Microfluidic platforms for probing spontaneous functional recovery in hierarchically modular neuronal networks.

The inherent capacity to flexibly reorganize after injury is a hallmark of brain networks, with recent studies suggesting that the functional consequences of damage are strongly influenced by the network's nonrandom connectivity. However, experimental platforms that enable bottom-up investigations of the structure-function relationships underlying damage and recovery processes remain limited. Here, we used polydimethylsiloxane microfluidic devices to construct hierarchically modular neuronal networks that mimic the topological features of the mammalian cortex. Laser microdissection was employed to selectively sever intermodular connections, enabling controlled damage to either hub or peripheral connections. Damage to hub connections leads to delayed recovery, requiring more than three days for correlations to re-emerge. Contrarily, peripheral damage resulted in faster recovery. Repeated injury to neuronal networks further revealed that recovery occurs through both new pathway formation and restoration of originals. These findings provide mechanistic insights into the intrinsic self-repair capacity of living neuronal networks.