My research examines how simple neuronal networks produce different behaviors and also how neuronal networks are altered with the formation of memories. To accomplish this, I perform large scale voltage-sensitive dye (VSD) imaging of neuronal populations in the central ganglia of the gastropod mollusk Tritonia diomedea that produce escape swimming and crawling behaviors. VSD imaging combined with Independent Component Analysis (ICA) allows for the simultaneous monitoring of dozens to hundreds of neurons with single-cell, sub-millisecond resolution. VSD imaging has revealed the presence of a class of neurons that participate in the escape swim network in a surprisingly unreliable manner, and optical data have also revealed a novel population of multifunctional swim/crawl motor neurons. Additionally, I am examining how neuronal networks can be reconfigured with the formation of simple types of non-associative learning such as sensitization and habituation.
VSD imaging combined with ICA allows us to monitor large numbers of neurons during different fictive motor programs. Above the activity of 67 Tritonia pedal ganglion neurons is shown during the sequential escape swimming and crawling motor programs elicited by a stimulus given to pedal nerve 3 (arrow). Ce – cerebral ganglion, Pl – pleural ganglion, Pd – pedal ganglion.
In collaboration with the Stutzmann lab at RFUMs, I am also performing VSD imaging of neural activity in mouse hippocampal slices. In particular, we are comparing network activity in normal mice with that of a mouse model of Alzheimer's disease.
VSD imaging in the mouse hippocampus. In response to a stimulus given to the CA3 region, large depolarizing responses were observed throughout the CA1 region.