Beyond a spherical neuron: Subcellular calcium activity in the Caenorhabditis elegans nervous system

Abstract

Population level recordings in freely behaving animals can provide new and exciting information on the relationship between neural activity and behavior. Recent advances allow recording calcium activity at cellular resolution across the whole brain of the completely unrestrained nematode Caenorhabditis elegans. However, this only records from the neuronal nuclei, while there are known instances of independent subcellular signals. We explore this by recording calcium activity of single plane from the whole brain. A clustering algorithm finds activity groups, and shows that these cytoplasmic groups are actually explained fairly well by calcium activity just from cell somas. A second set of recordings are taken from five individual neurons (AIB, AIY, AIZ, RIA, RIB) to further explore the prevalence of subcellular calcium activity, find compartments in each neuron. This evidence, along with previous literature results, suggest calcium compartments are more widespread than previously thought, and may potentially serve important computational roles. While nuclear localization may effectively approximate whole brain activity, we lose information on subcellular computations, potentially missing important relationships.