Davi Bock

Janelia Research Campus

Tracing Memory Circuits in Drosophila melanogaster Using Whole-Brain Electron Microscopy

12:00 pm, Friday 07 October 2016

Location: The Sherrington Library; Department of Physiology, Anatomy and Genetics; Sherrington Building

Abstract: We imaged the complete brain of a female adult fruit fly at EM resolution. The resulting dataset comprises 21 million images occupying 106 TB. A cluster-backed image processing pipeline was developed to stitch, register, and intensity correct these images, enabling manual tracing of neuronal connectivity throughout the brain. Pilot efforts have focused on the interface between the olfactory system and the mushroom body (MB), the site of associative learning. Each MB contains ~2,000 Kenyon cells (KCs), which receive olfactory input from the antennal lobe via second-order olfactory projection neurons (PNs) in the MB calyx, in what is thought to be a random fashion. KC axons then form a bundle called the pedunculus, which gives rise to the lobes of the mushroom body, where synaptic modulation underlying memory occurs. We traced about 10% of the KCs in the calyx, and their presynaptic PN inputs, to generate a PN-to-KC connectivity graph. We find that KCs that fasciculate with one another in the pedunculus are much more likely to receive input from a common PN, and are also more likely to make axo-axonic synapses with one another. This network structure might be used to sharpen and amplify olfactory signals prior to their arrival in the MB lobes, where synapses are modified during associative learning.

Biography: Davi Bock received his AB in Biology from Brown University and a PhD in Neurobiology under the supervision of Clay Reid at Harvard Medical School. He has been a group leader at Janelia Research Campus since 2011.