Adam Truong studied the role of gap junctions in mediating synchronous membrane potential oscillations in projection neurons in Drosophila pupae. He then designed experiments using the more developed and complex neural connections of adult Drosophila brains and discovered a novel connection between projection neurons. In 2012, Adam received a Master’s Degree in Global Medicine from the University of Southern California, and is currently studying to receive his degree in medicine from the University of California, Irvine School of Medicine. He hopes to use both degrees to unite his twin passions of international public health and allopathic medicine.

Chemical synaptic transmission mediates information transfer between neurons in the insect antennal lobe and plays an important role in processing olfactory information. In contrast, while electrical synapses (gap junctions) play a clear role in neuronal communication in the mammalian olfactory bulb, relatively little is known about their role in the antennal lobe. A recent study reported that electrical synapses mediated by innexin8 encoded gap junction proteins form specifically between projection neurons (PNs) that innervate the same but not different antennal lobe glomeruli in the intact adult fly brain. The current study showed correlated membrane potential oscillations between randomly selected PNs. This led to the hypothesis that gap junctions are important for synchronizing activity between PN pairs that innervate both the same and different glomeruli. Recordings were made from pairs of projection neurons and the dendrites for each projection neuron were located. This demonstrated that PN pairs innervating different glomeruli showed correlated electrical activity even with chemical synaptic transmission blocked. Correlated activity also was reduced in PN pairs in innexin8 mutants compared to wildtype. These data show that innexin8 encoded gap junction proteins are important in synchronizing activity between PNs that innervate different and the same antennal lobe glomeruli.

Diane K. O'Dowd School of Biological Sciences

Adam joined the lab in the summer following his freshman year and did research every quarter until he graduated. Early on he enthusiastically applied himself to developing the fine micro-dissection skills required to remove the brain from the head of a tiny fruit fly. Adam then undertook the heroic task of recording simultaneously from two neurons in a well-defined neural circuit that processes olfactory information in the fly brain. The data in his excellent paper demonstrate coordinated activity between two different neuronal subtypes, revealing a novel pathway of communication between neurons in this circuit. Adam took full advantage of his time in the lab, learning do science and to think like a scientist.