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Memory relies on astrocytes, the brain's lesser known cells

When you're expecting something–like the meal you’ve ordered at a restaurant–or when something captures your interest, unique electrical rhythms sweep through your brain. These waves are called gamma oscillations and they reflect a symphony of cells– both excitatory and inhibitory–playing together in an orchestrated way. Though their role has been debated, gamma waves have been associated with higher-level brain function, and disturbances in the patterns have been tied to schizophrenia, Alzheimer’s disease, autism, epilepsy and other disorders.

Recently, Terrence Sejnowski and his colleagues showed that supportive cells in the brain known as astrocytes may in fact be major players that control these waves. They uncovered an unexpected strategy to turn down gamma oscillations by disabling not neurons but astrocytes–cell types traditionally thought to provide more of a support role in the brain. In the process, the team showed that astrocytes, and the gamma oscillations they help shape, are critical for some forms of memory.

Terrence Sejnowski

Terrence Sejnowski

“This is what could be called a smoking gun,” says Sejnowski, head of Salk’s Computational Neurobiology Laboratory and a Howard Hughes Medical Institute investigator. “There are hundreds of papers linking gamma oscillations with attention and memory, but they are all correlational. This is the first time we have been able to do a causal experiment, where we selectively block gamma oscillations and show that it has a highly specific impact on how the brain interacts with the world.”