Neurons renewed by gamma flashes
A new study on controlling the rhythms of the brain has come up with some startling results.
Each of our billions of neurons ‘fires’ when it is active, but on a larger scale, whole sections of the brain ‘fire’ simultaneously and rhythmically when they are engaged.
These large pulses are called ‘waves’ and they occur at different frequencies depending on what the brain is doing.
Deep sleep produces delta waves (1.5 Hz to 4 Hz), for example, while theta waves (4 Hz to 12 Hz) occur during running and deep meditation.
Gamma waves (25 Hz to 100 Hz) appear when the brain is excited or concentrating deeply.
Previous research has linked gamma waves to Alzheimer’s disease, specifically the creation of beta-amyloids, which go on to form a sort of plaque on neurons that inhibits their function.
MIT researchers Li-Huei Tsai, Ed Boyden, and colleagues have now shown that stimulating neurons to produce gamma waves at a frequency of 40 Hz reduces the amount of beta-amyloids in mice with early stage Alzheimer’s.
In one part of the study, the researchers simply exposed the mice to LEDs flickering at 40 Hz, something that could easily translate to human therapies.
Stimulation of gamma waves (both with LEDs and using optical fibres inserted into the brains of mice with brain cells modified to respond to light) reduced levels of beta-amyloids (technically referred to as ‘amyloid-β’) , decreased phosphorylation of tau, and triggered the brain’s immune cells – microglia, sometimes referred to as the ‘janitors of the brain’ - to clear away cellular debris, including beta-amyloid.
The study suggests that a lack of gamma activities might be part of the origin of Alzheimer’s disease, and that manipulating gamma activity could be a new way to suppress beta-amyloid production and increase its clearance.
But of course, these are mouse models (which rarely translate directly to human models), so much more work is needed.
More information is available in the video below.