세미나

The brain is the most structurally complex organ, spurring the development of numerous imaging techniques. Nevertheless, current imaging techniques have only revealed a minute portion of the entire brain architecture at the cellular level. In this talk, I will introduce recent brain engineering approaches to overcome various limitations of brain imaging. MAP technology physically expands the intact mouse brain linearly by more than fourfold and makes it transparent, while preserving its shape with protein content. Such clearing and expansion allows us to observe long-range connectivity of neurons and their nanoscale architecture, such as synapses, in the same brain by visualizing multiple protein targets and tuning the brain size. ELAST technology transforms brain tissue into an elastic material, making cleared tissue samples exceptionally stable, stretchable, and compressible. This engineering approach facilitates large-scale 3D microscopy of human brain tissue. Elasticized tissue can be transiently stretched or compressed to make it thinner, which accelerates molecular delivery. We demonstrated 100-times faster 3D immunostaining using thick human brain cortex. With advanced microscopy and brain engineering techniques probing brain-wide neural circuits at the single-neuron level still remains a major challenge. I will summarize current efforts and fundamental limitations to map the mammalian brain’s projectome and connectome, and discuss the need for new ideas to achieve this goal.