Fig. 6

Effect on ASR Habituation of Reduced Serotonin Content in DRN Serotonergic Neurons

(A-B) Representative images of labeling with serotonin antibody (red) in control larva (A) and in tg(Tph2:Gal4ff;UAS:DNGα_i,gap43-citrine) larva that co-expresses DN-Gα_i and citrine fluorescent protein (green) in DRN serotonergic neurons (B). Scale bars, 25 µm.

(C) DRN DNGα_i expressing larvae do not have significantly different numbers of serotonergic neurons in the DRN or hypothalamic serotonergic nuclei (n_DN-Gαi = 11, n_Control = 11, p > 0.9). Central mark of box plots is the median value, vertical edges are the 25^th and 75^th percentiles and whiskers are the extreme values of distribution of numbers of serotonergic neurons for each group.

(D) DRN neurons co-expressing DN-Gα_i and citrine fluorescent protein (green) have significantly lower mean serotonin content than neurons in the same DRN that do not express (n = 12 larvae, **p < 0.001).

(E) ASR probability under non-habituating conditions in DN-Gα_i expressing larvae compared to control sibling larvae (n_DN-Gαi = 171, n_Control = 156, z = 0.43, p > 0.06).

(F) DN-Gα_i larvae habituation index frequency distribution is shifted to higher values (more habituation) compared to control larvae (n_DN-Gαi = 122, n_Control = 116, z = 2.28, p = 0.011).

(G) Frequency distribution of total displacement during 10 min in DN-Gα_i larvae is shifted toward decreased displacement compared to control larvae (n_DN-Gαi = 146, n_Control = 106, z = 2.46, p = 0.014). Statistics: unpaired, two-tailed Student’s t test (C), paired, two-tailed Student’s t test (D), two-tailed Mann-Whitney test (E-G).