8 Leads Rat ECoG Acquisition System

Brain function research is an topic of scientific research, ECoG is widely used in research and application of epilepsy and brain-computer interface for its unique advantages. In the study of based on ECoG signals, people often choose animals such as rat for the experiment due to be tried for surgical operation. This paper designs an ECoG acquisition system of eight leads which used for acquiring rats ECoG.The design of ECoG acquisition system of eight leads is mainly divided into two parts of analog and digital. Analog part adopts instrumentation amplifier to constitute a preamplifier circuit, and designs the backward integration circuit to realize the effect of high pass filtering. Digital part mainly includes eight choose an electronic switch, ADC,DSP and USB chip. As the core device of digital part, DSP controls the electronic switch and ADC to achieve the eight-channel signal acquisition cycle and convert analog to digital quantity. Filtering the data in the DSP to filter the 50 Hz frequency interference and its harmonic interference. Finally via USB sent he processed data to the PC host machine in which user interface is designed, and users can realize the whole ECoG acquisition system operating through it.In order to test the performance of the acquisition system, all the indexes were tested on the system. And through filtering test, the results show that the routine in system can filter 50 Hz frequency interference and its harmonic interference. Then acquiring rats ECoG signals respectively in the resting state, to explore the status and state of epileptic seizures. After the time domain and power spectral density analysis of the ECoG signals, we may draw a conclusion that the ECoG signals is in accordance with the state of the rats brain activity at that time. Through the above tests, the system can be used for rats ECoG acquisition and research.