We propose and investigate two information-based measures of statistical dispersion of neuronal firing: the entropy-based dispersion and Fisher information-based dispersion. The measures are compared with the standard deviation. Although the standard deviation is used routinely, we show, that it is not well suited to quantify some aspects of dispersion that are often expected intuitively, such as the degree of randomness. The proposed dispersion measures are not entirely independent, although each describes the firing regularity from a different point of view.