissection scissors	Fine Science Tools	Cat# 14084-08
Dumont forceps	Fine Science Tools	Cat# 11270-20
Hot bead sterilizer	Fine Science Tools	Cat# 18000-50
Microliter syringe (model 701 RN, 33G)	Hamilton	Cat# 65460-05
Infusion microinjector and pump controller (not substitutable)	World Precision Instruments	MICRO4
Animal anesthesia system (not substitutable)	Harvard Apparatus	Cat# 75-0235
Temperature controller (not substitutable)	FHC	Cat# 40-90-8D
Heating pad (not substitutable)	FHC	Cat# 40-90-2
Stereomicroscope	Olympus	SZX10
Cotton bud	DM	Cat# 724841
Round plastic bar (outer diameter: 2 mm)	aero-naut Modellbau	Cat# 772831
Silver wire (diameter: 200 μm; not substitutable)	Science Products	AG-8W
Stereotaxic apparatus	Stoelting	Cat# 51603
Diode laser (473 nm; not substitutable)	Omicron-Laserage	LuxX 473-100
Optic patch cable (not substitutable)	Thorlabs	Cat# FG050UGA
Optical power meter	Thorlabs	Cat# PM121D
Recording optrode (1 shank, 16 channels, 50 μm inter-site spacing)	NeuroNexus	A1x16-5mm-50-703-OA16LP
Recording electrode (1 shank, 16 channels, 100 μm inter-site spacing)	NeuroNexus	A1x16-5mm-100-703-A16
Multichannel extracellular amplifier	NeuraLynx	Digital Lynx SX
Arduino Uno SMD	Arduino	A000073