 Photoactivated localization microscopy

PALM reconstructs a spatial map by activating sparse subsets of labels, estimating each isolated fluorophore's position and combining many frames. Optical resolution depends on localization uncertainty, labeling density, drift and linkage; repeatedly observing one label cannot recover unlabeled structures.

Photoactivated localization microscopy (PALM) is a super-resolution imaging technique used in fluorescence microscopy to achieve spatial resolution beyond the diffraction limit of light. This technique is particularly important for visualizing cellular structures and protein interactions at the nanometer scale. Here's how it works: 1. **Photoactivation**: In PALM, a population of fluorescent molecules is initially in a dark or non-fluorescent state.