Differences in activity and functional connectivity between bi-dimensional and three-dimensional neuronal cultures

Abstract

Three-dimensional (3D) neuronal cultures can provide a more desirable in vitro ap-proach to emulate brain-like conditions. To prove it, 2D and 3D neuronal cultures were compared. During different days in vitro (DIV) after formation, spontaneous neuronal activity was recorded through calcium fluorescence imaging for data extraction. We show that activity in 3D cultures is higher and more varied. These cultures are functionally organized in modules that are spatially localized. In comparison, 2D cultures show less variability in activity, higher connectivity between neurons and a poor organization in modules. We ascribe the differences to the capacity of 3D cul-tures to form connections of short distance, favouring small microcircuits that coexist, while the 2D cultures have long–range connections that shape a strongly coupled and rigid system