A balanced contribution of GABAergic and glutamatergic transmission to neuronal activity has been shown to be crucial for proper network function. Presence of sufficient glutamatergic neurons seems to be critical for maturity and function of a network41. However, GABAergic signaling has been shown to be as important for maturation and network development42. Therefore, the contribution of GABAergic and glutamatergic transmission to the neuronal activity in our co-cultures was studied using live cell calcium imaging. GABAergic and glutamatergic neurotransmission was studied at 3, 5, and 7 weeks after final plating by inhibiting their respective contributions. Responses were analyzed after recording baseline activity for 200 frames (61 frames per minute) by acute addition of respectively GABAA receptor inhibitor picrotoxin (50 μM) into the recording buffer or the combination of NMDA and AMPA receptor blockage with CNQX (20 μM) and DAP5 (50 μM) into the recording buffer. The effect of glutamatergic and GABAergic inhibition was recorded for another 200 frames.
