Nonlinear super-resolution signal processing allows intracellular tracking of calcium dynamics

Abstract

Objective. Traditional quantification of fluorescence signals, such as ΔF/F , relies on ratiometric measures that necessitate a baseline for comparison, limiting their applicability in dynamic analyses. Our goal here is to develop a baseline-independent method for analyzing fluorescence data that fully exploits temporal dynamics to introduce a novel approach for dynamical super-resolution analysis, including in subcellular resolution. Approach. We introduce ARES (Autoregressive RESiduals), a novel method that leverages the temporal aspect of fluorescence signals. By focusing on the quantification of residuals following linear autoregression, ARES obviates the need for a predefined baseline, enabling a more nuanced analysis of signal dynamics. Main result. We delineate the foundational attributes of ARES, illustrating its capability to enhance both spatial and temporal resolution of calcium fluorescence activity beyond the conventional ratiometric measure ( ΔF/F ). Additionally, we demonstrate ARES’s utility in elucidating intracellular calcium dynamics through the detailed observation of calcium wave propagation within a dendrite. Significance. ARES stands out as a robust and precise tool for the quantification of fluorescence signals, adept at analyzing both spontaneous and evoked calcium dynamics. Its ability to facilitate the subcellular localization of calcium signals and the spatiotemporal tracking of calcium dynamics—where traditional ratiometric measures falter—underscores its potential to revolutionize baseline-independent analyses in the field.