Suu

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Reason has always existed, but not always in a reasonable form- Karl Marx

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Member Back to Top Post by Suu on Findings:

Light has been used for imaging neural activity in technologies such as DOT (diffuse optical tomography) and fluorescence imaging. Light however, can also be used to stimulate neural activity as well, in a manner which provides benefits over the current gold standard of electrical stimulation. Using light to stimulate neuronal activity provides the benefits of: little to no tissue damage, better manipulation of space, and doesn't interfere with itself. These properties give a significant advantage over the standard electrical stimulation, which can cause necrosis and inflammation, is limited to areas of contact, and has no real spatial precision. Optical Stimulation can also inhibit neural stimulation, which I will not go into in this report.





-A picture of a DOT fiber Optical



Although there are a few methods for Neural Stimulation through EM radiation, the particular method that we are looking at is Infrared Neural Stimulation. Infrared light is used induce an electrical signal within a targeted neurons. How infrared light does this is poorly understood however, but is known to be the effect from the heating of neurons. Research is currently being undertaken to understand the exact mechanisms which cause this phenomenon.



Optical stimulation has the unique advantage of not requiring direct contact with tissue, which gives it spacial precision. This also makes it so there is no inflammation or necrosis from the storage of charge elicited through the use of electrodes. However, Infrared light can cause damage to heat-related damage from repeated heating over a short period of time. This can be circumvented through the effective use of wavelengths of light, changing it into the optimal wavelength for specific groups of nerves.



This technology has been used to successfully stimulate muscle neurons, causing activation of muscle fiber, and also has been successfully demonstrated as a peacemaker for a embryo. This proves the concept of Infrared Nerve Stimulation. There is currently research being done in the use of infrared light in place of electrical cochlear implants.



However, there has been some unexpected results, specifically in the inability for optical light to effectively activate cochlear nerves. This is believed to be caused by a difference in cochlear nerves to other nerve types, and is currently being investigated.



Studies have shown that the combination of electrical stimulation and optical stimulation lessens the threshold required for stimulation of cells, by around 300%. This suggests that electrical and optical stimulation can be combined to be even more effective than by themselves.



Optical neural stimulation is a relatively new field in neuroscience, and one which shows great promise in the future.



Cost/ Feasibility:

Not applicable at this stage. Very, very feasible though.



Personal Comments:

This new technology is honestly fascinating, and exciting, and I have high hopes for the application of this technology in this field.

It may even be the difference from having ugly electrodes planted into people and being able to use this product without contact.



Sources

1.) Warden, Melissa R., Jessica A. Cardin, and Karl Deisseroth. "Optical Neural Interfaces." Annual Review of Biomedical Engineering. U.S. National Library of Medicine, n.d. Web. <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4163158/>

2.) Jansen, E. Duco. "Optical Stimulation of Neural Tissue: Current State and Future Challenges." Vanderbilt, 23 Nov. 2011. Web. <http://www.bionicsinstitute.org/news/Conference_Presentations/0830-0900%20E%20Duco%20Jansen.pdf>

3.) Jenkins, M. W., A. R. Duke, S. Gu, H. J. Chiel, H. Fujioka, M. Watanabe, E. D. Jansen, and A. M. Rollins. "Optical Pacing of the Embryonic Heart." Nature Photonics. U.S. National Library of Medicine, n.d. Web. <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3059323/>

4.) Wells, Jonathon, Mark Bendett, Daniel J. Lee, Jonathan Cayce, Austin Duke, and Agnella Izzo Matic. "Infrared Nerve Stimulation: Hearing by Light." BioOptics World. PennWell Corporation, 11 Jan. 2008. Web. <http://www.bioopticsworld.com/articles/print/volume-1/issue-6/features/neurological-treatment/infrared-nerve-stimulation-hearing-by-light.html>

oaths

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Member Back to Top Post by oaths on The utilization of electro-magnetic radiation is very promising since it possesses a very unique capacity to penetrate tissues. Besides the obvious issues...are these studies ever done with higher energy wavelengths of light? It boils down to the same problem that microscopy faces: your minimal resolution would be limited by the wavelength of light. In the case of infrared, this ranges from ~5-100 micrometers. The added bonus of near UV, is that the photons are also higher energy....which is bad too.







On second thought... You could target neurons buried in the retina.



Edit - Near UV would still present UVB radiation which cause adjacent thymine base pairs to form pyrimidine dimers. This mutagenic process would inevitably lead to cell death.



volpone

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Member Back to Top Post by volpone on Suu said:

Personal Comments:

This new technology is honestly fascinating, and exciting, and I have high hopes for the application of this technology in this field.

It may even be the difference from having ugly electrodes planted into people and being able to use this product without contact.



Where did you see that this would be a contact-free solution? I've been rereading the research and from what I understood, the optical fibers need to be implanted, but the nerves themselves and other surrounding tissues don't need to be touched. The experiment on the rat, in Duco Jansen's presentation, also showed how the optical fiber was being implanted into the rat itself. If this kind of solution can become truly non-invasive, then I'd be all for it, but I think that implants can be quite deterring.

shodan

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Member Back to Top Post by shodan on



As for stimulating the brain:

"How infrared light does this is poorly understood however, but is known to be the effect from the heating of neurons."

- this severely limits the possible resolution of such a device. It becomes, essentially, similar to the microwave-based "Voice of God" machine - that causes people to hear a voice in their head. Side effects - brain damage from prolonged exposure. Heating neurons is bad.



And it is invasive, indeed.



As for DOT - it's principle is based on assessing the blood density within areas of the brain responsible for this or that kind of thinking. Fundamental limitations include low spatial and temporal latency - it takes over 0.5 seconds for the blood density in a particular part of the brain to change based on the user's cognitive process.



This is very similar to Neurooptics research conducted at the Wolfson Institute for Biomedical Research, UK, by Dr. Michael Häusser.

Long story short: you have to take drugs to mutate a certain type of sensory and/or motor neurons in your brain to become photosensitive and photemissive, respectively. And then have you head cut open and have a (low power) laser implanted into your head, that will "shoot" at individual neurons and make you see or hear or feel or smell things... And also look at motoneurons and read their activity. It works, but it looks like this:

puu.sh/l51Is/b3d52763be.jpg

or

puu.sh/l51PF/3ee1f6d600.jpg

Not exactly "non-invasive"

I think we looked into this back in DigiAxon...As for stimulating the brain:"How infrared light does this is poorly understood however, but is known to be the effect from the heating of neurons."- this severely limits the possible resolution of such a device. It becomes, essentially, similar to the microwave-based "Voice of God" machine - that causes people to hear a voice in their head. Side effects - brain damage from prolonged exposure. Heating neurons is bad.And it is invasive, indeed.As for DOT - it's principle is based on assessing the blood density within areas of the brain responsible for this or that kind of thinking. Fundamental limitations include low spatial and temporal latency - it takes over 0.5 seconds for the blood density in a particular part of the brain to change based on the user's cognitive process.This is very similar to Neurooptics research conducted at the Wolfson Institute for Biomedical Research, UK, by Dr. Michael Häusser.Long story short: you have to take drugs to mutate a certain type of sensory and/or motor neurons in your brain to become photosensitive and photemissive, respectively. And then have you head cut open and have a (low power) laser implanted into your head, that will "shoot" at individual neurons and make you see or hear or feel or smell things... And also look at motoneurons and read their activity. It works, but it looks like this:orNot exactly "non-invasive"