Recording neural activity in freely behaving animals with a random access two photon microscopy*

Recording neuroal activity in freely behaving animals is essential to study neural correlates of behavior, but the motion of the brain imposes challenges to reliably record calcium activity from multiple neurons. By implementing acousto-optic deflectors and a custom-designed compact dispersion compensator [1], we developed a random-access two-photon tracking microscope capable of recording activity from neurons in unrestrained freely behaving Drosophila larvae without motion artifacts. With extremely low latency (360 μs), this microscope can relocate the laser beam in constant time regardless of the distance within the field of view, which allows us to overcome the limits imposed by the inertia of the scanning elements that previously limited the number of neurons that can be recorded and the distance between them [2].

With this method, we recorded calcium activity of premotor- and inter- neurons in freely behaving larvae. We show the correlation between behavioral outputs and the neural activity of lateral visual neurons (5^th LaN) in response to blue visual stimulus that induce turn behavior.

[1] A. Yamaguchi, D. Karagyozov, M. Gershow. Optics Letters. doi 10.1364/OL.419682

[2] D. Karagyozov, M. M. Skanata, A. Lesar, M. Gershow. Cell Reports. doi 10.1016/j.celrep.2018.10.013