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International Journal of Bioprinting Laser bioprinting of hiPSC-derived neural stem cells and neurons

Figure 9. Impact of astrocytes on network bursts. Comparison of burst sizes in NSC cultures at Diff 0/25 with and without astrocytes. Cultures with 20%
astrocytes behave similarly as those without astrocytes, with average burst sizes of about 7% of the network. Cultures with 50% astrocytes exhibit a signif-
icant increase in burst size, of about 15% of the network on average, and indicate an excessive synchronization of the neurons. Significance analyzed by a
multiple comparison test in ANOVA. ** P<0.01.
both short and long distances. An alternative topological isolated was shaped. We must note that both culture types
representation of the functional neuronal communities is are active and healthy. The increased network functional
depicted in the right panel, in which neurons are grouped cohesion when astrocytes are present is not necessarily
by community, and communities are separated according to advantageous since neuronal circuits must balance local
their coupling within the network. A similar representation and global communication for optimal functioning, but
of printed NSCs with 50% astrocytes under same culture indicates that the presence of astrocytes is central in shaping
conditions is shown at the bottom row of Figure 10A. Here, global network activity.
too, all networks are extended over the entire observation
section. However, there are less communities (five instead To statistically analyze the differences in network
of eight), which are clearly much larger. The overall higher functionality with and without astrocytes, we compared two
cohesion of the network is also shown in the topological network measures, namely global efficiency G (left) and
eff
representation, where communities are closer to one another. community statistic Q (right), for culture realizations without,
Altogether, the results indicate that astrocytes accentuate the with 20% and with 50% astrocytes, as shown in Figure 10B.
synchronization among neurons and therefore strengthen The global efficiency captures the degree of overall network
their functional interactions, shaping a network where communication (see also Figure 7D) and is significantly
neurons are strongly coupled. Without the addition of higher for cultures with 50% astrocytes, which indicates an
astrocytes, a network where neurons are relatively more increased cohesion of the functional networks and that is

Volume 9 Issue 2 (2023) 361 https://doi.org/10.18063/ijb.v9i2.672