DYNAMIC BEHAVIOUR AND FUNCTIONAL ORGANIZATION OF NEURONAL CULTURES GROWN IN SUBSTRATES WITH SPATIAL ANISOTROPIES

Neuronal cultures are an excellent experimental tool to study the collective behaviour of neuronal assemblies in a controlled environment. However, neurons grown on flat substrates typically exhibit quasi-synchronous activity that does not capture the rich dynamical repertoire of the brain [1]. To overcome this limitation, we studied the capacity to break the isotropy in connectivity and enrich dynamics by topographically modulating the spatial arrangement of neurons in the substrate where they grow [2]. Spontaneous neuronal activity was recorded using calcium fluorescence imaging and analysed in the context of complex networks and criticality, using the phenomenological renormalization group approach [3]. Networks formed on topographical patterns were characterized by rich spatiotemporal activity patterns that comprised from localized regions to the entire culture, resulting in more complex dynamics compared to standard cultures on flat substrates. In addition, we explored the role of the excitatory-inhibitory balance in modulating network dynamics using pharmacological antagonists. We observed that inhibition plays a key role in regulating the activity repertoire, either by homogenizing bursting dynamics when inhibitory synaptic strength is reduced or by promoting spatial segregation when excitatory transmission is weakened [2]. Overall, this research illustrates the potential of spatial constraints to influence the activity and functional organization of neuronal cultures, enhancing the ability to obtain complex dynamics and providing a more realistic experimental platform.
[1] J. G. Orlandi et al., Nature Physics. (2013).
[2] M. Montalà et al., iScience. (2022).
[3] G. B. Morales et al., PNAS. (2023).