<title>Enhancement of spontaneous burst activity of hippocampal neuronal networks with low frequency close-loop stimulation</title>

Abstract

In this paper, we study the modulation of low frequency closed-loop electric stimulation on spontaneous activity in cultured hippocampal neuronal networks. First, we plated monolayer cultures of hippocampal neurons from rat embryos (E18) on multi-electrode arrays and the experiments were performed in the networks from the second week to the sixth week continuously. During the experiments, we detected the spontaneous spikes of the networks firstly, and then stimulated the networks at low frequency (0.2 Hz or 1 Hz) stimulation respectively until a desired response was observed 20-80msec after a stimulus. The protocol was closed-loop. After that, we detected the spontaneous spikes of the networks. It is observed that the spontaneous activity in the developing networks is developing, which is oscillatory and periodic. Low frequency (0.2 Hz or 1 Hz) stimulation enhanced the spontaneous synchronous burst activity of the developing networks. These results implicated that activity-dependent mechanism in the modulation of plasticity of synaptic transmission in the cultured neuronal networks. Closed-loop stimulation will give a better view on the functional significance of networks activities. Besides, close-loop stimulation could set up the stimulus-reward system in the neuronal networks, which is of great benefit to the plasticity of synaptic transmission in the cultured neuronal networks.