Statistical analysis of dose‐response curves in extracellular electrophysiological studies of single neurons

The application of polynomial regression and the analysis of covariance (ANCOVA) to dose‐response (DR) data derived from extracellular electrophysiological studies of midbrain dopamine neurons and noradrenergic locus coeruleus neurons in vivo is demonstrated and discussed. Third‐order polyomial regression was found to be a better method for estimating ED₅₀ values than probit analysis or linear regression. ANCOVA provides a more powerful statistical method than ANOVA for detecting significant differences in ED₅₀ values or DR curves when a confounding variable such as basal discharge rate is present. The methods of analysis presented herein should be useful in the analysis of other types of neurons in electrophysiol studies.