ABSTRACT
The dynamics of neuromodulators are essential for their functions. Optical sensors have transformed the study of neuromodulators because they capture neuromodulator dynamics with high spatial and temporal resolution. However, fluorescence intensity-based sensors are restricted to measure acute changes within one animal over a short period because intensity varies with sensor expression level and excitation light fluctuation. In contrast, fluorescence lifetime is impervious to sensor expression level or excitation light power, allowing comparison between individuals and across long periods. Here, we discover fluorescence lifetime response in multiple intensity-based neuromodulator sensors. Using the acetylcholine sensor GRABACh3.0 to investigate the power of lifetime measurement, we find that fluorescence lifetime correlates with animal behavior states accurately despite varying excitation power or changes in sensor expression level across weeks and animals. Thus, fluorescence lifetime of neuromodulator sensors enables comparison of neuromodulator dynamics at high resolution between animals and for chronic time scales.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
Updated with additional analysis and text revision.
