FIM$^{2c\;}$: Multicolor, Multipurpose Imaging System to Manipulate and Analyze Animal Behavior

Area of Science:

• Biomedical imaging
• Model organism research
• Optical physics

Background:

• In vivo whole-body imaging is crucial for biomedical studies using model organisms like fruit flies and nematodes.
• High-contrast imaging of translucent animals and fluorescent markers (e.g., green fluorescent protein) is challenging.
• Existing imaging systems have limitations for simultaneous posture, movement, and fluorescence detection.

Purpose of the Study:

• Introduce a novel optical imaging technique, FIM2c, for simultaneous detection of animal posture, movement, and fluorescence.
• Demonstrate the capability of FIM2c for high-contrast imaging of small model organisms.
• Showcase FIM2c's utility in advanced experimental approaches, including large-scale behavioral analysis and multitarget tracking.

Main Methods:

• FIM2c utilizes frustrated total internal reflection with two distinct wavelengths.
• The technique captures both reflected and emitted light for two-color imaging.
• It enables simultaneous recording of animal posture, movement, and fluorescent markers like GFP.

Main Results:

• FIM2c produces superb two-color, high-contrast images of small animals, outperforming existing systems.
• The method successfully resolved colliding larvae in a high-throughput approach, a feat not possible with prior tools.
• A comprehensive database of over 1300 resolved collisions with images and locomotion features was created.

Conclusions:

• FIM2c is a versatile and powerful tool for advanced imaging and locomotion analysis in various model organisms.
• The technique facilitates diverse experimental applications, including imaging fluorescent cells and integrating fluorescent tracers.
• FIM2c supports optogenetic studies and large-scale behavioral analysis for neuronal function research.