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. 2014 Aug 4;24(15):1723–1730. doi: 10.1016/j.cub.2014.05.078

Figure 4.

Figure 4

DEET:Sucrose Learning Forms Parallel Competing Appetitive and Aversive Memories

(A) Learning with DEET in 1 M sucrose depends on concentration. Wild-type flies starved overnight were trained with 0% to 0.6% DEET in 1 M sucrose. Increase of DEET concentration impaired appetitive memory performance and formed robust aversive performance when presented as 0.6%. Performance with 0.6% DEET is significantly different from that of all other groups (all p < 0.0001, ANOVA, n ≥ 10).

(B) Aversive DEET memory is longer lasting in TbhM18 mutant flies trained with 1 M sucrose plus 0.6% DEET. Wild-type flies exhibit robust aversive memory immediately after training, but the performance converts to stable and long-lasting conditioned approach 30 min later. In contrast, TbhM18 mutant flies show significant aversive memory 30 and 60 min after training, compared to that of the wild-type flies (both p < 0.005, t test). Memory performance of the TbhM18 mutant flies also converts to conditioned approach by 24 hr and was not significantly different from that of wild-type flies (p > 0.1, t test). All n ≥ 10.

(C) TbhM18 mutant flies lack short-term sweet-taste sucrose-reinforced memory but form long-term nutrition-dependent memory. Wild-type and TbhM18 mutant flies were starved overnight and trained with 1 M sucrose in 1% agar. TbhM18 flies showed significantly defective immediate memory performance (p < 0.005, t test) but were indistinguishable from wild-type flies 0.5, 1, 3, and 24 hr after training (all p > 0.1, t test). All n ≥ 8.

(D) Training paradigm for testing the role of MP1 and PAM dopaminergic neurons in DEET learning. The mushroom body lobe innervation of each type of dopaminergic neuron is illustrated.

(E) Blockade of rewarding PAM dopaminergic neurons enhanced aversive memory performance after learning with 1 M sucrose plus 0.3% DEET. Performance of 0104-GAL4 UAS-shits1 flies was significantly different from that of both control groups (p < 0.005, ANOVA, n ≥ 15).

(F) Blockade of the negatively reinforcing MP1 neurons enhanced appetitive memory performance after learning with 1 M sucrose plus 0.3% DEET. Performance of c061; MBGAL80; UAS-shits1 flies was significantly different from that of both control groups (p < 0.005, ANOVA, n ≥ 19).

Data are shown as mean ± SEM.