In vitro validation of stimulation parameters. The stimulation paradigm used for in vivo experiments was tested in slices of the AcbSh (A, B) and LH (C, D). A, EYFP+ neuron in an AcbSh slice recorded in current-clamp; current step delivery confirms neuron health and medium spiny neuron identity. B, Optogenetic stimulation of the neuron in A produces reliable action potential firing with the in vivo 10 s 20 Hz burst paradigm, repeated every 30 s for 10 min to confirm response stability. C, LH neuron recorded in a slice containing dense EYFP terminal labeling responds to current step delivery. D, Voltage-clamp recording of the neuron in C showing inward IPSCs in response to optogenetic AcbSh-LH terminal stimulation for 10 s at 20 Hz in the presence of kynurenic acid.