Neural circuits allow animals to store sensory information about their environments, helping them to better reap benefits or avoid dangers by appropriately adjusting their behaviors. However, the mechanisms of learning and memory that improve animal fitness through behavioral plasticity remain elusive. Because it is difficult to probe learning and memory throughout a whole nervous system, neuroscientists have generally focused on mechanisms for neural plasticity in selected cells or synapses. To gain deeper insight into how experience modulates behavior, it would be tremendously useful to monitor and manipulate the entire nervous system of an animal as it learns. Such a systems-level approach to the problem is feasible with the nematode C. elegans, whose tractable 302-neuron network has been characterized at the level of connectivity. Its transparency, along with its small size, allow optical access to every neuron in a constrained animal.
By monitoring neuronal activity using established calcium indicators and newer electrical sensors, this project aims to develop a tool that can systematically characterize how memories are formed in individual neurons. Combined with optogenetic stimulation, such a tool would allow read and write activity in the worm's brain. This approach may allow researchers to imprint, erase, or alter memories in the brain circuit, creating specific learned behaviors while circumventing actual sensory experience. The goal of this study is to provide insight into fundamental features of learning and memory shared by all animals.
