UBC Theses and Dissertations
A study of macroelectrode signals in the cat's optic tract Aube, Paul
The signal collected by a macroelectrode inserted in the cat's optic tract is made up of a slow component and fast variations (spike discharge). The mean amplitude of the peaks of the fast variations appears to be correlated with the slow component. The spike discharge is studied by an amplitude discriminator; the effect of filtering and overlapping are discussed, and it is seen that the mean counting value (weighted mean) obtained from the amplitude discriminator is a representation of the number of firings occurring in the neighbourhood of the macroelectrode. The curves obtained for the weighted mean show a high degree of similarity with the slow component. The relationship between the slow component and the weighted mean is calculated in the form of a transfer function. This transfer function appears to be the same for a wide range of stimulus conditions. These findings suggest that dendritic activity has little to do with generation of optic tract potentials. It also indicates that the nerve firing must be associated in the optic tract with a prompt positive overshoot allowing building up of positive macropotentials.
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