Terrence Sejnowski, Professor and Laboratory Head of the Computational Neurobiology Laboratory (credit: Salk Institute for Biological Studies) In a study
In a study published July 28 in the Proceedings of the National Academy of Sciences, Salk Institute for Biological Sciences researchers have found that brain cells called astrocytes — not neurons — can control the brain’s gamma waves.
They also found that astrocytes — a type of glial cell traditionally thought to provide more of a support role in the brain — and the gamma oscillations they help shape are critical for some forms of memory, such as object recognition.
(When you’re expecting something or when something captures your interest, unique high-frequency electrical rhythms called gamma waves sweep through your brain. 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.)
Evidence linking gamma waves with attention and memory, influenced by astrocytes
“This is what could be called a smoking gun,” says co-author Terrence Sejnowski, head of the Computational Neurobiology Laboratory at the Salk Institute for Biological Sciences, 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.”
A collaboration among the labs of Salk professors Sejnowski, Inder Verma, and Stephen Heinemann found that activity in the form of calcium signaling in astrocytes immediately preceded gamma oscillations in the brains of mice. This suggested that astrocytes, which use many of the same chemical signals as neurons, could be influencing these oscillations.