Fig. 1: Paired targets generate facilitated responses.

a CSTMD1’s Receptive Field with schematic stimulus pictogram superimposed (not to scale). The receptive field was mapped with a single 2°x 2° target moving horizontally (left-to-right) at 80°/s. The receptive field consists of two distinct zones, the excitatory hemifield (contralateral to the recording site in the axon) and the inhibitory hemifield (ipsilateral to the recording site.) b Left; Stimulus pictograms of four trial conditions (T₁ Probe locations shown; the same trials were also run using a T₂ Probe, i.e. mirrored). Top to bottom: Probe Alone, a 200 ms target Probe is presented alone. Local Primer, a Probe is spatiotemporally preceded by a facilitatory Primer on a matched trajectory. Distant Primer, the same Probe is preceded by a Primer on an unmatched trajectory (12° horizontal offset). Paired Primers, the same Probe is preceded by both a Local and Distant primer simultaneously. Right; Example spike trains drawn from the same neuron. Light green box indicates the 200 ms Probe period. Dark green box indicates the 100 ms analysis window. c, d Results for the presentation of Short Primers lasting 400 ms. c Box-and-whisker plots with overlaid swarm plots showing Probe response to the varying conditions. Each dot represents an individual trial (389 total trials across 15 dragonflies). Spike rate was calculated from a 100 ms period 50 ms following the onset of the probe (b, dark green window). d Frequency polygons of the same data. Merged Model (purple, dashed) represents the combined Local (red) and Distant (blue) Primer distributions. The empirical Paired Primer distribution (purple, solid) more closely matches Local Primer condition than a combination of local and distant primers, indicating overall facilitation. e, f The experiment with Long Primers (800 ms) exhibits similar results (507 total trials across 15 dragonflies), presented as in c, d. Note Probe Alone data is repeated from c.