Amplitude and Frequency encodings give cells a different lens to sense the environment

Cells continuously sense their surroundings to detect modifications and generate responses. Very often changes in extracellular concentrations initiate signaling cascades that eventually result in changes in gene expression. Increasing stimulus strengths can be encoded in increasing concentration amplitudes or increasing activation frequencies of intermediaries of the pathway. In this Letter we show how the different way in which amplitude and frequency encoding map environmental changes impact on the cell's information transmission capabilities. While amplitude encoding is optimal for a limited range of stimuli strengths around a finite value, frequency encoding information transmission can improve or remain relatively flat as the stimulus strength increases. The apparently redundant combination of both mechanisms in some cell types may then serve the purpose of expanding the range over which stimulus strengths can be reliably discriminated. In this Letter we also discuss a possible example of this mechanism.