Fig. 9

Long-term potentiation in the insular cortex varies based on sex and subregion. A, B A schematic illustration indicates the aIC and pIC, both delineated by red dashed lines. Stimulation and recordings were applied and gathered respectively from layer V pyramidal neurons in each insular cortex. C, D An examination of the input–output (I/O) relationship showed a comparable synaptic strength in both the aIC and pIC of adult males (C). Conversely, female aIC exhibited a greater synaptic strength in comparison to pIC. E–G The field excitatory postsynaptic potential (fEPSP), shown as a percentage of the baseline, was observed before and after the application of high-frequency stimulation (HFS). The point in time at which HFS was applied is shown by the arrow. E When HFS protocol was administered to layer V pyramidal neurons in adult males, it led to long-term potentiation (LTP) in both the anterior and posterior insular cortices. F The fEPSP magnitude at baseline (from 10 to 0 min) and during LTP (from 20 to 30 min after induction), corresponding to the normalized values in 'C', demonstrated a notable difference in the 10-min baseline period and the final 10 min of recording in both male insular cortices. G In contrast, the same protocol, when applied in adult females, only induced a strong LTP in the aIC. H The fEPSP magnitude at baseline (from 10 to 0 min) and during LTP (from 20 to 30 min post-induction), corresponding to the normalized values in 'F', showed a significant difference in the 10-min baseline period and the final 10 min of recording, but only in the aIC of adult females. C-D-E-G Data are presented as mean ± SEM in XY plots and analyzed via Mann–Whitney U test (C, D). P-values < 0.05 are depicted in the graphs. F–H Data are shown as pre-post individual experiments and analyzed via Wilcoxon P test. P-values < 0.05 are depicted in the graphs. C–H The sample sizes for aIC and pIC male and female were 8 and 7, respectively