大脳皮質培養神経回路の自発活動と可塑性

抄録

Activity-dependent plasticity probably plays an important role in learning and memory as well as proper network formation during development. Though synaptic plasticity has been widely and extensively investigated, little is known about its consequences in network activity. We have applied micro-electrode arrays (MEAs) for neuronal ensemble recording. The MEA is a dish for cell culture, on the surface of which multiple micro-electrodes are embedded. Cortical neurons were taken from E18 Wistar rat embryos and cultured on the MEAs. Spontaneous activity started at about 3 days in vitro (DIV). Relatively long-lasting activity with loose network coupling was observed. Then the activity grew up to periodic synchronized bursts with tight coupling. In about one month, it reached a steady state. The steady-state activity was composed of synchronized bursts at approximately 1 Hz, and some asynchronous components. The spatial propagation patterns were not unique, but could be classified into a few groups. The substrate-embedded electrodes could also be used for stimulation. Several evoked activities were recorded and the effects of focal high frequency stimulation were evaluated. After the high frequency stimulation, some of the signal propagation pathways were strengthened. The same high frequency stimulation weakened some of the pathways. The correlation analysis revealed that the pathways that were tightly correlated with the repeatedly activated pathway were selectively potentiated. The next step will be to study how spontaneous activity during development affects the network and single cell properties. [J Physiol Sci. 2006;56 Suppl:S14]