Fig. 2: Stimulation of the dorsal hippocampus-accumbens pathway induces lick-related mouth motion and deceleration.

a Injection schematic (top) and somatic expression of ChR2-EYFP in dorsal prosubiculum (bottom). 200 nl of AAV2-CaMKIIa-ChR2/EYFP were injected bilaterally. b Optic fiber placement (top) and axonal expression of ChR2-EYFP in the NAc, where light fibers are placed bilaterally (tracts indicated by white dotted lines; bottom). c Average motion energy in mouth region (magenta line) increases with licking. Golden line shows analog lick spout signal (top). Tracking of orofacial movements via infrared camera recordings. False-color coded motion energy (pixel-by-pixel intensity difference to previous image). Automatically segmented mouth region is indicated by a magenta line (bottom). d Representative examples of mouth motion around onset of optogenetic stimulation in an animal expressing ChR2 (top) or EYFP control (bottom). e Trial-averaged mouth motion activity around time of optogenetic stimulation in ChR2 (blue) and EYFP (gray)-expressing mice. f Mouth motion is significantly increased with optogenetic stimulation in ChR2 animals (t(3) = 7.485; P = 0.00494) but not EFYP animals (t(2) = 1.353; P = 0.309). Mixed ANOVA, main effect group F(1, 5) = 0.036, P = 0.856, main effect stimulation F(1, 5) = 42.47, P = 0.0013, interaction F(1, 5) = 14.72, P = 0.0122, followed by two-tailed post-hoc Bonferroni-corrected t-tests (n = 7 mice). g Trial-averaged relative velocity around time of optogenetic stimulation in ChR2 (blue) and EYFP (gray)-expressing mice. h Velocity is significantly decreased with optogenetic stimulation in ChR2 animals (t(3) = −3.551; P = 0.0381) but not EFYP animals t(2) = −1.263; P = 0.334. Mixed ANOVA, main effect group F(1, 5) = 0.112, P = 0.752, main effect stimulation F(1, 5) = 12.31, P = 0.017, interaction F(1, 5) = 2.80, P = 0.155, followed by two-tailed post-hoc Bonferroni-corrected t-tests (n = 7 mice). All data are presented as mean ± SEM. ns: not significant, *P < 0.05, **P < 0.01, circular data points refer to female mice, square data points to male mice. Source data are provided as a Source Data file.