Table 1.

Current in vitro systems applicable to study the interaction between circadian rhythms and cerebral waves in the brain neural cells

Physiological system to study	Type of in vitro system	Description of the in vitro system	Key features	Reference
Neuron-astrocytes bidirectional interactions: role of astrocytes in the synchronization of brain waves and synapses formation.	Transwell insert	Astrocytes are cultured into an insert (apical comp) and the neurons are seeded into the lower well (basolateral comp).	Astrocytes and neurons are in communication through the media exchange between the apical and basolateral comps without a physical interaction.	Buskila et al.6; Gottschling et al.45
	Circulatory Blocks™ CELLBLOKS® technology of Revivocell (Daresbury Lab, Cheshire, UK)	Multi-organ/cell type modular “plug and play” co-culture technology that emulates an organ microenvironment. Neurons and astrocytes are co-cultured in different comps.	Neurons and astrocytes form a tripartite synapse (pre-synaptic terminal, post-synaptic membrane, and cradling astrocytes) without a physical interaction.	Llabjani et al.46
Study and selective manipulation of an isolated neuronal networks.	Microfluidic systems	Multi-compartmentalized microfluidic device made of two parallel microfluidic comps separated by microgrooves. Neurons or NSCs are monocultured in the somato-dendritic comp. Cortical-cortical or cortical-thalamic neurons are co-cultured in different comps.	Neurons grow and extend their axons though the microgroove regions, which allow to guide the axonal growth, into an adjacent, isolated axonal comp.	Paranjape et al.47
			The cortical region is the site of initiation of burst firing events, whereas thalamo-cortical connections are needed to maintain a prolonged synchronized bursting pattern in the cortical cells culture.	Kanagasabapathi et al.48; Kanagasabapathi et al.49
		Models of neuronal circuits, blood–brain barrier and neurovascular unit in microfluidic systems.	Advanced microfluidic technologies for neurological disease research.	Holloway et al.50
Neuronal network communication and synchronization.	Micropatterning	Neurons are seeded on a micro-patterned device that can create a predefined neural network.	The geometry of the device induces a predefined neuronal connectivity and functional polarity, guiding the signal propagation among neurons population. The presence of astrocytes and extracellular matrix influence the excitability and synchronous activity of neurons.	Albers and Offenhäusser51
Early neurodevelopment, from neuroepithelial formation to assembly of rudimentary network and study of brain waves.	Cerebral organoids	Brain spheroids composed of a mixed population of neurons and glial cells from iPSC-derived NSCs.	Organoids contain dozens of ventricles lined with radial glia/progenitors that differentiate into cortical and mature glia. Cytoarchitectonic development typical of a human brain with complex functional activity (coordinated electrical activity).	Guy et al.52; Govindan et al.53; Marton and Pașca54
		Human brain cortical organoids.	Dynamic changes in cell population and increases in electrical activity. Spontaneous formation of neuronal networks with periodic and regular oscillatory events (GABAergic signals).	Trujillo et al.39
		Co-culture of brain organoids with endothelial cells or organoids containing engineered cells with ETV2.	ETV-2-expressing population contributed to vascularization, leading to enhanced functional maturation with BBB characteristics. Uniform size, morphology, and synchronized differentiation are the main factors to be considered.	Kim et al.55

comp(s), compartment(s); NSC, Neural stem cell; iPSC, induced pluripotent stem cell; BBB, blood–brain barrier.