In recent years, the interaction between glioma and brain cells has emerged as one important regulator of tumor progression. In order to investigate the molecular and physiologic alterations of the peritumoral neurons induced by glioma growth, we used two well-established glioma syngeneic cell lines: GL261 and CT-2A. We performed in vivo electrophysiological recordings of visual evoked potentials (VEPs) to longitudinally monitor the neural dysfunctions along with tumor progression. With respect to controls, glioma-bearing (GBM) mice showed a decay of visual responses that started from day 14 after tumor induction. At this stage, we microdissected layer II-III pyramidal neurons and performed RNA-sequencing of a panel of genes involved in synaptic transmission. We found that only gabra1 and SNAP25 were significantly reduced in peritumoral neurons of glioma-bearing mice. These data were also confirmed by immunohistochemical analyses that showed a decrease in the level of gabra1 and SNAP25 proteins. Next, we performed Local Field Potentials (LFPs) recordings in freely moving control and GBM mice before and after the treatment with a subconvulsive dose of DMCM (an inverse benzodiazepine agonist that inhibits GABA currents by binding to the α subunits of the GABA-A receptor). We found that DMCM triggered epileptiform activity in both glioma murine models but not in controls, suggesting an involvement of the GABA-A receptor in seizures’ susceptibility. In summary, these findings reveal novel molecular players in pyramidal neurons which may be targeted for preventing neuronal dysfunction and hyperexcitability in order to ameliorate patients’ quality of life.