FIGURE 4.

Activation of 5-HT2A ⁺ neurons promotes protein feeding behaviors. (A) Amino acid (AA) deprivation activates 5-HT2A ⁺ neurons in the superior medial protocerebrum (SMP, top) relative to amino acid replete controls (bottom). Quantification of SMP intensity (n = 10 and 9, two-sided t-test p = 0.009). (B) Activation of 5-HT2A ⁺ neurons (red bar indicates red light activation period) promotes acute interaction with a protein solution. Inset: Quantification of total interactions during the light period (n = 15 and 22, one-sided t-test p = 0.008). (C) Activation of 5-HT2A ⁺ neurons (red bar indicates red light activation period) does not significantly alter interactions with a sucrose-only solution. Inset: Quantification of total interactions during the light period (n = 18 and 15, two-sided t-test p = 0.32). (D) Inhibition of 5-HT2A ⁺ neurons (green bar indicates green light inhibition period) does not alter interactions with a protein solution. Inset: Quantification of total interactions during the light period (n = 15 and 17, two-sided t-test p = 0.5). (E) Closed-loop activation (red bar indicates red light reinforcement period) of 5-HT2A ⁺ neurons modestly increases interactions with a denatonium solution compared to activation of Npf ⁺ neurons. Inset: Quantification of total interactions for closed-loop activation of Npf ⁺ neurons (n = 6, two-sided t-test p < 0.001) and 5-HT2A ⁺ neurons (n = 24, two-sided t-test p = 0.008). All experiments were conducted in females.