New Technologies May Increase Our Understanding of the Brain

By Kylie Wolfe

Recent advances in microscopy have provided researchers with more detailed images of individual nerve cells in both fruit flies and mice. These techniques have also let scientists stimulate specific cells in mice, taking control of their eating behavior.

Innovative Imaging Opportunities

At the Howard Hughes Medical Institute’s Janelia Research Campus, researchers have developed a microscope that can see into deep layers of brain tissue. Known as a lattice light sheet microscope, it uses a thin laser to look at the brain’s cellular structures. There is a drawback to this method, however: it limits the ability to see the fine details of these cells.

Another method, developed at MIT, solves this problem. Researchers infused their samples with a gel that expands cells up to four times their normal size while still preserving the tissue’s structure. This method, called expansion microscopy, makes it easier to view small samples in greater detail.

Revealing the Results

Using these methods in combination, scientists were able to uncover features of individual nerve cells, or neurons, including those that produce the important chemical messenger dopamine. They managed to count synapses, the communication connections between neurons, and were able to see the formation of myelin, a fatty substance that helps signals travel quickly. These tools also provide information about neuron anatomy and the roles of different cells.

Building on this progress, researchers at Stanford University have found a way to use laser light to control genetically engineered neurons in mice. They targeted cells in the brain’s orbitofrontal cortex, the source of both eating and social behaviors. These actions are controlled by different neurons, making them difficult to study separately. But this method allowed researchers to identify the individual cells that control these behaviors.

After determining which neurons were linked to each action, they managed to control the mices’ eating behavior. When the cells were stimulated, the mice consumed more calorie-dense rewards than when stimulation was focused on nerve cells associated with social behavior.

Looking Ahead

Technological advances like these allow for experiments and studies that give us better insight into cells and their functions. In particular, scientists can study synapse differences across various diseases and how myelin develops and forms. The ability to control genetically engineered cells also allows for learning opportunities related to cell function.

Previously, neurons could only be viewed in large groups. Because they can now be studied individually, researchers hope to better understand diversity among neurons and unravel some unknowns about the brain.