Furthermore, cholinergic neuronal activity influences DMG cells in the midbrain through BDNF-TrkB signaling, which is known to promote proliferation and malignant synaptic plasticity in gliomas.6,10 Explants of cholinergic midbrain nuclei containing cholinergic neuronal soma and dendrites exhibited activity-regulated BDNF release that promoted DMG proliferation. This evidence concerns the gene NTRK2 and central nervous system cancer.