CAMP Seminar: Pan-neuronal Imaging in Behaving C. elegans
I will describe an imaging system that utilizes a confocal spinning disk microscope to track and record the calcium activity of every neuron of a freely behaving worm's brain at ten volumes per second. We developed a behavioral analysis algorithm that maps the movements of the head ganglia to the animal’s posture and locomotion, allowing us to correlate neuronal activity with posture. Image registration and analysis software automatically assigns an index to each nucleus and calculates the corresponding calcium signal. Neurons with highly stereotyped positions can be associated with unique indexes and subsequently identified using an atlas of the worm nervous system. To test our system, we analyzed the brainwide activity patterns of worms subjected to thermosensory inputs. We uncover a strikingly sparse representation of thermosensory perception involving two neurons (AFDL and AFDR), and a broadly distributed representation of the motor state across the nervous system. Our imaging setup and analysis pipeline, panneuronal imaging in roaming animals, or PANERA, provides a new platform to establish functional maps of sensory to motor transformation in behaving C. elegans and Drosophila larva.