OPTOGENETICS. APP/PSEN1 MODEL EXTRAPOLATION. IMMUNE SYSTEM ACTIVATION. A SIMPLE TREATMENT THAT WILL TOTALLY BE ON SHELVES IN WALGREENS WITHIN A YEAR.

Yes, high potential for either breakthrough or years of pseudoscience to come out of this. Much excitement. Wow! They're looking at others models now, but I'm probably not supposed to share that until it's at least being presented publicly.

Is the paper out? that is kind of a wild result. What was the optogenetics targeting? I'm assuming the neurons responsible for the gamma rhythm, and the microglia activation was unintentional, and that's why the decided to attempt the effect with an external light source?

Yep. Optogenetics targetted parvalbumin interneuron and did not show an effect in excitatory neurons (PV-Cre vs. αCamKII-Cre in fig 1) or at non-40 Hz pulses. Why the microglia get activated is anyone's guess / for follow-up work to determine.

The light source was used after the optogenetics experiments showed an effect because, as one prof put it: "We're more than a decade away from optogenetic therapies in humans". Note they switch the explanation from "hippocampus" to "visual cortex" when they explain that in the video though. In theory, any signal that gets a stimulus at 40 Hz to the hippocampus should be effective, but not all circuits from the eyes / ears / mouth / fingers / nose are as direct.

Had no one seen that before? Optogenetics and EEG stuff was never on my plate, so I have only a cursory understanding.

The closest is deep brain stimulation for Parkinson's, which sort of works okay but isn't very well understood. This is the first (mouse) therapy of the sort, and the first that I know of that links dysregulated signaling to stimulation to targeted activation of certain cells in a certain region to actual non-invasive therapy.