a, Left, time course of prolonged current block by 100 µM NASPM (red bar denotes duration of NASPM application; n = 8 cells, 5 mice). Data are mean ± s.e.m. Right, representative traces of evoked prolonged current (block) unaffected by NASPM (red). b, Quantification of data in a. Data are mean ± s.e.m; ns, not significant (two-tailed paired Student’s t-test). c, Alignment of phase-locked simultaneous recording of glioma prolonged potential with the field potential of firing neuronal population. d, Representative prolonged current traces with increasing stimulation intensity. Red denotes maximum intensity; blue and green denote intermediate intensities. Magnified view illustrates distinct spike-like waveforms consistent with responses to neuronal population firing. e, Relationship of extracellular field potential to magnitude of prolonged current (SU-DIPG-XIII-FL xenograft) illustrated by simultaneous field potential (fEPSP) and whole-cell glioma current-clamp recordings. f, Prolonged glioma potential amplitudes versus slope of fEPSPs elicited by electrical stimulation (10, 20, 30, 50, 70, 100 and 150 µA; R2 = 0.92; n = 14 cells or fields across 4 mice for each, except n = 11 cells or fields across 3 mice for 30 µA). g, Representative trace of potassium (K+)-induced prolonged current in SU-DIPG-XIII-FL xenografts (n = 9 cells, 2 mice). h, Effect of TBOA on prolonged current in glioma (SU-DIPG-XIII-FL) (n = 5 cells, 2 mice). (1) Representative trace of residual current left after application of d-AP5 and NBQX in prolonged response to stimulation. d-AP5 and NBQX are likely to reduce the prolonged current owing to the effect on CA1 pyramidal neurons, not through direct effect on the glioma cells themselves; (2) representative trace of residual current after trace 1 was then treated with glutamate transporter blocker 200 µM TBOA; (1 − 2) subtraction of trace 2 from trace 1 reveals a 2 pA current that can be accounted for by glutamate transporters. It should be noted that a small residual current remains. i, Synchronicity analysis of calcium peaks in glioma cells in Fig. 3 shown over the course of 10 min. Red lines indicate cells synchronized with one another at various time points during indicated period. j–o, Confocal micrographs of primary human glioma tissue samples illustrate density and length of nestin-immunopositive tumour microtubes. j–n, Primary human tissue samples of paediatric H3K27M+ DIPG, sampled at the time of autopsy. o, Analysis of primary tissue sample from an adult glioblastoma (SU-GBM092) illustrates the similarity of paediatric glioma to adult glioma. For all images, blue denotes DAPI; yellow denotes nestin; magenta denotes H3K27M (tumour-specific antigen). Scale bars, 20 µm (j–m, o), or 10 µm (n). Data independently replicated in three sections per sample.