CSAIL Event Calendar

IMAGING THE CONNECTOME

Theory and Beyond Lunchtime Seminar Series

Abstract: Connectional maps of the brain may have value in developing models of both how the brain works and how it fails when subsets of neurons or synapses are missing or misconnected. Such maps might also provide detailed information about how brain circuits develop and age. I am eager to obtain such maps in neonatal animals because of a longstanding interest in the ways neuromuscular circuitry is modified during early postnatal life as axonal input to muscle fibers is pruned. Work in my laboratory has focused on obtaining complete wiring diagrams (“connectomes”) of the projections of motor neuron axons in young and adult muscles. Each data set is large and typically made up of hundreds of confocal microscopy stacks of images, which tile the 3dimensional volume of a muscle.

In brain, as opposed to muscle, the high density of neuropil has precluded using the approaches that have worked in the peripheral nervous system. We have thus developed of lossless automated physical sectioning strategy that generates thousands of ultra thin (~25 nm) sections on a firm plastic tape, and have developed a thin-section scanning electron microscopy approach to visualize these sections at 3nm lateral resolution. This method makes large-scale serial microscopic analysis of brain volumes more routine. We are now focused on developing an automated pipeline to trace out neural circuits in brains using this technique.

Biography: Jeff Lichtman is the Jeremy R. Knowles Professor of Molecular and Cellular Biology at Harvard University. He is well known for his work on “Brainbow” transgenic mice, a technique for genetically modifying mice to allow segmenting axons by their unique fluorescent spectral hues. Jeff received his A.B. from Bowdoin College, and his M.D. and Ph.D. degrees from Washington University.

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