The purpose of these experiments is to provide quantitative data which will support the hypothesis that microscopically visible regression which occurs in Purkinje neurons with age and with ethanol treatment may become cumulative and perhaps synergistic when these agents act concomitantly. Network analysis of dendritic arborization will be applied to Purkinje neurons from control and ethanoltreated rats of three different ages. Three levels of ethanol dosage will be used within each age group to determine dose-effects of ethanol at each age. From this analysis it will be possible to determine deviations from the laws of number and of length (Horton's laws) which may develop in Purkinje cell branching patterns as a result of age and/or ethanol treatment. Spine counts will also be performed to detect relative changes in spine density. Changes in parameters of branching and in spine density may then be related to imbalance of afferent inputs to the Purkinje neuron. An age-dependent susceptibility of Purkinje neurons to ethanol effects, suggested in preliminary experiments, will be characterized in relation to the dose effects of ethanol at each age.
