Key resources table.

Reagent type (species) or resource	Designation	Source or reference	Identifiers	Additional information
Genetic reagent (Mus musculus)	Slc6a3tm1(cre)Xz/J	Provided by the Xiaoxi Zhuang lab (The University of Chicago), PMID:15763133	RRID:IMSR_JAX:020080	Also available at Jackson Laboratories: https://www.jax.org/strain/020080
Chemical compound, drug	3,3’-Diaminobenzidine	Sigma-Aldrich	D12384	50 mg/ml
Chemical compound, drug	Sodium cacodylate buffer, pH 7.4	Electron Microscopy Sciences	11653	0.2 M stock, use at 0.1 M
Chemical compound, drug	Sodium hydrosulfite	Sigma-Aldrich	157953	0.8% (w/v)
Chemical compound, drug	Sodium bicarbonate	Sigma-Aldrich	S5761	0.1 M stock, used at 60% (v/v)
Chemical compound, drug	Sodium carbonate	Sigma-Aldrich	S7795	0.1 M stock, used at 40% (v/v)
Chemical compound, drug	Osimum tetroxide	Electron Microscopy Sciences	19150	4% aqueous stock solution, use at 2%
Chemical compound, drug	Paraformaldehyde	Electron Microscopy Sciences	15710	16% aqueous stock solution, use at 2%
Chemical compound, drug	Glutaraldehyde	Electron Microscopy Sciences	16220	25% aqueous stock solution, use at 2.5%
Chemical compound, drug	Postassium ferrocyanide	Sigma-Aldrich	P3289	2.5%
Chemical compound, drug	Pyrogallol	Sigma-Aldrich	P0381	4%
Chemical compound, drug	Uranyl acetate	Electron Microscopy Sciences	22400–4	4% aqueous stock solution, use at 1%
Chemical compound, drug	Lead (II) nitrate	Sigma-Aldrich	228621	0.66%
Chemical compound, drug	Embed 812 kit	Electron Microscopy Sciences	14120	49% Embed 812, 28% DDSA, 21% NMA, and 2.0% DMP 30
Chemical compound, drug	Cocaine	Obtained through DEA license (Xiaoxi Zhuang, The University of Chicago)		10 mg/kg