Optogenetics And Controlling Neurons In The Brain
Watching And Manipulating Brain Function
Pictured in the video: Miniscope recording from a mouse running on a 2 meter linear track. The top left is the raw data of neural activity, the top right is the motion corrected dF/F data of neural activity, the middle is the mouse running back and forth, and the bottom is example dF/F traces from the recording.
A technique called optogenetics allows brain researchers to use light to directly control the activity of different neurons in the brains of freely behaving animals. By turning on or off the activity of each cell type, researchers can determine what role each cell type plays in different behaviors. First, researchers express engineered proteins that can make neurons more or less likely to fire impulses in the presence of light. They then insert optical fibers near groups of neurons. When light illuminates the brain, these neurons can be turned off and on and the behavior of the animal or the brain physiology can be monitored.
"We can record the signatures of fear memories, harmful habitual behaviors, or rewarding social interactions"
Peyman Golshani, MD
Conversely, researchers can record the activity of large groups of neurons by expressing a sensor for calcium in these groups of cells. When cells become activated, calcium rushes into the cell and the cells flash brightly. Dr. Peyman Golshani, associate professor in neurology, has used head-mounted microscopes that weigh less than 3 grams (slightly more than the weight of a dime) to follow the activity of thousands of neurons over several weeks as animals navigate, make decisions, or interact with other animals.
In collaboration with other investigators at UCLA, Dr. Golshani’s group has built new wireless head-mounted microscopes that allow the animals to explore very large naturalistic environments. Dr. Golshani has shared the designs of these microscopes with the neuroscience community and now over 300 laboratories are building the various versions of the microscopes.
“These tools can have a revolutionary effect on neuroscience.” Golshani explains. “Now we can peer down and record the activity of entire brain circuits as the animal is actually performing complicated tasks. For example we can record the signatures of fear memories, harmful habitual behaviors, or rewarding social interactions. We can use new tools to only look at cells connecting or receiving connections from specific structures. This way we can get an idea how different components of the circuit make these behaviors possible.” Learn more by visiting the Golshani Lab.