The Brain's Sensitivity To Radiation

[FrankM]

Moderation note: the 1st 3 posts of this thread were moved from "How Long Until We Could Make A Real Sword Art Online (sao) Nerve Gear Type Device" because they are a discussion of a different topic related to "FulDive" technology.

 

The brain is very sensitive to EM radiation. EM fields passing through the brain tissue can create heating. If the axon neural circuits have lengths that are close to specific frequencies the EM energy can be transferred efficiently; the circuits act like an antenna that has a length for a specific frequency. An example of how low power can damage a mammalian brain is in the following URL:

 

http://www.pathophysiologyjournal.com/article/S0928-4680(09)00013-3/pdf

 

Whatever the ultimate interface to the brain will be has to consider how sensitive the axons are to damage. A lot of broadband EM power can do serious damage. See my post:

 

http://www.scienceforums.com/topic/28182-electromagnetic-cause-of-shell-shock/?do=findComment&comment=335386

 

The purpose of the Specific Absorption Rate (SAR) regulations is to limit cellular heating from exposure to EM radiation.

 

It is possible to externally modify neural signals. See following article in IEEE Spectrum:

 

http://spectrum.ieee.org/biomedical/bionics/smart-neural-stimulators-listen-to-the-body

 

It would be better if you can do this without the wires.

[CraigD]

Good to see you joining this conversation, Frank! :thumbs_up

The brain is very sensitive to EM radiation.

I don’t think this is true in the way you mean it.

 

The human brain is very sensitive to electromagnetic radiation in the visible range because it is connected via nerves to specialized nerve cells in the eyes’ retinae. Nerve cells in the brain lack retinal cells light sensitivity (or sensitivity to EM radiation of other frequencies).

 

It’s possible to artificially change this, making brain cells light sensitive, but only at present by inserting genes into the brain cells that cause them to develop molecules similar to retinal nerves, and installing a transparent window in the skull to allow light to reach them. We discussed this work of Packer, Russell, Dalgleish & Häusser around here in this thread.

 

EM fields passing through the brain tissue can create heating.

I wrote a fairly long post on this upthread here. This is a fairly well-researched subject, with some practical applications (such as the Frey effect, by which speech-like sounds can be transmitted via microwaves to the inner ear), but doesn’t seem promising for high-resolution “writing” to the brain needed for to make a real device like the fiction NerveGear. Also, as you note, heating the brain enough to cause perceivable effects is likely to damage it.

 

It is possible to externally modify neural signals. See following article in IEEE Spectrum:

 

http://spectrum.ieee.org/biomedical/bionics/smart-neural-stimulators-listen-to-the-body

True and a good article, but note that the systems described in it all involve implanted electrodes.

 

With the exception of the "Simultaneous all-optical manipulation and recording of neural circuit activity with cellular resolution in vivo" described by Packer et al, there appears to me to be no alternatives to physical electrodes for reading and writing to the brain with individual neuron resolution. My focus, thus, has been on ways to do this so much less intrusively than is presently requires that it could be used in a consumer product – a “real-world SAO NerveGear-type device”.

[FrankM]

I stated in post #148, "The brain is very sensitive to EM radiation." CraigD took exception to that statement in post #153 by stating, "I don’t think this is true in the way you mean it." The purpose of the Specific Absorption Rate (SAR) regulations is to prevent cellular level heating, which will occur if cells are exposed long enough to electromagnetic radiation, of even moderate power, that have wavelengths that can efficiently couple their energy to cellular structures. The Nittby reference, (9), in my paper, vixra.org 1502.0159, reveals what happens to neuron structures that receive too much EM radiation exposure.

 

This also suggests that brain neuron structures can be stimulated by an outside EM source that provides a signal, with the correct wavelength, that will couple enough energy to the structure to create a neuron pulse. First we have to be able to identify the correct wavelength and power level required to stimulate a neuron structure remotely, without damaging it. Identifying the wavelengths for specific neurons is step one. An EM wave is attenuated when it goes through various biological material, so getting the correct power level to a specific area within the brain is going to be challenging. Also, an EM wave with a specific wavelength that passes through a material that has an index of refraction greater than one will alter the wavelength.

 

However, somewhere in our brains there are assembler areas that produce what we call thoughts and this can include images. This is where you want to couple VR devices. Although this would be a great way to become immersed in a game, it would be an impressive teaching device.

 

By the way, it has been determined that our brains continue to grow new neurons. “Newborn neurons in adult brain may help us adapt to environment” Science Daily, February 21, 2015.

http://www.sciencedaily.com/releases/2015/02/150221192244.htm.