Fig. 4

Synapse changes with TFC in larval zebrafish. (A) Total number of synapses before (t₁) and after (t₂) TFC for individual fish (P > 0.05 for L, PL, US, NS, and CS; *P < 0.05 for NL, Wilcoxon test). (B) Dorsal view of all identified excitatory synapses in the left pallium (highlighted in inset) of a learner fish before (white) and after (magenta) TFC alignment of the two synapse images was accomplished by manually identifying and then computationally aligning the labeled nuclei (not shown in images). (C) Schematic of algorithm to identify synapses lost or gained following TFC. All synapses were grouped into pairs, one from before TFC and the second from after, such that the distance between the pair is minimized. Each synapse could only be part of a single pair. All pairs separated by a distance greater than or equal to 4 μm are considered different synapses (i.e., lost if from before TFC or gained if from after). (D) Dorsal view of lost (cyan) and gained (yellow) synapses following TFC from the learner fish shown in B reveals more lost synapses medially and more gained synapses laterally. (E–G) Synapse turnover in fish before and after TFC did not show significant variation between different categories of fish (P > 0.05, Kruskal–Wallis test) except for PL and NS (loss fraction and unchanged fraction, P < 0.05, Dunn’s multiple comparison test). (Scale bars, 20 μm.) n = 11 L, 6 PL, 11 NL, 11 US, 11 NS, and 11 CS fish. Data available at: https://doi.org/10.25551/1/1-1Z04 (59).