Studies of local neuronal nets in the optic tectum of the frog

A system has been developed for multineuronal studies through a single extracellular microelectrode. This system is used to detect and study the behavior of local neuronal nets, formed by the dendritic appendages of tectral cells in the superficial tectum of the frog. The system consists of a software package for visual stimulation, spike detection, and classification, calculation of cross-correlograms of the spike trains, and visualization of the results. The sites of recording offer a large area for studying the interaction of units that participate in these local dendritic nets. Preliminary results suggest that there is a great number of direct functional interactions of excitatory nature mostly, modulated in part by the nature and location of the stimulus.