Art Meets Science: Best of Data Visualization
By Liz King for 410BC
This month’s best of data visualization was published in Nature last year in April of 2013. Karl Deisseroth and colleagues developed a novel method called CLARITY that turns the brain transparent to allow for the visualization of neuronal networks.
Traditional methods for visualizing neuronal networks are tedious. The brain must be sliced very finely and each slice individually analyzed in order to generate a composite image. The CLARITY method allows for the rapid visualization of neuronal networks in the whole brain and thus may provide insight into how neuronal networks are rewired in disease states.
In the first step of the CLARITY process, the brain is infused with acrylamide. When heated, acrylamide creates a mesh matrix that freezes the cell contents (proteins, nucleic acids, and other molecules) in place. Next, the detergent sodium dodecyl sulfate (SDS) is applied to break down the lipid bilayer that normally surrounds the cell and obstructs the view of the cell contents. Once these lipids are washed away, fluorescently-labeled antibodies can be added to identify specific neuronal proteins within the brain.
In the beautiful video linked below, you can see the CLARITY method in action. Here, the method is used to visualize fluorescently-labeled neurons in whole mouse brain. The method is also used to trace the path of a single neuron in a slice of autopsied human brain from a patient with Autism.