Figure 1. Increased excitation during the embryonic critical period (CP) alters network stability and motoneuron network synchrony.

(A) Schematic demonstrating timeline for picrotoxin (PTX) exposure and assay of network function. PTX-induced increase in activity during development increases third-instar larval duration of recovery from induced seizure (B) but does not change crawling velocity (C). (D) ROIs captured GCaMP signal generated by forward waves passing through ipsilateral anterior corner cell (aCC) motoneuron axons in the L3 ventral nerve cord, abdominal segments (A6-4). Inset: expanded view of ROIs 4 and 5. (E) Representative traces recorded in three adjacent abdominal segments (A6-A4), during two forward waves. Colours represent different segments. Synchrony was measured as the time lag (s) of activity passing between adjacent segments (i.e. between peaks, dotted lines). (F) Embryonic exposure to PTX caused a significant increase in synchronicity across segments A6-A4 vs. EtOH controls.