SEMINAR: Electrical imaging of axon function using an 11,000-electrode CMOS circuit

The Seminar: A growing body of literature suggests that central nervous system axons are not just stable transmission cables, but actively contribute to information processing, for example, by modulating action potential magnitude or velocity and cell excitability. However, the axon's submicron diameter makes conventional electrophysiology difficult. In this talk, Douglas Bakkum will introduce tools his team are developing to better access axonal function and help advance this field. Specifically, cortical networks are grown over custom high-density microelectrode arrays constructed using complementary metal-oxide-semiconductor (CMOS) technology. The arrays can electrically trigger and visualise axonal (and neuronal network) activity, non-invasively and for durations of months. In turn, they tracked axonal action potentials as they propagated across hundreds of sites. They found that many-fold velocity differences exist locally within a single neocortical axon. Tracking of a single axon over time demonstrated that the velocity profile varied significantly across days. In future steps, finding the molecular and genetic pathways that govern axon function may help provide new targets for treating currently intractable neurological disorders.

The Speaker: Douglas Bakkum received a Ph.D. in Neuroengineering from the Georgia Institute of Technology and Emory University in Atlanta, GA, USA. His interdisciplinary background spans research in mechanical engineering, robotics, artificial intelligence, neuroscience, and art. His current position is a group leader in the Department of Biosystems Science and Engineering at ETH Zurich, Switzerland. He is searching for the fundamental rules neurons use to communicate with each other and how such rules can scale to produce learning, memory, and creativity.