Figure 5. CT synapses in assembloids undergo LTP.

(A) Left: Schematic of the recording configuration to induce CT LTP. Right: The long (×3) STDP-induction protocol and example response.

(B) Bar graph showing the average responses in 14 cells from 9 assembloids after CT LTP induction in aCSF. Shades of gray indicate different batches of assembloids; vertical lines denote separate assembloids.

(C) Time course demonstrating that ×3 STDP delivery (arrows) induces LTP in CT synapses (black, n = 14 cells/9 assembloids). MPEP (blue, n = 8 cells/6 assembloids), AP5 (green, n = 15 cells/7 assembloids), or iBAPTA (orange, n = 7 cells/3 assembloids) blocked LTP. Shaded area depicts the presence of bath-applied drugs. The first (1) and final (2) 5 min of the experiment are noted.

(D) Time course of Rs demonstrating that CT LTP is not due to changes in Rs.

(E) Bar graph of group data from (C). Differences from baseline were evaluated by one-sample t-test (μ = 100, ##p <0.01). Differences between treatments and aCSF were evaluated by one-way ANOVA, p = 0.0053. Dunnett’s test: **p <0.01.

(F) Example traces from the first (1) and final (2) 5 min of the experiment across conditions. Circles indicate electrical stimulation.

Scale bars for (A): 40 mV, 100 ms. Scale bars for (F): 50 pA, 200 ms. Data shown are mean ± SEM (C), (D) with individual data points overlaid in (E).

See Figure S7 for PPR analysis and analysis of organoid/assembloid age and CT LTP expression.