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Figure 1 | BMC Neuroscience

Figure 1

From: Role of serotonergic neurons in the Drosophila larval response to light

Figure 1

Representative locomotor patterns during the ON/OFF assay of 3rd instar Ddc:TNT larvae. Centroid tracks (A-D) and perimeter stacks (1–3) were generated using DIAS. A, C, UAS-TNT-G/+;Ddc-GAL4/+ (Ddc:TNT-G) larvae. B, D, UAS-TNT-VIF/+;Ddc-GAL4/+ (Ddc:TNT-VIF, control) larvae. In each case, panel 1 represents 5 seconds (s) prior the beginning of the assay and the first 15 s of the assay, panel 2 depicts the following 20 s and panel 3 represents the last 25 s of the assay. Behavior recorded during the light (ON) pulses is shown as empty larval outlines, whereas behavior in the dark (OFF) pulses is shown as shaded larval outlines. Analysis of centroid paths of early 3rd foraging (65–68 h AH) larvae reveals a higher degree of centroid clustering and of irregular centroid arrangement in Ddc:TNT-G larvae (A) compared with those in Ddc:TNT-VIF larvae (B), particularly during the light (ON) pulses. This suggests that, in the presence of light, Ddc:TNT-G larval locomotion is characterized by longer and/or more frequent pausing and change of direction and less linear movement. Inspection of corresponding perimeter stacks further supports these observations. During the light (ON) pulses, foraging Ddc:TNT-G larvae exhibited increased head swinging behavior and change of direction when compared with Ddc:TNT-VIF larvae (compare 1a-3a with 1b-3b). Although not as pronounced, similar behaviors were observed in Ddc:TNT-G larvae during early 3rd instar wandering stage (91–94 h AH) (C), indicating that these larvae still respond to light (1c-3c). In contrast, early wandering Ddc:TNT-VIF larvae (D) mostly maintained linear movement and rarely head swung or changed direction over the course of the assay (1d-3d).

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