FS cells in tumour-bearing slices demonstrate decreased entrainment to RS cell firing after mTOR inhibition. (A) In treated tumour-bearing slices, 15% of sorted units were subclassified as FS cells versus 5% in untreated slices. (B) FS cells from treated slices fired at 0.70 ± 0.09 spikes/s, as opposed to 0.26 ± 0.03 spikes/s in untreated slices (untreated tumour: n = 44, treated tumour: n = 119, P < 0.01, Mann–Whitney U-test, two-tailed). (C) In comparison to those from untreated tumour-bearing slices, pairwise cross-correlograms from treated ones revealed decreased RS cell firing in temporal relationship to FS cell firing, suggesting greater FS cell activity between SLEs (untreated tumour: n = 92 pairs, treated tumour: n = 199 pairs, P < 0.01, Mann–Whitney U-test, two-tailed). (D) Similarly, spike-triggered averaging of the local GCaMP response to FS cell firing was decreased in treated tumour-bearing slices in the first (untreated tumour: n = 41, treated tumour: n = 117, P < 0.05, Mann–Whitney U-test, two-tailed) (i) and second (untreated tumour: n = 43, treated tumour: n = 118, P < 0.01, Mann–Whitney U-test, two-tailed) (ii) halves of the recording. There was no significant difference for spike-triggered averaging of the local GCaMP responses to RS cell firing.