Improved methods for marking active neuron populations

Area of Science:

• Neuroscience
• Molecular Biology
• Biochemistry

Background:

• Mapping neuronal ensembles requires high spatiotemporal resolution.
• The initial CaMPARI sensor had limitations including background photoconversion and slow kinetics.
• Existing methods struggle with precise labeling of active neuronal populations.

Purpose of the Study:

• To develop an improved fluorescent protein sensor, CaMPARI2, for enhanced neuronal activity marking.
• To overcome the limitations of the first-generation CaMPARI sensor.
• To establish a reliable immunohistochemical method for detecting photoconverted CaMPARI.

Main Methods:

• Engineering of the CaMPARI2 fluorescent protein with optimized properties.
• Testing CaMPARI2 performance in mammalian neurons and in vivo models (zebrafish, mouse).
• Development and validation of an anti-CaMPARI-red antibody for immunohistochemistry.

Main Results:

• CaMPARI2 exhibits brighter fluorescence, faster kinetics, and reduced background photoconversion compared to CaMPARI1.
• Successful in vivo demonstration of CaMPARI2 in larval zebrafish and mouse visual cortex.
• Development of a specific anti-CaMPARI-red antibody for robust detection of activated neurons in rodent brain tissue.

Conclusions:

• CaMPARI2 represents a significant advancement for neuronal ensemble tracing.
• The improved sensor and antibody method enhance the ability to study neural circuits.
• This work provides powerful tools for systems neuroscience research.