WE show here, by means of evolutionary spectral analysis and synthesis of cytosolic Ca2+([Ca2+]c) spiking observed at the single cell level using digital imaging fluorescence microscopy of fura-2-loaded mouse cerebellar granule cells in culture, that [Ca2+]cspiking can be resolved into evolutionary spectra of a characteristic set of frequencies. Non-delayed small spikes on top of sustained [Ca2+]cwere synthesized by a main component frequency, 0.13 2 ± 0.01 2 Hz, showing its maximal amplitude in phase with the start of depolarization (2 5 mM KCl) combined with caffeine (1 0 mM) application. Delayed complex responses of large [Ca2+]cspiking observed in cells from a different set of cultures were synthesized by a set of frequencies within the range 0.018–0.11 7 Hz. Differential frequency patterns are suggested as characteristics of the [Ca2+]cspiking responses of neurons under different conditions.