In the 19th century people started to think of “nerves as wires,” which corresponded with electrical discoveries occurring around the time. I’m primed to think about electrical systems in musical terms, such as through the input/output and signal generation/modulation systems of synthesizers. It’s fascinating to me, then, to understand how similar the tools are for measuring the electricity generated by a neuron, to the those used in analogue electronic instruments and DIY electronics.
While reviewing the structures that comprise brain cells, I learned that neuronal shape can be regulated by various signals within the neuron, and that microtubules are part of the structure of neurites. MAPs (microtubule associated proteins) help keep microtubules together and connected with other parts of the neuron, although many MAP functions are not yet known. Changes to the axonal area of MAPs are called tau, and these show up in Alzheimer’s disease.
I happened to hear an interview with neuroscientist Li-Huei Tsai on the pop science podcast “Radiolab” with recent updates on her research of Alzheimer’s in animal models. Tsai and her team had flashed light at 40hz, or the “gamma frequency” (which is present in brainwave patterns during focused states) to mice in early stages of the disease. This non-invasive measure significantly increased microglia (referred to as “janitor cells” in the podcast) in the visual cortex, impacting the pathology.
My first thought when learning this, is that you could also play a sine wave at 40hz (with an adequate subwoofer) and complete the minimalist-mousey-rave. Turns out, this is what the update was about and there is a recent paper demonstrating the outcomes with auditory and multi-modal (audio-visual) inputs.
In short: auditory exposure to gamma frequencies over 7 days improved memory and spatial recognition while reducing amyloid in the auditory cortex and hippocampus, and reducing phosphorylated tau. The combination of audio and visual stimuli caused “microglial clustering” and reduced amyloid in the medial prefrontal cortex (Martorell et. al, 2019)
It’s fascinating that these simple tools can have a direct effect on a cellular level, but then it’s also intuitive, because our brains are constantly being changed by our sensory interaction with the outside world. Approaching my study of neuroscience through a sound/new media background, it’s neat to see (and hear) where the two fields intersect.
WNYC Studios. 2020. Bringing Gamma Back, Again | Radiolab | WNYC Studios. [online] Available at: <https://www.wnycstudios.org/podcasts/radiolab/articles/bringing-gamma-back> [Accessed 13 September 2020].
Martorell, A., Paulson, A., Suk, H., Abdurrob, F., Drummond, G., Guan, W., Young, J., Kim, D., Kritskiy, O., Barker, S., Mangena, V., Prince, S., Brown, E., Chung, K., Boyden, E., Singer, A. and Tsai, L., 2019. Multi-sensory Gamma Stimulation Ameliorates Alzheimer’s-Associated Pathology and Improves Cognition. Cell, 177(2), pp.256-271.e22.