Abstract
For development of bioinspired system or information processing system utilizing biological components, it is critical to understand the network electrical dynamics fundamental for information processing in living neuronal network. Basic activity such as spontaneous activity is considered to be basic unit composing internal states of the living neuronal network. Spontaneous activity is generated by mutual interaction between neuronal cells in brain and it is also observed in the cultured rat hippocampal neurons. The spontaneous activity has complex and dynamic spatiotemporal patterns. Therefore, it is likely that reproducibility of the electrical activity patterns, expressed after transient blockade of network activity, is not necessarily guaranteed. In this study, spontaneous activity in a dissociated neuronal culture was recorded by extracellular-potential-multisites-recording-system and we compared the activity patterns recorded before and after a transient pharmacological blockade of spontaneous activity. As a result, frequency of spontaneous activity was increased and temporal pattern of the activity became to be intermittent pattern. Modified temporal pattern of the network activity lasted for several hours and gradually recovered to the initial state. These results suggested that the equilibrium between neuronal activities was broken by a transient abolishment of spontaneous activity, and that the internal states in the system were changed. Thus, it is required to consider the dynamic features of electrical activity in living neuronal activity when we decode information from neuronal activity.
