Effect Of The Activation Of Inhibitory Network On The Spike Firings Of Hippocampal Neurons

The hippocampus plays an important role in learning, memory, spatialization and other functions of brain. The spike firings of main neuron (pyramidal cell) receive regulation from feedforward and feedback inhibitions of inhibitory interneurons in the neural network in rat’s CA1region. As the basis of information transmission between neurons, the regulation mechanism of spike has an important significance in electrophysiology research.In this thesis, we delivered electrical stimulation to Schaffer collateral and Alveus in rat’s CA1region to activate the inhibitory network, then we recorded the spikes of single pyramidal cell and interneuron by micro electrode array. The main works are list as follows:(1) the change of spike firings of pyramidal cell after orthodromic and antidromic stimulation.(2) the change of spike firings of interneuron after orthodromic stimulation.(3) the change of spike firings of pyramidal cell after orthodromic dual stimulation and DBS.The main results of this thesis were summarized as follows:(1)The inhibitory network activated by electrical stimulation completely inhibited the spike firings of pyramidal cell. The duration of inhibition is from403±43ms to425±26ms in the case of orthodromic stimulation and from218±40ms to267±37ms of antidromic stimulation. The duration of inhibition of spike firings and activity of inhibitory network is consistent.(2)The spike firing of interneuron after stimulation also was inhibited. The duration of inhibition is400-1000ms. The duration of inhibition of spike firings has a correlation with the amplitude of population spike induced by electrical stimulation.(3)We observed the evidence that some interneurons were involved in feedback inhibition.(4)Repeated electrical stimulation can enhance the effect of inhibitory network.In conclusion, we revealed the regulation of spike firings of pyramidal cell and interneuron by feedforward and feedback inhibitions induced by electrical stimulation in CA1region in vivo study, which is very significant to understanding of the working mechanism of neural circuits and regulation of electrical stimulation.