When our brains are healthy, we barely notice this marvel of engineering that controls our every thought, feeling, and move. But the many people suffering from brain disorders, including addiction, know that malfunctions in the brain can change who we are and how we manage our lives.
For a closer look into how our brains function—or malfunction—scientists have discovered a new way to turn individual neurons and cell circuits on and off using light.
Neurons in the brain pass electrical impulses back and forth thousands of times a minute, but turning them on and off isn’t quite as simple as flipping a light switch. First, researchers have to insert light-sensitive genes, taken from algae, into specific neurons. Then, using lasers connected to thin fiber optic threads, they can activate or deactivate the modified cells to see how neurons or groups of neurons work together. So far, this new field of optogenetics research is limited to animal studies.
Working To Understand Brain Disorders
Scientists have successfully switched mouse neurons on and off to see how different brain circuits control habits, emotions, and behaviors. The technique may also help scientists understand the causes and potential treatment of specific brain disorders such as schizophrenia.
Optogenetics is also helping scientists understand how addiction affects the brain.
Researchers at the Massachusetts Institute of Technology trained mice to run through a maze for a chocolate reward. Out of habit, the mice continued to run through the maze even after the reward was no longer present. But by using optogenetics to activate cells of a brain area called the basal ganglia, the researchers turned off the chocolate-chasing habit. (The basal ganglia contain the brain’s reward circuits, which are involved in addictions.)
Scientists are hopeful that optogenetics could eventually help treat addiction and other neurological conditions in people.