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How does a small brain decide on an action?

Tomoko Ohyama
Department of Biology McGill University

October 25, 2017 at  11:00 AM
McConnell Engineering Room 437


To make optimal decisions and adapt successfully to our environments, we need to make use of all of the sensory cues we can detect (e.g., visual, olfactory, tactile, noxious), which initially arrive through selective channels. A central question in neuroscience is how nervous systems transform these originally segregated inputs into holistic multisensory representations, and how they use these representations to guide the selection of actions. My research is focused on discovering the fundamental circuit principles that underlie these processes. To tackle this challenge, we have been studying escape behaviors in larval Drosophila melanogaster.

Drosophila larvae, or “maggots”, have a rich repertoire of behaviors they produce in response to specific stimuli and use various strategies to escape from unpleasant stimuli. Furthermore, maggots' small brains contains more than 10,000 neurons and now we have a partial connectivity map of the neurons. We combine high-throughput behavior analysis with live imaging/physiology of neural activity and transmission electron microscopy (TEM) reconstruction of neuronal circuits. To analyze neuron-behavior relationships, we use 1) genetic tools to manipulate individual neurons; 2) a high-throughput behavioral tracking system that allows temporally controlled stimulation of many freely moving larvae at once; 3) TEM neuron reconstruction (in collaboration with the Cardona lab, Janelia Research campus); and 4) unsupervised structure learning methods to categorize behaviors in an unbiased fashion.

I would like to discuss how we are capturing animal behavior, analyzing behavioral data, and reconstructing neuronal circuits from TEM images.


Tomoko Ohyama received her Ph.D degree in 2009 from the Baylor College of Medicine, where she performed her thesis work in Dr. Hugo Bellen's Lab studying synaptic vesicle cycling using the Drosophila fly. Her Ph.D work involved novel components that regulate neurotransmitter release and recycling. She then worked as a post-doctoral researcher under Prof. Marta Zlatic at the Janelia research campus of the Howard Hughes Medical Institute to study the behavior and neural circuits of Drosophila larvae. She is interested in how sensory information is processed to generate specific behavior and she would like to understand the structural circuits and functional mechanisms. To elucidate neuronal circuits and mechanisms involved in multi-sensory integration and sensory-motor integration of behavior, she uses Drosophila larvae as a model system. She has taken a forward genetic approach using GAL4 lines library, which have been made by G. Rubin, to identify the neurons involved in specific behaviors. Currently, she is focusing on the similarities and differences between the neural circuits that underlie avoidance and escape responses. She began her current position in the Department of Biology at McGill University in January 2017.