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Comment by dkarapetyan | Hacker News Reader

I understand this is valid science but at the same time I'm extremely creeped out. Seems to me like all these findings follow from some physics and chemistry and the mice didn't need to be implanted with these devices. Don't really see the point of making them go in circles either.

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Which findings, specifically?

Because I feel like the article makes a pretty good case for the benefits of studying optogenetics. These three paragraphs in particular succinctly outline that case:

Neuroscientists study these patterns of electricity, but they’ve been limited by the imprecision of their tools. Much progress in biology depends on observation, which means scientists need tools to both meddle with an organism’s natural bodily systems and watch what happens. Typical neuroscience techniques rely on electricity, using electrodes on the scalp or implanted inside the brain to stimulate and record from groups of neurons. These electrodes are relatively large and crude, though, and can’t target very specific cells, such as the neurons in the hippocampus that encode distinct memories.

This limitation bothers me. From an engineer’s point of view, the study of living creatures can seem messy. When I’m tinkering with an integrated circuit, I can swap out one transistor and check to see if the chip still works. If it doesn’t, I can be sure the new transistor is responsible for the glitch. In biological systems, it’s far harder to isolate a variable of interest.

With optogenetic technology, we can turn neurons on and off as if they were transistors in a circuit. Geneticists have various ways (which we won’t go into here) to deposit the necessary genes into very specific clusters of cells. With our light-up devices, we can then switch on a particular set of neurons. The neurons react to light within milliseconds, making the result of our tinkering fairly obvious.

Parts that you mention are part of those findings. Seems to me all this could have been done in vitro. No mice brain cage mutilation necessary to see if a cell with some genes reacts to a certain wavelength of light.

You are right that testing whether the gene changes how cells react can be tested in vivo, and that's how it was done originally. But the point of these studies is to figure out how certain parts of the brain work. Since the brain produces behavior, we can best understand how it works by changing brain activity and then seeing how that changes behavior. That can't be done in a dish, at least not now, even though we often use modeling whenever possible to make sure we're doing the right experiments. The goal was definitely not to control mice or make them suffer and I find it a little regrettable that the professor did not emphasize that. The fact that making neurons in motor cortex fire causes movement is proof of concept, but no neuroscientist wants to just sit around making mice just turn in circles all day. The goal here is to better understand how neurons firing produce behavior. For example if we can crack the code for movement, we can e.g. help patients better recover function after a stroke. The techniques we've had for a hundred years have not gotten us all the way to an answer on that yet. Think of it this way: do you want to debug your program with only print statements, or would you rather be able to put in a break point?

I think it's more intended as a proof of concept to allow researchers to target specific neurons and a live animal would help demonstrate that. If I'm understanding correctly they would be able to target the optogentic cells to very specific parts of the brain.

That's not the purpose of this experiment, as the capability to target specific neuron types has been well demonstrated in the past. It's approaching a toolbox technique at this point much like regular electrophysiology and electrical stimulation.

From the IEEE article (I did not read the original research paper) the goals of this experiment are lost in the veil of journalism, as it boils down to the following items:

1. Implantable chronic optogenetics (fairly novel)

2. Wireless RF power for said implant (novel context, not necessarily novel technique)

3. Use the optogenetics to do "something". This is the worst part of the article and is the meat of the Neuroscience - which neuron types are targeted (genetically), with which opsin, and histological evidence of where the opsins are located are all important features. The article seems to take at face that making rats pause and run in circles is interesting but scientifically speaking if you can't say anything about why they run in circles it's not a particularly good or useful study, as it doesn't actually give people any information.

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