TNFSF14 and viral infectious disease: After expressing a light-sensitive ion channel, i.e., channelrhodopsin-2 (ChR2), in the primary rat cortical neurons cultured within collagen by a viral infection with AAV-EF1α-ChR2-eGFP (Supplementary Fig. 16 and Supplementary Movie 5), We successfully measured activated neural signals from ChR2-neurons by light stimulation (0.2 Hz with a 50% duty cycle, 76 mW⋅mm−2 with a total power of 0.15 mW) despite the stimulation artifact by the photovoltaic effect during the transition between the light ON and OFF49,50 (Supplementary Fig. 17).