Research The Integration Characteristic Of Visual Information Based On Combing Spike With Local Filed Potential

The brain’s visual system is the main perception system of animal to obtain information from the outside world. The visual information was processed first in the primary visual cortex(V1), and then they was passed to the more advanced visual cortex. V1 area is the first area of the cortex to participate in visual information integration, The neurons in V1 area can modulate the neuron’s response within receptive filed, The modulation effects play a key role in the visual information integration. Therefore, research the integration effect of the integration wild for visual information stimulation has the great significance in further studying the information processing mechanism of visual system and solving the complex image processing problems.Spike and the local potentials(LFP)are two different frequency band signals, They carry the different visual information, and the were both involved in the process of visual information processing. In this paper, rat was chosen to be the model animal, spike and the local field potential signals of the neurons on V1 area were collected by using the multichannel microelectrode arrays, and then the integration characteristics of the integration filed in different stimulation patterns was studied. The specific contents and results as follows:(1)The location and the type of integration filed of the neurons on the V1 area were determined.First, the checkerboard stimulation was combined with reverse correlation method to determine center location of neuron’ receptive field, which was took as the center coordinates of the integration filed; Then, the annular grating whose radius decrease gradually was designed to determine the size of the neuron’ integration field; Finally, the circular grating whose radius increases gradually was designed determine the type of neuron’ integration field. The results show that with the increase of the circle area which was used to shade the receptive field, the intensity of neuron’ response was much bigger and then became much smaller, and the neurons’ integration field all showed the inhibitory modulation characteristics in our experiment.(2)The joint characteristics combined Spike and LFP were extracted to study the integration characteristics of integration field.First, Spike and LFP signal were preprocessed. Then, the spike rate and LFP gamma band power were extracted; Then, according to the correlation between Spike and LFP, the matching pursuit algorithm and triggered average technology was used to analyzes the changes of waveform’ amplitude of Spike triggered average gamma LFP waveform at different times after the beginning of the stimulus, and then the time interval of Spike triggered LFP was determined, and then the method of extract the Spike triggered the gamma LFP instantaneous energy in the time interval. The results show that:the wavelet transform and clustering method could realize the classification and denoising for Spike, and the adaptive filter method can be used to remove the power frequency noise and high frequency noise in LFP; After the beginning of the stimulus, the waveform of gamma LFP changed with firing time of Spike, then the different neurons were statistical analysis, we found that after the beginning of the stimulus, the time interval of Spike triggered LFP was between 1ms and 8ms.(3) The integration characteristics of the integration filed of neurons in V1 area under spatial frequency, orientation and contrast information, and verify the effectiveness of the Spike triggered the gamma LFP instantaneous energy on the analysis of the integration characteristics of the integration filed.First, the spike firing rate, the power of gamma LFP and the Spike triggered the gamma LFP instantaneous energy were extracted under the different spatial frequency, different orientation and different contrast circular grating stimulation pattern, and then the integration characteristic of the integration filed in the spatial frequency, orientation and contrast information were analyzes. The results show that when the visual stimulation parameters in the receptive field and in the integration filed were same, the integration filed showed the strongest integration effect, and when the difference of visual stimulation parameters became bigger, the integration effect of integration filed became weaker. Then, the suppress index was took as the indicator to measure the integration degree of the integration filed, and then the result of using the Spike triggered the gamma LFP instantaneous energy and spike firing rate and the power of gamma LFP were compared. The results show that the integration effect of integration filed was more significant when using the response characteristic which was extracted in this paper, and the response changed more intuitive with the change of the difference of the visual stimulation parameters, so this proved that the new response characteristic can be the effective response characteristic to analyzes the integration characteristic of the integration filed, on the other hand, when compared with the traditional response characteristic, the new response characteristic had more advantages on the express the integration characteristic of integration filed.(4) The integration characteristic of neuron in spatial frequency、orientation and contrast information in V1 areas was analyzed using Spike trigger gamma LFP instantaneous energy.First, three factors orthogonal experiment which contains spatial freuquency, orientation and contrast was designed; Then, the Spike triggered gamma LFP instantaneous energy under the orthogonal stimulation pattern was extracted, and then using the intuitive analysis method and variance analysis method to analysis the neurons’ integration characteristic of integration filed under the change of spatial frequency, orientation and contrast visual information at the same time in V1 areas. The results show that the integration filed of neurons showed the different degree integration characteristic under the change of spatial frequency, orientation and contrast visual information at the same time, and the integration effect was the most obvious under orientation information, information,and the integration effect were relatively weak under the spatial frequency and contrast information.