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. 2020 Nov 20;9:e58544. doi: 10.7554/eLife.58544

Figure 3. Chemogenetic stimulation of indirect spiny projection neurons (iSPNs) in the posterior dorsomedial striatum (pDMS) leaves goal-directed learning intact.

(A) Schematic depicting the viral injections, retro-Cre was injected bilaterally into the globus pallidus (GPe) and DIO-hM3D or DIO-mCherry was injected bilaterally into the pDMS. (B) Confocal image (scale bar, 1000 µm) from one rat showing retro-Cre expression in the GPe (left) and a confocal image (scale bar, 100 µm) from one rat showing DIO-hM3D expression on pDMS iSPNs. (C) Summary of experimental groups; blue arrows represent direct pathway, red arrows represent indirect pathway, and thicker arrows indicate increased activity in stimulated pathway. (D) An example trace from one iSPN from injection of a depolarizing current step (at resting membrane potential) before and after bath application of clozapine-N-oxide (CNO). (E) Number of action potentials evoked from an identical size current step injection before and during CNO application in hM3D-expressing iSPNs. The chosen step size in each neuron was when current injection first elicited action potentials, before drug. Individual data points represent each recorded cell. (F) Mean (± SEM) lever presses per minute averaged across each day of instrumental training for each group. (G) Mean lever presses per minute on the devalued and valued lever for each rat in each group, averaged across 2 days of non-rewarded choice tests. For all data, bars represent group means. *p<0.05.

Figure 3.

Figure 3—figure supplement 1. Verification of the hM3D virus for the DREADDs stimulation experiment.

Figure 3—figure supplement 1.

(A) An example biocytin-labelled indirect spiny projection neuron expressing hM3D from recording (scale bar, 30 µm). (B) The extent of virus spread for DIO-mCherry (left) and DIO-hM3D (right), for all included animals, mapped at five different anteroposterior coordinates. (C) Schematic showing the extent of retro-Cre spread in the globus pallidus, imaged at the widest point of expression for all included animals. (D) Total number of mCherry positive cells/mm2 in the pDMS for each rat in each experimental group. Bars represent group means ± SEM.