BDNF and optic pathway glioma: Additional evidence of BDNF and NLGN3 involvement in glioma is reflected in the discovery that photic stimulation can modulate the growth of glioma cells, specifically in mouse models of neurofibromatosis type 1 with optic pathway glioma.96 Light deprivation, achieved by rearing mice in the dark during weeks when tumors are normally expected to develop, decreased the formation and growth of optic pathway gliomas.