UC Berkeley

A central question in neuroscience is how synapses are assembled within neuronal circuits to regulate and maintain complex behaviors. These fundamental nodes of information transfer must be malleable yet maintain stability, all within a nervous system of a developing, learning, and behaving animal. In my thesis work, I have sought to help bridge some of these divides between the many scales of the nervous system and disentangle the overwhelming intricacy that lies between molecules at the synapse and emergent behavior. Behavioral variability in animal populations is thought to increase fitness and aid adaptation to environmental change, yet the underlying neural mechanisms are poorly understood. We found that variation between individuals in neuromodulatory input contributes to individuality in short-term habituation of the zebrafish (Danio Rerio) acoustic startle response (ASR). From here, I studied heterogeneity on a different scale and began researching the synaptic diversity of the model system, the Drosophila neuromuscular junction (NMJ). Most electrophysiological studies of the NMJ have ignored the functional differences between its two distinct motor neuron inputs, the Ib and Is, both of which are comprised of hundreds of synapses of varying vesicular release properties. We found that the Ib and Is inputs generate distinct forms of excitatory drive during crawling and differ in key transmission properties. Finally, after a desire to connect the synaptic level of the NMJ to the behavioral level of the larval zebrafish, my most recent work investigates how circuits increase motor neuron output to maintain normal behavior in response to a reduction in synaptic strength at the NMJ. Although diverse in nature, these model systems provide a unique insight into the complex interplay between generating diversity and maintaining stability in the nervous system.