Immunocytochemistry for neuronal (neurofilament) and glioma (nestin) markers, together with a presynaptic marker (synapsin 1) and GABRG2–GFP revealed colocalization of neuronal presynaptic puncta with glioma postsynaptic GABRG2–GFP puncta by confocal microscopy (Fig. 2b,c, Extended Data Fig. 4a and Supplementary Video 1). Here, SYN1 is linked to glioma.