Slow electrical stimuli to affect connectivity in cultured neuronal networks

Learning, or more generally, plasticity may be studied using cultured neuronal networks on multi electrode arrays. Many protocols have been proposed to change connectivity in such networks. One of these protocols, proposed by Shahaf and Marom, aimed to change the input-output relationship of a selected connection in a network. Although the results were quite promising, the experiments appeared difficult to repeat and the protocol did not serve as a basis for wider investigation yet. Here, we repeated their protocol, and compared our ‘learning curves’ to the original results. Although in some experiments the protocol did not seem to work, we found that on average, the protocol showed a significant learning effect indeed. Furthermore, the protocol always induced connectivity changes that were much larger than changes that occurred after a comparable period of random stimulation. Finally, our data suggest that network connectivity changes are induced more easily using stimulation at a fixed, than using randomly changing electrodes.